2024, Volume 31 Issue 1
25 January 2024
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环境变化与生物圈层相互作用

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“Earth Science Frontiers 30th Anniversary Special Issue”
Long-range effects of mid-ocean ridge dynamics on earthquakes, magmatic activities, and mineralization events in plate subduction zones
CHENG Qiuming
2024, 31(1): 1-14. 
DOI: 10.13745/j.esf.sf.2024.1.23

Abstract ( 1051 )   HTML ( 30 )   PDF (6135KB) ( 199 )  

The deep processes of plate subduction zones are closely related to extreme geological events that occur in continental magmatic arcs. The processes of plate subduction and mountain building can lead to events such as earthquakes, magmatic activity, and mineralization. The occurrence of these extreme events is closely related to factors such as crust-mantle interaction, mantle wedge formation, partial melting of the lithosphere, and tectonic magmatism during subduction. However, little is known about the long-term and long-range effects of heterogeneities or innate defects in the newly formed crust at mid-ocean ridges on the extreme events described above. During the formation of new crust at mid-ocean ridges, due to factors such as plate expansion, pressure reduction, and asthenospheric material upwelling, the temperature of the new crust increases, pores and cracks develop, the density decreases, and the structure is complex. Therefore, the newly formed crust has heterogeneities in density, strength, temperature, thickness, etc. These crustal differences will influence and decide the behavior of plates during expansion and subduction, with long-term effects on events such as earthquakes, volcanoes, and mineralization caused by subduction. Analyses of the Pacific subduction and the Andes orogen have revealed that sudden changes in plate movement speed, plate subduction angle, plate slab tearing, lithospheric thickness, Moho depth, etc., have long-range effects on the spatiotemporal distribution of earthquakes, volcanoes, and porphyry copper deposits. These understandings are of great significance for predicting the spatiotemporal distribution of extreme geological events in plate subduction and collision zones.

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Two modes of deep carbon cycling in a big mantle wedge: Differences and effects on Earth's habitability
LI Shuguang, WANG Yang, LIU Sheng’ao
2024, 31(1): 15-27. 
DOI: 10.13745/j.esf.sf.2023.10.7

Abstract ( 1047 )   HTML ( 12 )   PDF (7453KB) ( 190 )  

In this paper we summarize the evidence for the deep carbon cycling in a big mantle wedge composed of the deeply subducted Western Pacific Plate in the mantle transition zone and the exposed Late Cretaceous and Cenozoic intraplate basalts. We explore the differences in the carbon cycle between the big mantle wedge and island arc systems regarding metasomatic agents, carbonate species, redox reactions and mechanisms of partial melting of carbonated mantle, as well as their effects on maintaining a stable oxygen level in the Phanerozoic atmosphere and on the periodic changes in the greenhouse effect. We point out that quantitative estimate of the proportion of carbon left in the mantle transition zone through reduction of deep subducted carbonates into diamond, and carbon returned to the atmosphere through intraplate basaltic volcanoes, is an important topic for future study.

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The continental lower crust
ZHANG Yanbin, ZHAI Mingguo, ZHOU Yanyan, ZHOU Ligang
2024, 31(1): 28-45. 
DOI: 10.13745/j.esf.sf.2023.12.27

Abstract ( 1047 )   HTML ( 8 )   PDF (4524KB) ( 155 )  

The lower crust, linking the lithospheric mantle and the upper crust, is the most active place of energy exchange between the crust and the mantle; and partial melting of the lower crust and upper mantle, and delamination of the lower crust can directly lead to crust/mantle material exchange, re-cycling, recombination. In other words, the lower crust is one of the most important site for mantle-crust interactions where magma underplating, anatexis, delamination, high-grade metamorphism, and other processes take place. However, the lower crust has been largely overlooked by previous studies of the deep Earth. In this paper, the lower crustal profile of the North China Craton is described in detail. On this basis, the craton-type lower crust processes are discussed, and their dynamic significance and important position in the study of continental dynamics are emphasized. Cratonization is the transition of the formerly chaotic crust of the continent to stable upper and lower crust, and thus establishing a stable lithosphere. This unprecedented stable relationship between the crust and the mantle has been maintained from the beginning to the present, and is the basis for continental evolution, ocean-continent interaction, and crust-mantle interaction. The cratonic crust is not static after formation, and the continental boundaries can change during ocean-continental subduction-collisions. Especially during continent-continent collisions, the continental crust that can form different continental blocks is superimposed, thickened, collapsed, disassembled, underpinned and re-stabilized. At the root of the continental orogenic belt, a new lower crust is formed to become the lower crust of the orogenic belt type. We, therefore, suggest in this paper that the craton-type lower crust processes should receive full attention in the study of the deep Earth as well as in the designing of geoscience curricula.

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Meta-Earth and Digital Twin: Breakthrough concept, technological revolution and paradigm shift
LI Sanzhong, SUO Yanhui, DAI Liming, WANG Liangliang, JIANG Zhaoxia, CAO Xianzhi, SU Guohui, LIU Lijun, ZHOU Jianping, LI Xiyao, LIU Jie, ZHU Junjiang, QIAO Lulu, WANG Guangzeng, JIANG Suhua, WANG Xiujuan, LIU Lin, GUAN Hongxiang, LI Xiaohui, HU Jun, LIU Peng, LIU Ze, DONG Dongdong, GUO Lingli, ZOU Zhihui, DONG Hao, ZHONG Shihua, SUN Guozheng, LIU Yang, YU Shengyao, WU Lixin, ZOU Zhuoyan, SUN Yi
2024, 31(1): 46-63. 
DOI: 10.13745/j.esf.sf.2024.1.48

Abstract ( 987 )   HTML ( 3 )   PDF (9509KB) ( 93 )  

Digital Twin has been used in aerospace and industrial manufacturing for more than 20 years, but it is only introduced into marine science recently. Here we adopt Digital Twin technology to realize the integration of real- and virtual-Earth, and build a virtual-real, symbiotic community of real- and digital-Earth which we call “meta-Earth.” We first summarize the essential differences between meta-Earth and the early proposed digital-Earth, virtual-Earth, glass-Earth and smart-Earth, and then highlight the great breakthroughs in the concept or idea of “meta-Earth.” The core idea is that under the current metaverse BIGANT technic system we can realize gapless, cross-sphere dynamic simulation of the Earth system, which allow to build a global, multi-sphere, real-time, all-weather, three-dimensional Earth observing system, reconstruct the deep-time Earth beyond the present-day Earth, and realize space-time travel. By doing so we can integrate all previous Earth models—digital, virtual, glass, smart, present and deep-time—into a community called meta-Earth. This novel concept should bring a technological paradigm shift surpassing real- and virtual-Earth, thus opening a new way for mankind to understand, explore and develop the Earth. Promoting multi-tier application of meta-Earth while making research paradigm shift shall advance the development of new trillion-RMB industries in the future.

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Calculation methods for fluid composition and water-rock interaction in the deep Earth based on DEW model—a review
LAN Chunyuan, ZHANG Lifei, TAO Renbiao, HU Han, ZHANG Lijuan, WANG Chao
2024, 31(1): 64-76. 
DOI: 10.13745/j.esf.sf.2023.12.20

Abstract ( 975 )   HTML ( 1 )   PDF (2082KB) ( 60 )  

Water-rock interactions can lead to changes in the valency and chemical form of elements in fluids and thereby affect the enrichment and mineralization of elements as well as their cycling fluxes. Due to limited availability of deep Earth samples and experimental data, establishing and utilizing models of deep aqueous fluids can effectively enhance our understanding of water-rock interactions in deep Earth. The Deep Earth Water (DEW) model is a database used to describe the thermodynamic properties of aqueous species in deep aqueous fluids, and it can be used together with mineral thermodynamic databases for modeling water-rock interactions in deep Earth. In this review, we discuss the necessity of using the DEW model to describe deep aqueous fluids. We first describe the basic principles of using the DEW model to calculate aqueous species in deep fluids resulting from water-rock interactions in deep Earth. We then introduce “FluidsLab”, a software we developed to calculate aqueous species, and summarize applications of the DEW model in deep Earth researches. Finally we discuss future application of the DEW model and its development directions.

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Neoarchean magmatism in the North China Craton: Implication for tectonic regimes and cratonization
WAN Yusheng, DONG Chunyan, XIE Hangqiang, LI Pengchuan, LIU Shoujie, LI Yuan, WANG Yuqing, WANG Kunli, LIU Dunyi
2024, 31(1): 77-94. 
DOI: 10.13745/j.esf.sf.2023.12.21

Abstract ( 993 )   HTML ( 4 )   PDF (4886KB) ( 93 )  

Following a brief introduction to the Archean basement of the North China Craton (NCC), this paper summarizes the age distribution pattern, geochemistry and Nd-Hf-O isotopic compositions of late Neoarchean (mainly 2.55-2.5 Ga) magmatic rocks in the NCC. The late Neoarchean basement has the following features: 1) Late Neoarchean rocks are widespread while late Mesoarchean-early Neoarchean strata occur in many areas. 2) The magmatic zircon ages are mainly between 2.55-2.5 Ga and has a peak around 2.52 Ga. 3) Compared with pre-early Neoarchean (> 2.6 Ga) TTG (tonalite, trondhjemite, granodiorite), late Neoarchean tonalite and granodiorite are much more abundant, so are potassic granite, diorite-gabbro and sanukitoid with increased distribution range and scale. Voluminous potassic granites are mainly distributed in the east, forming a potassic granite belt-one of the double magmatic rock belts of the late Neoarchean (another is a TTG belt in the west). 4) Late Neoarchean supracrustal rocks are present in almost every area of basement outcrop, but occurring on a small scale when associated with TTG and potassic granite. The supracrustal rock types include metabasalt, meta-andesite, metadacite and clastic metasedimentary rocks, with meta-ultramafic rocks occurring in some areas. 5) In general, geological evolution of the late Neoarchean basement rocks began with supracrustal rock formation, then TTG intrusion, followed by metamorphism, deformation and emplacement of crust-derived potassic granite. The 2.6-2.55 Ga interval was a “quiet period” of magmatic and tectonothermal activity. 6) The late Neoarchean TTG rocks show large variations of Sr/Y and La/Yb ratios, consistent with medium-high formation pressures; their high abundances indicate significant continental crustal thickening in the late Neoarchean. Potassic granites were mostly derived from re-working of continental crust, with some, at least, involving sedimentary rocks. 7) All TTG rock types have similar whole-rock Nd and magmatic zircon Hf isotopic compositions, and the Nd-Hf isotope depleted mantle model ages are mainly between 3.0-2.5 Ga, similar to or slightly younger than that of late Mesoarchean-early Neoarchean rocks. The Nd-Hf isotopic composition of potassic granites is mostly constrained by the formation and evolutionary history of the source region on early Earth. Magmatic zircon has similar but more variable O isotopic composition compared to Archean magmatic zircon worldwide. Combined with results from other studies we arrive at the following conclusions: i) Similar to many other cratons, the late Mesoarchean-early Neoarchean was the most important period of rapid production of continental crust in the North China Craton, however, the NCC underwent strong magmatic and tectonothermal modification during the late Neoarchean. ii) “Modern-style” plate tectonic regimes began to form in the late Neoarchean in the NCC. iii) BIFs (banded iron formations) are mostly distributed along the double magmatic rock belts along the western margin of the Eastern Ancient Block of the NCC, thus the important exploration targets for BIF-hosted Fe resource should be between Anshan-Benxi and eastern Hebei and between eastern Hebei and western Shandong. iv) The initial cratonization of the NCC had completed by the end of the late Neoarchean.

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Multi-phase metamorphism in the Hongqiying Complex, northern Hebei: Records of Paleoproterozoic subduction/collision, late Paleozoic extension and early Mesozoic compression events
WEI Chunjing, ZHAO Yanan, CHU Hang
2024, 31(1): 95-110. 
DOI: 10.13745/j.esf.sf.2024.1.41

Abstract ( 944 )   HTML ( 2 )   PDF (5176KB) ( 67 )  

The Hongqiying Complex of northern Hebei in the middle northern margin of the North China Craton (NCC) recorded multiple tectono-thermal events from the Paleoproterozoic to early Mesozoic. This complex potentially holds the crucial geological evidence supporting the Paleoproterozoic oceanic subduction, however, its formation age, metamorphic evolution history and tectonic attributes remain debatable. In this paper, the metamorphic processes and geochronology of the Hongqiying Complex are summarised; its complicated, multi-stage tectonic evolution is discussed. The Hongqiying Complex comprises three rock units: orthogneisses (1.87-1.82 Ga, 2.55-2.53 Ga), (Chicheng) mélange (>1.88 Ga) and supracrustal sequence (2.1-2.0 Ga). The orthogneisses are dominated by Paleoproterozoic granodiorite-monzogranite-granite, with minor Neoarchean tonalite-granodiorite. The mélange exhibits a typical ophiolitic affinity, consisting of retrograded eclogite (amphibolite) and peridotite blocks within a metasedimentary matrix. The supracrustal sequences comprise dominantly carbon-bearing clastic-carbonate rocks interlayered with minor volcanics with different metamorphic grades. Integrated analyses of retrograded eclogites and amphibolite from the mélange and staurolite-bearing garnet mica schists at Fengshan reveal five phases of metamorphism. The first phase (M1) identified from the mica schists at Fengshan is a medium-p type, characterized by clockwise p-T paths, with peak conditions of p between 1.0-1.1 GPa, T>780 ℃ and a metamorphic age of >1.95 Ga. The second phase (M2) recognised from the eclogites is a high-p type, showing a clockwise p-T path, with stages of compression-heating to peak and post-peak isothermal decompression; the peak p-T conditions are roughly p>2.2 GPa, T≈750 ℃ and a geothermal gradient of ~9 ℃/km. Despite zircons predominantly yield late Paleozoic metamorphic ages, the eclogite metamorphism is regarded to have occurred at >1.88 Ga. The third phase (M3) is also revealed from the mica schists at Fengshan and is marked by the overprinting of staurolite assemblages on the high-grade (M1) assemblages; it exhibits a clockwise p-T path, with the peak condition of p between 0.6-0.7 GPa, T between 610-630 ℃ and metamorphic ages of 1.88 Ga. The fourth phase (M4) is identified from amphibolites that are overprinted on eclogites in the Chicheng mélange; it exhibits a ‘greater-than sign’-shaped p-T trajectory, including pre-peak decompression-heating and post-peak decompression-cooling processes, having peak conditions of p between 0.5-0.7 GPa, T between 780-830 ℃ and a geothermal gradient of ~35 ℃/km (low-p type). This low-p metamorphism is interpreted to take place during the late Paleozoic (354-289 Ma), accompanied by extensive anatexis. The fifth phase (M5) is locally developed, represented by overprinting of greenschist facies assemblages; it displays a clockwise p-T path, with probable metamorphic ages of 255-234 Ma. The M1 medium-p metamorphism is interpreted to relate to a crustal thickening orogeny (2.0-1.95 Ga) in the western NCC. The M2 high-p metamorphism may attribute to an oceanic subduction (1.95-1.88 Ga) along the northern margin of the NCC, robustly evidencing that the plate tectonics of the modern style may have operated during the Paleoproterozoic Era. The M3 medium-p metamorphism suggests another crustal thickening orogeny (1.88-1.83 Ga) along the northern margin of the NCC. The M4 low-p metamorphism is related to late Paleozoic extension in the northern NCC. The M5 low-T metamorphism is associated with the early Mesozoic collision event along the Solon Suture Zone. The above five phases of metamorphism recorded complex tectonic processes involving Paleoproterozoic collision-subduction-collision, late Paleozoic extension and early Mesozoic compression. In addition, the Hongqiying Complex might have located in different crustal depths after having undergone the 1.88-1.83 Ga orogeny. The supracrustal rocks at Hongqiying and the Chicheng mélange were situated in mid-lower crustal depths, in which zircons recorded multiple tectono-thermal events at 1.72-1.66 Ga, ~450 Ma, 354-289 Ma and 255-234 Ma. In contrast, the supracrustal rocks of eastern Fengshan may have situated at the mid-upper crust therefore lack both the zircon and monazite records of the later tectono-thermal events.

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The disappearance of banded iron formations: Research progress and perspectives on the origin of rhythmic Fe-rich/Si-rich laminae
WANG Ruimin, SHEN Bing
2024, 31(1): 111-126. 
DOI: 10.13745/j.esf.sf.2023.11.8

Abstract ( 960 )   HTML ( 10 )   PDF (9263KB) ( 167 )  

Banded iron formations (BIFs) are chemical sediments consisting of rhythmic Fe-rich and Si-rich laminae that are millimeters to centimeters thick. BIFs not only are an important iron resource, but also record the Earth's early evolution, early microbial activity, and atmosphere-ocean redox status. First appeared prior to 3.8 Ga, BIFs were common in the Archean and Paleoproterozoic, but they started to disappear about 1.8-0.8 Ga and were absent throughout the rest of Earth's history except for a brief appearance in the Cyogenian during global glaciation. The traditional model suggests that the abundance of BIFs is mainly controlled by dissolved Fe(II) contents in the ocean, and weakened tectonic/magmatic/hydrothermal activities, ocean oxidation, or oceanic euxinia about 1.8-0.8 Ga were responsible for the depletion of Fe (II) in the mid-Proterozoic ocean to drive to BIFs to disappear. However, geochemical evidence revealed that mid-Proterozoic ocean was predominantly ferruginous (Fe2+ rich) with large amounts of non-BIF ironstone deposits, challenging the traditional model. Here, we argue that the disappearance of BIFs in the mid-Proterozoic might result from changes in rhythmic deposition of Fe-rich/Si-rich laminae. We review the geological characteristics of BIFs and discuss different deposition models in detail. Additionally, we comprehensively review recent researches on the origin of rhythmic Fe-rich/Si-rich laminae in BIFs focused on Fe (II) source, Fe(II) oxidation, and Fe(III) preservation in sediments. Based on this, we attempt to identify possible directions for solving the mystery of BIFs’ disappearance by considering the coupling between iron and silicon biogeochemical cycles, so as to develop new insights into the evolution of the early Earth.

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Late Mesozoic-Early Cenozoic tectonic events in Daqingshan and Panyangshan, Inner Mongolia, and its implication for the tectonic evolution of the northern margin of the North China Craton
ZHANG Jinjiang, ZHENG Jianlei, WANG Haibin, GUO Lei, LIU Jiang, QI Guowei
2024, 31(1): 127-141. 
DOI: 10.13745/j.esf.sf.2023.10.11

Abstract ( 977 )   HTML ( 4 )   PDF (6056KB) ( 70 )  

The Daqingshan and Panyangshan in Inner Mongolia are located in the northern margin of the North China Craton (NCC), and their complex geological structures can provide a constraint on the Mesozoic-Cenozoic tectonic evolution of the northern NCC. To the north of Daqingshan is the Panyangshan thrust system, which formed originally in the Late Permian-Early Triassic by the closure of the Paleo-Asian Ocean and reactivated in the Late Jurassic possibly by the termination of the Mongolia-Okhotsk Ocean. Mesozoic-Cenozoic deformation of Daqingshan passed through four successive stages: the Hohhot metamorphic core complex (MCC) with SE-NW extension; the NW-ward Daqingshan thrust system; domes cored by undeformed granites; and the Daqingshan Front Fault and high-angle normal faults. The SE-NW extension took place from ca. 142 to 132 Ma and formed the Hohhot MCC and the related detachment system. This extension possibly resulted from gravitational collapse of the thickened crust caused by the Panyangshan thrusting. The Daqingshan thrust system formed between ca. 130-120 Ma, indicating a tectonic inversion from competition between plate convergence and crustal load as extension progressed. Another possible cause for the inversion is remote effect of Paleo-Pacific subduction. Since ca. 120 Ma Daqingshan has been in a tectonic-thermal relaxation regime represented by domes cored by undeformed granites of ca. 114 Ma and cooling events of ca. 120-90 Ma. These events might be related to the peak destruction of the NCC. The activation of the Daqingshan Front Fault and high-angle normal faults since the Eocene may be caused by remote effect of the India-Asia collision and change in the Pacific Plate movement. The closure of the Paleo-Asian and Mongolia-Okhotsk Oceans caused crustal thickening along the northern margin of the NCC, giving rise to the Early Cretaceous collapse, extension, and formation of the MCCs. The destruction of the NCC began to impact Daqingshan since 120 Ma, while in the Cenozoic the Neo-Tethys and Pacific realms remotely controlled the tectonic regime of Daqingshan.

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Mesozoic superposed orogenic system in eastern China
REN Jishun, LIU Jianhui, ZHU Junbin
2024, 31(1): 142-153. 
DOI: 10.13745/j.esf.sf.2023.7.15

Abstract ( 996 )   HTML ( 3 )   PDF (5607KB) ( 120 )  

The Indosinian and Yanshanian orogenic movements are both important Mesozoic orogenies in eastern China. The resulted tectonic belts are neither products of the third stage of crustal evolution, as proposed by Chen Guoda, nor intracontinental (or intraplate) orogenic belts generated by intraplate dynamics, as argued by some scholars—rather, they are superposed orogenic belts created on the preformed continental crust in eastern China due to Mosozoic Paleo-Pacific dynamic system. In the past, these orogenic belts were called the peri-Pacific continent-marginal reactivated belts of eastern China. In the Mesozoic, under the effect of Paleo-Pacific dynamic system, the East Asia margin orogenic system formed along Northeast Russia-Sikhote Alin (Russia)-Japan-Ryukyu-Taiwan (China)-Palawan (Philippines) regions, while simultaneously the Mesozoic superposed orogenic system formed in the pre-existing continental crust in eastern China adjacent to the East Asia continental margin. The two orogenic systems, both driven by Mesozoic Paleo-Pacific dynamic system, developed synchronously to form the giant Mesozoic orogenic system in the Pacific tectonic domain in eastern Asia, radically changing the pre-Indosian tectonic framework of eastern Asia.

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Evolutionary geodynamics and remote effects of the uplift of the Qinghai-Tibet Plateau
LIU Demin, WANG Jie, JIANG Huai, ZHAO Yue, GUO Tieying, YANG Weiran
2024, 31(1): 154-169. 
DOI: 10.13745/j.esf.sf.2024.1.146

Abstract ( 1042 )   HTML ( 9 )   PDF (5959KB) ( 145 )  

The formation of the Qinghai-Tibet Plateau as Earth's “third pole” is the most distinguishing and significant result of neotectonic movements under Earth's rhythmic tectonic events since the Cenozoic era. The characteristics and importance of tectonic landforms in the region, the tectonic regime of the plateau, the evolutionary dynamics and the impact and long-range effects of the plateau uplift on peripheral basins and even the entire Chinese subcontinent have been the focus of academic attention to this day. This article redefines the range of tectonic landforms of the Qinghai-Tibet Plateau, and establishes the importance of the plateau uplift to global tectonics. According to the results, the remote effects of the Qinghai-Tibet Plateau and its south/north extension spans across Asian along 105°E longitude, in general, reaching the Arctic Ocean in the north and reaching the Pacific Ocean in the south. Hence, this article uses the large circle of 105°E longitude as the dividing line between the Eastern (to the east of the line) and Western Hemispheres. The Qinghai-Tibet Plateau is location at the intersection of the world's largest and most important north-south and east-west structures, and the Pamir Plateau is the backbone of regional structures. The Qinghai-Tibet Plateau originates from the Pamir Plateau, a thermal dome during the Indosinian period, which later transformed into an abnormal gravity column with a diameter of 200 km and sank 600 km vertically to form a vertical open-close structure to be completed in the Cretaceous period. From the Pamir Plateau at the center there are three horizontal compressional-extensional tectonics expanding to the east, and one to the west. During the Xishan period, the Pamir Plateau also experienced igneous intrusion, while its Cretaceous structure remained largely undeformed. In the Paleogene, the India-Asia collision formed the magnificent Himalayan orogenic belt that was first compressed and then uplifted. Expanding northward from the Himalayas three mantle branches rose during the Quaternary, causing the entire Qinghai-Tibet Plateau to rise. According to the deep dynamics model established in this article, the early stage of the plateau uplift is manly manifested by centrifugal movement of geological bodies in vertical direction and extensional movement in horizontal direction, and the later stage of mainly compression, is manifested by centripetal vertical movement and horizontal compression movement of geological bodies. In terms of driving force, thermal energy is the main driving force in the early stage and gravity potential energy in the later stage.

The uplift of the Qinghai-Tibet Plateau is the most remarkable geological event of the Cenozoic era within the Eurasian continent. It has direct impacts on the shallow lithosphere and the crust's surface layer through short- and long-range effects, affecting topography, energy and natural resources, ecology, environment, and geohazards closely related to human survival and development. Under the remote effects of the Qinghai-Tibet Plateau uplift the Baikal Lake Rift, the Fenwei Rift, and the East Africa Great Rift Valley are formed. Finally, five issues are briefly discussed: the naming and timing of the Indosinian movement; the timing of start/termination and types of the Indosinian movement; the Qinghai-Tibet Plateau being the best place to study various types of orogenic belts; the determination of the eastern and western tectonic structures of the Himalayan orogenic belt; and the exploration of the four-dimensional dynamics model of the Pamir Plateau.

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Crustal structure beneath the Cuonadong dome in southern Tibet revealed by receiver functions from a short-period dense array
CAI Wei, LU Zhanwu, HUANG Rong, LI Wenhui, LUO Yinhe, WANG Guangwen, MU Qing, CHENG Yongzhi, CHEN Si, WANG Guan, CHEN Zilong
2024, 31(1): 170-180. 
DOI: 10.13745/j.esf.sf.2023.10.15

Abstract ( 964 )   HTML ( 4 )   PDF (5742KB) ( 52 )  

Located at the front edge of the subduction zone, the northern Himalayan tectonic zone is one of the typical regions to study crustal thickening and deep crustal magmatism during continental collision. The northern Himalayan gneiss domes (NHGD), as a critical extensional unit of the tectonic zone, have a formation process closely related to crustal thickening from orogenic movement and crustal flow due to partial melting. In this study, we used common-conversion-point stacking of teleseismic P-wave receiver functions to image the crustal structure beneath the recently discovered Cuonadong dome. We found large crustal structural variations from east to west of the Cuonadong dome with the occurrence of several discontinuous crustal interfaces, even crustal faulting. We also found a low velocity zone in the upper and middle crust beneath the Cona rifts and Cuonadong dome. Combining the above results and previous studies, we consider that the southeastern Himalayan lithosphere underwent crustal-scale tensional deformation as a result of continuing Indo-Eurasian collision. Under the long-term continental subduction, crustal thickening and continuous high-temperature metamorphism, the middle and upper crust underwent partial melting following the extension and decompression of the southern Tibet detachment (STD). The subsequent continuous magma upwelling along the weakened STD and magma accumulation beneath the dome region resulted in the weakened crustal zone, which promoted the east-west regional extension and then formed the Cuonadong dome through magmatic diapirism.

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Application of the magnetotelluric method in the Sichuan-Yunnan region—a review
DENG Yan, XU Yuchao, FAN Ye, SUN Guicheng, DONG Zeyi, HAN Bing
2024, 31(1): 181-200. 
DOI: 10.13745/j.esf.sf.2024.1.25

Abstract ( 967 )   HTML ( 4 )   PDF (5030KB) ( 84 )  

Magnetotelluric sounding (MTs, including audio-magnetotelluric, broadband-magnetotelluric and long-period-magnetotelluric) is a geophysical method to probe the near-surface to the upper mantle. Due to its sensitivity to low resistivity bodies, magnetotelluric plays an important role in deep structure, seismogenic environment, geothermal and resource exploration and geodynamics. The Sichuan-Yunnan region, located in the eastern section of the Tethys tectonic domain where many (micro) plates collide and merge, serves as an important channel for the eastward flow of materials and lateral extrusion of blocks within the Tibetan Plateau. The region is an important window to study the regional tectonic deformation, seismogenic environment and material migration due to the mutual cutting and influence of fault zones or suture zones of the plate boundary. This review first gives a brief introduction to the theory of magnetotelluric, then focuses on its application in the Sichuan-Yunnan region as well as the emerging CSELF (control source extremely low frequency) electromagnetic technique in recent years, and finally discusses the application of magnetotelluric in seismogenic environment, volcanic and geothermal activities, metallogenic activities, tectonic and dynamics, and electromagnetic coseismic effects. This review offers a comprehensive perspective on the application of magnetotelluric in the Sichuan-Yunnan region.

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Very low-grade metamorphic rocks in southern Tibet and their significance on geological processes and resources
BI Xianmei, MO Xuanxue, LIU Yanbin
2024, 31(1): 201-210. 
DOI: 10.13745/j.esf.sf.2024.1.66

Abstract ( 1038 )   HTML ( 5 )   PDF (4083KB) ( 48 )  

Very low-grade metamorphism is one of the contemporary topics of frontier research since very low-grade metamorphic rocks contain important information on the geological processes related to oil and gas resources. Diagenetic sedimentary rocks, very low-grade metamorphic rocks and low-grade metamorphic rocks are widely distributed in southern Tibet, and these rocks preserve critical information on the evolution of the Neotethys and the Tibetan Plateau, as well useful clues for the exploration of oil and gas resources. This paper presents 71 data sets on illite crystallinity (Ic) and other parameters of clay mineral-bearing rock samples collected from different locations and tectonic units in southern Tibet. The illite crystallinity (Ic) of these rocks is in the range of 0.21°-1.61°(Δ2θ), and falls in the lower diagenetic, higher diagenetic, very low-grade metamorphic and low-grade metamorphic zones respectively. The different tectonic units display diverse metamorphic characteristics. Strata of P2, J-K, K2 in the North Himalayan carbonate platform all underwent very low-grade metamorphism, but N strata show the characteristics of early diagenetic stage. Strata of P1, T1, T2, T3, J1, J-K, K1 and K2 are developed in the Laguigangri passive marginal basin, most of which experienced low-grade metamorphism, and show patterns of normal burial with increasing metamorphism from younger to older strata. The Ic of some samples also falls in the diagenetic zone, which provides clues for finding oil and gas. Two sets of data were obtained from sedimentary rock samples in the Yarlung Zangbo ophiolites. One is in the diagenetic stage, and another group corresponds to very low grade metamorphism. Preliminary interpretation suggests that the former may reflect the paleo-environmental conditions at the time of ophiolite formation, whereas the latter may represent the tectonic position of the ophiolite during collision. The strata of K2 in Xigaze fore-arc basin are only in the high diagenetic grade, presumably indicating that Late Cretaceous strata in the fore-arc basin were not involved in subduction. Intrusive rocks, volcanic rocks and sedimentary rocks are all developed in the Gangdisê magmatic arc. The illite crystallinity (Ic) of the sedimentary rocks falls within a wide range of low-grade metamorphic-very low-grade metamorphic-diagenetic zone, and shows the characteristics of burial metamorphism superimposed by magmatism. Also, the very low-grade metamorphic rocks and diagenetic sedimentary rocks in southern Tibet contain information about oil and gas. In particular, the worldwide oceanic anoxic event that took place in the middle of the Cretaceous also affected southern Tibet, and very thick beds of typical black shale were found in the Gamba-Tingri basin. Previous studies also suggested that the Tingri-Gamba passive continental margin, Qiangtang peripheral foreland basin and Gangdese back-arc basin have good prospects for oil and gas exploration. The preliminary study on very low-grade metamorphism and very low-grade metamorphic rocks in southern Tibet in this paper opens scope for further detailed studies in future.

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Deep process and lithospheric architectural control of Cu-REE mineralization in continental collision zone: Insights from a case study of the Gangdese and Sanjiang collisional belts
WANG Rui, ZHANG Jingbo, LUO Chenhao, ZHOU Qiushi, XIA Wenjie, ZHAO Yun
2024, 31(1): 211-225. 
DOI: 10.13745/j.esf.sf.2023.12.19

Abstract ( 976 )   HTML ( 2 )   PDF (6639KB) ( 90 )  

Situated in an archetypal continental collision zone the Tibetan Plateau developed world-class porphyry Cu and carbonate REE metallogenetic belts, yet there is no scientific consensus about the mechanism of continental collision control of Cu-REE mineralization in the region. The outstanding issues include the exact trigger mechanism for melting of the thickened lithosphere, the relationship between the lithospheric framework and Cu-REE metallogenesis, and the source of Cu, REE and volatiles and their depositional processes. To better understand the deep process and lithospheric architectural control of Cu-REE metallogenesis, this paper summarizes the lithospheric architecture of the Gangdese forward and oblique collision zones had been imaged and analyzed using joint inversion of surface wave and satellite gravity data, combined with magnetotelluric (MT) array and geochemical data. During the India-Asia collision in the Cenozoic the subducting Indian lithosphere experienced significant tearing, allowing asthenospheric upwelling to rework the overlying Asian lithosphere and cause melting. The resulting ultrapotassic melt ascended and accumulated at the bottom of the crust, providing high heat flow and volatiles for the melting of the juvenile lower crust. In the hydrous melt, amphibole fractionation led to melt oxidation, promoting Cu recycling and enrichment. The above results revealed three key factors controlling the formation of collisional porphyry deposits: moderate-angle subduction, slab tearing, and reactivation of the sulfide-enriched juvenile lower crust. At the margin of the Yangtze craton, Sanjiang oblique collision zone, vertical upwelling and horizontal flow of asthenosphere, driven by subduction of the Indian plate or mantle convection, caused thermal erosion and partial melting of the cratonic continental lithosphere. The lithosphere beneath the craton margin was REE enriched due to prior metasomatism by REE/CO2-rich fluid from recycled oceanic sediment, and enriched REEs were carried by ascending carbonate melt along the lithosphere discontinuity (e.g., strike-slip fault, rift) to form large scale carbonate REE deposits. Without prior lithospheric metasomatism, carbonatic, ultrapotassic and mafic melts produced from the melting of the cratonic lithosphere had limited potential to form carbonate REE deposits.

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Mesozoic intraplate metallogenesis in South China
HU Ruizhong, GAO Wei, FU Shanling, SU Wenchao, PENG Jiantang, BI Xianwu
2024, 31(1): 226-238. 
DOI: 10.13745/j.esf.sf.2024.1.9

Abstract ( 1458 )   HTML ( 7 )   PDF (6348KB) ( 121 )  

Intraplate metallogenesis is a significant global scientific issue. The South China block is renowned for its large-scale mineralization occurring far away from active continental margins during the Mesozoic. It formed a low-temperature metallogenic province of gold, antimony, lead, and zinc deposits in the west (Yangtze block) and a high-temperature metallogenic province of tungsten-tin polymetallic deposits in the east (Cathaysia block), making it an ideal natural laboratory for intraplate metallogenesis studies. The two metallogenic provinces of South China have long been considered distinct systems due to their spatial separation. However, our research revealed that the low-temperature mineralization in the west (230-200 Ma and 160-130 Ma) occurred simultaneously with the high-temperature mineralization in the east, and has similar geochemical fingerprints to the latter. Both types of mineralization were probably driven by the Indosinian intracontinental orogeny and Yanshanian asthenosphere upwelling beneath South China. Therefore, there is a genetic linkage between the two metallogenic provinces, and together they constitute a giant polymetallic domain spreading planarly under intraplate setting. The current distribution status of the low- and high-temperature mineralization types in the west and east is controlled by the eastward increase of denudation degree in South China after ore formation. It is predicted that there may exist high-temperature W-Sn polymetallic deposits beneath the eastern region of the low-temperature metallogenic province. A new intraplate metallogenesis model for South China was established. The significant features of the new model include metallogenesis occurring within preexisting weakness zones of lithosphere, continental crust serving as sources for metallogenic elements, and coexistence of high- and low-temperature mineralization exhibiting a distinct planar distribution. The model differs from the metallogenic mechanism in continental plate margins.

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Developing structural control models for hydrothermal metallogenic systems: Theoretical and methodological principles and applications
YANG Liqiang, YANG Wei, ZHANG Liang, GAO Xue, SHEN Shilong, WANG Sirui, XU Hantao, JIA Xiaochen, DENG Jun
2024, 31(1): 239-266. 
DOI: 10.13745/j.esf.sf.2024.1.40

Abstract ( 1076 )   HTML ( 5 )   PDF (5137KB) ( 152 )  

A defining feature of a hydrothermal metallogenic system (HMS) is strong structural control on ore mineralization. A systematic analysis of the geometry, kinematics, thermodynamics, and rheology of multiscale ore control structures is crucial for understanding the genesis of HMSs and for ore prospecting. The main challenges include: transitioning from static to multiscale spatiotemporal analysis of the 4D dynamical system involving ore-control structural frameworks, permeability structures, ore-forming fluid pathways, and mineralization deformation networks; identifying key influencing factors of fluid pathways that control ore deposition; and unraveling the mechanism of structure-fluid coupling control of ore formation and localization. This study presents the theoretical and methodological principles and application for developing structural control models for HMSs in the following aspects. (1) The theoretical core. It states that fluid, not structure, is at the core of a structural control model. Fluid flow and ore formation within a hydrothermal system are influenced by the fault zone architecture and permeability structure, where permeability, in linking fluid flow and fluid pressure variation, is key to understanding ore control structures. (2) Stress and pressure dynamics. It considers that differential stress and fluid pressure difference result in diverse combinations of ore control structures, while differences in regional stress field and host rock strength result in variations in mineralization type. (3) Growth of fluid pathways. It considers that fluid pathways initiate from isolated microfractures within the upstream host rocks of overpressured fluid reservoirs which evolve along the direction of the steepest pressure gradient to form new extended fractures through growth and interconnection. These extended fractures eventually interconnect to form fluid pathways. As ore deposition takes place during brief periods of high fluid flux when repeated fault sliding induces rapid changes in fluid pressure, flow velocity, and stress, rapid pressure release—caused by a disruption of dynamic equilibrium in the fluid system due to fluid pathways growth—is a key factor driving metal precipitation. (4) Integrated research. Methodology involves integrating macro and microscopic examination of ore control structures, integrating geological history and stress analysis, combining local and regional analyses, adopting shallow and deep perspectives, and employing a multidisciplinary, multiscale approach to study various ore-controlling factors. (5) Geological mapping. Methodology involves using structure-alteration-mineralization network mapping to characterize alteration-mineralization rock blocks in terms of geometric parameters for ore control structures (such as type, shape, size, occurrence, spacing), and performing quantitative analyses (such as topological analysis of hydrothermal vein-fracture systems, 3D geometric analysis of ore bodies) to determine ore-control structural frameworks and permeability structures and reveal the connectivity of mineralization deformation networks and their ore-forming potential. (6) Numerical modeling. Methodology involves developing geological models, selecting appropriate thermodynamic parameters and dynamic boundary conditions, and utilizing methods such as HCh and COMSOL to perform quantitative simulation of spatiotemporal variations in fluid flow, heat-mass transfer, stress deformation, and chemical reactions during ore formation. This is an effective approach to unveil the mechanism of ore formation controlled by structure-fluid coupling and ore localization pattern, predict ore-forming centers, and identify mineral exploration targets. Based on the above principles, this paper proposes a research methodology for model building, focusing on deriving metallogenic models and ore deposition patterns based on structure-fluid coupling control. Briefly, hydrothermal veins-fracture systems and structure-alteration-mineralization networks are selected as primary research subjects. Research methods include geometric description, kinematic assessment, rheological/dynamic analyses, and thermodynamic synthesis, seeking to delineate ore-control structural frameworks, identify mineralization centers, trace the developments of ore-forming fluid pathways and various mineralization styles, and reveal the spatiotemporal evolution patterns of permeability structures. Additionally, the causal relationship between tectonic reactivation and ore localization is explored. Finally, a metallogenic model based on structure-fluid coupling is constructed to support strategic mineral exploration. This research methodology was applied for mineral prediction in the Jiaojia gold field, Jiaodong Peninsula; its validity and effectiveness were tested and approved.

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Research advances on the geochronology of Carlin-type gold deposits in the Youjiang Basin, southwestern China
GAO Wei, HU Ruizhong, LI Qiuli, LIU Jianzhong, LI Xianhua
2024, 31(1): 267-283. 
DOI: 10.13745/j.esf.sf.2023.11.39

Abstract ( 1009 )   HTML ( 7 )   PDF (9477KB) ( 63 )  

The Youjiang Basin hosts the world's second largest Carlin-type gold province after Nevada, USA. However, due partly to the uncertainty of their mineralization age the geodynamic setting of the Carlin-type gold deposits remains unclear. During the past forty years significant efforts have been made to accurately constrain the timing of these gold deposits, ranging from the early dating methods (with low reliability) such as quartz fission track and fluid inclusion Rb-Sr isochron dating, to the midterm dissolution-based bulk analyses of mineral separates such as sulfide Re-Os, to the latest in-situ precise U-Pb dating of hydrothermal U-bearing minerals including rutile, monazite, and apatite. It has now been clearly considered that there existed two episodes of Carlin-type gold mineralization in the Youjiang Basin ca. 215-200 Ma and 155-140 Ma, probably in response, respectively, to the Indosinian post-collisional intracontinental orogeny and the Yanshanian asthenospheric upwelling and lithospheric extension in southern China.

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Fluctuation analysis for sedimentary basins: Review and outlook
JIN Zhijun, CHEN Shuping, ZHANG Rui
2024, 31(1): 284-296. 
DOI: 10.13745/j.esf.sf.2024.1.30

Abstract ( 999 )   HTML ( 4 )   PDF (3575KB) ( 72 )  

The fluctuation of sedimentary basins is the primary manifestation of crustal movement within the plates, while the formation and evolution of the basins result from the superposition of various fluctuation processes within the Earth system. Fluctuation analysis for sedimentary basins involves decomposition of periodic fluctuation curves from sedimentation rate time series, which has led to a new understanding of the evolutionary history of sedimentary basins. New insights include the fluctuation cycles controlling basin evolution and hydrocarbon accumulation episodes; the relationships between basin crustal uplift/subsidence and hydrocarbon generation or thermal evolution; the spatial-temporal distribution of unconformities and erosion recovery; the spatial-temporal distribution of stratigraphic frameworks and configuration of source-reservoir-cap strata controlled by the superposition of multi-scale fluctuation processes; and the relationship between tectonic evolution patterns and hydrocarbon reservoir preservation. Through fluctuation analysis by integrating basin formation and hydrocarbon generation and accumulation with crustal fluctuation, a quantitative description of the dynamic evolution process of hydrocarbon accumulation can be achieved to guide oil and gas exploration practices. Future outlooks for this research field are clarifying the mechanism of basin fluctuation driven by long-term astronomical periods and deep Earth dynamic cycles, integrating geological evidence with numerical simulation techniques, advancing the fluctuation analysis method, and promoting the use of new theoretical insights to comprehensively understand the multi-spherical interactions and their environmental and resource impacts. Leveraging the predictive value of basin fluctuation analysis in hydrocarbon accumulation patterns can provide scientific support for the exploration and long-term evaluation of oil and gas resources.

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Research progress and insight on non-tectonic fractures in shale reservoirs
DING Wenlong, WANG Yao, WANG Shenghui, LIU Tingfeng, ZHANG Ziyou, GOU Tong, ZHANG Mengyang, HE Xiang
2024, 31(1): 297-314. 
DOI: 10.13745/j.esf.sf.2023.12.5

Abstract ( 975 )   HTML ( 4 )   PDF (3515KB) ( 60 )  

Shale oil and gas exploration and development in China has become increasingly important strategically, as breakthroughs are continually to be made with the improvement of unconventional oil and gas exploration theory and technology. The resource potential of shale reservoirs is largely constrained by reservoir quality, where fracture development is key to oil/gas enrichment and reservoir productivity. Fractures have always been a research focus of organic-rich shale oil and gas reservoirs as they play an important role in petroleum storage space and seepage channels. Shale reservoirs in China are naturally fractured in general and have relatively wide distribution of non-tectonic fractures. Presently, tectonic fractures have been studied more in depth. This paper, therefore, focuses on non-tectonic fractures with comprehensive review of recent domestic and foreign research achievements, focusing on fracture classification, identification and characterization as well as fracture controlling factors, stages and evolutionary sequences. Non-tectonic fractures are characterized by complex formation mechanism and morphology, irregular distribution pattern and small scale. According to their formation mechanism, non-tectonic fractures can be divided into four categories: diagenetic fractures, abnormal high-pressure fractures, bedding fractures and supergene fractures; whereas fracture identification and characterization are still largely based on descriptive analysis. Although the main fracture controlling factors differ between different fracture types, they share certain commonalities as all fractures are controlled, to some degrees, by sedimentation, diagenesis, mineral composition/content and rock mechanical properties. This paper further analyzes the key research challenges and points out key development trends in the field. First, a novel method should be developed to perform comprehensive and effective identification and quantitative characterization of non-tectonic fractures of different types and scales, based on typical characteristics of shale reservoir core, thin section, imaging logging and conventional logging, combined with advanced image technology. Second, as non-tectonic fractures exhibit “multi-genetic type, multi-control factor, multi-stage evolution” characteristics, with paleotemperature/paleopressure, paleofluids and paleodiagenesis playing a key role in their generation and evolution, advanced experimental analysis techniques, such as fluid geochemistry, isotope geochemistry (C, O, Sr) and in situ isotope chronology (U-Pb, Sm-Nd) of common filling materials such as calcite should be the key techniques to determine their formation time, active stages and evolutionary sequence. Last, the future trend is a shift from qualitative/semi-quantitative analyses of fracture development under a single controlling factor to quantitative, multi-factor coupling analysis. That is, using mathematical methods to determine the weights of different controlling factors and construct a quantitative relationship model to quantify the relationship between a comprehensive fracture development index and multiple controlling factors.

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Technological progress and trend in shale gas on-site testing—a critical review
ZHANG Jinchuan, WANG Xiangzeng, LI Zhongming, LIU Shugen, NIU Jialiang, YUAN Tianshu, LI Xingqi, TANG Xuan
2024, 31(1): 315-326. 
DOI: 10.13745/j.esf.sf.2023.9.30

Abstract ( 950 )   HTML ( 1 )   PDF (1617KB) ( 26 )  

Gas content is a key parameter for shale gas evaluation and production decision-making, while on-site determination of desorption gas content using “large three-stage” desorption curves is preferred based on accuracy, cost, and speed considerations. Different from coalbed methane, shale gas content analysis has made significant progress in testing methodologis, methods, technologies, and instruments. The adaptation of pipeless testing technology using “small three-stage” desorption curves provides more valuable information while improving the accuracy of desorption gas testing. From conditional extrapolation, borrowed from coalbed methane, to multi-point constraint fitting, shale gas loss can now be calculated with less dependency on assumptions. Based on the principle of non-contact torque transmission, whole-process air sealing during residual gas testing has been achieved. Accurate gas content measurement using dual three-stage desorption curves lays the foundation for calculating key parameters such as total gas content, free/absorption ratio, and recoverable coefficient. However, the total recoverable shale gas is not simply the sum of lost and desorbed gases. High-precision, on-site desorption gas content analysis has wide applications. Its development directions include systematic high-precision data acquisition, mult-parameter evaluation, and intelligent-evaluation technology application.

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Geological characteristics and mechanism of helium accumulation in typical abiotic helium-rich gas fields in the United States
YANG Yiqing, TAO Shizhen, CHEN Yue
2024, 31(1): 327-339. 
DOI: 10.13745/j.esf.sf.2024.1.70

Abstract ( 962 )   HTML ( 1 )   PDF (4929KB) ( 57 )  

Economically viable abiotic helium-rich gas fields are widely developed in the United States. He-rich N2 gas fields, for example, contain as much as 10% He, as the basement rocks in situ and in the surrounding area provides sufficient crustal He and N2 to yield an N2/He (He > 0.1%) ratio typically between 5-50. However, He-rich N2 gas fields so far are only found in the United States, and further research is needed to determine whether they are due to unique geological conditions, or yet to be discovered elsewhere. He-rich CO2 gas fields also contain significant quantity of crustal helium. He-rich CO2 gas fields in the Colorado Plateau are all thought to have originated from late Cenozoic magmatism, and the magmatic rocks in the region have high U/Th contents. The groundwater gas stripping and re-dissolution (GGS-R) model is commonly used to explain the trapping mechanism of noble gases in CO2 gas reservoirs. According to this model, mantle-sourced CO2 carrier gas stripes air-sourced noble gases dissolved in the groundwater to charge reservoirs along with crustal-derived noble gases, and dissolution equilibrium subsequently reestablishes between the noble gases and groundwater. While the water/gas ratios at equilibrium differ between different gas fields, they are similar in all gas fields in the Colorado Plateau ranging between 0-100 (at reservoir pressure and temperature). By systematic analysis and summarization of the source, migration, and accumulation mechanisms of helium in helium-rich abiotic gas reservoirs in the United States, and discuss the enrichment of helium of primary migration by diffusion in helium source rocks, and of secondary migration by water phase mass flow or multiphase porous flow/seepage with inorganic carrier gases N2 and CO2, this paper provides a theoretical basis for helium exploration in China, and can be used as a reference for geological evaluation of CO2 reservoirs and development of CO2 safe storage.

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Crustal helium: Accumulation controlling factors and resource evaluation methods
WU Yiping, WANG Qing, TAO Shizhen, WANG Jianjun, LI Qian, ZHANG Ningning, WU Xiaozhi, LI Haowu, WANG Xiaobo
2024, 31(1): 340-350. 
DOI: 10.13745/j.esf.sf.2024.1.3

Abstract ( 996 )   HTML ( 4 )   PDF (6768KB) ( 63 )  

Presently there is no systematic helium (He) resource evaluation method, nor evaluation parameter standard. This study, by comparing the accumulation controlling factors of natural gas and crustal helium, identifies eight key controlling factors of crustal helium accumulation and three co-occurrence styles between carrier-gas and helium, namely, different sources in one reservoir, same source in one reservoir, and same source in different reservoirs. For preliminary quantitative evaluation of helium resource, four classification and evaluation methods using ten different algorithms are established—with percentage method using five; statistical method, one; analogy method, three; and genetic method, one. Helium-rich gas reservoirs are generally characterized by normal to low pressure. The helium content is positively correlated with three parameters—source type, U/Th contents, and source rock volume, and negatively correlated with three parameters—distance from the main fault, burial depth, and hydrocarbon-generating intensity; while moderate basal tectonic activity is conducive to helium release and enrichment. Analogy method is established based on the quantitative relationships between the eight key factors and helium content. Scale sequence method is based on the principle that gases from different sources in one reservoir have different scale sequences. And genetic method is based on the radioactive decay model of helium release and accumulation. The evaluation methods are used widely both at home and abroad, and their application shall effectively contribute to the discovery of large-scale helium reserves in China.

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Helium: Accumulation model, resource exploration and evaluation, and integrative evaluation of the entire industrial chain
TAO Shizhen, WU Yiping, TAO Xiaowan, WANG Xiaobo, WANG Qing, CHEN Sheng, GAO Jianrong, WU Xiaozhi, LIU-SHEN Aoyi, SONG Lianteng, CHEN Rong, LI Qian, YANG Yiqing, CHEN Yue, CHEN Xiuyan, CHEN Yanyan, QI Wen
2024, 31(1): 351-367. 
DOI: 10.13745/j.esf.sf.2024.1.71

Abstract ( 977 )   HTML ( 4 )   PDF (4043KB) ( 83 )  

China's helium industrial chain needs scientific and technological support, but there lack a systematic theoretical understanding of helium geology, along with the lacks of targeted helium resource evaluation methods and parameter selection standard, comprehensive accurate detection of helium content, helium prospecting methods, cost index system, as well as methodology for integrative evaluation of the entire helium industrial chain. To address these knowledge/technology gaps we developed a helium accumulation model and three key technologies for helium resource and asset evaluation, using interdisciplinary research methodology and experimental techniques involving geology, geochemistry, gravity-aeromagnetic-electrical-seismic, and investment and economics. Through detailed investigation of typical helium-rich gas reservoirs, combined with analysis of “helium-natural gas-water” phase equilibria and phase-potential coupling in underground fluids, we revealed three helium occurrences—water-dissolved, gas-dissolved, free-particle; three migration mechanisms—mass-flow, seepage, diffusion; and four dispersion-enrichment controlling factors—proximity to source, adjacent faults, low-pressure zone, high-location. We developed a theoretical framework for the understanding of helium geology, recognizing high-quality source, efficient migration, suitable gas-carrier are the three key controlling factors of effective helium accumulation. To overcome a series of challenges in helium detection, such as variable detection techniques, low accuracy, large discrepancies with foreign data, and no targeted resource evaluation methods, we developed a comprehensive, accurate detection technique for helium content, with helium source and content at the core, and established 10 resource evaluation methods under four categories, solving the technical bottleneck in helium resource classification and evaluation. A normalized gravity/magnetic downward extension scheme was created to address challenges in helium source-rock distribution, lithofacies identification, source-fault characterization, and reservoir evaluation. An intelligent identification technique for multi-scale faults based on deep learning and a simulation method for acoustic properties of gas reservoir under different helium contents were developed, laying the foundation of predicting source-rock distribution, characterizing source-faults, logging interpretation, and evaluating helium-bearing gas reservoirs. By establishing a multi-process helium control model for helium-rich gas zones and target optimization methodology, the problem of target optimization for helium-rich gas zones is solved. Facing the reality of helium deficiency in China, with the goal of promoting cost-effective investment in helium extraction equipment, we developed a methodology for integrative evaluation of the entire helium industrial chain by adopting response surface methodology to build a nonlinear regression model between optimization target and various main process parameters, which preliminarily addressed the technical demand for cost-effective helium extraction from natural gas. Results from this research provide effective support for China's long-term, safe, and large-scale utilization of its natural helium asset.

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Novel metallogenic model of sandstone-type uranium deposits: Mineralization by deep organic fluid
LIU Chiyang, ZHANG Long, HUANG Lei, WU Bailin, WANG Jianqiang, ZHANG Dongdong, TAN Chengqian, MA Yanping, ZHAO Jianshe
2024, 31(1): 368-383. 
DOI: 10.13745/j.esf.sf.2024.1.7

Abstract ( 988 )   HTML ( 2 )   PDF (8074KB) ( 51 )  

Most existing metallogenic models maintain that sandstone-type uranium (U) deposits are formed by infiltration of exogenous uranium carried by near-surface oxygenated waters from erosion source areas into basins. However, this study finds that these traditional models fail to explain the geological evolution, geomorphological characteristics, and mineralization of sandstone-type uranium deposits in eastern Yimeng Uplift, northern Ordos Basin. The key issue is the material source of uranium mineralization. Geochemical analysis of representative minerals from this area, including coffinite (formed in a strongly reducing environment) and its associated minerals, reveal the existence of two distinct uranium mineralization environments: low-salinity meteoric waters and medium-high-salinity hydrothermal fluids, and primary uranium mineralization occurred less than 80 Ma. Considering the U-rich source rocks of coal-bearing strata in the basin, the enormous dissipation of natural gas, and the widespread distribution of various hydrocarbon alteration products and condensate oil traces related to the dissipation of mature coal-type gas in the Yimeng Uplift, a novel metallogenic model of large uranium deposits is proposed based on comprehensive simulation experiments and testing analysis. According to the new model, the uranium source originates from deep U-rich coal strata in the middle of the basin, where dissolved gases from thermal fluids migrate and dissipate towards higher elevations in the eastern Yimeng Uplift, extracting and carrying uranium from the source rock and uranium-rich strata along the way to shallower layers to cause sparry calcite and coffinite to precipitate as temperature/pressure decreases; meanwhile along with the near-surface, low temperature mineralization, massive exsolved natural gas creates a reducing environment for the preservation of uranium deposits. This new model of uranium mineralization opens up new horizons for uranium exploration in terms of exploration approaches and domains, and strengthens the scientific basis for polymineralization involving different mineral (metallic, non-metallic) and energy (hydrothermal, hydrocarbon) types, as well as prediction and evaluation of such polyminealization occurrences.

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Distribution and source of nitrate in high-chromium groundwater in Jingbian, northern Shaanxi
GUO Huaming, YIN Jiahong, YAN Song, LIU Chao
2024, 31(1): 384-399. 
DOI: 10.13745/j.esf.sf.2024.1.24

Abstract ( 1003 )   HTML ( 3 )   PDF (6595KB) ( 44 )  

Natural high-chromium (Cr) groundwater usually contains high concentration of nitrate, but the source of nitrate and its relationship to Cr enrichment are unclear. In this study, water and sediment samples were collected at different depths from the high-Cr region of southwestern Jingbian, Loess Plateau, northern Shaanxi, and the dissolved Cr, soluble ionic species, δ18O, δD, δ18O-NO3, δ15N-NO3, and main and soluble sediment components were analyzed. Unconfined groundwater from Quaternary loess aquifers was mainly of HCO3-Na and HCO3-Ca-Mg types. Confined groundwater from sandstone aquifers of the Cretaceous Huanhe-Luohe Formations was of complex hydrochemical types, mainly HCO3-SO4-Cl-Na-Mg, HCO3-SO4-Na-Mg and SO4-Cl-Na-Mg types. The groundwater environments were weakly alkaline and oxic, with high concentrations of dissolved salts. The hydrochemical components of unconfined groundwater mainly derived from silicate weathering, while dissolution of evaporites mainly controlled the chemistry of confined groundwater. The average concentration of nitrate in confined groundwater was higher compared to unconfined groundwater and surface water. Spatial distribution of nitrate concentrations in groundwater showed a high-low-high trend from northeast to southwest in the study area. Nitrate contents in sediment and groundwater samples had similar variation trends with depth, indicating that nitrate in groundwater mainly originated from aquifer sediments. δ18O-NO3 and δ15N-NO3 values indicated that nitrification was the main process of nitrogen cycling and transformation in groundwater systems. Under alkaline, oxic groundwater environments, the presence of dissolved oxygen, nitrate, and nitrification was conducive to chromium oxidation in aquifer solids and release of Cr(VI) into groundwater.

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Geothermal resources exploration and development technology: Current status and development directions
SUN Huanquan, MAO Xiang, WU Chenbingjie, GUO Dianbin, WANG Haitao, SUN Shaochuan, ZHANG Ying, LUO Lu
2024, 31(1): 400-411. 
DOI: 10.13745/j.esf.sf.2023.9.25

Abstract ( 1075 )   HTML ( 7 )   PDF (4567KB) ( 76 )  

Geothermal energy is an important non-carbon-based renewable energy with several advantages such as local availability, deployment stability/reliability, and low carbon emissions. It represents an unique resource for ensuring energy security and promoting green, low-carbon transition. Since the beginning of the 21st century China's geothermal industry has experienced rapid development, making it a world leader in direct geothermal use, particularly in direct utilization of medium and deep geothermal resources for heating. However, as the majority of China's land regions are within tectonic plates and the country lacks medium-high temperature geothermal resources in the energy-intensive regions in the east, the development of geothermal power generation in China has been slow. In this study, the main distribution characteristics and development status of geothermal resources in China are discussed, and the current geothermal exploration, development, and utilization technologies are summarize, which involve exploration techniques based on geothermal genesis models, site selection evaluation techniques, thermal storage description technologies, sustainable development techniques, and key engineering technologies related to “heat extraction without water consumption.” In order to increase the geothermal energy market size amid energy transition, it is necessary to tap into deep geothermal resources with higher quality and broader applications in the future. Recommendations from this study include continuing strengthening basic theoretical research and technical innovation, inventorying China's deep geothermal resources as early as possible, addressing key technology challenges (e.g., high-temperature drilling/completion, complex-structure well, deep thermal storage retrofitting, underground heat exchange, EGS), and promoting synergistic development of “geothermal plus” multisource energy. Efforts should also be made to increase construction of demonstration projects and foster application market development. At the same time, it is essential to establish a sound policy and regulatory system, increase policy support, strengthen management and supervision, and create a favorable environment for the healthy, standardized, and sustainable development of the geothermal industry.

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International Continental Scientific Drilling Project of the Songliao Basin: Terrestrial Geological Records of the Cretaceous Dinosaur Age
WANG Chengshan, GAO Yuan, WANG Pujun, WU Huaichun, LÜ Qingtian, ZHU Yongyi, WAN Xiaoqiao, ZOU Changchun, HUANG Yongjian, GAO Youfeng, XI Dangpeng, WANG Wenshi, HE Huaiyu, FENG Zihui, YANG Guang, DENG Chenglong, ZHANG Laiming, WANG Tiantian, HU Bin, CUI Liwei, PENG Cheng, YU Enxiao, HUANG He, YANG Liu, WU Zhengxuan
2024, 31(1): 412-430. 
DOI: 10.13745/j.esf.sf.2024.1.4

Abstract ( 1015 )   HTML ( 3 )   PDF (5717KB) ( 105 )  

Over the past century the Earth has experienced continued warming, and it may enter a Greenhouse Earth state in the future with no ice at the poles. The Cretaceous was a typical Greenhouse period in deep time; thus, understanding the Cretaceous climate is important for interpreting past climate changes and predicting future trends. The ICDP (International Continental Drilling Program) Songliao Basin drilling project is the world's first continental scientific drilling project to penetrate the Cretaceous continental strata; it is aimed to investigate Cretaceous terrestrial climate and environmental changes, and to explore the mechanisms of massive terrestrial organic accumulation and enrichment. Spanning 16 years, this project achieves a continuous, complete 8187-meter core (recovery rate >97%, establishes a high-precision chronostratigraphic framework for the Cretaceous continental strata, reconstructs multi-temporal-scale terrestrial climate cycles and climate events during the Cretaceous period, reveals the mechanisms of Cretaceous sea-level fluctuations, and confirms marine incursion events in the Songliao Basin. This project has promoted global collaboration among geologists to study the Cretaceous greenhouse Earth, leading to a series of high-impact research achievements, and it has provided crucial scientific support for the sustainable development of oil and gas exploration in the Songliao Basin, generating significant social benefits and substantial international and domestic influence. This project represents a milestone in exploring deep-time Earth, and it is foreseeable that in the future, with the aid of scientific drilling, humans will continue to enhance their understanding of deep-time climatic and environmental evolution.

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Integrated chronostratigraphic framework for Cretaceous strata in the Songliao Basin
WU Huaichun, LI Shan, WANG Chengshan, CHU Runjian, WANG Pujun, GAO Yuan, WAN Xiaoqiao, HE Huaiyu, DENG Chenglong, YANG Guang, HUANG Yongjian, GAO Youfeng, XI Dangpeng, WANG Tiantian, FANG Qiang, YANG Tianshui, ZHANG Shihong
2024, 31(1): 431-445. 
DOI: 10.13745/j.esf.sf.2024.1.22

Abstract ( 1070 )   HTML ( 5 )   PDF (8617KB) ( 82 )  

The Cretaceous is a typical greenhouse period with global large scale formation of organic-rich source rocks. However, we have only limited understanding of the terrestrial environmental status, climate change and biosphere responses and evolution during the greenhouse period; the effect of climate and environmental changes on the terrestrial organic accumulation and large scale source rock formation remains unclear. To study these issues the Songliao Basin in northeastern China offers an unique opportunity. The Songliao Basin has widespread distribution of Cretaceous source rocks and possesses the most complete sedimentary record of the Cretaceous in the world. One challenges, however, was the lack of high-quality rock records due to low continuity and low completeness of the records, which has caused controversies over the stratigraphic division of the Songliao Basin. Recently, the 8197 m drill core obtained from ICDP (Continental Scientific Drilling Program) boreholes (SK-1, SK-2, SK-3) provided a virtually complete terrestrial stratigraphic record of Cretaceous strata of the basin. In this study, by evidence synthesis using results of lithostratigraphy, biostratigraphy, magnetostratigraphy, radioisotope geochronology, and cyclostratigraphy, we constructed a high-resolution, integrated Cretaceous chronostratigraphic framework for the Songliao Basin, which provided fine chronological reference for studying the evolution of deep-time Cretaceous climate and environment as well as promoting sustainable oil and gas development in the Songliao Basin.

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Earth sphere interaction reflected in microbial fingerprints through Earth's history—a critical review
XIE Shucheng, ZHU Zongmin, ZHANG Hongbin, YANG Yi, WANG Canfa, RUAN Xiaoyan
2024, 31(1): 446-454. 
DOI: 10.13745/j.esf.sf.2023.10.4

Abstract ( 1042 )   HTML ( 1 )   PDF (2996KB) ( 61 )  

Interactions between Earth's spheres, particularly between deep Earth and surface processes or within the surface system between sea, land and the atmosphere, are a critical issue in Earth system science. Such a large-scale geological process could be recorded by tiny microbes preserved in the fossil record. Triggered by volcanic activities during the Permian-Triassic transition and in the Late Ordovician, the bloom of nitrogen-fixation bacteria including cyanobacteria and the subsequent expansion of eukaryotes including algae, radiolarians and foraminifers clearly reflected a volcanism-induced shift from prokaryotes to eukaryotes. Furthermore, it has been shown that microbial activity could lead to banded iron formations to trigger Pre-Cambrian volcanic activity and even initiate plate movement in the early Earth. These data demonstrated the critical interaction between volcanic activity and the microbial community impacting carbon cycling. Microbes could also trace the complex interaction between sea, land, and the atmosphere and its associated long-range material transport process. Using microbial proxies for hydroclimate we identified the tri-pole mode of spatial variability of dry/wet status in eastern China on different time scales, as well as the extreme drought events in northwestern China triggered by the upper-ocean thermal condition in the tropical western Pacific Oceans. The spatiotemporal variations in dry/wet status reflected in the microbial records are due to variations in sea-land-atmosphere interactions between high- and low-latitude environments. The carbon- and water cycle-associated cross-sphere processes reflected in microbial fingerprints only represent a small portion of Earth sphere interactions. The great contribution of the microbial community in shaping the habitable Earth has yet to be fully deciphered. With research advancement and technical/methodological innovation in geobiology more questions can be addressed, including the interaction between geomicrobiological and deep Earth processes, microbial contribution to the major paleoclimatic shifts and paleoenvironmental changes, and impact of the microbial community on ecological evolution.

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Biogeochemical cycles in the Anthropocene and its significance
LIU Congqiang, LI Siliang, LIU Xueyan, WANG Baoli, LANG Yunchao, DING Hu, HAO Liping, ZHANG Qiongyu
2024, 31(1): 455-466. 
DOI: 10.13745/j.esf.sf.2024.1.26

Abstract ( 1024 )   HTML ( 3 )   PDF (1322KB) ( 51 )  

The Earth has entered a new geological epoch - the “Anthropocene”, wherein humanity has become the principal driving force behind global changes. These activities, through their transformative effect on biogeochemical processes and the cycles of essential biogenic elements, are exerting a direct and indirect impact on the Earth's ecosystem's vital functions, thereby posing numerous challenges to human well-being and the sustainability of our development. Drawing from the latest advancements in Earth System Science, this paper offers an exhaustive review of the Anthropocene's global change dynamics, the pivotal role and evolving patterns of biogeochemical cycles across various Earth spheres, and their transformation. It specifically delves into the repercussions of human actions, including the exploitation of natural resources and shifts in production and consumption paradigms, on these biogeochemical cycles and their consequent climatic, ecological, and environmental effects. This study underscores the necessity of a holistic grasp of the complex, multi-scaled biogeochemical cycle processes propelled by human activities and their ecological and environmental ramifications. It advocates for an integrated approach in research, amalgamating natural and social sciences, anchored in the principles and methodologies of Earth System Science, aimed at deciphering the intricacies of the Anthropocene's social-ecological systems. Conclusively, the paper delineates strategic research areas and trajectories for investigating the Anthropocene's biogeochemical cycles, emphasizing the critical need to resolve the intricate scientific challenges posed by these cycles in an epoch deeply influenced by human endeavors and climatic change.

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Interactions between clay minerals and microbes: Mechanisms and applications in environmental remediation
DONG Hailiang, ZENG Qiang, LIU Deng, SHENG Yizhi, LIU Xiaolei, LIU Yuan, HU Jinglong, LI Yang, XIA Qingyin, LI Runjie, HU Dafu, ZHANG Donglei, ZHANG Wenhui, GUO Dongyi, ZHANG Xiaowen
2024, 31(1): 467-485. 
DOI: 10.13745/j.esf.sf.2024.1.19

Abstract ( 1049 )   HTML ( 5 )   PDF (3834KB) ( 73 )  

Clay minerals and microbes co-exist in natural environments, and their interaction can influence energy flow and element cycling. Clay minerals provide microbes with physical/chemical protection against environmental stress, as well as nutrients boosting their metabolism. Structural iron in clay mineral is an important electron acceptor/donor for iron-reducing/oxidizing microbes, where in redox environment many iron-reducing/oxidizing bacteria can reduce/oxidize structural Fe(III)/Fe(II) in clay minerals as they gain energy from the redox process. During such process redox microbes can alter the atomic structure of clay minerals through dissolution, transformation and precipitation where secondary minerals are also produced. Clay mineral-microbe interaction plays important role in geochemical cycling of carbon, nitrogen, silicon and phosphorus. Clay mineral can reduce organic carbon bioavailability and mineralization rate through adsorption; whereas under fluctuating redox conditions it can activate molecular oxygen to produce reactive oxygen species to degrade organic matters thus increasing their bioavailability. Through adsorption clay mineral can also reduce extracellular enzyme activity in organic matter degradation. Microbes can affect nitrogen cycling in clays by coupling iron oxidation (reduction) with nitrate reduction (ammonia oxidation) in clay. Phosphorus adsorption on clays and silicon release during weathering can affect the metabolic activity of microbes. Clay mineral-microbe interaction can find a wide range of application in heavy metal stabilization, organic pollutant degradation and sterilization.

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Transient and time-slice simulations of global climate change during the Last Interglacial: Model-model and model-data comparisons
JIANG Nanxuan, YAN Qing, WANG Huijun
2024, 31(1): 486-499. 
DOI: 10.13745/j.esf.sf.2024.1.5

Abstract ( 1018 )   HTML ( 1 )   PDF (9002KB) ( 53 )  

Performing transient simulation during 129-124 ka (TGCS-LIG) at high temporal and spatial resolutions (~1° × 1°, without orbital acceleration) and time-slice experiment at 127 ka (127ka-LIG) can advance our knowledge on the role of experimental setup in the simulation of climate change during the Last Interglacial (LIG). Here, we quantitatively estimate the impact of the experimental setup on the simulated global climate change during the LIG, which may shed light on the potential reasons for model-data discrepancies during the LIG. According to TGCS-LIG/127ka-LIG experiments, the global annual mean surface temperatures decreased by 0.4 ℃/0.2 ℃ during LIG relative to the preindustrial era, with the summer surface temperature over the Northern (Southern) Hemisphere increased (decreased) by 1.2 ℃/1.5 ℃ (0.9 ℃/0.7 ℃). During LIG, the annual mean monsoonal precipitation increased (decreased) over the Northern (Southern) Hemisphere, with large discrepancies across sub-regions. The hit rates (i.e., percentage agreement between model and reconstructed data) and root mean square errors were comparable between the two experiments. For global annual (summer) sea surface temperatures, the hit rates between TGCS-LIG and reconstructions were 34.9%-44.7% (36.8%-42.5%), biased by ~2%-4% (~5%-7%) compared with that of 127ka-LIG; root mean square errors between TGCS-LIG and reconstructions were 2.9-3.2 ℃ (2.9-3.4 ℃), which were ~0.1 ℃ biased compared with 127ka-LIG (generally consistent with 127ka-LIG). For global annual precipitation, the hit rate between TGCS-LIG and multi-proxies was 63.8%, higher by 0.7% relative to 127ka-LIG. The above results indicated that model-model differences were relatively small compared with model-data discrepancies. It is worth noting that TGCS-LIG suggested that the interannual variability of the ENSO showed an increasing trend, whereas the interannual variability of the Northern Hemisphere Annular Mode and Southern Hemisphere Annular Mode fluctuated. These characteristics of varied interannual variability revealed by TGCS-LIG were hardly deciphered in 127ka-LIG. Overall, we suggest that the differences in experimental setup for LIG climate simulations ((i.e. using the time-slice experiment or the transient simulation) may have limited impact on reconciling model-data discrepancies during the LIG, nevertheless, we still highlight the importance of performing transient simulation at high resolution in the investigation of climate variability during the LIG.

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High-resolution reconstruction of carbonate compensation depth in the South China Sea since 27 Ma
WANG Jiahao, HU Xiumian, JIANG Jingxin, MA Chao, MA Pengfei
2024, 31(1): 500-510. 
DOI: 10.13745/j.esf.sf.2024.1.35

Abstract ( 1028 )   HTML ( 2 )   PDF (4027KB) ( 41 )  

The reconstruction of carbonate compensation depth (CCD) in the Cenozoic Ocean has been a focus of attention from the academic community. In this paper, based on the IODP (Integrated Ocean Drilling Program) substances data and age-depth models from 20 boreholes at 14 sites in the South China Sea, the paleo-water depths in the boreholes were restored, the carbonate accumulation rate (CAR) was calculated, and CCD changes in the South China Sea since 27 Ma were reconstructed using linear regression method. Results showed that CCD in the South China Sea significantly decreased by more than 2000 m during the basin stretching period (27-18 Ma), while during Middle Miocene Climate Optimum (MMCO) it became shallower by 800 m. Since 8 Ma, CCDs in the South China Sea and the equatorial Pacific Ocean exhibited different evolutionary trends, with the former fluctuating between 3500-4000 m and the latter continuing to decline from 4000 m to ~4500 m. Prior to 27 Ma, extensive terrigenous input and development of upwelling led to shallow CCD in the South China Sea. The deepening of the sea basin and the weakening of the upwelling caused by tectonic tension during 27-18 Ma were interpreted as the main factors contributing to the decline of CCD during this period. Climate-driven sea-level fluctuations during MMCO led to changes in the core region of carbonate deposition, which was an important reason for CCD fluctuations. The differential evolution of CCD in the South China Sea and the Pacific Ocean since 8 Ma was the result of poor bottom water exchange between the Pacific Ocean and the South China Sea.

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环境变化与生物圈层相互作用
International Continental Scientific Drilling Project of the Songliao Basin: Terrestrial Geological Records of the Cretaceous Dinosaur Age
2024, 31(1): 511-534. 
DOI: 10.13745/j.esf.sf.2024.1.4-en

Abstract ( 1022 )   HTML ( 1 )   PDF (5783KB) ( 46 )  

Over the past century global temperatures continue to rise, and the Earth may enter a greenhouse period in the future with no ice at the poles. The Cretaceous was a typical greenhouse period in deep time, and thus understanding the Cretaceous climate is significant for interpreting past climate changes and predicting future trends. The International Continental Scientific Drilling Project of the Songliao Basin is the world's first continental scientific drilling project to penetrate the Cretaceous continental strata within the framework of the ICDP. This project is aimed to investigate Cretaceous terrestrial climate and environmental changes, and to explore the mechanisms of massive terrestrial organic matter accumulation and enrichment. Spanning 16 years, this project achieves a continuous and complete 8187-meter core with a recovery rate exceeding 97%, establishes a high-precision chronostratigraphic framework for the Cretaceous continental strata in the Songliao Basin, reconstructs multi-temporal-scale terrestrial climate cycles and climate events during the Cretaceous period, reveals the mechanisms of Cretaceous sea-level fluctuations, and confirms marine incursion events in the Songliao Basin. The International Continental Scientific Drilling Project of the Songliao Basin has promoted global collaboration among geologists to study Cretaceous greenhouse climates, leading to a series of high-impact research achievements. It has provided crucial scientific support for the sustainable development of oil and gas exploration in the Songliao Basin, and has generated significant social benefits and substantial international and domestic influence. The International Continental Scientific Drilling Project of the Songliao Basin represents a milestone stage in exploring deep-time Earth, and it is foreseeable that in the future, humans will continue enhancing the understanding of deep-time climate and environmental evolution with the aid of scientific drilling.

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Earth Science Frontiers: Journal influence assessment based on bibliometric analysis
ZHAO Yu, CHENG Li, YANG Liying, LI Li, XIANG Peng
2024, 31(1): 535-549. 
DOI: 10.13745/j.esf.sf.2024.1.6

Abstract ( 982 )   HTML ( 3 )   PDF (8004KB) ( 51 )  

Earth Science Frontiers is a top-ranked Earth science journal in China. In this article, we performed bibliometric analysis to evaluate the journal's development over the past decade (2014-2023), using data from five well-known domestic and international databases: Incopat, F5000, CSCD, SCIE and Scopus. First, we performed citation, keyword co-occurrence, co-citation, and co-authorship analyses, focusing on the publication numbers, paper quality, core authors and research groups, and topics. Earth Science Frontiers ranked among top Chinese geological journals in terms of publication numbers, with steady growth over the past decade, but there is still room for improvement compared to top-ranking international journals. It ranked fifth in F5000 paper quality and fourth in impact factor rankings. To aid the editorial office in manuscript selection in the future a co-authorship network was constructed. Using cluster analysis “hot topics” categories were identified, which included mineral resource development and utilization, oil and gas accumulation laws, environmental pollution and climate change, and geological hazards and tectonic plates; while emerging topics (such as livable environments and climate change) were more likely the topic of special issues. Next, we evaluated the journal's influence in the areas of scientific and technological innovation, development of academic disciplines, and academic representation. Notably, Earth Science Frontiers was the only Chinese geological journal to publish world-leading paleontology researches that made the Year-End Top Ten Advances in Chinese Paleontology list (2020). In another example, a publication of an innovative research entitled “Natural mineral photoelectric effect: non-classical mineral photosynthesis” (2020) had since generated three patents and influenced five. Earth Science Frontier played an active role in bridging basic and applied geoscience researches. In the past decade it had doubled its publications related to the United Nations Sustainable Development Goals (SDGs). In particular, the special issue “Demand and Challenges of Urban Underground Space Development and Utilization in China” (2019) had generated broader impact extending to the field of engineering technology, far surpassing other publications on the same topic. According to big data analysis, the main contributing factors to the high journal influence included maintaining close contact with leading research groups as source of high-quality manuscripts, fully utilizing the editorial board's initiative in selecting topics, and conducting extensive international promotion and precise content dissemination. In future, big data should aid the editorial office with intelligent decision-making, so as to further enhance journal influence and its role in developing Earth science disciplines, providing a platform for research publication and knowledge dissemination, promoting innovation and breakthroughs in the field of geology, as well as in supporting national development strategies.

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