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重震联合反演密度结构可以提供更多的岩石圈深部热动力学信息。本研究以琼东南盆地3条多道地震骨干剖面为约束,采用重力异常数据反演岩石圈密度结构,探究琼东南盆地岩石圈非均一伸展的深部成因机制。研究结果显示,琼东南盆地普遍受控于深部地幔上隆底侵,特别是西部乐东凹陷和东部宝岛凹陷两大强烈减薄区,上地幔、下地壳均表现出异于正常岩石圈的高密度值,分别为2.92～2.96 g/cm3和3.30～3.40 g/cm3。不同于琼东南盆地东部宝岛凹陷,西部乐东凹陷的高密度异常体范围更为广泛,甚至在上地壳底部也有高密度异常体分布,局部密度值达2.82～2.90 g/cm3。然而,盆地裂陷期末的高热流中心、地壳减薄中心和高密度异常中心,三者并非完全重合,且东部宝岛凹陷非均一程度更高。综合分析发现,琼东南盆地不仅存在东、西部伸展差异,自深部至浅部的热动力控制模式也是非均一的。本研究成果为进一步约束南海西北部陆缘伸展演化模式提供了数据基础。
Abstract：Gravity-seismic inversion of density structures provides more information on deep lithospheric thermomechanical processes. This study employs gravity anomaly data, constrained by three multichannel seismic profiles across Qiongdongnan Basin, to invert the lithospheric density structure and investigate the deep-seated genetic mechanisms of non-uniform extension within the basin. The results reveal that Qiongdongnan Basin is generally controlled by deep mantle upwelling and underplating. Particularly in the intensely thinned Ledong Sag in the west and Baodao Sag in the east, the upper mantle and lower crust exhibit anomalously high densities of 2.92～2.96 g/cm3 and 3.30～3.40 g/cm3 respectively, which deviate from normative lithospheric values. Compared to Baodao Sag in the east, Ledong Sag in the west displays more extensive high-density anomalies, with anomalous bodies distributed even at the base of the upper crust, where local densities reach 2.82～2.90 g/cm3. However, the high thermal flow center, the crustal thinning center, and high-density anomaly center during the late rifting stage are not completely coincident. Baodao Sag in the east demonstrates higher degree of nonuniformity. A comprehensive analysis finds that Qiongdongnan Basin exhibits not only differences in extension between the eastern and western regions but also non-uniform thermo-mechanical controls from the deep mantle to shallow crustal levels. This study provides a data basis for further constraining the extensional evolution models of the continental margin of the northwestern South China Sea.
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基本信息:
DOI：10.16452/j.cnki.sdkjzk.2026.01.004
中图分类号:P313
引用信息:
[1]李朝阳,徐乔,胡毅,等.基于重震联合反演的琼东南盆地岩石圈密度结构和非均一伸展模式研究[J].山东科技大学学报(自然科学版),2026,45(01):37-48.DOI:10.16452/j.cnki.sdkjzk.2026.01.004.
基金信息:
福建省海洋物理与地质过程重点实验室开放基金课题（KLMPG-23-02）; 国家自然科学基金项目（42406077）; 山东省自然科学基金项目（ZR2022QD087）
2025-07-10
2025
2025-12-04
2026-01-22
2026
1
2026-02-15
2026-02-15