洋中脊动力学与俯冲带地震-岩浆-成矿事件远程效应

doi:10.13745/j.esf.sf.2024.1.23

摘要/Abstract

摘要：

板块俯冲带和大陆岩浆弧的深部过程与极端地质事件之间存在密切的关系。板块俯冲与造山过程会导致地震、岩浆活动和成矿等事件的发生。这些极端事件的发生与俯冲过程中的壳幔相互作用、地幔楔形成、岩石圈部分熔融、构造-岩浆活动等因素密切相关。然而,人们对洋中脊新生地壳的不均匀性或先天“缺陷”对以上的极端事件的长远影响和远程效应了解甚少。在洋中脊新的地壳形成过程中,由于受到板块扩张、压力降低、软流圈物质上涌等因素的作用,导致新生地壳温度升高、孔隙度和裂缝发育、密度降低、结构复杂的正反馈过程。因此,新生地壳在密度、强度、温度、厚度等方面存在非均质性。这些地壳的差异性将影响和决定板块在扩张和俯冲过程中的行为,并对板块俯冲作用形成的地震、岩浆和成矿等事件产生远程影响。以太平洋俯冲和安第斯造山带为例研究发现,板块运动速度、板块俯冲角度、板片撕裂、岩石圈厚度、Moho面深度等的突变与地震、火山和斑岩矿床的时空分布存在远程关联效应,这些认知对预测板块俯冲-碰撞带发生的极端地质事件的时空分布具有重要意义。

关键词: 洋中脊, 板块俯冲, 地震, 火山, 成矿, 远程关联

Abstract:

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.

Key words: mid-ocean ridges, plate subduction, earthquakes, volcanoes, mineralization, long-range effects

中图分类号:

成秋明. 洋中脊动力学与俯冲带地震-岩浆-成矿事件远程效应[J]. 地学前缘, 2024, 31(1): 1-14.

CHENG Qiuming. Long-range effects of mid-ocean ridge dynamics on earthquakes, magmatic activities, and mineralization events in plate subduction zones[J]. Earth Science Frontiers, 2024, 31(1): 1-14.

图/表 10

图1 大洋岩石圈年龄分布图(图像来自文献[2])

Fig.1 A map shows the age (m.y.) of the oceanic lithosphere. Basemap adapted from [2].

图2 沿环太平洋和特提斯成矿域中新生代斑岩铜矿床分布图(数据来源于USGS斑岩铜矿数据库)

Fig.2 A map showing the spatial distribution of Mesozoic and Cenozoic porphyry copper deposits along Pacific and Tethys orogenic belts (Data from USGS porphyry copper deposit database)

图3 岩石圈相变剖面示意图和Moho面处的分形密度 A—岩石圈相变剖面示意图;B—Moho面岩石应力差异;C—Moho面以下地震分布密度梯度变化的三种形式:线性、对数线性、双对数线性。(C来源于文献[18])

Fig.3 Diagram illustrating lithosphere phase transition and the fractal density around the Moho interface. (A) Lithosphere phase transition. (B) Differential stress around the Moho interface. (C) Spatial distribution of earthquakes below the Moho interface, characterized by three frequency-depth relationship types: linear, log-linear, and double log-linear. C derived from [18].

图4 洋中脊岩石圈结构示意图 (图4来源于文献[10];A数据来源于文献[26])A—布格重力异常图;B—洋中脊岩石圈结构示意图;C—插图显示岩石圈、水圈、软流圈的相互共存。

Fig.4 Structure of the lithosphere over the mid-ocean ridge (Derived from [10]). (A) Bouguer gravity anomalies across the north mid-Atlantic ridge (Data from [26]). (B) Thematic diagram showing the structure of lithosphere plates at the mid-ocean ridge. (C) Enlarged diagram showing the interface between seawater, the lithosphere, and the asthenosphere.

图5 沿南大西洋西部地壳地震反射实验剖面的地壳物理性质 (A来源于文献[23];B,C和D来源于文献[10])A—地震波速;B—空隙率;C—重力推断岩石圈密度;D—多重级联模型模拟岩石圈密度分布。

Fig.5 Physical property profiles for crust along the Crustal Reflectivity Experiment Southern Transect (CREST). (A) Seismic velocity extracted from tomographic velocity models (Derived from [23]). (B) Fractional porosity calculated from the velocity data in A using the Carlson equation. (C) Gravity-derived density (Derived from [10]). (D) Cascade processes simulated lithosphere density (Derived from [10]).

图6 东太平洋板块重力异常图(A)和磁异常图(B) 图中白色空心圆代表斑岩铜矿床,绿色三角形代表火山分布。 (A数据来源于文献[35];B来源于文献[36])

Fig.6 Gravity (A) and magnetic (B) anomaly maps of the East Pacific Plate. White circles and green triangles represent porphyry copper mineral deposits and volcanoes, respectively. Data in A derived from [35]; B derived from [36].

图7 斑岩铜矿成矿模式图(来源于文献[44])

Fig.7 A schematic model showing the formation of porphyry copper deposit. Image from [44].

图8 斑岩铜矿与板块构造运动的时空关系分布图(视频截图) 直方图数据来源于 USGS斑岩铜矿数据库; 构造图数据来源于 Gplates 软件;红线表示运动的瞬时时间。

Fig.8 The relationship between spatial and temporal distribution of porphyry copper deposits and the evolution of plate tectonics (Video screenshot). The porphyry copper deposit data are from the USGS porphyry copper deposit database； the tectonic map data is derived from the GPlates software.

图9 斑岩铜矿与板块构造运动速度变化时间序列关系图 A—安提斯成矿带斑岩铜矿分布图,地图为数字地形图,白色点代表斑岩铜矿分布位置,三角形代表GPlates模拟参考点;B—斑岩铜矿分布直方图与板块运动相对速度(A中两个参考点之间的速度差)、剪切方向速度变化关系图,计算方法见文中。

Fig.9 Time series relationship between porphyry copper deposits and plate tectonic movement speed changes. (A) Distribution map of porphyry copper deposits in the Antis metallogenic belt. The background map is a digital elevation model. The white dots represent locations of porphyry copper deposits, and the triangles represent GPlates simulation reference points. (B) Porphyry copper deposit distribution histogram and relative velocity of plate movement (velocity difference between the two reference points in A). See text for calculation method for velocity change diagram in shear direction.

图10 斑岩铜矿床分布与深部地质结构的关联性 A—每一区间内斑岩铜矿累计储量;B—每一区间内斑岩铜矿个数直方图;C—沿剖面Moho面深度;D—位于矿化集中区的剖面和斑岩矿床的空间分布图,背景为数字地形图。

Fig.10 The relationship between the distribution of porphyry copper deposits and deep geological structures. (A) cumulative reservoir of porphyry copper deposits within each distance bin. (B) histogram of number of porphyry copper deposits. (C) Moho depth. (D) Profile of ore accumulation area showing the spatial distribution of ore bodies. Red curve presents a profile across the centric of porphyry copper deposits along the orogen; white circles represent porphyry copper deposits of variable sizes; background color represents the digital elevation model of the area.

参考文献 50

[1]	FRUEH-GREEN G L, KELLEY D S, LILLEY M D, et al. Diversity of magmatism, hydrothermal processes and microbial interactions at mid-ocean ridges[J]. Nature Reviews Earth & Environment, 2022, 3(12): 852-871.
[2]	MÜLLER R D, SDROLIAS M, GAINA C, et al. Age, spreading rates, and spreading asymmetry of the world's ocean crust[J]. Geochemistry, Geophysics, Geosystems, 2008, 9(4), Q04006.
[3]	CHENG Q. Singularity analysis of global zircon U-Pb age series and implication of continental crust evolution[J]. Gondwana Research, 2017, 51: 51-63. DOI URL
[4]	CHENG Q. Extrapolations of secular trends in magmatic intensity and mantle cooling: implications for future evolution of plate tectonics[J]. Gondwana Research, 2018, 63: 268-273. DOI URL
[5]	CHEN G, CHENG Q, PETERS S E, et al. Feedback between surface and deep processes: insight from time series analysis of sedimentary record[J]. Earth and Planetary Science Letters, 2022, 579: 117352. DOI URL
[6]	ZHANG Z J, CHEN G X, KUSKY T, et al. Lithospheric thickness records tectonic evolution by controlling metamorphic conditions[J]. Science Advances, 2023, 9(50): eadi2134.
[7]	ANDERSON D L. Composition of the Earth[J]. Science, 1989, 243(4889): 367-370. PMID
[8]	ESCARTÍN J, LIN J. Ridge offsets, normal faulting, and gravity anomalies of slow spreading ridges[J]. Journal of Geophysical Research: Solid Earth, 1995, 100(B4): 6163-6177.
[9]	ESCARTIN J, LIN J. Tectonic modification of axial crustal structure: Evidence from spectral analyses of residual gravity and bathymetry of the Mid-Atlantic Ridge flanks[J]. Earth and planetary science letters, 1998, 154(1/2/3/4): 279-293. DOI URL
[10]	CHENG Q. Singularity of lithosphere mass density over the mid-ocean ridges and implication on floor depth and heat flow[J]. Geoscience Frontiers, 2023, 14(5): 101591. DOI URL
[11]	CHENG Q. Fractal density and singularity analysis of heat flow over ocean ridges[J]. Scientific Reports, 2016, 6(1): 19167. DOI
[12]	ZHAI M, PENG P. Origin of early continents and beginning of plate tectonics[J]. Science Bulletin, 2020, 65(12): 970-973. DOI PMID
[13]	ANDERSON D L. Top-down tectonics?[J]. Science, 2001, 293(5537): 2016-2018. DOI URL
[14]	CHEN L, WANG X, LIANG X, et al. Subduction tectonics vs. Plume tectonics: discussion on driving forces for plate motion[J]. Science China Earth Sciences, 2020, 63: 315-328. DOI
[15]	FJELDSKAAR W. Viscosity and thickness of the asthenosphere detected from the Fennoscandian uplift[J]. Earth and Planetary Science Letters, 1994, 126(4): 399-410. DOI URL
[16]	ANDERSON D L. Lithosphere, asthenosphere, and perisphere[J]. Reviews of Geophysics, 1995, 33(1): 125-149. DOI URL
[17]	BOONMA K, KUMAR A, GARCÍA-CASTELLANOS D, et al. Lithospheric mantle buoyancy: the role of tectonic convergence and mantle composition[J]. Scientific reports, 2019, 9(1): 17953. DOI PMID
[18]	CHENG Q. Fractal derivatives and singularity analysis of frequency-depth clusters of earthquakes along converging plate boundaries[J]. Fractal and Fractional, 2023, 7(10): 721. DOI URL
[19]	CHENG Q. Quantitative simulation and prediction of extreme geological events[J]. Science China Earth Sciences, 2022, 65(6): 1012-1029. DOI
[20]	MCKENZIE D P. Some remarks on heat flow and gravity anomalies[J]. Journal of Geophysical Research, 1967, 72(24): 6261-6273. DOI URL
[21]	SALMI M S, JOHNSON H P, TIVEY M A, et al. Quantitative estimate of heat flow from a mid-ocean ridge axial valley, Raven field, Juan de Fuca Ridge: observations and inferences[J]. Journal of Geophysical Research: Solid Earth, 2014, 119(9): 6841-6854. DOI URL
[22]	KAWAKATSU H, KUMAR P, TAKEI Y, et al. Seismic evidence for sharp lithosphere-asthenosphere boundaries of oceanic plates[J]. Science, 2009, 324(5926): 499-502. DOI PMID
[23]	KARDELL D A, CHRISTESON G L, ESTEP J D, et al. Long-lasting evolution of layer 2A in the Western South Atlantic: evidence for low-temperature hydrothermal circulation in old oceanic crust[J]. Journal of Geophysical Research: Solid Earth, 2019, 124(3): 2252-2273. DOI URL
[24]	KARDELL D A, ZHAO Z, RAMOS E J, et al. Hydrothermal models constrained by fine-scale seismic velocities confirm hydrothermal cooling of 7-63 Ma South Atlantic crust[J]. Journal of Geophysical Research: Solid Earth, 2021, 126(6): e2020JB021612.
[25]	WANG T, TUCHOLKE B E, LIN J. Spatial and temporal variations in crustal production at the Mid-Atlantic Ridge, 25° N-27° 30' N and 0-27 Ma[J]. Journal of Geophysical Research: Solid Earth, 2015, 120(4): 2119-2142. DOI URL
[26]	TALWANI M, LE PICHON X, EWING M. Crustal structure of the mid-ocean ridges: 2. Computed model from gravity and seismic refraction data[J]. Journal of Geophysical Research, 1965, 70(2): 341-352. DOI URL
[27]	STEIN C A, STEIN S. A model for the global variation in oceanic depth and heat flow with lithospheric age[J]. Nature, 1992, 359(6391): 123-129. DOI
[28]	HASTEROK D, CHAPMAN D S, DAVIS E E. Oceanic heat flow: implications for global heat loss[J]. Earth and Planetary Science Letters, 2011, 311(3/4): 386-395. DOI URL
[29]	CARDOSO R R, HAMZA V M. Finite Half pace model of oceanic lithosphere[M]//VERESS B, SZIGETHY J. Horizons in Earth science research, Volume 5. New York: Nova Science Publishers, Inc, 2011, Chapter 11. ISBN 978-1-61209-923-1.
[30]	RICHARDS F D, HOGGARD M J, COWTON L R, et al. Reassessing the thermal structure of oceanic lithosphere with revised global inventories of basement depths and heat flow measurements[J]. Journal of Geophysical Research: Solid Earth, 2018, 123(10): 9136-9161. DOI URL
[31]	ZHENG X, LEE H, WEISGRABER T H, et al. Ultralight, ultrastiff mechanical metamaterials[J]. Science, 2014, 344(6190): 1373-1377. DOI PMID
[32]	NICOLIS G, PRIGOGINE I. Exploring complexity: an introduction[M]. New York: W.H. Freeman, 1989: 328.
[33]	TURCOTTE D L. Modeling geocomplexity:“A new kind of science”[M]//MANDUCA C A, MOGK D W. Earth and mind: how geologists think and learn about the Earth. Colorado: Geological Society of America (GSA) Special Papers, 2006(413): 39-50. https://doi.org/10.1130/2006.2413(04)
[34]	MCKENZIE D P, PARKER R L. The North Pacific: an example of tectonics on a sphere[J]. Nature, 1967, 216(5122): 1276-1280. DOI
[35]	INCE E S, BARTHELMES F, REIBLAND S, et al. ICGEM-15 years of successful collection and distribution of global gravitational models, associated services, and future plans[J]. Earth System Science Data, 2019, 11(2): 647-674. DOI URL
[36]	MAUS S, BARCKHAUSEN U, BERKENBOSCH H, et al. EMAG2: a 2are min resolution Earth Magnetic Anomal Grid compiled from satellite, airborne, and marine magnetic measurements[J]. Geochemistry, Geophysics, Geosystems, 2009, 10, Q08005.
[37]	COOKE D R, HOLLINGS P, WALSHE J L. Giant porphyry deposits: characteristics, distribution, and tectonic controls[J]. Economic Geology, 2005, 100(5): 801-818. DOI URL
[38]	ANNEN C, BLUNDY J D, SPARKS R S J. The genesis of intermediate and silicic magmas in deep crustal hot zones[J]. Journal of Petrology, 2006, 47(3): 505-539. DOI URL
[39]	RICHARDS J P. Giant ore deposits formed by optimal alignments and combinations of geological processes[J]. Nature Geoscience, 2013, 6(11): 911-916. DOI
[40]	YAO Z, QIN K, MUNGALL J E. Tectonic controls on Ni and Cu contents of primary mantle-derived magmas for the formation of magmatic sulfide deposits[J]. American Mineralogist, 2018, 103(10): 1545-1567. DOI URL
[41]	HEDENQUIST J W, LOWENSTERN J B. The role of magmas in the formation of hydrothermal ore deposits[J]. Nature, 1994, 370(6490): 519-527. DOI
[42]	RICHARDS J P. Tectono-magmatic precursors for porphyry Cu-(Mo-Au) deposit formation[J]. Economic Geology, 2003, 98(8): 1515-1533. DOI URL
[43]	PARK J W, CAMPBELL I H, CHIARADIA M, et al. Crustal magmatic controls on the formation of porphyry copper deposits[J]. Nature Reviews Earth & Environment, 2021, 2(8): 542-557.
[44]	RICHARDS J P. Magmatic to hydrothermal metal fluxes in convergent and collided margins[J]. Ore Geology Reviews, 2011, 40(1): 1-26. DOI URL
[45]	CHENG Q. Integration of deep-time digital data for mapping clusters of porphyry copper mineral deposits[J]. Acta Geologica Sinica (English Edition), 2019, 93(Suppl 3): 8-10.
[46]	MÜLLER R D, CANNON J, QIN X, et al. GPlates: Building a virtual Earth through deep time[J]. Geochemistry, Geophysics, Geosystems, 2018, 19(7): 2243-2261. DOI URL
[47]	CHIARADIA M. Copper enrichment in arc magmas controlled by overriding plate thickness[J]. Nature Geoscience, 2014, 7(1): 43-46. DOI
[48]	PROFETA L, DUCEA M N, CHAPMAN J B, et al. Quantifying crustal thickness over time in magmatic arcs[J]. Scientific Reports, 2015, 5(1): 17786. DOI
[49]	ZHANG H, LÜ Q T, WANG X L, et al. Seismically imaged lithospheric delamination and its controls on the Mesozoic Magmatic Province in South China[J]. Nature Communications, 2023, 14(1): 2718. DOI PMID
[50]	HOU Z Q, XU B, ZHANG H, et al. Refertilized continental root controls the formation of the Mianning-Dechang carbonatite-associated rare-earth-element ore system[J]. Communications Earth & Environment, 2023, 4(1): 293.