Asymmetry in oceanic crustal structure of the South China Sea basin and its implications on mantle geodynamics
Asymmetry in oceanic crustal structure of the South China Sea basin and its implications on mantle geodynamics
复制标题
南海盆地洋壳结构的不对称性及其对地幔地球动力学的意义
DOI：
10.1080/00206814.2018.1425922
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发表时间：
2020-05
影响因子：
2.6
通讯作者：
J. Zhu
中科院分区：
文献类型：
--
作者：
Zhang F.;J. Lin;X. Zhang;W. Ding;T. Wang;J. Zhu
摘要：我们通过对剩余重力异常和测深数据进行综合分析，并结合地震约束以及地球动力学解释，研究了南海盆地的大洋地壳结构和岩石圈动力学。
ABSTRACT We investigated the oceanic crustal structure and lithospheric dynamics of the South China Sea (SCS) basin through a comprehensive analysis of residual gravity anomaly and bathymetry combined with seismic constraints and interpretation from geodynamic modelling. We first calculated the residual mantle Bouguer anomaly (RMBA) of the oceanic crustal regions of the SCS by removing from free-air gravity anomaly the predicted gravitational attractions of water-sediment, sediment-crust, and crust-mantle interfaces, as well as the effects of lithospheric plate cooling, using the latest crustal age constraints including IODP Expedition 349 and recent deep-tow magnetic surveys. We then calculated models of the gravity-derived crustal thickness and calibrated them using the available seismic refraction profiles of the SCS. The gravity-derived crustal thickness models correlate positively with seismically determined crustal thickness values. Our analysis revealed that the isochron-averaged RMBA are consistently more negative over the northern flank of the SCS basin than the southern conjugate for magnetic anomaly chrons C8n (~25.18 Ma) to C5Dn (~17.38 Ma), implying warmer mantle and/or thicker crust over much of the northern flank. Computational geodynamic modelling yielded the following interpretations: (1) Models of asymmetric and variable spreading rates based on the relatively high-resolution deep-tow magnetic analysis would predict alternating thicker and thinner crust at the northern flank than the southern conjugate, which is inconsistent with the observed systematically thicker crust on the northern flank. (2) Models of episodic southward ridge jumps could reproduce the observed N-S asymmetry, but only for crustal age of 23.6–20 Ma. (3) Southward migration of the SCS ridge axis would predict slightly thinner crust at the northern flank, which is inconsistent with the observations. (4) Models of higher mantle temperatures of up to 25–50°C or >2% less depleted mantle sources on the northern flank could produce large enough anomalies to explain the observed N-S asymmetries.
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影响因子：
2.9
作者：
Y. Pin;Z. Di;Zhao-shu Liu
通讯作者：
Y. Pin;Z. Di;Zhao-shu Liu
DOI：
10.1007/s11430-011-4324-9
发表时间：
2011
期刊：
Science China Earth Sciences
影响因子：
--
作者：
Zhenli Wu;Jiabiao Li;A. Ruan;Hai Lou;W. Ding;X. Niu;Xibing Li
通讯作者：
Zhenli Wu;Jiabiao Li;A. Ruan;Hai Lou;W. Ding;X. Niu;Xibing Li
影响因子：
--
作者：
D. Sparks;E. Parmentier;J. Morgan
通讯作者：
D. Sparks;E. Parmentier;J. Morgan
DOI：
--
发表时间：
2012
期刊：
--
影响因子：
--
作者：
Ao Wei
通讯作者：
Ao Wei
影响因子：
3
作者：
E. He;Minghui Zhao;X. Qiu;J. Sibuet;Jian Wang;Jiazheng Zhang
通讯作者：
E. He;Minghui Zhao;X. Qiu;J. Sibuet;Jian Wang;Jiazheng Zhang