东海陆架盆地西湖凹陷岩石圈热流变性质

发布时间：2018-01-22 18:31

本文关键词： 东海陆架盆地西湖凹陷岩石圈热结构流变性质　出处：《大地构造与成矿学》2017年03期 　论文类型：期刊论文

【摘要】：为了探讨东海陆架盆地西湖凹陷岩石圈热流变性质,本文以实测地温数据为依据,模拟西湖凹陷岩石圈热结构,在此基础上,应用流变学原理模拟确定西湖凹陷岩石圈流变性质。结果表明,西湖凹陷岩石圈为一个冷地壳-热地幔、强地壳-弱地幔的"奶油蛋糕"型岩石圈。西湖凹陷平均地表热流密度为71 m W/m~2,地幔热流密度为40~65 m W/m~2,对地表热流密度的贡献度达73%~79%,地表热流受地幔热流控制,莫霍面温度在700℃左右,热岩石圈平均厚度为66 km。西湖凹陷岩石圈流变分层明显,上、中地壳基本为脆性层,下地壳和岩石圈上地幔为韧性层,岩石圈总流变强度平均约为2.65′10~(12) N/m,其中地壳流变强度为2.12′10~(12) N/m,地幔流变强度为5.29′10~(11) N/m,有效弹性厚度为11.7~14.5 km,地壳的流变性质控制了岩石圈的流变行为。此外,西湖凹陷岩石圈总强度较低,在构造应力作用下易于变形,且存在壳幔解耦现象。西湖凹陷岩石圈热状态及流变性质决定了西湖凹陷东部地区主要以浅部地壳的断层滑动和地层破裂来调节深部的构造应力。
[Abstract]:In order to investigate the lithospheric thermal rheological properties of West Lake sag of the East China Sea shelf basin, based on the measured temperature data, the simulation of thermal structure of lithosphere in West Lake depression, on the basis of simulation, determine the rheological properties of the lithosphere rheology principle applied in West Lake depression. The results show that West Lake sag is a cold crust and lithosphere mantle crust - mantle, strong weak the "cake" type lithosphere. West Lake depression average surface heat flow density is 71 m W/m~2, 40~65 m W/m~2 mantle heat flow density, the surface heat flux contribution of up to 73%~79%, the surface heat flow of mantle heat flow control, Moho temperature at 700 degrees Celsius, the average thickness of 66 km. thermal lithosphere rheological layered lithosphere in West Lake sag obviously, in the basic layer is brittle crust, lower crust and lithospheric mantle ductile layer, the general rheological strength of lithosphere with an average of about 2.65 '10~ (12) N/m, the crustal flow Variable intensity is 2.12 '10~ (12) N/m, 5.29' 10~ mantle rheology strength (11 N/m), the effective elastic thickness of 11.7~14.5 km, the rheological properties of the crust to control the rheological behavior of the lithosphere. In addition, the West Lake sag total strength of the lithosphere is low, under the action of tectonic stress is easy to deformation, and the existence of the shell mantle decoupling phenomenon. West Lake sag thermal state and rheological properties of the lithosphere of Eastern West Lake depression area is mainly decided by the slip of the shallow crust and fracture structure to adjust the deep stress.

【作者单位】：中国海洋大学海洋地球科学学院;海底科学与探测技术教育部重点实验室;
【基金】：中国地质调查局项目(GZH200900504-217-3) 国家科技重大专项(2016ZX05027-002-005)联合资助
【分类号】：P736.1
【正文快照】： 0引言岩石圈的流变性质不仅决定了岩石圈板块的几何形态及运动机制,也制约了主要地质构造的形成和演化(嵇少丞等,2008;Burov,2011),对岩石圈热流变性质的研究有助于理解不同尺度的地质演化过程及其地球动力学意义(Ranalli,2000;Burov,2010)。地表构造是深部构造的响应,沉积盆

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