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南海西南次海盆扩张期热液循环与洋壳增生的数值模拟

  • 张慧慧1,3

    机 构：

    1. 中国科学院边缘海与大洋地质重点实验室,南海海洋研究所,南海生态环境工程创新研究院,广东广州, 510301

    3. 中国科学院大学,北京, 100049

    ×
  • ，许鹤华1,2

    机 构：

    1. 中国科学院边缘海与大洋地质重点实验室,南海海洋研究所,南海生态环境工程创新研究院,广东广州, 510301

    2. 南方海洋科学与工程广东省实验室(广州),广东广州, 511458

    ×
  • ，姚永坚2,4

    机 构：

    2. 南方海洋科学与工程广东省实验室(广州),广东广州, 511458

    4. 广州海洋地质调查局自然资源部海底矿产资源重点实验室,广东广州, 510760

    ×
  • ，邵佳5

    机 构：

    5. 南方科技大学海洋科学与工程系,广东深圳, 518055

    ×
  • ，纪顺奎6

    机 构：

    6. 中国矿业大学,北京, 100083

    ×

1. 中国科学院边缘海与大洋地质重点实验室,南海海洋研究所,南海生态环境工程创新研究院,广东广州, 510301；
2. 南方海洋科学与工程广东省实验室(广州),广东广州, 511458；
3. 中国科学院大学,北京, 100049；
4. 广州海洋地质调查局自然资源部海底矿产资源重点实验室,广东广州, 510760；
5. 南方科技大学海洋科学与工程系,广东深圳, 518055；
6. 中国矿业大学,北京, 100083；

Numerical simulation of hydrothermal circulation and oceanic crust accretion during the expansion period of the southwestern sub-basin of the South China Sea

  • ZHANG Huihui1,3

    Affiliation：

    1. Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, Guangdong 511458 , China

    3. University of Chinese Academy of Sciences, Beijing 100049 , China

    ×
  • ，XU Hehua1,2

    Affiliation：

    1. Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, Guangdong 511458 , China

    2. Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, Guangdong 511458 , China

    ×
  • ，YAO Yongjian2,4

    Affiliation：

    2. Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, Guangdong 511458 , China

    4. Key Laboratory of Submarine Mineral Resources, Ministry of Natural Resources,Guangzhou Marine Geological Survey, Guangzhou, Guangdong 510760 , China

    ×
  • ，SHAO Jia5

    Affiliation：

    5. Department of Marine Science and Engineering, Southern University of Science and Technology,Shenzhen, Guangdong 518055 , China

    ×
  • ，JI Shunkui6

    Affiliation：

    6. China University of Mining and Technology, Beijing 100083 , China

    ×

1. Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, Guangdong 511458 , China；
2. Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, Guangdong 511458 , China；
3. University of Chinese Academy of Sciences, Beijing 100049 , China；
4. Key Laboratory of Submarine Mineral Resources, Ministry of Natural Resources,Guangzhou Marine Geological Survey, Guangzhou, Guangdong 510760 , China；
5. Department of Marine Science and Engineering, Southern University of Science and Technology,Shenzhen, Guangdong 518055 , China；
6. China University of Mining and Technology, Beijing 100083 , China；

作者简介:

张慧慧,女,1995年生。在读硕士研究生,主要从事地球动力学数值模拟研究。E-mail:zhanghuihui@scsio.ac.cn。

通讯作者:

许鹤华,男,1965年生。副研究员,主要从事地球动力学数值模拟研究。E-mail:xhhcn@scsio.sc.cn。

DOI:10.19762/j.cnki.dizhixuebao.2022157

参考文献
Bai Hailong, Montési L G J, Behn M D. 2017. MeltMigrator: a MATLAB-based software for modeling three-dimensional melt migration and crustal thickness variations at mid-ocean ridges following a rules-based approach. Geochemistry, Geophysics, Geosystems, 18(1): 445~456.
查找原文
参考文献
Baker E T, Chen Y J, Phipps Morgan J. 1996. The relationship between near-axis hydrothermal cooling and the spreading rate of mid-ocean ridges. Earth and Planetary Science Letters, 142(1): 137~145.
查找原文
参考文献
Baker E T, Edmonds H N, Michael P J, Bach W, Dick H J B, Snow J E, Walker S L, Banerjee N R, Langmuir C H. 2004. Hydrothermal venting in magma deserts: the ultraslow-spreading Gakkel and Southwest Indian Ridges. Geochemistry, Geophysics, Geosystems, 5(8): 29~58.
查找原文
参考文献
Batchelor G K. 2000. An Introduction to Fluid Dynamics. Cambridge: Cambridge University Press.
查找原文
参考文献
Becker K, Sakai H, Adamson A C, Alexandrovich J, Alt J C, Anderson R N, Bideau D, Gable R, Herzig P M, Houghton S, Ishizuka H, Kawahata H, Kinoshita H, Langseth M G, Lovell M A, Malpas J, Masuda H, Merrill R B, Morin R H, Mottl M J, Pariso J E, Pezard P, Phillips J, Sparks J, Uhlig S. 1989. Drilling deep into young oceanic crust, Hole 504B, Costa Rica Rift. Reviews of Geophysics, 27(1): 79~102.
查找原文
参考文献
Braitenberg C, Wienecke S, Wang Y. 2006. Basement structures from satellite-derived gravity field: South China Sea ridge. Journal of Geophysical Research: Solid Earth, 111(B5): 15~30.
查找原文
参考文献
Briais A, Patriat P, Tapponnier P. 1993. Updated interpretation of magnetic anomalies and seafloor spreading stages in the south China Sea: implications for the Tertiary tectonics of Southeast Asia. Journal of Geophysical Research: Solid Earth, 98(B4): 6299~6328.
查找原文
参考文献
Brunelli D, Cipriani A, Bonatti E. 2018. Thermal effects of pyroxenites on mantle melting below mid-ocean ridges. Nature Geoscience, 11(7): 520~525.
查找原文
参考文献
Ding Hanghang, Ding Weiwei, Fang Yinxia. 2019. Morphological characteristics and controlling factors of the basal floor of the southwest sub-basin of the South China Sea. Earth Science Frontiers, 26: 222~232(in Chinese with English abstract).
查找原文
参考文献
Ding Hanghang, Ding Weiwei, Zhang Fan, Wu Zhaocai, Yin Shaoru, Fang Yinxia. 2021. Asymmetry and control factors of deep structure in the South China Sea basin. Earth Science, 46: 929~941(in Chinese with English abstract).
查找原文
参考文献
Ding Weiwei, Li Jiabiao, Clift P D. 2016. Spreading dynamics and sedimentary process of the Southwest Sub-basin, South China Sea: constraints from multi-channel seismic data and IODP Expedition 349. Journal of Asian Earth Sciences, 115: 97~113.
查找原文
参考文献
Forsyth D W. 1993. Crustal thickness and the average depth and degree of melting in fractional melting models of passive flow beneath mid-ocean ridges. Journal of Geophysical Research: Solid Earth, 98(B9): 16073~16079.
查找原文
参考文献
Gozzard S, Kusznir N, Franke D, Cullen A, Reemst P, Henstra G. 2018. South China Sea crustal thickness and oceanic lithosphere distribution from satellite gravity inversion. Petroleum Geoscience, 25(1): 112~128.
查找原文
参考文献
Guo Zhikui. 2019. Numerical simulation of hydrothermal circulation mechanism of ultra-slow expansion of ocean ridges. PhD thesis of China University of Geosciences (in Chinese with English abstract).
查找原文
参考文献
Healy D, Kusznir N J, Karner G D, Manatschal G, Pinheiro L M. 2007. Early kinematic history of the Goban Spur rifted margin derived from a new model of continental breakup and sea-floor spreading initiation. In: Healy D, Kusznir N J, Karner G D, Manatschal G, Pinheiro L M, eds. Imaging, Mapping and Modelling Continental Lithosphere Extension and Breakup Geological Society of London, 282(1): 199~215.
查找原文
参考文献
Huang Haibo, Qiu Xueli, Pichot T, Klingelhoefer F, Zhao Minghui, Wang Ping, Hao Tianyao. 2019. Seismic structure of the northwestern margin of the South China Sea: implication for asymmetric continental extension. Geophysical Journal International, 218: 1246~1261.
查找原文
参考文献
Koepke J, Feig S T, Snow J. 2005. Hydrous partial melting within the lower oceanic crust. Terra Nova, 17(3): 286~291.
查找原文
参考文献
Langmuir C H, Klein E M, Plank T. 1992. Petrological systematics of mid-ocean ridge basalts: constraints on melt generation beneath ocean ridges. Mantle Flow and Melt Generation at Mid-Ocean Ridges, 71: 183~280.
查找原文
参考文献
Larson R L, Fisher A T, Jarrard R D, Becker K. 1993. Highly permeable and layered Jurassic oceanic crust in the western Pacific. Earth and Planetary Science Letters, 119(1): 71~83.
查找原文
参考文献
Li Jiabiao, Ding Weiwei, Wu Ziyin, Zhang Jie, Dong Chongzhi. 2012. The gradual expansion of the southwest basin of the South China Sea. Chinese Science Bulletin, 57: 1896~1905 (in Chinese with English abstract).
查找原文
参考文献
Lowell R P, Rona P A, Vonherzen R P. 1995. sea floor hydrothermal systems. Journal of Geophysical Research-Solid Earth, 100(B1): 327~352.
查找原文
参考文献
Luan Xiwu, Zhao Yiyang, Qin Yunshan, Chu Fengyou. 2002. Estimation of heat flux of hydrothermal systems transported to the oceans. Acta Oceanaria Sinica (Chinese Edition), 121: 59~66 (in Chinese with English abstract).
查找原文
参考文献
Morgan J P, Chen Y J. 1993. The genesis of oceanic crust-magma injection, hydrothermal circulation, and crustal flow. Journal of Geophysical Research, 98: 6283~6297.
查找原文
参考文献
Nguyen T N, Van Kha T, Van Nam B, Nguyen H T T. 2020. Sedimentary basement structure of the Southwest Sub-basin of the East Vietnam Sea by 3D direct gravity inversion. Marine Geophysical Research, 41(1): 7.
查找原文
参考文献
Niu Yaoling, Bideau D, Hëkinian R, Batiza R. 2001. Mantle compositional control on the extent of mantle melting, crust production, gravity anomaly, ridge morphology, and ridge segmentation: a case study at the Mid-Atlantic Ridge 33-35N. Earth and Planetary Sciences Letters, 186: 383~399.
查找原文
参考文献
Qiu Xuelin, Zhao Minghui, Ao Wei, Lü Chuanchuan, Hao Tianyao, You Qingyu, Ruan Aiguo, Li Jiabiao. 2011. OBS Detection and Crustal Structure of sub-basins and Nansha massifs in the southwestern South China Sea. Chinese Journal of Geophysics, 54(12): 3117~3128.
查找原文
参考文献
Shao Jia, Xu Hehua, Chen Yongqiang, Shi Xiaobin, Wang Xiaofang. 2021. Effects of upper mantle moisture content on ocean crust thickness during seafloor expansion: numerical simulation. Earth Science, 46: 826~839(in Chinese with English abstract).
查找原文
参考文献
Song Juechen, Li Jianghai, Feng Bo. 2021. Hydrothermal activity and mechanism of slow-ultra-slow expansion of mid-ocean ridges. Acta Geologica Sinica, 95: 2273~2283(in Chinese with English abstract).
查找原文
参考文献
Stein C A, Stein S. 1994. Constraints on hydrothermal heat flux through the oceanic lithosphere from global heat flow. Journal of Geophysical Research: Solid Earth, 99(B2): 3081~3095.
查找原文
参考文献
Theissen-Krah S, Rüpke L H, Hasenclever J. 2016. Modes of crustal accretion and their implications for hydrothermal circulation. Geophysical Research Letters, 43(3): 1124~1131.
查找原文
参考文献
Wang Xingtao. 2014. Hydrothermal circulation and chimney body study of modern seafloor hydrothermal activity. PhD thesis of Ocean University of China (in Chinese with English abstract).
查找原文
参考文献
Wang Yanlin, Wang Jun, Yan Pin, Qiu Yan. 2017. An Anomalous Seamount on the Southwestern Mid-Ridge of the South China Sea. Acta Geologica Sinica (English edition), 91(6): 2340~2341.
查找原文
参考文献
Xu Hehua, Ma Hui, Song Haibin, Chen Aihua. 2011. Numerical simulation of the expansion process of the basin in the eastern South China Sea. Chinese Journal of Geophysics, 54: 3070~3078(in Chinese with English abstract).
查找原文
参考文献
Xu Jiarui. 2018. Petrology and geochemistry of calcareous carbonate veins in IODP349 basal basalt in the South China Sea. Master degree thesis of University of Chinese Academy of Sciences (Guangzhou Institute of Geochemistry, Chinese Academy of Sciences) (in Chinese with English abstract).
查找原文
参考文献
Yu Junhui, Yan Qian, Lin Jian. 2017. Comparison of crustal structure of the southwest sub-basin of the South China Sea and ultra-slow expansion of the mid-ridge ridge of the southwest Indian Ocean. Journal of Tropical Oceanography, 36: 51~61(in Chinese with English abstract).
查找原文
参考文献
Yu Junhui, Yan Pin, Wang Yanlin, Zhang Jinchang, Qiu Yan, Pubellier M, Delescluse M. 2018. Seismic Evidence for Tectonically Dominated Seafloor Spreading in the Southwest Sub-basin of the South China Sea. Geochemistry, Geophysics, Geosystems, 19(9): 3459~3477.
查找原文
参考文献
Wu Zhaocai, Gao Jinyao, Ding Weiwei, Shen Zhongyan, Zhang Tao, Yang Chunguo. 2017. The moho depth of the south china sea basin from threo dimensional gravity inversion with constraing points and its cherecteristics. Chinese Journal of Geophysics, 60: 368~383.
查找原文
参考文献
Zhang Jie, Li Jiabiao, LI Xibing, Wu Zhenli. 2011. Comparison of evolutionary characteristics of the Gulf of Aden in the progressive expansion basin and the southwest sub-basin in the South China Sea. Chinese Journal of Geophysics, 54: 3079~3088(in Chinese with English abstract).
查找原文
参考文献
Zhou Huaiyang, Zhu Qikuan, Ji Fuwu, Yang Qunhui. 2020. New discoveries on deep-water seamounts in the South China Sea. Science & Technology Review, 38: 83~88(in Chinese with English abstract).
查找原文
参考文献
丁航航, 丁巍伟, 方银霞. 2019. 南海西南次海盆基底形态特征及控制因素. 地学前缘, 26: 222~232.
查找原文
参考文献
丁航航, 丁巍伟, 张帆, 吴招才, 殷绍如, 方银霞. 2021. 南海海盆区深部结构的不对称性及控制因素. 地球科学, 46: 929~941.
查找原文
参考文献
郭志馗. 2019. 超慢速扩张洋脊热液循环机制的数值模拟研究. 中国地质大学博士学位论文.
查找原文
参考文献
李家彪, 丁巍伟, 吴自银, 张洁, 董崇志. 2012. 南海西南海盆的渐进式扩张. 科学通报, 57: 1896~1905.
查找原文
参考文献
栾锡武, 赵一阳, 秦蕴珊, 初凤友. 2002. 热液系统输向大洋的热通量估算. 海洋学报(中文版), 24(6): 59~66.
查找原文
参考文献
丘学林, 赵明辉, 敖威, 吕川川, 郝天珧, 游庆瑜, 阮爱国, 李家彪. 2011. 南海西南次海盆与南沙地块的OBS探测和地壳结构. 地球物理学报, 54(12): 3117~3128.
查找原文
参考文献
邵佳, 许鹤华, 谌永强, 施小斌, 王晓芳. 2021. 上地幔含水量对海底扩张过程中洋壳厚度的影响: 数值模拟. 地球科学, 46: 826~839.
查找原文
参考文献
宋珏琛, 李江海, 冯博. 2021. 慢速-超慢速扩张洋中脊热液活动及其机理. 地质学报, 95: 2273~2283.
查找原文
参考文献
王兴涛. 2004. 现代海底热液活动的热液循环及烟囱体研究. 中国海洋大学博士学位论文.
查找原文
参考文献
许鹤华, 马辉, 宋海斌, 陈爱华. 2011. 南海东部海盆扩张过程的数值模拟. 地球物理学报, 54: 3070~3078.
查找原文
参考文献
许佳锐. 2018. 南海IODP349基底玄武岩中钙质碳酸盐岩脉的岩石学和地球化学研究. 中国科学院大学(中国科学院广州地球化学研究所)硕士学位论文.
查找原文
参考文献
于俊辉, 阎贫, 林间. 2017. 南海西南次海盆与超慢速扩张西南印度洋中脊地壳结构对比. 热带海洋学报, 36: 51~61.
查找原文
参考文献
张洁, 李家彪, 李细兵, 吴振利. 2011. 渐进式扩张海盆亚丁湾与南海西南次海盆扩张演化特征的对比. 地球物理学报, 54: 3079~3088.
查找原文
参考文献
周怀阳, 朱启宽, 季福武, 杨群慧. 2020. 南海深水海山上的新发现. 科技导报, 38: 83~88.
查找原文
目录contents

    摘要

    洋壳厚度受多方面因素的影响,前人大多关注地幔温度、地幔源成分等岩石圈深部因素,很少关注岩石圈浅层的热液循环对洋壳厚度的影响。利用基于有限元的数值模拟手段,对扩张期不同背景(洋中脊、拆离断层)、不同扩张速率的热液循环与洋壳增生的关系进行研究。结果表明:洋壳增生达到稳定前,热液循环导致理论洋壳厚度发生阶段性减薄,减薄量随时间改变,并且推迟了上地幔中熔融体出现的时间;当洋壳增生达到稳定后,热液循环下产生的理论洋壳厚度反而比无热液循环的更厚。结合洋壳增生过程中对流热通量的变化分析,在洋壳增生前期的上地幔温度低,驱动热液循环的热源小,产生的对流热通量相对较小且不稳定,热液循环缓慢冷却上地幔顶部的温度,进而推迟上地幔初始熔融的时间,减弱上地幔的熔融,并造成一定时间阶段内的生成理论洋壳比正常理论洋壳厚度更薄;当洋壳增生达到稳定后,对流热通量达到最大并稳定,热液循环持续快速的冷却上地幔顶部温度,导致上地幔深部的热向上地幔顶部补给,反而增大了上地幔顶部的温度和熔融量,进而增大了理论洋壳厚度。随着扩张速率的增大,理论洋壳厚度增大,对流热通量增大,热液循环导致的洋壳阶段性减薄的最大减薄量也增大,阶段性减薄的时间缩短。结合南海西南次海盆的洋壳结构特征分析:两条横跨南海西南次海盆的地震剖面显示,海盆内存在异常薄的洋壳区域,并且两条地震剖面的最薄洋壳厚度相差0.85 km,推测海盆内异常薄洋壳和不同扩张时期的最薄洋壳厚度差异受到扩张期热液循环阶段性减薄洋壳作用的影响。

    Abstract

    The thickness of the oceanic crust is affected by many factors. Most of the predecessors have paid attention to the deep factors of the lithosphere such as mantle temperature and mantle source composition, and rarely to the influence of hydrothermal circulation in the shallow lithosphere on the thickness of the oceanic crust. The relationship between hydrothermal circulation and oceanic crust accretion under different backgrounds of expansion period (mid-ocean ridge, disassembly faults) and different expansion rates was studied by finite element-based numerical simulations. The results show that before the oceanic crust accretion reaches stability, the hydrothermal circulation leads to a phased thinning of the theoretical oceanic crust thickness. The thinning amount changes with time, and delays the occurrence of melt in the upper mantle; when the oceanic crust accretion reaches stability, the theoretical oceanic crust thickness produced under the hydrothermal circulation is thicker than that with no hydrothermal circulation. Combined with the analysis of the change of convective heat flux in the process of oceanic crust accretion, the upper mantle temperature in the early stage of oceanic crust accretion is low, the heat source driving the hydrothermal circulation is small, the convective heat flux generated is relatively small and unstable, and the hydrothermal circulation slowly cools the temperature of the top of the upper mantle, thereby delaying the initial melting time of the upper mantle, weakening the melting of the upper mantle, and causing the formation of the theoretical ocean crust thinner than the normal theoretical ocean crust within a certain time period. When the oceanic crust accretion reaches stability, the convective heat flux reaches the maximum and stable. The hydrothermal circulation continues to cool the temperature of the top of the upper mantle continuously and rapidly, resulting in the heat of the deep part of the upper mantle being replenished upward to the top of the mantle, which in turn increases the temperature and melting of the top of the upper mantle, thereby increasing the thickness of the theoretical oceanic crust. With the increase of the expansion rate, the thickness of the theoretical oceanic crust increases, the convective heat flux increases, and the maximum thinning of the phased thinning of the oceanic crust caused by the hydrothermal circulation also increases, and the time of phased thinning is shortened. Combined with the analysis of the structural characteristics of the oceanic crust in the southwest sub-basin of the South China Sea: two seismic profiles across the southwest sub-basin of the South China Sea show that there is an abnormally thin oceanic crust area in the ocean basin, and the thinnest oceanic crust thickness difference between the two seismic profiles is 0.85 km, and it is speculated that the difference in the thickness of the abnormally thin oceanic crust in the ocean basin and the thinnest oceanic crust at different expansion periods is affected by the phased thinning of the oceanic crust during the hydrothermal cycle during the expansion period.

  • 目前,地球物理探测是研究地球深部结构的最主要途径,钻穿莫霍面以真切地“看见”地球内部是人类一直以来的梦想,而地幔距地球表面隔着几十千米厚的地壳阻止了这一梦想的实现。相较于陆壳而言,洋壳的厚度更薄,且呈现厚度不均一性,在某些地方甚至缺失,因此寻找薄洋壳的发育位置可以为钻穿莫霍面提供良好的备选钻址。研究海底扩张过程中影响洋壳厚度生成的因素可以为预测较薄洋壳的位置提供理论支持,也能为这一现象的发生机制提供合理解释。洋壳增生是从地表到地幔的大尺度循环过程,因此洋壳厚度既受深层的地幔温度、地幔源成分和地幔含水量的影响(Niu Yaoling et al., 2001; Brunelli et al., 2018; 邵佳等, 2021),也可能受喷发到浅层的热液活动影响。

  • 热液循环对洋壳厚度的影响主要体现在能量方面,循环过程中低温流体从海底渗入岩石圈,被加热后密度变小,受浮力作用再从海底喷出,因此可以将深部岩石圈中的热量带到海底。在洋中脊扩张中心,由热液循环导致的热量散失约占全球大洋热通量的10%(Stein et al., 1994; Baker et al., 1996),Lowell et al.(1995)根据已有的热通量数据估算洋脊喷口场的总热通量在10到104MW量级之间;其中传导热通量远小于对流热通量,单个喷口的对流热通量约11.5MW,传导热通量约为39.7kW (栾锡武等, 2002; 王兴涛等, 2004);栾锡武等(2002)根据热液烟囱估算的总热通量是357GW;因此扩张期的热液循环将可能影响岩石圈的温度结构 (Morgan et al., 1993),从而对洋壳增生产生影响。

  • 前人对热液活动已经进行了大量的研究,最开始有学者认为在洋中脊扩张速率比较低的区域几乎不可能发育热液活动(Baker et al., 1996),然而之后的研究发现在慢速—超慢速扩张洋中脊处也存在许多热液活动(Baker et al., 2004)。因此,根据热液活动发育的不同区域背景,可以分为岩浆主控型和构造主控型两种热液活动。快速扩张洋中脊处的热液循环属于前者,主要分布在洋中脊轴部中央裂谷中;在慢速扩张洋中脊处,由于岩浆匮乏,热液活动受间歇性岩浆侵入活动的控制,常发育在拆离断层和非转换不连续间断系统内 (宋珏琛等, 2021)。

  • 南海西南次海盆扩张期发育大量热液活动,是南海形成过程中的重要组成部分(许佳锐等, 2018; 周怀阳等, 2020;丁航航等, 2021)。通过分析地球物理探测资料发现南海可能存在异常薄地壳。一些学者通过重力反演认为南海西南次海盆的洋壳厚度为1~4km(Braitenberg et al., 2006;Wu Zhaocai et al., 2017;Gozzard et al., 2018; Nguyen et al., 2020), Yu Junhui et al.(2018)通过解释地震测线认为海盆内薄洋壳厚度为2.4~3.6km;Ding Weiwei et al.(2016)通过对地震测线分析也认为海盆内存在异常薄洋壳,厚度约为2.6~3.6km。

  • 为了更好地寻找薄洋壳的发育位置和深入了解热液循环与洋壳生成厚度的关系及机制,本文基于有限元的数值模拟手段,构建扩张期不同背景(洋中脊、拆离断层)、不同扩张速率下的热液循环与洋壳增生的数值模型,分析海底扩张期热液循环对洋壳厚度的影响规律,为大洋钻探选址提供一定的理论支持。

  • 1 地质背景

  • 南海位于三大板块(欧亚板块、太平洋板块和印度-澳大利亚板块)交汇之处,形成于西部特提斯构造和东部太平洋构造的双层构造作用之下。自新生代以来,该区域经历了陆缘张裂、海底扩张和俯冲碰撞等复杂的演化过程,是研究海洋演化动力学的最佳区域(李家彪等, 2012),也是我国走向深海大洋研究的突破口。

  • 西南次海盆是南海的三大海盆之一,位于南海的西南部(张洁等, 2011;李家彪等, 2012),是一个呈NE向开口的V字形海盆(图1);海盆整体上呈渐进式扩张(张洁等,2011),中部有一个残余扩张脊,具有分段性,分为东北段、中段和西南段;其中东北段最先开始扩张,扩张时间是23.5~16Ma,扩张速率是13~36mm/a,洋中脊发育有大型海山,表明东北段在扩张期间的岩浆供应充足;中段的扩张时间是19~16Ma,扩张速率是19mm/a,属于慢速扩张洋中脊,洋中脊保留着原始的中央裂谷形态,扩张期的岩浆供应匮乏;西南段位于扩张中心的最前端,没有识别出可对比的磁异常条带(Briais et al., 1993),可能尚未发生海底扩张就停止生长了。

  • 西南次海盆东北段的基底类型表现为平坦基底和掀斜断块型基底交替出现(丁航航等, 2019),主要是因为东北段的扩张速率呈周期性变化,从而导致岩浆主导和构造主导两种扩张方式交替出现;海盆中段的基底类型表现为掀斜断块型基底,主要由构造作用主导,重力揭示中段存在异常薄洋壳。并通过重力模拟分析认为位于中央裂谷西南侧的龙门海山由异常低密度的物质组成,推测可能是地幔蛇纹岩化形成的蛇纹石泥海山(Wang Yanlin et al., 2017)。

  • 图1 南海西南次海盆地质背景图

  • Fig.1 Geological background map of the Southwest sub-basin of the South China Sea

  • 2 数学模型

  • 2.1 模型建立

  • 洋壳增生是在一定扩张速率下岩石圈发生拉张减薄、熔融、破裂,最终形成稳定洋壳的过程,模型选取固体力学物理场来模拟岩石圈拉张减薄过程,并基于角落流公式计算上升离散地幔流;同时,考虑到热液循环在岩石圈顶部的断裂或裂隙中流动,流速较慢,选取达西速度场表示。因此,本研究通过达西定律、多孔介质传热和固体力学三个物理场耦合实现对扩张期热液循环与洋壳增生过程的模拟。

  • 岩石圈几何模型设置成宽400km,深120km,分上地壳(5km)、下地壳(5km)、上地幔(110km)三层,为了直观地模拟出热液循环的形态,在岩石圈顶部分别设置一个5km和10km深的洋中脊断层和拆离断层,作为热液循环通道(图2)。在多孔介质传热物理场中的上边界温度设置为接近海底水温度(2℃)的开放边界,下边界温度为1350℃,岩石圈内部温度初始值采用线性插值设置成等地温梯度变化,两侧为热绝缘。海底基底地形通常呈现起伏变化,造成基底上覆海水压力不同,热液循环的海水一般从基底地形低、上覆海水压力大的区域渗入岩石圈,基底地形高、上覆海水压力小的区域喷出,因此在模型上边界断层两侧和顶部分别设置35MPa、30MPa的初始压力,以驱动热液循环。

  • 在热液循环与洋壳增生的模型中,岩石圈渗透率、驱动热液循环的热源、断层的深度等是确定热液循环形态和对流热通量大小的最主要因素(王兴涛等, 2004)。地幔熔融之前,热传导边界层是驱动热液循环的热源,地幔熔融之后,主要由上地幔熔融体为热液循环提供热源,并且随着地幔熔融区域的扩大和熔融体的上升,热源不断增大,加快了热液循环的速度,进而增大了对流热通量;当岩石圈上地幔达到温-压平衡的稳定状态时,驱动热液循环的熔融区域达到稳定,对流热通量也稳定。断层的深度和宽度在洋壳增生过程中不发生变化,不会对热液循环产生影响。岩石圈的渗透率结构一般是在实验室对玄武岩样品进行测量得到,获得的渗透率范围大概在10-17~10-13 m2之间(Becker et al., 1989; Larson et al., 1993),并且岩石圈渗透率具有温度依赖性,当岩石圈温度超过800℃时,岩石渗透率趋于0(郭志馗, 2019),因此在模型中设置了一个阶跃函数step(T)(当T ＜800℃时,step(T)=1;当T ＞800℃时,step(T)趋于0),并对阶跃函数进行平滑处理,过渡区为20℃,函数二阶连续可导。岩石圈的渗透率为:上地壳为1×10-15×step(T);下地壳为1×10-16×step(T);热液喷口为1×10-14×step(T);上地幔为0;模型中的网格划分采用极细化网格,流体材料使用的COMSOL5.6材料库里面的材料参数,其他参数取值见表1。

  • 图2 初始模型设置

  • Fig.2 Initial model configuration

  • (a)—洋中脊处热液循环的洋壳增生模型的初始设置;(b)—拆离断层处热液循环的洋壳增生模型的初始设置

  • (a)—The initial setup of the hydrothermal circulation oceanic crust hyperplasia model at the mid-ocean ridge; (b)—the initial setup of the hydrothermal circulation oceanic crust hyperplasia model at the disassembly fault

  • 表1 模型参数及取值

  • Table1 Definitions and values of model parameters

  • 2.2 理论依据

  • 2.2.1 控制方程

  • 达西定律:

  • ν→=∅u→→=-Kuf(∇P-ρg→)
    (1)

  • 质量守恒方程:

  • ∂∂t(∅ρ)=-∇⋅(∅ρu→)
    (2)

  • 因为孔隙率不随时间改变,并且流体是不可压缩的,故:

  • ∂∂t(∅ρ)=0
    (3)

  • 将(3)式代入(2)式,得到:

  • -∇⋅(∅u→)=0
    (4)

  • 能量守恒方程:

  • ρCPdTdt+ρCfνν→⋅∇T+ρCmV⋅∇T-∂∂xk∂T∂x-∂∂yk∂T∂y=Q
    (5)

  • 其中ν→是达西速度(单位为m/s), ∅是孔隙率, u→是流体在孔隙中的流速(单位为m/s),K是渗透率(单位为m2),P是压力(单位为MPa),uf是黏度(单位为Pa·s),ρ是密度(单位为kg/m3), g→是重力加速度(单位为m/s2),CP是恒压热容(单位为J·K/kg),T是温度(单位为℃),t是时间(单位为s),Cf为恒压下的流体热容(单位为J/(kg/K)),Cm为恒压下熔融体的热容(单位为J·K/kg),V是基于角落流公式计算得到的上升离散地幔流流速(单位为m/s),k为热导率(单位为W/(m·K)),Q为总热源(单位为W/m3),x、y分别为水平和垂直坐标(单位为km)。

  • 2.2.2 地幔部分熔融

  • 洋壳厚度主要是由岩浆供给量决定,地幔熔融的主要机制是由岩石上升引起的减压熔融,图3所示,地幔岩石的固相线的温度相对于压力的梯度大约是0.13℃/MPa(Healy et al., 2007),而在板块扩张中心,随着板块的扩张地幔被动上涌,其温度相对于压力的梯度可达到0.01~0.02℃/MPa(Langmuir et al., 1992)。地幔岩石绝热上升与地幔岩石固相线相交导致部分熔融,熔融区一般是一个三角形,三角形的底部是岩石固相线(图4)。

  • 图3 地幔岩石绝热上升引起的部分熔融过程示意图 (据许鹤华等, 2011)

  • Fig.3 Schematic pressure-temperature path for adiabatic melting resulting from upwelling (after Xu Hehua et al.,2011)

  • 图中的0%、5%、10%、15%、20%代表地幔发生部分熔融时的熔融分数

  • The 0%, 5%, 10%, 15%, and 20%in the figure represent the melting fraction when the mantle is partially melted

  • 图4 地幔岩石部分熔融区域示意图

  • Fig.4 Schematic diagram of the partially melted area of the mantle rock

  • 模型中描述扩张期洋壳增生的过程是建立在上升离散地幔流模型的基础上的,上升离散地幔流由等黏度的角落流模型给出:

  • ∇4ψ=0
    (6)

  • 其中ψ是流函数,Batchelor给出了流函数的解析解(Batchelor, 2000):

  • ψ=(Ax+By)+(Cx+Dy)arctan⁡yx
    (7)
  • Vx=-B-Darctan⁡yx+(Cx+Dy)-xx2-y2
    (8)
  • Vy=A+CCarctan⁡yx+(Cx+Dy)-yx2+y2
    (9)

  • 其中A、B、C、D是常数,由边界条件确定;Vx和Vy是上升流的速度分布(单位为m/s),如图5。

  • 图5 上升离散地幔流模型示意图(据Healy et al., 2007)

  • Fig.5 The schematic diagram of upwelling model (after Healy et al.,2007)

  • 上升离散地幔流模型的边界条件为:

  • 在 x=0 时, Vx=0,Vy=vy
    (10)
  • 在 y=0 时, Vy=0,Vx=vx,x>0-vx,x<0
    (11)

  • 其中vx,vy分别是水平和垂直速度分量,vx也代表半扩张速率, vx=vy;将上述边界条件带入Vx、Vy,就能得到A、B、C、D的值和上升地幔流的速度分布。(8)和(9)式得到的上升离散地幔流速度与多孔介质传热方程(5)耦合得到:

  • ρCPdTdt+ρCfν→⋅∇T+ρCfVx∂T∂x+Vy∂T∂y-∂∂xk∂T∂x-∂∂yk∂T∂y=Q
    (12)

  • 2.2.3 理论洋壳厚度计算

  • 本研究主要是通过积分相关区域的熔融生产率来估算理论洋壳厚度(Forsyth, 1993);熔融生产率是熔融分数在垂向上的微分(∂F∂y)和地幔上升流速度在相关模型网格区域的积分。在洋壳生成的过程中,岩石发生熔融后并不会全部被萃取成为洋壳,有一部分会保留在地幔中,模型中设置保留熔融分数为0.01(Bai Hailong et al., 2017);熔融生产率的计算公式为:

  • R=0;F<FcmaxVy∂F∂y,0;F>Fc
    (13)
  • H=∫0L ∫zb0 R2vxdxdy
    (14)

  • 其中F是熔融分数,Fc是保留熔融分数的临界值,vx是半扩张速率(单位为m/s),Vy是地幔上升流速度(单位为m/s),R是熔融生产率,zb是熔融区域的最小深度(单位为km),H代表洋壳厚度(单位为km),是相关熔融区域的宽度。

  • 3 模拟计算结果和讨论

  • 3.1 洋中脊处热液循环的洋壳增生模型

  • 在半扩张速率为1.5cm/a的洋壳增生模型中,模拟了有和无热液循环的洋壳增生过程(图6)。考虑到热液循环主要以热对流方式传输热量,并且热通量受很多因素影响,例如渗透率、断层的大小、扩张速率等,为了控制单一变量,研究热液循环对洋壳增生的影响,只在无热液循环的洋壳增生模型的基础上叠加了达西定律物理场,增加了对热液循环的模拟,两个模型中其他的参数和设置相同。

  • 在无热液循环的洋壳增生早期(0~3.4Ma),岩石圈处于拉张减薄阶段,上地幔温度升高, 3.4Ma时上地幔开始发生熔融,3.4~10Ma期间熔融区域不断扩大,并上升达到地幔顶部,10Ma之后,积聚在顶部的熔融体在岩石圈破裂后萃取结晶生成洋壳(图6a~e)。由于本文主要研究热液循环对理论洋壳厚度的影响,因此没有严格划定岩石圈破裂的时间,而是通过设置保留熔融分数(熔融体中没有萃取形成洋壳的部分)为0.01,再对区域的熔融生产率积分获得理论洋壳厚度(Bai Hailong et al., 2017)。

  • 在有热液循环的洋壳增生早期(~6.3Ma),岩石圈处于拉张减薄阶段,上地幔温度低没有达到地幔岩石固相线,主要以热传导边界层作为驱动热液循环的热源,对流热通量相对较小且不稳定,热对流效应弱,但也会缓慢地降低上地幔顶部的温度,推迟上地幔熔融体出现的时间;6.3Ma时上地幔开始发生熔融,与无热液循环的洋壳增生模型相比,推迟了2.9Ma;6.3~10Ma期间,上地幔熔融体作为驱动热液循环的热源,随着熔融区域不断扩大、上升,增强了热液对流效应,并改变了热液循环形态(如图6f~j中白线和箭头);10Ma之后,由于热源(上地幔熔融体)不断增大,热液循环形态也不断改变,并逐渐趋于稳定。

  • 图6 洋中脊处热液循环的洋壳增生模型

  • Fig.6 Model of oceanic crust accretion in hydrothermal circulation in the mid-ocean ridge

  • 图中地幔熔融体用相变等值线表示的,不同的颜色代表不同的相变转换程度(如图例所示),即熔融分数;(a)~(e)表示无热液活动的洋壳增生过程; (f)~(j)表示有热液活动的洋壳增生过程(图中白色的线和箭头是热液循环的流线和方向)

  • The mantle melt is represented by a phase change contour line, and different colors represent different degrees of phase transition (as shown in the legend), that is, the melting fraction;(a)~(e) represent the process of oceanic crust hyperplasia without hydrothermal activity; (f)~(j) represent the process of oceanic crust hyperplasia with hydrothermal activity (the white lines and arrows are the streamlines and directions of the hydrothermal cycle)

  • 对模型结果进行后处理,积分相关区域的熔融生产率与扩张速率的比值,得到半扩张速率为1.5cm/a,洋中脊处有无热液循环下洋壳增生的理论洋壳厚度随时间变化的曲线(图7a);积分岩石圈顶部上下洋壳的对流热通量,得到热液循环产生的对流热通量随时间的变化曲线(图7b)。结果显示,有无热液循环下产生的理论洋壳厚度都具有洋壳生成、增厚,并逐渐稳定的变化过程(图7a)。在5.45~16.9Ma期间,热液循环造成理论洋壳厚度发生阶段性的减薄,并且洋壳的减薄量(0~2.3km)随时间发生改变,但当洋壳增生达到稳定时,热液循环下生成的理论洋壳厚度却更厚。结合对流热通量随时间的变化曲线分析认为,在洋壳增生前期,上地幔没有发生熔融或熔融区域小,热传导边界层和较小的熔融区域充当驱动热液循环的热源,热源相对较小,对流热通量也比较小且不稳定,热液循环缓慢的冷却上地幔顶部的温度,从而在一定程度上减少了熔融量;当熔融体上升到上地幔顶部并不断积聚扩大达到稳定时,驱动热液循环的热源也逐渐增大并稳定,对流热通量达到最大且稳定,热液循环持续快速的冷却上地幔顶部的温度,导致上地幔深部的热向上地幔顶部补给,进而增大了上地幔顶部的温度,增大了地幔熔融量,产生更厚的理论洋壳厚度。并且深尺度的热液循环会导致部分熔融体在下地壳原位结晶(Theissen-Krah et al., 2016),结晶潜热充当驱动热液循环的热源可以进一步增大热对流效应,还有可能造成下地壳发生含水重熔(Koepke et al., 2005),进一步增大岩浆供给量。

  • 图7 理论洋壳厚度与对流热通量

  • Fig.7 The oretical oceanic crust thickness and convective heat flux

  • 在实际的洋壳增生过程中,新生成的洋壳展布在洋中脊附近1~2km内,随着地幔物质的涌出,冷凝形成的新洋壳会推着老洋壳向两边移动,因此距离洋中脊越远的洋壳年龄越老;热液循环造成阶段性减薄的理论洋壳也会随着时间推移而远离洋中脊,造成区域性洋壳减薄。

  • 为了研究不同扩张速率下扩张期的热液循环对洋壳增生的影响规律,分别在模型中设置1cm/a、1.5cm/a、2cm/a的半扩张速率,得到在不同扩张速率下的理论洋壳厚度(图8),随着扩张速率的增大,理论洋壳厚度增大,理论洋壳初始生成的时间提前,符合洋壳厚度与扩张速率之间的变化规律。

  • 对模型计算得到的理论洋壳厚度数据进行处理,得到同一扩张速率下的阶段性洋壳减薄量随时间发生变化;不同扩张速率下,阶段性洋壳的最大减薄量随扩张速率的增大而增大,最大减薄量出现的时间也随扩张速率的增大而提前。图9a中的x轴上侧曲线所示,半扩张速率为1cm/a时,洋壳的最大减薄量出现在16.4Ma, 减薄量为1.48km;半扩张速率为1.5cm/a时,洋壳最大减薄量出现在10.6Ma,减薄量为2.3km;半扩张速率为2cm/a时,洋壳最大减薄量出现在8.15Ma,减薄量为3.21km。对不同扩张速率下的对流热通量积分,得到对流热通量也随着扩张速率的增大而增大(图9b),因此,不稳定阶段的对流热通量增大也是造成阶段性理论洋壳的最大减薄量随扩张速率增大的原因。模型结果得到的热液循环造成阶段性理论洋壳减薄阶段的减薄量随时间变化特征,代表着实际洋壳增生过程中热液活动会造成不同扩张时期形成的洋壳区域的薄洋壳厚度也不同。

  • 图8 不同扩张速率v下的理论洋壳厚度

  • Fig.8 Theoretical crust thickness at different rates v of expansion

  • 图9 不同扩张速率v下的阶段性洋壳减薄量(a)与对流热通量(b)

  • Fig.9 Staged thinning of the oceanic crust (a) and convective heat flux (b) at different expansion rates v

  • 3.2 拆离断层处热液循环的洋壳增生模型

  • 热液循环系统可以发育在不同的地质背景下,岩浆作用主控的热液循环常发育在洋中脊的中央裂谷处,构造作用主控的热液循环常发育在拆离断层或非转换不连续间断系统内(宋珏琛等, 2021)。为了研究扩张期不同地质背景下热液循环对洋壳增生的影响,构建了半扩张速率为1.5cm/a的拆离断层处热液循环的洋壳增生模型,在洋壳增生过程中拆离断层处热液循环的流线形态依然不断变化 (图10f~j);在4.6~6Ma时,流线随熔融体的上升向洋中脊处流动,表明洋中脊处岩浆的上涌可能会将一部分流体带出。

  • 扩张期拆离断层处热液循环在洋壳增生的过程中依然起到阶段性减薄洋壳的作用(图11a),并且随着扩张速率的增大,对流热通量增大(图13b),理论洋壳厚度增大,上地幔发生熔融的时间提前(图12);同时热液循环造成的阶段性理论洋壳的减薄随时间发生改变,理论洋壳阶段性减薄的最大减薄量也随着扩张速率的增大而增大(图13a),与扩张期洋中脊处热液循环的洋壳增生模型得到的结论相同。

  • 与洋中脊处热液循环下的理论洋壳的阶段性最大减薄量对比,半扩张速率为1cm/a时,洋中脊处热液循环造成的最大阶段性洋壳减薄量为1.48km,拆离断层处热液循环造成的最大阶段性洋壳减薄量为0.65km;半扩张速率为1.5cm/a时,洋中脊热液循环造成的最大阶段性洋壳减薄量为2.3km,拆离断层处热液循环造成的最大阶段性洋壳减薄量为0.94km;半扩张速率为2cm/a时,洋中脊热液循环造成的最大阶段性洋壳减薄量为3.21km,拆离断层处热液循环造成的最大阶段性洋壳减薄量为1.42km,表明拆离断层处热液循环造成的阶段性洋壳减薄量(图13a)比洋中脊处热液循环造成的阶段性洋壳减薄量(图9a)小。这是由于拆离断层处热液循环只受到上地幔熔融体右侧区域提供的热源驱动,热源相对较小,产生的对流热通量较小(图13b),导致阶段性洋壳减薄量也较小。

  • 3.3 南海西南次海盆洋壳结构

  • 目前对于南海西南次海盆是否存在异常薄洋壳仍存在争议,一些学者认为西南次海盆属于正常洋壳厚度,例如丘学林等(2011)认为南海西南次海盆的洋壳厚度为5~6km,莫霍面埋深约为11km;Huang Haibo et al.(2019)也认为西南次海盆的平均洋壳厚度为5.3km,莫霍面埋深为10~12km,属于正常的洋壳厚度;但也有些学者通过多道地震和OBS等地球物理探测手段分析认为南海西南次海盆存在异常薄的洋壳,其中Yu Junhui et al.(2018)对NH973-1测线分析认为,海盆南部的洋壳厚度小于整体平均洋壳厚度,薄洋壳厚度为2.3~3.9km;Ding Hanghang et al.(2016)对N10测线分析也认为海盆内存在异常薄洋壳,厚度约为2.6~3.6km。

  • 本文选取NH973-1和500两条地震测线约束模型计算得到的结果,两条测线都呈NNW—SSE向展布,NH973-1测线横跨海盆的中段尾端,500测线横跨海盆中段前端(图14)。Yu Junhui et al.(2018)之前已经对NH973-1整条测线的地震剖面进行解释、时深转换,并建立P波速度模型,分析认为南海西南次海盆的洋壳厚度为2.4~3.6km(图15),表明在南海西南次海盆存在异常薄的洋壳区域。于俊辉等(2017)解释NH973-1地震剖面时也认为在海盆中发育很多深达地幔顶部的拆离断层,这些现存的深尺度拆离断层也证明了南海西南次海盆扩张期具有发生热液活动的条件;并且地震剖面的基底变化显示海盆基底呈平坦和隆起交替出现,洋壳厚度不均一,表明海盆在洋壳增生过程中的地质背景和动力学作用比较复杂。对500测线的地震剖面进行解释得到基底到莫霍面的双程走时为1~1.7s(图16),洋壳速度取6.5km/s,计算得到洋壳厚度约为3.25~5.5km,表明海盆其他区域也存在异常薄的洋壳。

  • 图10 拆离断层处热液循环的洋壳增生模型

  • Fig.10 Model of oceanic crust accretion in hydrothermal circulation at the disassembly fault

  • 图中地幔熔融体用相变等值线表示的,不同的颜色代表不同的相变转换程度(如图例所示),即熔融分数;(a)~(e)—无热液活动的洋壳增生过程,(f)~(j)—有热液活动的洋壳增生过程(图中白色的线和箭头是热液循环的流线和方向)

  • The mantle melt in the figure is represented by a phase change contour line, and the different colors represent different degrees of phase transition (as shown in the legend), that is, the melt fraction;(a)~(d)—the oceanic crust hyperplasia process without hydrothermal activity; (e)~(h)—the oceanic crust hyperplasia process with hydrothermal activity (the white lines and arrows in the figure are the streamlines and directions of the hydrothermal cycle)

  • 图11 理论洋壳厚度与对流热通量

  • Fig.11 The oretical oceanic crust thickness and convective heat flux

  • 图12 不同扩张速率v下的理论洋壳厚度

  • Fig.12 The oretical crust thickness at different rates v of expansion

  • 图13 不同扩张速率v下的阶段性洋壳减薄量与对流热通量

  • Fig.13 Staged thinning of the oceanic crust and convective heat flux at different expansion rates v

  • 结合模型结果分析,在半扩张速率为1cm/a时,热液循环在洋壳增生23.5Ma(洋中脊处)、20.2Ma(拆离断层处)之后才会造成理论洋壳厚度增厚(图8、12),而南海西南次海盆的扩张期约为23.5~16Ma,扩张期比较短,并且属于慢速扩张,海底扩张没有达到稳定阶段就停止了,因此,南海西南次海盆在扩张期并没有受到热液循环导致的理论洋壳厚度增厚阶段的影响,可能在热液循环造成的阶段性理论洋壳减薄期间就已经停止扩张。

  • 对比两条测线中最薄洋壳的厚度,NH973-1测线地震剖面中的最薄洋壳厚度位于残余洋中脊的西北侧,最薄洋壳厚度为2.4km,500测线地震剖面中的最薄洋壳厚度也位于残余扩张脊的西北侧,而最薄洋壳厚度为3.25km,两条测线中的最薄洋壳厚度相差0.85km,并且由于南海西南次海盆具有从东北段到西南段渐进式扩张的特征,两条测线所在的洋壳区域不是同一扩张时期内生成的,表明在南海西南次海盆内相近区域在不同扩张时期生成的最薄洋壳厚度也存在厚度差。洋壳厚度主要受地幔温度、地幔含水量、扩张速率的影响,而西南次海盆中两条测线的最薄洋壳区域的距离相近,且都位于残余洋中脊的西北侧,在扩张时的地幔温度、地幔含水量、扩张速率等影响洋壳厚度的因素是相同的,因此,两条地震剖面的最薄洋壳厚度差异可能是由扩张期热液循环下的阶段性洋壳减薄作用导致的。

  • 图14 NH973-1地震测线分布图 (据Yu Junhui et al., 2018)

  • Fig.14 The NH973-1seismic survey line (after Yu Junhui et al., 2018)

  • 综上所述,南海西南次海盆扩张期比较短,只受到热液循环在洋壳增生前期造成的阶段性洋壳减薄作用的影响,两条测线地震剖面也都表明海盆中存在异常薄洋壳区域。再分析两条测线地震剖面的最薄洋壳区域发现,500测线的最薄洋壳厚度为3.25km,NH973-1测线的最薄洋壳厚度为3.1km,表明在不同扩张时期,海盆内相近区域的最薄洋壳厚度也存在厚度差,与模型结论中得到的洋壳阶段性减薄期间的减薄量随时间改变相符。

  • 图15 NH973-1测线地震剖面及解释(据于俊辉等, 2017)

  • Fig.15 Seismic profile and interpretation of the NH973-1survey line (after Yu Junhui et al., 2017)

  • (a)—NH973-1测线中位于残余洋中脊西北侧的一段地震剖面; (b)—测线中位于残余洋中脊西南侧的一段地震剖面

  • (a)—A section of seismic profile in the NH973-1survey line located on the northwest side of the residual mid-ocean ridge; (b)—a section of the seismic profile in the survey line located on the southwest side of the residual mid-ocean ridge

  • 图16 500测线地震剖面及解释

  • Fig.16 Seismic profile and interpretation of the500survey line

  • 3.4 模拟的可靠性检验

  • 为了验证模拟手段的可靠性,分别构建了不同岩石圈渗透率的热液循环模型,验证模拟结果是否符合以下实际规律:① 随着渗透率增大,热液循环产生的热通量大小增大;② 对流热通量远大于传导热通量。分别将岩石圈渗透率设置为1×10-14、1×10-15、1×10-16,计算得到的结果如图17、18所示,从图17、18可以看出通过COMSOL5.6软件建立的热液循环模型得到的结果是符合实际规律的。

  • 图17 不同岩石圈渗透率下的对流热通量大小

  • Fig.17 The magnitude of the convective heat flux at different lithosphere permeability rates

  • 4 结论

  • 本文利用基于有限元的数值模拟手段,研究海底扩张期不同扩张速率、不同背景下的热液循环对洋壳增生的影响规律,建立了不同扩张速率下洋中脊、拆离断层处热液循环与洋壳增生的模型,对模型结果分析得到以下结论:

  • (1)在相同扩张速率下洋中脊处热液循环的洋壳增生模型中,洋壳增生稳定前,热液循环会使洋壳厚度产生阶段性减薄,阶段性洋壳减薄期间的减薄量随时间改变,并且推迟了上地幔熔融体出现的时间;当洋壳增生稳定后,热液循环下产生的理论洋壳厚度反而更厚。结合扩张期热液循环与洋壳增生过程中对流热通量的变化分析认为,洋壳增生前期是由热传导边界层或较小的上地幔熔融区作为驱动热液循环的热源,热源较小,对流热通量小且不稳定,热液循环缓慢冷却上地幔顶部的温度,在一段时间内减弱了地幔熔融;当洋壳增生稳定之后,较大且稳定的熔融区域作为驱动热液循环的热源,对流热通量也达到最大并稳定,热液循环持续快速的冷却上地幔顶部的温度,导致上地幔深部的热向顶部补给,反而增大了上地幔顶部温度和熔融量,从而产生更厚的理论洋壳。随着扩张速率的增大,对流热通量增大,热液循环导致的最大阶段性洋壳减薄量也逐渐增大,阶段性洋壳减薄的时间逐渐缩短。

  • 图18 热液系统中传导与对流热通量对比

  • Fig.18 Conduction versus convective heat flux in hydrothermal systems

  • (2)在相同扩张速率下,拆离断层处的热液循环模型,与洋中脊处热液循环模型相比,热液循环对洋壳增生的影响规律相似。热液循环会阶段性的减薄洋壳,减薄量也随时间发生改变,并推迟上地幔中熔融体出现的时间,随着扩张速率的增大,对流热通量增大,阶段性减薄的时间缩短,造成的最大减薄量增大。不同的是,拆离断层处的对流热通量和阶段性洋壳减薄量都比洋中脊处的小,推测可能是由于拆离断层位于上地幔熔融体右侧,使驱动热液循环的热源变小,产生的对流热通量减少,减弱了热液循环对上地幔顶部的冷却,进而造成理论洋壳厚度的阶段性减薄量变小。

  • (3)结合南海西南次海盆的实际地球物理探测资料分析认为:西南次海盆扩张期短,在热液循环造成的阶段性洋壳减薄期间就停止海底扩张了,因此,扩张期的热液循环会造成南海西南次海盆存在一些薄洋壳,并且相近区域的最薄洋壳存在厚度差,与模型结果得到的热液循环造成的洋壳阶段性减薄的减薄量随时间发生变化相符。

  • 致谢:感谢几位审稿专家及编辑提出的建设性的修改意见!

  • 参考文献

    • Bai Hailong, Montési L G J, Behn M D. 2017. MeltMigrator: a MATLAB-based software for modeling three-dimensional melt migration and crustal thickness variations at mid-ocean ridges following a rules-based approach. Geochemistry, Geophysics, Geosystems, 18(1): 445~456.

    • Baker E T, Chen Y J, Phipps Morgan J. 1996. The relationship between near-axis hydrothermal cooling and the spreading rate of mid-ocean ridges. Earth and Planetary Science Letters, 142(1): 137~145.

    • Baker E T, Edmonds H N, Michael P J, Bach W, Dick H J B, Snow J E, Walker S L, Banerjee N R, Langmuir C H. 2004. Hydrothermal venting in magma deserts: the ultraslow-spreading Gakkel and Southwest Indian Ridges. Geochemistry, Geophysics, Geosystems, 5(8): 29~58.

    • Batchelor G K. 2000. An Introduction to Fluid Dynamics. Cambridge: Cambridge University Press.

    • Becker K, Sakai H, Adamson A C, Alexandrovich J, Alt J C, Anderson R N, Bideau D, Gable R, Herzig P M, Houghton S, Ishizuka H, Kawahata H, Kinoshita H, Langseth M G, Lovell M A, Malpas J, Masuda H, Merrill R B, Morin R H, Mottl M J, Pariso J E, Pezard P, Phillips J, Sparks J, Uhlig S. 1989. Drilling deep into young oceanic crust, Hole 504B, Costa Rica Rift. Reviews of Geophysics, 27(1): 79~102.

    • Braitenberg C, Wienecke S, Wang Y. 2006. Basement structures from satellite-derived gravity field: South China Sea ridge. Journal of Geophysical Research: Solid Earth, 111(B5): 15~30.

    • Briais A, Patriat P, Tapponnier P. 1993. Updated interpretation of magnetic anomalies and seafloor spreading stages in the south China Sea: implications for the Tertiary tectonics of Southeast Asia. Journal of Geophysical Research: Solid Earth, 98(B4): 6299~6328.

    • Brunelli D, Cipriani A, Bonatti E. 2018. Thermal effects of pyroxenites on mantle melting below mid-ocean ridges. Nature Geoscience, 11(7): 520~525.

    • Ding Hanghang, Ding Weiwei, Fang Yinxia. 2019. Morphological characteristics and controlling factors of the basal floor of the southwest sub-basin of the South China Sea. Earth Science Frontiers, 26: 222~232(in Chinese with English abstract).

    • Ding Hanghang, Ding Weiwei, Zhang Fan, Wu Zhaocai, Yin Shaoru, Fang Yinxia. 2021. Asymmetry and control factors of deep structure in the South China Sea basin. Earth Science, 46: 929~941(in Chinese with English abstract).

    • Ding Weiwei, Li Jiabiao, Clift P D. 2016. Spreading dynamics and sedimentary process of the Southwest Sub-basin, South China Sea: constraints from multi-channel seismic data and IODP Expedition 349. Journal of Asian Earth Sciences, 115: 97~113.

    • Forsyth D W. 1993. Crustal thickness and the average depth and degree of melting in fractional melting models of passive flow beneath mid-ocean ridges. Journal of Geophysical Research: Solid Earth, 98(B9): 16073~16079.

    • Gozzard S, Kusznir N, Franke D, Cullen A, Reemst P, Henstra G. 2018. South China Sea crustal thickness and oceanic lithosphere distribution from satellite gravity inversion. Petroleum Geoscience, 25(1): 112~128.

    • Guo Zhikui. 2019. Numerical simulation of hydrothermal circulation mechanism of ultra-slow expansion of ocean ridges. PhD thesis of China University of Geosciences (in Chinese with English abstract).

    • Healy D, Kusznir N J, Karner G D, Manatschal G, Pinheiro L M. 2007. Early kinematic history of the Goban Spur rifted margin derived from a new model of continental breakup and sea-floor spreading initiation. In: Healy D, Kusznir N J, Karner G D, Manatschal G, Pinheiro L M, eds. Imaging, Mapping and Modelling Continental Lithosphere Extension and Breakup Geological Society of London, 282(1): 199~215.

    • Huang Haibo, Qiu Xueli, Pichot T, Klingelhoefer F, Zhao Minghui, Wang Ping, Hao Tianyao. 2019. Seismic structure of the northwestern margin of the South China Sea: implication for asymmetric continental extension. Geophysical Journal International, 218: 1246~1261.

    • Koepke J, Feig S T, Snow J. 2005. Hydrous partial melting within the lower oceanic crust. Terra Nova, 17(3): 286~291.

    • Langmuir C H, Klein E M, Plank T. 1992. Petrological systematics of mid-ocean ridge basalts: constraints on melt generation beneath ocean ridges. Mantle Flow and Melt Generation at Mid-Ocean Ridges, 71: 183~280.

    • Larson R L, Fisher A T, Jarrard R D, Becker K. 1993. Highly permeable and layered Jurassic oceanic crust in the western Pacific. Earth and Planetary Science Letters, 119(1): 71~83.

    • Li Jiabiao, Ding Weiwei, Wu Ziyin, Zhang Jie, Dong Chongzhi. 2012. The gradual expansion of the southwest basin of the South China Sea. Chinese Science Bulletin, 57: 1896~1905 (in Chinese with English abstract).

    • Lowell R P, Rona P A, Vonherzen R P. 1995. sea floor hydrothermal systems. Journal of Geophysical Research-Solid Earth, 100(B1): 327~352.

    • Luan Xiwu, Zhao Yiyang, Qin Yunshan, Chu Fengyou. 2002. Estimation of heat flux of hydrothermal systems transported to the oceans. Acta Oceanaria Sinica (Chinese Edition), 121: 59~66 (in Chinese with English abstract).

    • Morgan J P, Chen Y J. 1993. The genesis of oceanic crust-magma injection, hydrothermal circulation, and crustal flow. Journal of Geophysical Research, 98: 6283~6297.

    • Nguyen T N, Van Kha T, Van Nam B, Nguyen H T T. 2020. Sedimentary basement structure of the Southwest Sub-basin of the East Vietnam Sea by 3D direct gravity inversion. Marine Geophysical Research, 41(1): 7.

    • Niu Yaoling, Bideau D, Hëkinian R, Batiza R. 2001. Mantle compositional control on the extent of mantle melting, crust production, gravity anomaly, ridge morphology, and ridge segmentation: a case study at the Mid-Atlantic Ridge 33-35N. Earth and Planetary Sciences Letters, 186: 383~399.

    • Qiu Xuelin, Zhao Minghui, Ao Wei, Lü Chuanchuan, Hao Tianyao, You Qingyu, Ruan Aiguo, Li Jiabiao. 2011. OBS Detection and Crustal Structure of sub-basins and Nansha massifs in the southwestern South China Sea. Chinese Journal of Geophysics, 54(12): 3117~3128.

    • Shao Jia, Xu Hehua, Chen Yongqiang, Shi Xiaobin, Wang Xiaofang. 2021. Effects of upper mantle moisture content on ocean crust thickness during seafloor expansion: numerical simulation. Earth Science, 46: 826~839(in Chinese with English abstract).

    • Song Juechen, Li Jianghai, Feng Bo. 2021. Hydrothermal activity and mechanism of slow-ultra-slow expansion of mid-ocean ridges. Acta Geologica Sinica, 95: 2273~2283(in Chinese with English abstract).

    • Stein C A, Stein S. 1994. Constraints on hydrothermal heat flux through the oceanic lithosphere from global heat flow. Journal of Geophysical Research: Solid Earth, 99(B2): 3081~3095.

    • Theissen-Krah S, Rüpke L H, Hasenclever J. 2016. Modes of crustal accretion and their implications for hydrothermal circulation. Geophysical Research Letters, 43(3): 1124~1131.

    • Wang Xingtao. 2014. Hydrothermal circulation and chimney body study of modern seafloor hydrothermal activity. PhD thesis of Ocean University of China (in Chinese with English abstract).

    • Wang Yanlin, Wang Jun, Yan Pin, Qiu Yan. 2017. An Anomalous Seamount on the Southwestern Mid-Ridge of the South China Sea. Acta Geologica Sinica (English edition), 91(6): 2340~2341.

    • Xu Hehua, Ma Hui, Song Haibin, Chen Aihua. 2011. Numerical simulation of the expansion process of the basin in the eastern South China Sea. Chinese Journal of Geophysics, 54: 3070~3078(in Chinese with English abstract).

    • Xu Jiarui. 2018. Petrology and geochemistry of calcareous carbonate veins in IODP349 basal basalt in the South China Sea. Master degree thesis of University of Chinese Academy of Sciences (Guangzhou Institute of Geochemistry, Chinese Academy of Sciences) (in Chinese with English abstract).

    • Yu Junhui, Yan Qian, Lin Jian. 2017. Comparison of crustal structure of the southwest sub-basin of the South China Sea and ultra-slow expansion of the mid-ridge ridge of the southwest Indian Ocean. Journal of Tropical Oceanography, 36: 51~61(in Chinese with English abstract).

    • Yu Junhui, Yan Pin, Wang Yanlin, Zhang Jinchang, Qiu Yan, Pubellier M, Delescluse M. 2018. Seismic Evidence for Tectonically Dominated Seafloor Spreading in the Southwest Sub-basin of the South China Sea. Geochemistry, Geophysics, Geosystems, 19(9): 3459~3477.

    • Wu Zhaocai, Gao Jinyao, Ding Weiwei, Shen Zhongyan, Zhang Tao, Yang Chunguo. 2017. The moho depth of the south china sea basin from threo dimensional gravity inversion with constraing points and its cherecteristics. Chinese Journal of Geophysics, 60: 368~383.

    • Zhang Jie, Li Jiabiao, LI Xibing, Wu Zhenli. 2011. Comparison of evolutionary characteristics of the Gulf of Aden in the progressive expansion basin and the southwest sub-basin in the South China Sea. Chinese Journal of Geophysics, 54: 3079~3088(in Chinese with English abstract).

    • Zhou Huaiyang, Zhu Qikuan, Ji Fuwu, Yang Qunhui. 2020. New discoveries on deep-water seamounts in the South China Sea. Science & Technology Review, 38: 83~88(in Chinese with English abstract).

    • 丁航航, 丁巍伟, 方银霞. 2019. 南海西南次海盆基底形态特征及控制因素. 地学前缘, 26: 222~232.

    • 丁航航, 丁巍伟, 张帆, 吴招才, 殷绍如, 方银霞. 2021. 南海海盆区深部结构的不对称性及控制因素. 地球科学, 46: 929~941.

    • 郭志馗. 2019. 超慢速扩张洋脊热液循环机制的数值模拟研究. 中国地质大学博士学位论文.

    • 李家彪, 丁巍伟, 吴自银, 张洁, 董崇志. 2012. 南海西南海盆的渐进式扩张. 科学通报, 57: 1896~1905.

    • 栾锡武, 赵一阳, 秦蕴珊, 初凤友. 2002. 热液系统输向大洋的热通量估算. 海洋学报(中文版), 24(6): 59~66.

    • 丘学林, 赵明辉, 敖威, 吕川川, 郝天珧, 游庆瑜, 阮爱国, 李家彪. 2011. 南海西南次海盆与南沙地块的OBS探测和地壳结构. 地球物理学报, 54(12): 3117~3128.

    • 邵佳, 许鹤华, 谌永强, 施小斌, 王晓芳. 2021. 上地幔含水量对海底扩张过程中洋壳厚度的影响: 数值模拟. 地球科学, 46: 826~839.

    • 宋珏琛, 李江海, 冯博. 2021. 慢速-超慢速扩张洋中脊热液活动及其机理. 地质学报, 95: 2273~2283.

    • 王兴涛. 2004. 现代海底热液活动的热液循环及烟囱体研究. 中国海洋大学博士学位论文.

    • 许鹤华, 马辉, 宋海斌, 陈爱华. 2011. 南海东部海盆扩张过程的数值模拟. 地球物理学报, 54: 3070~3078.

    • 许佳锐. 2018. 南海IODP349基底玄武岩中钙质碳酸盐岩脉的岩石学和地球化学研究. 中国科学院大学(中国科学院广州地球化学研究所)硕士学位论文.

    • 于俊辉, 阎贫, 林间. 2017. 南海西南次海盆与超慢速扩张西南印度洋中脊地壳结构对比. 热带海洋学报, 36: 51~61.

    • 张洁, 李家彪, 李细兵, 吴振利. 2011. 渐进式扩张海盆亚丁湾与南海西南次海盆扩张演化特征的对比. 地球物理学报, 54: 3079~3088.

    • 周怀阳, 朱启宽, 季福武, 杨群慧. 2020. 南海深水海山上的新发现. 科技导报, 38: 83~88.

  • 基本信息

    DOI: 10.19762/j.cnki.dizhixuebao.2022157

    基金信息

    本文为NSFC-广东联合基金项目(编号U20A20100)；
    中国科学院战略性先导科技专项(A类)(编号XDA13010303)联合资助的成果；

    引用信息

    张慧慧, 许鹤华, 姚永坚, 邵佳, 纪顺奎. 2022. 南海西南次海盆扩张期热液循环与洋壳增生的数值模拟. 地质学报, 96(8): 2927~2941.

    Zhang Huihui, Xu Hehua, Yao Yongjian, Shao Jia, Ji Shunkui. 2022. Numerical simulation of hydrothermal circulation and oceanic crust accretion during the expansion period of the southwestern sub-basin of the South China Sea. Acta Geologica Sinica, 96(8):2927~2941.

    稿件历史

    收稿日期: 2022-05-20

  • 参考文献

    • Bai Hailong, Montési L G J, Behn M D. 2017. MeltMigrator: a MATLAB-based software for modeling three-dimensional melt migration and crustal thickness variations at mid-ocean ridges following a rules-based approach. Geochemistry, Geophysics, Geosystems, 18(1): 445~456.

    • Baker E T, Chen Y J, Phipps Morgan J. 1996. The relationship between near-axis hydrothermal cooling and the spreading rate of mid-ocean ridges. Earth and Planetary Science Letters, 142(1): 137~145.

    • Baker E T, Edmonds H N, Michael P J, Bach W, Dick H J B, Snow J E, Walker S L, Banerjee N R, Langmuir C H. 2004. Hydrothermal venting in magma deserts: the ultraslow-spreading Gakkel and Southwest Indian Ridges. Geochemistry, Geophysics, Geosystems, 5(8): 29~58.

    • Batchelor G K. 2000. An Introduction to Fluid Dynamics. Cambridge: Cambridge University Press.

    • Becker K, Sakai H, Adamson A C, Alexandrovich J, Alt J C, Anderson R N, Bideau D, Gable R, Herzig P M, Houghton S, Ishizuka H, Kawahata H, Kinoshita H, Langseth M G, Lovell M A, Malpas J, Masuda H, Merrill R B, Morin R H, Mottl M J, Pariso J E, Pezard P, Phillips J, Sparks J, Uhlig S. 1989. Drilling deep into young oceanic crust, Hole 504B, Costa Rica Rift. Reviews of Geophysics, 27(1): 79~102.

    • Braitenberg C, Wienecke S, Wang Y. 2006. Basement structures from satellite-derived gravity field: South China Sea ridge. Journal of Geophysical Research: Solid Earth, 111(B5): 15~30.

    • Briais A, Patriat P, Tapponnier P. 1993. Updated interpretation of magnetic anomalies and seafloor spreading stages in the south China Sea: implications for the Tertiary tectonics of Southeast Asia. Journal of Geophysical Research: Solid Earth, 98(B4): 6299~6328.

    • Brunelli D, Cipriani A, Bonatti E. 2018. Thermal effects of pyroxenites on mantle melting below mid-ocean ridges. Nature Geoscience, 11(7): 520~525.

    • Ding Hanghang, Ding Weiwei, Fang Yinxia. 2019. Morphological characteristics and controlling factors of the basal floor of the southwest sub-basin of the South China Sea. Earth Science Frontiers, 26: 222~232(in Chinese with English abstract).

    • Ding Hanghang, Ding Weiwei, Zhang Fan, Wu Zhaocai, Yin Shaoru, Fang Yinxia. 2021. Asymmetry and control factors of deep structure in the South China Sea basin. Earth Science, 46: 929~941(in Chinese with English abstract).

    • Ding Weiwei, Li Jiabiao, Clift P D. 2016. Spreading dynamics and sedimentary process of the Southwest Sub-basin, South China Sea: constraints from multi-channel seismic data and IODP Expedition 349. Journal of Asian Earth Sciences, 115: 97~113.

    • Forsyth D W. 1993. Crustal thickness and the average depth and degree of melting in fractional melting models of passive flow beneath mid-ocean ridges. Journal of Geophysical Research: Solid Earth, 98(B9): 16073~16079.

    • Gozzard S, Kusznir N, Franke D, Cullen A, Reemst P, Henstra G. 2018. South China Sea crustal thickness and oceanic lithosphere distribution from satellite gravity inversion. Petroleum Geoscience, 25(1): 112~128.

    • Guo Zhikui. 2019. Numerical simulation of hydrothermal circulation mechanism of ultra-slow expansion of ocean ridges. PhD thesis of China University of Geosciences (in Chinese with English abstract).

    • Healy D, Kusznir N J, Karner G D, Manatschal G, Pinheiro L M. 2007. Early kinematic history of the Goban Spur rifted margin derived from a new model of continental breakup and sea-floor spreading initiation. In: Healy D, Kusznir N J, Karner G D, Manatschal G, Pinheiro L M, eds. Imaging, Mapping and Modelling Continental Lithosphere Extension and Breakup Geological Society of London, 282(1): 199~215.

    • Huang Haibo, Qiu Xueli, Pichot T, Klingelhoefer F, Zhao Minghui, Wang Ping, Hao Tianyao. 2019. Seismic structure of the northwestern margin of the South China Sea: implication for asymmetric continental extension. Geophysical Journal International, 218: 1246~1261.

    • Koepke J, Feig S T, Snow J. 2005. Hydrous partial melting within the lower oceanic crust. Terra Nova, 17(3): 286~291.

    • Langmuir C H, Klein E M, Plank T. 1992. Petrological systematics of mid-ocean ridge basalts: constraints on melt generation beneath ocean ridges. Mantle Flow and Melt Generation at Mid-Ocean Ridges, 71: 183~280.

    • Larson R L, Fisher A T, Jarrard R D, Becker K. 1993. Highly permeable and layered Jurassic oceanic crust in the western Pacific. Earth and Planetary Science Letters, 119(1): 71~83.

    • Li Jiabiao, Ding Weiwei, Wu Ziyin, Zhang Jie, Dong Chongzhi. 2012. The gradual expansion of the southwest basin of the South China Sea. Chinese Science Bulletin, 57: 1896~1905 (in Chinese with English abstract).

    • Lowell R P, Rona P A, Vonherzen R P. 1995. sea floor hydrothermal systems. Journal of Geophysical Research-Solid Earth, 100(B1): 327~352.

    • Luan Xiwu, Zhao Yiyang, Qin Yunshan, Chu Fengyou. 2002. Estimation of heat flux of hydrothermal systems transported to the oceans. Acta Oceanaria Sinica (Chinese Edition), 121: 59~66 (in Chinese with English abstract).

    • Morgan J P, Chen Y J. 1993. The genesis of oceanic crust-magma injection, hydrothermal circulation, and crustal flow. Journal of Geophysical Research, 98: 6283~6297.

    • Nguyen T N, Van Kha T, Van Nam B, Nguyen H T T. 2020. Sedimentary basement structure of the Southwest Sub-basin of the East Vietnam Sea by 3D direct gravity inversion. Marine Geophysical Research, 41(1): 7.

    • Niu Yaoling, Bideau D, Hëkinian R, Batiza R. 2001. Mantle compositional control on the extent of mantle melting, crust production, gravity anomaly, ridge morphology, and ridge segmentation: a case study at the Mid-Atlantic Ridge 33-35N. Earth and Planetary Sciences Letters, 186: 383~399.

    • Qiu Xuelin, Zhao Minghui, Ao Wei, Lü Chuanchuan, Hao Tianyao, You Qingyu, Ruan Aiguo, Li Jiabiao. 2011. OBS Detection and Crustal Structure of sub-basins and Nansha massifs in the southwestern South China Sea. Chinese Journal of Geophysics, 54(12): 3117~3128.

    • Shao Jia, Xu Hehua, Chen Yongqiang, Shi Xiaobin, Wang Xiaofang. 2021. Effects of upper mantle moisture content on ocean crust thickness during seafloor expansion: numerical simulation. Earth Science, 46: 826~839(in Chinese with English abstract).

    • Song Juechen, Li Jianghai, Feng Bo. 2021. Hydrothermal activity and mechanism of slow-ultra-slow expansion of mid-ocean ridges. Acta Geologica Sinica, 95: 2273~2283(in Chinese with English abstract).

    • Stein C A, Stein S. 1994. Constraints on hydrothermal heat flux through the oceanic lithosphere from global heat flow. Journal of Geophysical Research: Solid Earth, 99(B2): 3081~3095.

    • Theissen-Krah S, Rüpke L H, Hasenclever J. 2016. Modes of crustal accretion and their implications for hydrothermal circulation. Geophysical Research Letters, 43(3): 1124~1131.

    • Wang Xingtao. 2014. Hydrothermal circulation and chimney body study of modern seafloor hydrothermal activity. PhD thesis of Ocean University of China (in Chinese with English abstract).

    • Wang Yanlin, Wang Jun, Yan Pin, Qiu Yan. 2017. An Anomalous Seamount on the Southwestern Mid-Ridge of the South China Sea. Acta Geologica Sinica (English edition), 91(6): 2340~2341.

    • Xu Hehua, Ma Hui, Song Haibin, Chen Aihua. 2011. Numerical simulation of the expansion process of the basin in the eastern South China Sea. Chinese Journal of Geophysics, 54: 3070~3078(in Chinese with English abstract).

    • Xu Jiarui. 2018. Petrology and geochemistry of calcareous carbonate veins in IODP349 basal basalt in the South China Sea. Master degree thesis of University of Chinese Academy of Sciences (Guangzhou Institute of Geochemistry, Chinese Academy of Sciences) (in Chinese with English abstract).

    • Yu Junhui, Yan Qian, Lin Jian. 2017. Comparison of crustal structure of the southwest sub-basin of the South China Sea and ultra-slow expansion of the mid-ridge ridge of the southwest Indian Ocean. Journal of Tropical Oceanography, 36: 51~61(in Chinese with English abstract).

    • Yu Junhui, Yan Pin, Wang Yanlin, Zhang Jinchang, Qiu Yan, Pubellier M, Delescluse M. 2018. Seismic Evidence for Tectonically Dominated Seafloor Spreading in the Southwest Sub-basin of the South China Sea. Geochemistry, Geophysics, Geosystems, 19(9): 3459~3477.

    • Wu Zhaocai, Gao Jinyao, Ding Weiwei, Shen Zhongyan, Zhang Tao, Yang Chunguo. 2017. The moho depth of the south china sea basin from threo dimensional gravity inversion with constraing points and its cherecteristics. Chinese Journal of Geophysics, 60: 368~383.

    • Zhang Jie, Li Jiabiao, LI Xibing, Wu Zhenli. 2011. Comparison of evolutionary characteristics of the Gulf of Aden in the progressive expansion basin and the southwest sub-basin in the South China Sea. Chinese Journal of Geophysics, 54: 3079~3088(in Chinese with English abstract).

    • Zhou Huaiyang, Zhu Qikuan, Ji Fuwu, Yang Qunhui. 2020. New discoveries on deep-water seamounts in the South China Sea. Science & Technology Review, 38: 83~88(in Chinese with English abstract).

    • 丁航航, 丁巍伟, 方银霞. 2019. 南海西南次海盆基底形态特征及控制因素. 地学前缘, 26: 222~232.

    • 丁航航, 丁巍伟, 张帆, 吴招才, 殷绍如, 方银霞. 2021. 南海海盆区深部结构的不对称性及控制因素. 地球科学, 46: 929~941.

    • 郭志馗. 2019. 超慢速扩张洋脊热液循环机制的数值模拟研究. 中国地质大学博士学位论文.

    • 李家彪, 丁巍伟, 吴自银, 张洁, 董崇志. 2012. 南海西南海盆的渐进式扩张. 科学通报, 57: 1896~1905.

    • 栾锡武, 赵一阳, 秦蕴珊, 初凤友. 2002. 热液系统输向大洋的热通量估算. 海洋学报(中文版), 24(6): 59~66.

    • 丘学林, 赵明辉, 敖威, 吕川川, 郝天珧, 游庆瑜, 阮爱国, 李家彪. 2011. 南海西南次海盆与南沙地块的OBS探测和地壳结构. 地球物理学报, 54(12): 3117~3128.

    • 邵佳, 许鹤华, 谌永强, 施小斌, 王晓芳. 2021. 上地幔含水量对海底扩张过程中洋壳厚度的影响: 数值模拟. 地球科学, 46: 826~839.

    • 宋珏琛, 李江海, 冯博. 2021. 慢速-超慢速扩张洋中脊热液活动及其机理. 地质学报, 95: 2273~2283.

    • 王兴涛. 2004. 现代海底热液活动的热液循环及烟囱体研究. 中国海洋大学博士学位论文.

    • 许鹤华, 马辉, 宋海斌, 陈爱华. 2011. 南海东部海盆扩张过程的数值模拟. 地球物理学报, 54: 3070~3078.

    • 许佳锐. 2018. 南海IODP349基底玄武岩中钙质碳酸盐岩脉的岩石学和地球化学研究. 中国科学院大学(中国科学院广州地球化学研究所)硕士学位论文.

    • 于俊辉, 阎贫, 林间. 2017. 南海西南次海盆与超慢速扩张西南印度洋中脊地壳结构对比. 热带海洋学报, 36: 51~61.

    • 张洁, 李家彪, 李细兵, 吴振利. 2011. 渐进式扩张海盆亚丁湾与南海西南次海盆扩张演化特征的对比. 地球物理学报, 54: 3079~3088.

    • 周怀阳, 朱启宽, 季福武, 杨群慧. 2020. 南海深水海山上的新发现. 科技导报, 38: 83~88.

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