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2014, Volume 21 Issue 6
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The origin and evolution  of the Moon and its geological mapping. OU Yang-Zi-Yuan, LIU Jian-Zhong 2014, 21(6): 1-6.  Abstract ( 1031 )   PDF (1349KB) ( 1403 )   According to the Giant Impact hypothesis, the Moon was born from a great impact event, during which the ejected material was splashed to the earth orbit and then accreted to form the Moon. The original lunar core and mantle differentiated rapidly, and the global molten magma resulted in the formation of the lunar magma ocean, which evolved into the lunar crust by crystallization differentiation and solidification. The impact event was the most important geological process in the following lunar history, and a large number of craters and basins of different sizes came into being in different periods. Especially, the greatest basins were all produced in the early history of the Moon. Lunar map is an important tool to study the origin and evolution of the Moon. The first series of lunar maps were completed during 1960s to 1970s, which summarized the achievements in the Apollo age. The second lunar exploration upsurge started from 1990s, and a large number of new findings about the lunar origin and evolution have been discovered. However, never has a lunar geological map been published. This condition makes it very urgent to carry out a new lunar mapping plan to conclude the exploration and study results in the postApollo age. In this lunar mapping plan, much more attention should be paid to the scale, the subdivisions of lunar geochronology, and the expression of lunar tectonic and geological formation. Related Articles | Metrics

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The lunar geological mapping based on Chang’e data: Serenitatis-Tranquillitatis area as an example CHEN Jian-Peng, WANG Xiang, WANG Nan, LI Jing, YAO Mei-Juan, LI Hong-Ke 2014, 21(6): 7-18.  DOI: 10.13745/j.esf.2014.06.002 Abstract ( 947 )   PDF (2415KB) ( 1483 )   The geological map of the moon, also known as the geological map of the lunar surface or the lunar surface geological zoning map, shows the characteristics of the distribution of different kinds of matter in the lunar surface in different periods. Mapping the lunar maps and atlases is one of the most important works of lunar exploration and scientific research. Through full analysis of the first lunar geological map finished 50 years ago and the recently completed Sinus Tridum, Copernicus geological map,and using Chang’e I, II CCD data, and digital elevation, IIM and LRO data,we selected Serenitatis-Tranquillitatis area as the study area and completed the first Serenitatis-Tranquillitatis area lunar geological map, in which the geological background, structure type, stratigraphic age, material unit, basin structure, pyroclastic distribution, and basalt thickness are the main elements. We developed a systematic mapping engineering plan, combined with domestic technical standards and specifications of digital geological mapping and established our own lunar and planetary geological mapping standards, specifications and mapping processes. The experience can be extended to geological mapping of Mars and Venus as the technical foundation. Related Articles | Metrics

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The lunar digital geological mapping based on ArcGIS：Taking the Arctic region as an example Ding-Xiao-Zhong, WANG Liang, HAN Kun-Yang, LONG Jian-Feng, LIU Jian-Zhong, GUO Di-Jun, DING Wei-Cui, JU Yuan-Jing 2014, 21(6): 19-30.  DOI: 10.13745/j.esf.2014.06.003 Abstract ( 888 )   PDF (2302KB) ( 6225 )   The lunar digital geological mapping is based on the data, which includes the Chang’E-1 (CE-1) CCD3C image data, interference imaging spectrometer(IIM) data, laser altimeter (LAM) data, Chang’E-2 (CE-2) CCD3C image data as well as other lunar geological data to study the material compositions of the lunar surface, structures elements and the information of geochronology, to compile the lunar geological map and to establish spatial database of the moon by using the ArcGIS platform and Geodatabase model. In this paper,taking the Arctic region as an example, we have made the standard, process, method and legend for the lunar geological mapping, preliminarily complied the geological map of the Lunar Arctic Region(YQ-1) at a scale of 1∶2.5M and established the spatial database, which have laid the foundation for the geological comprehensive study of the moon, the geological mapping of the global moon, and also the geological mapping of other celestial bodies in the future. Related Articles | Metrics

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Lunar geological spatial data management system based on 3D WebGIS WANG Xiang, CHEN Jian-Peng, FAN Hai-Meng, LI Ke, ZHANG Hao, ZHENG Xiao 2014, 21(6): 31-37.  DOI: 10.13745/j.esf.2014.06.004 Abstract ( 1130 )   PDF (1766KB) ( 4118 )    With the rapid development of spatial information technology, earth science information technology and GIS technology, a spatial database management WebGIS system based on lunar multisource geologic material (2D and 3D) is established with QT and Open GRL technology. The system contains three subsystems, the 2D research result managing subsystem,  the research result publishing subsystem and  the 3D lunar research data subsystem, which can improve the utilizing efficiency of lunar information. The latest research results of the Chinese lunar exploration program, including topography, rock, soil, resources, environment and other relevant data, as well as foreign research documents, articles and reports, are integrated to establish this Chinese first lunar geologic data information system. The system contains management functions (data management, data consolidation and integration) and service functions for research and decisionmaking. It can realize classification management, rapid retrieval and online query, in addition, it has a strong comprehensive data analysis capability and provides a strong support for Chinese lunar exploration program.   Related Articles | Metrics

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Crater sizefrequency distribution measurements and the secondary craters features of lunar highlands Li-Yan-Qiu, CHEN Sheng-Bo, GUO Feng-Ju, CHA Feng-Li, HUANG Shuang, LU Feng 2014, 21(6): 38-44.  DOI: 10.13745/j.esf.2014.06.005 Abstract ( 814 )   PDF (1594KB) ( 818 )   Crater sizefrequency distribution is a powerful method for estimating the age of a planet’s surface, including the cumulative sizefrequency distribution method and the relative sizefrequency distribution one. According to the diameter range of craters, three chronology functional expressions are available for calculating the geologic age of stratigraphic units, including Melosh and Vickery 1989 (＞4 km craters), Neukum 1983(＞1 km craters), and LI Kun et al 2012(＜1 km craters). The SELENE TC  data are used to interpret the Apollo 14 and Apollo 16  landing sites areas owing to their high spatial resolution (10 m/pixel). Thus, a crater numbering criteria and new chronology functional expressions are built by the real isotope ages surrounding Apollo 14 and Apollo 16 landing sites areas. By comparison, it shows that the algorithm with larger than 1 km craters by Neukum 1983, performs better than the others. The influences of age uncertainty, degradation and secondary impact craters have been analyzed.   Related Articles | Metrics

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The methods of lunar geochronology study and the subdivisions of lunar geologic history Guo-Di-Jun, LIU Jian-Zhong, ZHANG Li, JI Jin-Zhu, LIU Jing-Wen, WANG Liang 2014, 21(6): 45-61.  DOI: 10.13745/j.esf.2014.06.006 Abstract ( 1347 )   PDF (2000KB) ( 3431 )   The dating methods of relative age and absolute age of lunar stratigraphic units are summarized. There are four ways to establish the relative age: the geological law of superposition, crater sizefrequency distribution, crater morphology as degradation, and soil maturity, whereas the absolute age can be determined only by isotopic geochronology or lunar cratering chronology. To better know about the lunar stratigraphic subdivisions presently used, the formation and evolution of the stratigraphic units are reviewed here. Based on the analysis of the established lunar stratigraphic subdivisions and lunar evolution theory, we suggest that use the term Eolunarisian Eon for representation of the lunar history when endogenic process dominated, that use the term Paleolunarisian Eon for the lunar history when endogenic process and exogenic process were both weighty, and that use the term Neolunarisian Eon for the lunar history when exogenic process dominated. And we propose that the pre-Nectarian Period could be substituted by pre-Aitkenian Period and Aitkenian Period, and the two periods are divided by the impact event forming south poleaitken basin. The pre-Aitkenian Period was included in Eolunarisian Eon, while the Aitken Period represents the early stage of Paleolunarisian Eon, during which the impact event was the most typical geologic process. This kind of modified subdivisions not only corresponds to the lunar dynamic evolvement rule, but also provides convenience for the study of lunar farside.   Related Articles | Metrics

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Element abundances in Oceanus Procellarum: Data analysis of Chang’E-2 X-ray spectrometry Ban-Chao, ZHENG Yong-Chun, ZHANG Feng, ZHU Yong-Chao, ZOU Yong-Liao 2014, 21(6): 62-73.  DOI: 10.13745/j.esf.2014.06.007 Abstract ( 887 )   PDF (1868KB) ( 1292 )   Element abundances of lunar surface material is one of the important clues to study the geologic history of the Moon. China’s Chang’E-2 (CE-2) lunar orbiter carried an X-ray spectrometer (XRS) to map the element abundances on the lunar surface. During seven months XRS observation to the lunar surface, several events of solar flares occurred. The X-ray solar monitor onboard recorded simultaneous spectra of solar X-ray. In this paper, the XRS data obtained during an M solar flare event occurred on Feb. 16, 2011 are selected for quantitative inversion of the element abundances, and the contents of Mg, Al, Si, Ca and Fe in Oceanus Procellarum region on the nearside of the moon are presented. The comparison of the element contents from six regions found that from south northwards, the Si content along the orbital track is increasing. It might reflect the different composition of the erupted lavas during the filling history of the maria basins. The region II has higher Fe content than the other five regions. However, the Ca, Mg, and Al contents are lower than those from the other 5 regions. It suggests that the surface material in the region II is the least contaminated by the highland material.The average abundances of the elements obtained in Oceanus Procellarum are Mg 7.3%, Al 8.4%, Si 15.8%, Ca 6.0%, Fe 18.6%, respectively.Finally,we also discussed the factors that influence the accuracy of the inversion of element abundances.   Related Articles | Metrics

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Reflectance spectroscopy of the Moon and its application WU Yun-Zhao 2014, 21(6): 74-87.  DOI: 10.13745/j.esf.2014.06.008 Abstract ( 869 )   PDF (2409KB) ( 1814 )   Reflectance spectroscopy plays an important role in the exploration of the Moon and planets. The payloads using the reflectance spectroscopy technology have been onboard almost all the missions except for some very few missions with  special objects. This paper firstly briefly introduces the principles of reflectance and its research domain. Then two examples describing the application of the reflectance spectroscopy are shown. The first one shows the elements, spectra, and separation of basaltic units using reflectance spectroscopy. The second example shows the mineral diversity of the Imbrium region derived from the Moon Mineralogy Mapper (M3) data. The calibration of the instruments, quantitation of minerals and the mechanism dominating and altering the absorption are the key fields deserving of study in the future. The highland exhibits a mafic character and is dominated by the noritic composition. Imbrium has both the oldest and the youngest basalts of the Moon, suggesting the geologic diversity of this area. Mafic mineralogy of the basalts is characterized by abundant olivine in the latestage Eratosthenian basalts and pigeonite to subcalcic augite in Imbrian units, suggesting Cadepletion of the Procellarum KREEP Terrane (PKT) compared to nonPKT.   Related Articles | Metrics

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Forward modelling of the lunar regolith layer using radar detection based on FDTD Chen Sheng-Bo, CHA Feng-Li, LIAN Yi, HUANG Shuang, LI Yan-Qiu 2014, 21(6): 88-91.  DOI: 10.13745/j.esf.2014.06.009 Abstract ( 861 )   PDF (1338KB) ( 5981 )   Lunar Penetrating Radar equipped on the rover of CE-3 can observe the shallow structure of lunar surface on acrosssectional observational style and detect 30 meters soil layer structure under the lunar by the antenna of 500 MHz. In order to analyze the exploration results of lunar penetrating radar better,this paper builds forward modelling using ground penetrating radar technology in order to study the lunar regolith layer; we adopted the electrical parameter of Apollo 15 which is nearest to the landing position of CE3 as the dielectric constant of rock layer; the dielectric constant of the lunar regolith is a value related to density and varied with depth.To establish the model according to the above parameters, based on the finite difference time domain (FDTD) principle, the lunar regolith layer was simulated by the GprMax, and the established model included the model of the surface dielectric constant change with depth and waterice distribution simulation inside the lunar soil, aiming for finding the general rules of the lunar regolith layer and the thickness of the waterice. We have analyzed the wave features of radar reflectance wave, which can provide the theoretical basis for future moon probe program.   Related Articles | Metrics

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The petrography, mineral chemistry and classification of 6 new desert meteorites collected from Xinjiang Dai De-Qiu, YANG Rong-Feng, CHEN Xin-Yue 2014, 21(6): 92-101.  DOI: 10.13745/j.esf.2014.06.010 Abstract ( 1305 )   PDF (2342KB) ( 1474 )   Meteorite samples can be better preserved in Antarctic ice sheet and arid desert regions. Fortyseven desert meteorites were collected from Xinjiang during the meteorite expedition since April to May, 2013. Petrography and mineral chemistry of the 6 samples of them have been studied, in order to determine their chemicalpetrographic types. Modal compositions of the Arlatager 004, 006, 0014, 0022 and TuzLeik001 meteorites are similar, mainly consisting of olivine, lowCa pyroxene, metallic FeNi and troilite. Due to intensive thermal metamorphism the spherulitic textures in the chondrules are poorly defined, with only a few fragments remaining spherulitic. The olivine and lowCa pyroxene in these meteorites are similar in composition, which in some degree reflects the thermodynamic equilibrium during their development. According to the structures of chondrules and mineral chemistry there are 5 petrographic types to be classified. The four meteorite samples (Arlatager 004, 006, 0014 and 0022) are classified into chemical group L, and TuzLeik001 is classified into chemical group H. Kumtag005 meteorite sample shows typical spherulitic texture, combined with its Fa value in olivine and ferrosilite content (Fs) in low Ca pyroxene and its petrographical features,it is assigned to common chondrite of L3 type.Based on Percent Mean Deviation (PMD) of Fa content of olivine and its correction with petrographic subtype of unequilibrated meteorites, Kumtag005 is subdivided as L3.4. The 6 samples of meteorites belong to 3 chemical groups, combining  the other analytical results of meteorites collected from this region, it is suggested that the desert of Hami in Xinjiang is likely a new meteoriteenriched region. The collection and study of desert meteorite will help to promote the development of meteoritics and cosmochemistry in China.   Related Articles | Metrics

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A study of the depth of basalt in lunar Oceanus Procellarum Liu Wan-Song, CHEN Ku-Bei, XU Yan, LU Feng, YANG Hong-Wei 2014, 21(6): 102-106.  DOI: 10.13745/j.esf.2014.06.011 Abstract ( 735 )   PDF (1477KB) ( 1772 )   The paper uses Residual Bouguer anomaly of gravity to infer the depth of basalt in the lunar regolith, which provides evidence for lunar geological mapping. On the basis of the results of Grant H. Herken et al.(1993), Residual Bouguer anomaly of gravity in Oceanus Procellarum is first extracted by Butterworth filtering from GRAIL 660 Bouguer anomaly of gravity in this area. The extent of basalt in Oceanus Procellarum is outlined by remote sensing spectra. And the boundary element method is used to repeatedly simulate and correct the model. Finally, the basalt depth distribution of this area is attained. The depth of basalt in Oceanus Procellarum is less than 1.5 km. Related Articles | Metrics

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The lunar rock types as determined by Chang’E-1 IIM data: A case study of Mare Imbrium-Mare Frigoris  region (LQ-4) LING Zong-Cheng, LIU Jian-Zhong, ZHANG Jiang, LI Bo, WU Zhong-Chen, NI Yu-Heng, SUN Ling-Zhi 2014, 21(6): 107-120.  DOI: 10.13745/j.esf.2014.06.012 Abstract ( 999 )   PDF (1988KB) ( 3286 )   The lunar rock types are the key to the understanding of their formation history and lunar magma ocean evolution. With the increasing of datasets from lunar explorations, the applications of recent lunar remotely sensed data for the understanding of lunar history are of high priority. In this study, we further calibrated the Chang’E-1 IIM dataset and obtained the lunar FeO and TiO2, Mgnumber mapping results. Eight rock types including the ferroan anorthosite, Mgsuite, KREEP, and mare basalts of 5 levels of TiO2 content are mapped for the Mare ImbriumMare Frigoris  region (LQ-4) based on the survey of previous classifications of lunar rock types according to the lunar compositions derived from the Chang’E-1 IIM data. The rock distribution and petrogenisis of LQ-4 region is also discussed in relation to the isotopic dating of lunar rocks.  This region includes a series of mare basalt lava flows, whose stratigraphical relationships are of great values for the study of the evolution of extrusive magmas. In addition, we estimated the FeO, TiO2 and Mgnumber of Chang’E-3 landing site, which could be validated by the in situ measurements of Yutu Rover.   Related Articles | Metrics

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Spectrum characteristics analysis of four lunar rocks based on the CE-1 gamma-ray spectrometry data LIU Jing-Hua, WANG Zhu-Wen, CHEN Sheng-Bo, HU Ri-Le, ZHOU Da-Peng 2014, 21(6): 121-128.  DOI: 10.13745/j.esf.2014.06.013 Abstract ( 923 )   PDF (1691KB) ( 924 )   Based on the gamma-ray spectrometry data obtained from CE-1, this paper deals with the measured raw data and gets the gamma-ray spectrum data for each grid of 5°×5°. Twelve gammaray spectrum curves at different locations, which stand for basalt, anorthosite, magnesiumrich rock and KREEP rock respectively, were selected for analysis; we found that the spectrum curves behave the similarity for the same kind of rock, and show differences for different kinds of rocks. The results show that the elemental characteristic peaks varied with the different kinds of rocks; for basalt the characteristic peaks mainly express the elements of Th, K, Si, Ca, C, Fe, and Ti; for anorthosite the characteristic peaks represent the elements of U, Ca, C, Mg, Al, and Mn; the characteristic peaks of KREEP rock are high content of K, Th, U, Si, Ca, and Fe and low content of C and Al; for magnesiumrich rock the characteristic peaks show the characteristics of high content of K, Mg, Th, and Fe and low content of U, Si, Ca, and Cl. In conclusion, the energies of elemental characteristic peaks for identifying different lunar rocks are suggested, and these results can provide the basis for quantitative elemental analysis of lunar rocks. Related Articles | Metrics

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Effect of reflectance standard contaminations on quantitative analysis of typical lunar minerals WU Zhong-Chen, LING Zong-Cheng, ZHANG Jiang, BI Yun-Feng, CHU Qing-Bo 2014, 21(6): 129-136.  DOI: 10.13745/j.esf.2014.06.014 Abstract ( 816 )   PDF (1561KB) ( 1710 )    Lunar dust contaminant is one of primarily influential factors on the working status of insitu spectrometer on lunar surface. In this work, the influences on the accuracy of quantitative analysis and the NIR reflectance fingerprints of typical lunar mineral mixtures (i.e., orthopyroxene, labradorite, ilmenite and olivine) were analyzed by using different contamination levels of reflectance standards (i.e. pollutionfree, slight pollution, heavy pollution). Significant differences in fingerprints were observed from reflectance spectra of 15 samples which were recorded using the pollutionfree and various pollution levels of reflectance standards, respectively. More differences were found with higher pollution levels of reflectance standards. The prediction precisions were decreased by using PLS model based on pollutionfree samples to predict the contaminated ones. Instead, the prediction precisions were increased by using the PLS model based on contaminated samples to predict the ones at same pollution level. This work shows that the contamination of reflectance standard is the key influential factor on the prediction precision of quantitative analysis. Our results have scientific significance for insitu planetary load design, data rectification and assessment of model predictive ability.   Related Articles | Metrics

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Spectrometric study of lunar pyroclastic deposits ZHANG Xue-Wei, JIANG Yun, LIU Han, ZHANG Xun-Yu, ZHOU Xian-Feng, CHEN Yuan, TANG Xiao, WU Yun-Zhao 2014, 21(6): 137-149.  DOI: 10.13745/j.esf.2014.06.015 Abstract ( 1014 )   PDF (2084KB) ( 2246 )   Lunar pyroclastic deposits (LPDs) originating from the explosive volcanism represent the deeper materials than the basalts in mare; they are the prior target for the lunar exploration. Reflectance spectroscopy is an important tool to study LPDs. We studied the spectrum of 29 LPDs which have been identified previously，established the distinguishing indicator of volcanic glass and proposed a new idea to compare the relative contents of FeO and TiO2 among the glassrich LPDs. The result shows that Sulpicius Gallus， Gauss，Walther A，Birt E and Aristarchus are glassrich LPDs. The titanium contents of Aristarchus, Sulpicius Gallus and Birt E are lower than those of Walther A and Gauss. The Birt E has the shallower absorption depth, and the left shoulder moves to shorter wavelength at 1 μm band. It may be caused by the very low Fe2+ content of Birt E or by its more mature material.   Related Articles | Metrics

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idirectional reflectance of lunar olivine with the consideration of grain size ZHANG Yuan-Zhi, HUANG Chao-Jun, ZHOU Chao, CHEN Sheng-Bo 2014, 21(6): 150-154.  DOI: 10.13745/j.esf.2014.06.016 Abstract ( 953 )   PDF (1437KB) ( 998 )   The distribution of mineral abundances on lunar surface is one of the significant kinds of information which contains important data such as the geological formation, origin and evolution of the Moon. Although lunar mineral samples were brought back and analyzed in laboratory, remote sensing technology still plays important role in lunar study. This paper briefly introduces the bidirectional reflectance feature of olivine based on grain size. In order to distinguish the olivine’s composition, a method is proposed to simulate reflectance with the consideration of grain size. We discussed the spectral characteristics of Mgrich olivine and Ferich olivine based on the reflectance which calculated by Mie theory and Hapke’s radiative transfer model in this study. The simulated results showed that the spectral reflectance of Mgrich olivine was higher than the reflectance of Ferich olivine. Finally, the linear relationships between reflectance difference and mean size weighted by cross sectional area were analyzed. The results provide the basis of identifying the olivine using absorptive positions and depths of the olivine, which can also be applied to future remote sensing data processing.   Related Articles | Metrics

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The classification and filling process of underlying basaltic units in Chang’E-3’s landing area LI Bo, LING Zong-Cheng, ZHANG Jiang, WU Zhong-Chen, NI Yu-Heng, CHEN Jian 2014, 21(6): 155-164.  DOI: 10.13745/j.esf.2014.06.017 Abstract ( 993 )   PDF (1752KB) ( 1030 )   The crust of Moon that has undergone little to none tectonic, atmospheric, or fluvial activity, is blanketed by the ubiquitous surface soil, or regolith, and there is hardly any bedrock exposed. It is produced from billions of years of physical and chemical weathering and exposure to the solar wind. These processes tend to blend and obscure the lithology of true crustal bedrock. So it is hard to detect the characteristics of the underlying basalts using conventional remote sensing methods. The key to the determination of true crustal compositions is to look beneath the obscuring regolith. This paper analyzes the spectra of the floor and wall in craters which have the low optical maturity to study the compositions and information (depth, succession and distribution) of the underlying basalts in Chang ’E-3’s landing area. The details are as follows: (1) selecting craters and extracting spectra based on multiband remote sensing data of LISM, (2) defining the types and determining the information of the basaltic units and building the relationships between discrete craters and the continuous geological unit. The results show that there are at least six basaltic filling processes in the study area, and we can define six basaltic units from young to old age. The depth of unit 13 is reduced gradually from south to north until disappears. The unit 46 may exist in all study area, and in south region they are covered by the first three basaltic units and not exposed, while in north region they are located at the top of the underlying basalts. As to the element abundances of all basaltic units, titanium content changes a lot, from 1.26% to 6.65%, while iron content shows small change, between 16.31% and 17.57%. Finally, we found that there is a link between basaltic unit age and element abundance, that is the younger the age of basaltic units, the more enrichment in titanium and iron in it.   Related Articles | Metrics

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Extraterrestrial organic compounds YANG Jing, LIN Yang-Ting, OU Yang-Zi-Yuan 2014, 21(6): 165-187.  DOI: 10.13745/j.esf.2014.06.018 Abstract ( 799 )   PDF (2160KB) ( 1581 )   The organic compounds in chondrites were originated from the interstellar media, and they were precursor components of the solar nebula. The organic compounds incorporated with other material into asteroids and planets by accretion processes. In the parent bodies of meteorites, organic compounds underwent various degrees of aqueous alteration and thermal metamorphism. Regardless of their abiogenic origin, extraterrestrial organic matter is very complex, consisting mainly of kerogenlike insoluble macromolecular materials with less abundant soluble organic material (SOM). Most of the SOM have identical counterparts in the terrestrial biosphere, but the former has distinct isotopic compositions of C, H and N, the critical evidence for their extraterrestrial origins. The irradiation of cosmic rays and UV light in the nebula and the secondary processes (e.g., aqueous alteration and thermal metamorphism) in meteorite parent bodies are the main contributions to the evolution of the organic matter. The extraterrestrial organic compounds have probably played a critical role in the origins of life. Meanwhile, Mars exploration has showed that at least the paleoclimate on Mars was favorable for the existence of microbes. In addition, several hints for past biotic processes were found in Martian meteorites. The first evidence of extraterrestrial life will likely be found on Mars in the future.   Related Articles | Metrics

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The spectral characteristics and remote detection of minerals in lunar Orientale Basin SUN Ling-Zhi, LING Zong-Cheng, LIU Jian-Zhong 2014, 21(6): 188-203.  DOI: 10.13745/j.esf.2014.06.019 Abstract ( 928 )   PDF (2774KB) ( 921 )   Orientale Basin is one of the youngest lunar impact basins. The topography and minerals distribution of Orientale Basin will provide information on the basin forming process and lunar evolution history. As shown by data from Lunar Orbiter Laser Altimeter (LOLA), Orientale Basin is a wellpreserved multiring impact basin. We discovered various mineral types like spinel, crystalline plagioclase, pyroxene and olivine in Orientale Basin using hyperspectral data from Moon Mineralogy Mapper (M3).  The spectra of  mineral mixtures are deconvoluted by Modified Gaussian Model(MGM).The minerals distribution of Maunder Crater are mapped by the method of Spectral Angle Mapper (SAM). Our findings of pure crystalline plagioclase are consistent with the recent lunar missions (e.g., Kaguya) and can provide new constraint for the lunar magma ocean hypothesis. The spinel was found in the central peaks of Lowell Crater with the aid of Multiband Imager (MI) data to validate the discovery. The mineral mixture of spinel and crystalline plagioclase was also found in Maunder Crater, which suggests that spinel might have a broader distribution in the Outer Rook Ring of Orientale Basin.   Related Articles | Metrics

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The principle of substitution of equation of state and error analysis for crater simulation YUE Zong-Yu, DI Kai-Chang, LIU Zao-Qin, HU Wen-Min, GOU Sheng 2014, 21(6): 204-211.  DOI: 10.13745/j.esf.2014.06.020 Abstract ( 772 )   PDF (1527KB) ( 778 )   Impact cratering is an important surface process on most of the terrestrial planets in solar system. In this paper we described the impact crater formation mechanism, and then introduced the method of numerical simulation for crater study. We first expounded the basic theories and strategies of impact cratering simulation, during which we stressed that Equation of State (EoS) played an important role in the numerical simulation. However, compared to the varieties in the real world, only a few materials’ EoS is available and the substitution is inevitable in craters’ numerical simulation. We elaborated the concept and principle of substituting the EoS with that of another material that their Hugoniot curves should be similar, and we further analyzed the deviation of different physical quantities and ejection velocities from the substitution theoretically. Finally, we carried out numerical simulations to two small craters with targets of granite and quartzite,respectively, and the similarities with the deviations in peak pressure,temperature and densities are directly shown through the results. We think this kind of analyses could support future study in the field of planetary science, especially under the background that much more data would be transmitted from lunar, Mars, and other celestial bodies.   Related Articles | Metrics

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Geomorphometric multi-scale analysis for the automatic detection of linear structures on the lunar surface LI Ke, CHEN JianPeng, Paolo TAROLLI, Giulia SOFIA, FENG Zeng-Wen, LI Jing 2014, 21(6): 212-222.  DOI: 10.13745/j.esf.2014.06.021 Abstract ( 860 )   PDF (1971KB) ( 791 )    Moon surface features have great significance in understanding and reconstructing the lunar geological evolution. Linear structures like rilles and ridges are closely related to the internal forced tectonic movement. The extremely rare availability of samples and the difficulty for field works make remote sensing the most important approach for planetary studies. New and advanced lunar probes launched by China, U.S., Japan and India provide nowadays a lot of highquality data, especially in the form of highresolution Digital Terrain Models (DTMs), bringing new opportunities and challenges for feature extraction on the moon. The aim of this study is to recognize and extract lunar features using geomorphometric analysis based on multiscale parameters and multiresolution DTMs. The considered digital datasets include CE-1LAM (Chang’E One, Laser Altimeter) data with resolution of 500 m/pix, LRO-WAC (Lunar Reconnaissance Orbiter, Wide Angle Camera) data with resolution of 100 m/pix, LRO-LOLA (Lunar Reconnaissance Orbiter, Lunar Orbiter Laser Altimeter) data with resolution of 60 m/pix, and LRO-NAC (Lunar Reconnaissance Orbiter, Narrow Angle Camera) data with resolution of 25 m/pix. We introduced landform curvature to recognize the linear structures including Rilles and Ridges. Different window scales and thresholds are considered for feature extraction. Quantitative analyses of the test results in the study area show that the automatic extraction method of linear structures based on landform curvature is effective and feasible; the results can provide important reference for the lunar surface linear structural interpretation and improve the structural interpretation efficiency and accuracy.   Related Articles | Metrics

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A new automated approach to detecting and extracting the linear structures on the lunar surface: A case study on the lunar mare ridge of Mare Serenitatis LI Jing, CHEN Jian-Peng, WANG Nan, HE Shu-Jun 2014, 21(6): 223-228.  DOI: 10.13745/j.esf.2014.06.022 Abstract ( 788 )   PDF (1716KB) ( 2042 )   Lunar mare ridge is one of the most common linear structures of the moon surface; it can reflect the regional tectonic characteristics and stress state; and it is of great significance for studying the geological evolution. Previous mode of the interpretation of the lineaments was usually artificial visual interpretation. We use the data of remote sensing image,  laser altimeter data and so on for interpretation and extraction lineaments of the lunar surface. With the improvement of the data and the requirement of the efficiency, an effective method for the automatic extraction of linear structure is of necessity. This study is based on the landform curvature method and the digital datasets including CE-1-LAM (Chang’E-1, Laser Altimeter) data, LRO-WAC (Lunar Reconnaissance Orbiter, Wide Angle Camera) data, and LRO-LOLA (Lunar Reconnaissance Orbiter, Lunar Orbiter Laser Altimeter) data with resolution of 60 m/pix; the study area is Mare Serenitatis and its linear structures were automatically extracted. The result shows that the method of using landform curvature is feasible. Compared with the results of the artificial interpretation, the accuracy of this method is higher, and the efficiency was improved. It can provide the basis for further study of the tectonic evolution and improve the interpretation precision and efficiency.   Related Articles | Metrics

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The main lineament quantitative extraction and the analysis of their evolution on lunar surface:  The ridges and the rills in Mare Tranquillitatis as an example WANG Nan, CHEN Jian-Peng, WANG Xiang, LI Jing, HE Shu-Jun 2014, 21(6): 229-242.  DOI: 10.13745/j.esf.2014.06.023 Abstract ( 965 )   PDF (2376KB) ( 3866 )    The lineaments, besides ring structures, are another important structural style, which present linear extension on lunar surface. There are a great variety of lineaments and their origins are diverse. The lineaments which are of great significance to study the tectonic evolution of the moon, could reflect whole lunar or regional tectonic characteristics and their stress state, and in a certain extent the geological information inside the moon, which is important in the research on the tectonic evolution of the moon. In this paper, taking Mare Tranquillitatis as the research region, 284 ridges and 71 rills are identified on the basis of Chang’E II CCD images and DEM data. Then the ridges and the rills can be classified and statistical analysis be conducted. The evolution processes are analyzed by using slope map and contour map combining the distribution of the lineaments on mare region. The result shows that the ridges and rills are mostly distributed in a lower elevation area in the west; the time of the rill formation in Mare Tranquillitatis is nearly the same as the formation of the basin and the filling of basalts, and the time of the ridge formation is almost equivalent with the formation of the impact craters; the formation model of the ridges that one end of Mare Tranquillitatis extends to a crater belongs to the dike model of volcanic process.   Related Articles | Metrics

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Earth system dynamics and reducing disaster and emission by development of geothermal energy LI De-Wei 2014, 21(6): 243-253.  DOI: 10.13745/j.esf.2014.06.024 Abstract ( 1036 )   PDF (1680KB) ( 1578 )   On the basis of a lot of geological and geophysical evidence, a new model of earth system dynamics is proposed as the multistage cycle in the open earth system driven by thermal energy for reasonable explanation of dynamic mechanism of oceancontinent system and related basinmountain system and the interaction of resource, natural hazard, environment and economic growth. Under the guidance of innovative ideas of earth system dynamics, a comprehensive summary of the feature of thermal tectonic system in active crust，preliminary study of the structure and earthquake trends of happened and ongoing thermal disaster chains in the North China and Southwest China, and a systematic analysis for the importance, necessity and feasibility of reducing disaster and emission by development of geothermal energy reveals ideas and methods for development of hot dry rock geothermal energy, and new way of sustainable development. Therefore this paper suggests a new idea for coming new earth science revolution and energy revolution.   Related Articles | Metrics

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The impact of northern South China Sea paleotectonic framework on development of Mesozoic and Cenozoic Zhang-Li, CENG Wei-Jun, HUI Zhen-Quan, LIN Zhen, LEI Zhen-Yu, SHUAI Qing-Wei 2014, 21(6): 254-263.  DOI: 10.13745/j.esf.2014.06.025 Abstract ( 848 )   PDF (2002KB) ( 1622 )    Mesozoic is a new field and a new layer of hydrocarbon exploration in northern South China Sea (SCS). Its formation, evolution and distribution feature attract geologists interests consequently. The results of geological-geophysical investigation revealed that the block boundary between northern SCS and eastern South China (SC), which is Zhuwai-Taiwan strait fault zone and Lishui-HaifengQiongdongnan fault zone, is definite. Therefore, north margin of SCSTaiwan block can be considered as a part of SC activity zone, and its formation closely related to SC Caledonian tectonic cycle. The development characteristics of Mesozoic and Cenozoic were affected by suture zone and crustal subblock feature remained by Caledonian orogency between northern margin of SCS block and eastern SC block. It is also proved by the discovery of transitional strata of upper Triassiclower Jurassic, upper Jurassiclower Cretaceous, and upper CretaceousEocence in Northeastern SCS.   Related Articles | Metrics

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Petrogenesis of the Lianyang composite granite, Nanling region: U-Pb zircon geochronology, geochemistry and Nd-Hf isotopes constraints MA Xing-Hua, CHEN Bin, WANG Zhi-Qiang, GAO Lin, SUN Ke-Ke 2014, 21(6): 264-280.  DOI: 10.13745/j.esf.2014.06.026 Abstract ( 1497 )   PDF (2352KB) ( 2087 )   In this paper, we present zircon U-Pb ages, in situ Hf isotopic, wholerock chemical and Nd isotopic data for the Lianyang composite granite in the Nanling region. Zircon LA-ICPMS U-Pb dating of the supplementary intrusion yielded ages of 100104 Ma, which is significantly younger than the predominant intrusion (144 Ma), suggesting that the former (finegrained biotite granite) is unlikely to be residual melts through fractionation of the latter (coarsegrained porphyritic biotite granite). Both of the two rocks show high SiO2(65%79%), Na2O+K2O(6.9%9.5%) and K2O/Na2O(1.32.5). They are metaluminous to peraluminous (A/CNK=0.91.2), depleted in Ba, Sr, P and Ti, and enriched in Rb, Pb and LREE. The supplementary intrusion shows highly fractionated characteristics (SiO2 77%79%), with extremely negative Eu anomaly (δEu=0.030.06). The NdHf isotopic data (εNd(t)=-10.6-8.4 for the predominant intrusion, εNd(t)=-9.1-6.6 and εHf(t)=-8.5-1.8 for the supplementary intrusion) suggest that the basement rocks should be dominated by Proterozoic parametamorphic rocks. The Lianyang pluton was formed under an extensional setting during the late Yanshanian in the South China. Based on the comparison with W, Sn and Nb/Tabearing granites, it is suggested that the latestage supplementary intrusion is the most important target for Sn prospection.   Related Articles | Metrics

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The rule of tectonic control and the zoning division of coalmine gas occurrence in Guizhou Province GIA Tian-Rang, WANG Wei, YAN Jiang-Wei, TANG Chun-An 2014, 21(6): 281-288.  DOI: 10.13745/j.esf.2014.06.027 Abstract ( 1266 )   PDF (1878KB) ( 1696 )   The unclear understanding of the gas occurrence rule is the fundamental reason of frequent gas outburst disaster. Based on stepwise tectonic control theory of gas occurrence, and combined with datum of Guizhou Province gasgeology map, the tectonic level control rule and zoning division of gas occurrence have been discussed. The results show that Guizhou Province is located in the copulae of the circumPacific tectonic tract and the western Tethyan tectonic domain, and its tectonic evolution controlled the coalforming environments and gas occurrence. During Yanshan movement, a series of folds, overthrust fault and nappe tectonics formed, then resulting in the tectonic coal developed; those were the primary reason of serious coal and gas outburst in Guizhou Province. Moreover, Yanshanian magmatism increased coal metamorphism and hydrocarbon productivity was enhanced. Coalmine gas occurrence and distribution in Guizhou Province were divided into four zones, namely Liupanshui, ZhinaLiuzhiGuiyangbei and northern Guizhou province three high and outburst gas zones and eastern Guizhou province gas zone.   Related Articles | Metrics

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Zircon U-Pb dating of Yanshanian intrusive rocks in Ningzhen District, Jiangsu: The chronology evidence for a new stage of petrogensis and metallogeny in the Middle and Lower Reaches of Yangtze River Wang Xiao-Long, ZENG Jian-Nian, MA Chang-Qian, LI Xiao-Fen, WU Ya-Fei, LIU Shun-Fu 2014, 21(6): 289-301.  DOI: 10.13745/j.esf.2014.06.028 Abstract ( 1386 )   PDF (1922KB) ( 846 )   The LA-ICP-MS zircon U-Pb dating for three typical Mesozoic intrusions(AnjishanFuniushan rockmass, XiashuGaozi rockmass and Shima rockmass) in Ningzhen district yielded 109.1±1.9101.6±1.1 Ma, which represents the formation of these intrusions age and provides a precise formation time constraints for the intrusive rocks in the region. Copper polymetallic mineralization in Ningzhen district was related to the calcium alkaline magma activity around 100110 Ma in time, space and genesis, and both magmatism and mineralization in the area were continuous processes. Yanshanian intrusive rocks in Ningzhen district formed during the Early Cretaceous, while the calcalkaline intrusive rocks in Jiurui region and other regions formed in the Early Cretaceous; there are a difference of about 2535 Ma between both. Combined with the restrict from the Pacific plate activity characteristics since the Cretaceous to the petrogensis and metallogeny in the eastern China, the chronology data reveals that the magmatic activities in Yanshanian and metallogenetic response in Ningzhen region were the new diagenesismineralization events belonging to the largescale magmatic and metallogenic activities of the metallogenic belt in the middle and lower reaches of Yangtze River in the Mesozoic Era, as well as the geodynamic setting corresponds to the Mesozoic Era lithospheric thinning in eastern China. Lithospheric thinning of middle and the middle and lower reaches of Yangtze River started from 135 Ma, and might continue until around 100 Ma.   Related Articles | Metrics

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The Early Mesozoic continental crust reformation in Yanshan area: Giving discussion to Indosinian movement SHAO Ji-An, ZHANG Ji-Heng 2014, 21(6): 302-309.  DOI: 10.13745/j.esf.2014.06.029 Abstract ( 760 )   PDF (1619KB) ( 2702 )   Combined with recent studies, this paper represents the crustal movements of different layers from shallow to deep in the middle segment of the northern margin of the North China Craton during Indosinian epoch through studying underplating of basaltic magma, crustmantle mixing, deformation and metamorphism at different depths, upwelling and denudation, and sedimentation and formation. Comparison of εNd(t)-ISrof igneous rocks of Late Triassic and Early Cretaceous suggested that the threshold of a new tectonic framework at Late Triassic from the depth as a response to the transformation of the global deep tectonic framework. It was the deep tectonothermal activities that caused crustal thickening and isostatic adjustments and resulted in differential uplifts of the fault blocks, which was an intracontinental orogeny that was essentially different from conventional compressional orogeny. Meanwhile, input of the mantel materials and heat also initiated the reconstruction of the lithosphere in the North China in the Early Mesozoic.   Related Articles | Metrics

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Quantitative prediction of the Yanchang Formation Chang 63 reservoir tectonic fracture in the QingchengHeshui Area, Ordos Basin. JU Wei, HOU Gui-Ting, FENG Sheng-Bin, ZHAO Wen-Tao, ZHANG Ji-Zeng, YOU Yuan, ZHAN Yan, YU Xuan 2014, 21(6): 310-320.  DOI: 10.13745/j.esf.2014.06.030 Abstract ( 1142 )   PDF (2375KB) ( 640 )   The Upper Triassic Yanchang Formation sandstone characterized by low permeability is the main reservoir in the Qingcheng—Heshui area of Ordos Basin, within which the tectonic fractures serve as important seepage pathways. On the basis of rock mechanics parameters testing, considering the influence of sandstone distribution, the paleostress field in the main fracture forming period was simulated, and the tectonic fractures were predicted with the constraints of cores using 3D Finite Element Method (FEM). The results show that the Yanshanian tectonic fracture density is high in Well Zhuang 72, Well Zhuang 47, Well Ning 88 and Well Zheng 20 areas, with the density up to 0.10 m-1, while the Himalayan tectonic fracture density is high in Well Zhuang 156, Well Ning 45 and Well Zheng 20 areas. Comparing to the Himalayan tectonic period, the Yanshanian tectonic fracture density as a whole is higher. The study results can provide us basic geological data for building conceptual fracture distribution and fracture porosity calculation model, and are able to support the reservoir prospecting and exploitation as well in the QingchengHeshui area. Related Articles | Metrics

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The identification of longchain diols and ketools in Site4B sediment from the Pearl River Mouth Basin and its implication Zhu-Xiao-Wei, SUN Yong-Ge, MAO Sheng-Yi, GUAN Gong-Xiang, WU Neng-You 2014, 21(6): 321-334.  DOI: 10.13745/j.esf.2014.06.031 Abstract ( 887 )   PDF (1821KB) ( 692 )   1,15-C30 (ω16) and 1,15-C32(ω18) alkyl diols and ketools were identified in Site4B sediment (65300 cm below the seafloor) from the Pearl River Mouth Basin, and the total contents of diols and ketools were distributed from 0.0264.373 μg/g dry sediment and 0.0051.549 μg/g dry sediment, respectively. The carbon isotope compositions were substantially enriched in 13C for 1,15-C30 diol (δ13C=-26.6‰±0.9‰) relative to the nC30 alkanol (δ13C=-32.8‰±1.5‰), suggesting the absence of terrigenous higher plants. Either the absence of high abundance of sedimentary sterols relative to longchain alkyl diols and ketodiols or the undetectability of these biomarkers in the surface sediment (065 cm) indicates that eustigmatophyceae was not a potential source, since the location of Site4B sediment was on the continental slope where nutrition salinity is so poor that it is not suitable for algae. δ13C of 1,15-C30 diol(-24.6‰-28.4‰) is similar to that of short chain nfatty acid (-25.5‰-28.6‰) in the sediment and revealed the same source as marine bacteria. In addition, the ketools have similar sources as diols or they are produces from different organisms but having strong couplings with each other; the ketools were not from the oxidization of the corresponding diols because the ketools ratios in the oxidized sediment (6595 cm) showed no significantly high values. The diol indices and ketool indices in the sediment having similar patterns, combined with the contents of these biomarkers, suggested the impact of the monsoon climate of South China Sea and the fresh water. Both the high diol indices and high diol concentration and the low diol indices and low diol concentration reflect the dominant impact of sea surface temperature, while the low diol indices and high diol concentration implied the major factor of increased intrusion of fresh water. Related Articles | Metrics

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Characteristics and developing mechanism of Sinian Dengying Formation dolomite reservoir with multi-stage karst ZHU Dong-E, JIN Zhi-Jun, ZHANG Rong-Qiang, ZHANG Dian-Wei, HE Zhi-Liang, LI Shuang-Jian 2014, 21(6): 335-345.  DOI: 10.13745/j.esf.2014.06.032 Abstract ( 1098 )   PDF (2274KB) ( 3564 )   Under the impact of strong tectonic uplifts of Tongwan Ⅰ and Ⅱ in the early Caledonian orogeny, the top of the second and fourth members of the Sinian Dengying Formation underwent intensive longterm unconformity karstification, respectively. In addition to the karst associated with unconformity on the top, there are also some stratiform shortterm karst layers within the second and fourth members of dolomite. The shortterm karst layers were developed under fourthorder sequence boundaries and were associated with multiple shortterm tectonic upliftsubside cycles during the sedimentation of the second and fourth member of dolomite. Under the impact of shortterm tectonic uplifts as well as the fall of relative sea level, the dolomite exposed to surface and underwent contemporaneous/penecontemporaneous karstification which formed some layers of several meters with a large number of dissolution pores and caves within the second or fourth dolomite members. The sediment between two karst layers is always the compact cryptocrystalline dolomite, argillaceous dolomite or siliceous dolomite formed in deep water environment during tectonic subsidence. Four and eight shortterm karst layers were respectively identified in the second and fourth members of the Sinian Dengying Formation in the Yingshuiba outcrop in the north of the Sichuan Basin; and six were identified in the second member in the LeshanLongnüsi uplift by well correlation. The multiple shortterm contemporaneous / penecontermporaneous karst layers within dolomite members stacked each other vertically, which made the present Dengying Formation dolomite reservoir with relatively big thickness. The reservoir property associated with shortterm karst was further enhanced by the longterm unconformity karstification associated with tectonic uplifts of Tongwan Ⅰ and Ⅱ in the early Caledonian orogeny. Related Articles | Metrics

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Lower Cambrian tempestites and their geological significances in Sugaitblak area, Tarim Basin SONG Jin-Min, LUO Peng, LIU Shu-Gen, YANG Di, WANG Xin, LI Peng-Wei 2014, 21(6): 346-355.  DOI: 10.13745/j.esf.2014.06.033 Abstract ( 1116 )   PDF (1962KB) ( 2393 )   Lower Cambrian tempestites are found in Xiaoerbulak Formation in Sugaitblak area, Tarim Basin. The major storm sedimentary markers are scouring filling structures, storm flowgenerated gravelstones and hummocky cross stratifications (HCS). Based on outcrop observation in the field and thin section, a total of five types of storm deposits are recognized according to the synthesis of storm sediments, sedimentary position and depositional markers. Type Ⅰ is represented by the graded lamination in millimeter or centimeter scale downcutting the underlying microbial reef. They are formed by distal storm turbidity currents below stormwave base. Type Ⅱ is composed of allodapic storm gravelstone (of member A), graded member (B), parallel lamination member (C) and black calcareous shale with horizontal bedding (E2), which are deposited at the lower part of gentle slope between the storm and the fine weather wave bases. Type Ⅲ consists of storm bioclast, gravelstone, parallel lamination and HCS, depositing at the upper part of the slope. Type Ⅳ is characterized by gutter casts and composite HCS, which are formed in the vicinity of the fair weather wave base. Type Ⅴ develops storm intraclastic limestones and scouring filling structures (A) and parallel lamination (C), overlying cyanobacteria reefbank collapsing deposition in fair weather. They are formed in the front of platform margin above fair weather wavebase. The depositional evolution of tempestites is: the deep water shelf→the lower part of gentle slope→the upper part of gentle slope→the front of platform margin, which are characteristic of shallowing upward. The discovery and researches of tempesites in the studied area are of great significances for understanding the palaeolatitude and palaeoplate evolution as well as the palaeogeographic environments and sedimentary evolution in the Early Cambrian of Tarim plate.   Related Articles | Metrics

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Geothermal fluid genesis and mantle fluids contributions in NimuNaqu, Tibet LIU Zhao, LIN Wen-Jing, ZHANG Meng, XIE E-Jun, LIU Zhi-Meng, WANG Gui-Ling 2014, 21(6): 356-371.  DOI: 10.13745/j.esf.2014.06.034 Abstract ( 1305 )   PDF (2648KB) ( 2191 )   Study area is located in the Nimu—Naqu hightemperature geothermal belt, within the MiddleNorth section of the DangxiongYangbajain—Duoqingcuo active tectonic belt. Eleven unexploited geothermal fields are selected for this study, the hydrochemistry, hydrogen and oxygen isotope data, geothermal gases and their isotope data are collected and gathered from the study area, and the comparison with shallow and deep reservoirs in Yangbajain are conducted, in order to improve the study of genetical mechanism of the hightemperature geothermal systems and provide guidance for exploration and drilling in the area. Based on the analytical data of hydrochemistry of geothermal fluids, the chemical types of the high temperature thermal water are mainly of Cl-Na or Cl·HCO3-Na type, and the lowtemperature thermal water is mainly of HCO3-Na type. There is likely a positive correlation between Li, F, SiO2, HBO2 and Cl, which indicates the possible mixing of magmatic water. From stable isotope data, the thermal water showed mainly meteoric recharge. The thermal water show slight “18O drift” in Dongweng, Ningzhong hightemperature geothermal fields. The phenomenon is more obvious in Gulu geothermal field than the others. The tritium contents are less than 1 TU in Ningzhong, Gulu and Luoma, indicating mainly submodern water recharge, the trtium content at Yuela is 8.4 TU, which can be inferred to modern water recharge. The underground thermal water from other geothermal fields is the hybrid water recharge of submodern with recent water. The geothermal gases are mainly composed of carbon dioxide and nitrogen; there is a good negative correlation between the contents of carbon dioxide and nitrogen. Judging from the carbon isotopes and helium isotopes from carbon dioxide, combining with comprehensive index analysis, the source of the geothermal gases is mainly derived from the crust. However, the monitored R/Ra values are greater than 1 in Ningzhong and Yuzhai,showing that there must be a significant release of mantle material. The proportion of mantle helium ranges from 2.73 to 30.93 percent. Finally, the comprehensive study of the genesis model for typical, high-temperature geothermal field in the study area, will provide an important scientific basis for the further research as well as the development and utilization of the geothermal fields.   Related Articles | Metrics

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The constraints of the fission track thermochronology on active time of the Southern Tibetan Detachment System in Cho Oyu, Tibet. Gao-Cheng, LIU Jiao, LI De-Wei, WANG Fan, LIU De-Min 2014, 21(6): 372-380.  DOI: 10.13745/j.esf.2014.06.035 Abstract ( 1303 )   PDF (1881KB) ( 2664 )   This research uses fission track experiments to study the geological activity of the South Tibetan Detachment System (STDS) based on 5 zircon samples and 4 apatite samples from the Cho Oyu in the Tibetan Himalayan. The age range of the zircons is 11.217.1 Ma and that of the apatites is 12.414.3 Ma. After integrating the ageclosure temperatures measured for these samples, we found that the crustal cooling rate of the Lhotse detachment fault along the Cho Oyu increased gradually during the Miocene：(1) during 17.115.2 Ma the crustal cooling rate was approximately 37.8 ℃/Ma; (2) during 15.213.5 Ma the average crustal cooling rate was ~82.4 ℃/Ma, and the tectonic activity was most intense at ~14.3 Ma; (3) during 13.512.4 Ma the crust cooling rate during that time was up to 100 ℃/Ma.   Related Articles | Metrics

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Petrography, zircon U-Pb geochronology and geochemistry of the maficultramafic intrusion in Xiarihamu Cu-Ni deposit from East Kunlun,with implications for geodynamic setting Wang-Guan, SUN Feng-Yue, LI Bi-Le, LI Shi-Jin, ZHAO Dun-Wei, AO Zong, YANG Qi-An 2014, 21(6): 381-401.  DOI: 10.13745/j.esf.2014.06.036 Abstract ( 1265 )   PDF (3130KB) ( 2686 )   In this paper, we present petrographical, zircon U-Pb dating and geochemical data for the maficultramafic intrusion in Xiarihamu CuNi deposit to constrain its formation time, petrogenesis and the tectonic setting. Xiarihamu No.1 maficultramafic intrusion locates in the middle of the Eastern Kunlun middle uplifted basement and granitic belt, south of the North Kunlun Fault. The intrusion covers an area of 0.7 km2, in shape of a flat lopolith, with the strikes of NEE. The intrusion is mainly composed of gabbronorite, orthopyroxenite, olivine pyroxenites, plagiolherzolite and orthopyroxene peridotite. Pyroxenite and peridotite are the main host rocks for the Cu-Ni ores. Major element contents of Xiarihamu complex show subalkalic series and are characterized by low SiO2 contents (SiO2 36.68%52.58%), low TiO2 contents (TiO2 0.13%0.47%) and alkali contents (Na2O+K2O 0.26%1.95%), but high MgO contents (MgO 10.91%35.81%). The m/f values of the rocks range from 3.88 to 6.29, falling into the range of ferrousultramafic rocks. Similar LREErich pattern ((La/Yb)N=1.442.98) and no Eu anomaly indicate that Xiarihamu complex have the same magma source. Trace elements are enriched in LILE (Rb, Th, U, K) and relatively depleted in HFSE (Nb and Ta). The presence of Neoproterozoic granite relicts and the La/Yb, Ce/Yb, Th/Yb, Nb/La, and La/Sm values suggest the limited crustal contamination during the rise of the magma. Zircon LA-MC-ICPMS、U-Pb dating of gabbronorite yielded 423±1 Ma, MSWD=0.14, i.e., the Late Silurian. Zircon 176Hf/177Hf values are in the range of 0.2826280.282833 with corresponding εHf(t) values of 4.010.9. Lu-Hf singlestage modal ages (tDM1) vary from 610 to 875 Ma and mean age (788 Ma) , which is older than U-Pb age. We suggest that the primary magma derived from a depleted mantle, and may have been added metasomatic enriched lithospheric mantle components, and contaminated by crustal material. Combined with regional tectonic evolution, we believe that the intrusion formed in the post-collisional extension setting, perhaps triggered by slab break-off. The fractional crystallization of olivine and orthopyroxene and addition of crustal S appear to be directly related to trigger S saturation.   Related Articles | Metrics