南海北部陆缘热流变化特征及其影响因素分析

发布时间：2018-04-27 12:30

本文选题：构造热演化 + 数值模拟　；参考：《地学前缘》2017年03期

【摘要】：热流调查和构造热演化数值模拟是油气地热研究不可或缺的重要内容。沉积盆地在其演化过程中往往叠加了特殊构造事件。通过热流调查和构造热演化数值计算可以更好地约束这些特殊过程,重建更为真实的构造热演化历史。该文通过对南海北部琼东南盆地和珠江口盆地中段热流变化特征分析和构造热演化数值模拟,探讨了影响其热流变化的主要因素。结果表明,琼东南盆地可分3个热流分区:北部陆架与上陆坡区(50~70mW/m~2)、中央坳陷带深水区(70~85mW/m~2)和盆地东部深水区高热流带(85mW/m~2);珠江口盆地中段从陆架往海盆方向热流呈阶梯式抬高,西江凹陷平均热流为55mW/m~2,番禺低隆起为58mW/m~2,白云凹陷为70mW/m~2,下陆坡区为85mW/m~2;陆坡区高热流不仅与岩石圈强烈减薄相关,而且还受到岩石圈破裂时引起的深部热物质上涌的影响,后者对现今陆坡区还有约20mW/m~2的热流贡献;琼东南盆地东部高热流值则主要受到晚中新世以来的岩体侵位热事件的影响,岩体侵入热事件对现今热流值贡献可达10~25mW/m~2。分析表明,在南海深水盆地开展构造热演化数值计算时,需要考虑沉积过程、海底扩张以及岩浆活动等影响因素。
[Abstract]:The investigation of heat flow and numerical simulation of tectonic thermal evolution are important contents of oil and gas geothermal research. During the evolution of sedimentary basins, special tectonic events are often superimposed. Through the investigation of heat flux and numerical calculation of tectonic thermal evolution, these special processes can be restrained better and a more real history of tectonic thermal evolution can be reconstructed. Based on the analysis of the characteristics of heat flux variation and the numerical simulation of tectonic thermal evolution in the Qiongdongnan Basin and the Pearl River Estuary Basin in the north of the South China Sea, the main factors affecting the variation of heat flux are discussed in this paper. The results show that the Qiongdongnan basin can be divided into three heat flow zones: the northern shelf and the upper slope area, the north shelf and the upper slope area, the deep water area of the central depression belt, the deep water area of the central depression, and the high heat flow zone of the eastern deep water area of the basin, the heat flow in the middle section of the Pearl River mouth basin is raised step by step from the continental shelf to the sea basin. The average heat flow in Xijiang sag is 55mW / mm2, Panyu low uplift is 58mW / mm2, Baiyun sag is 70mW / mt2, and downslope is 85mW / m2.High heat flux in continental slope is not only related to lithosphere thinning, but also affected by deep thermal material upwelling caused by lithosphere rupture. The latter contributes about 20mW/m~2 to the present continental slope, while the high heat flux in the eastern part of Qiongdongnan basin is mainly affected by emplacement heat events since late Miocene, and the contribution of intrusive heat events to the current heat flux is 1025 MW / mm2. The analysis shows that in the numerical calculation of tectonic thermal evolution in the deep-water basin of the South China Sea, the influence factors such as sedimentary process, undersea spreading and magmatic activity should be considered.
【作者单位】：中国科学院边缘海地质重点实验室中国科学院南海海洋研究所;中国科学院大学;
【基金】：国家自然科学基金项目(41176050,41576036,41376059)
【分类号】：P314;P736

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