南海海盆IODP349钻井岩心的生热元素测试与应用研究

发布时间：2018-03-28 17:13

本文选题：南海　切入点：岩心　出处：《大地构造与成矿学》2017年06期

【摘要】：放射性生热率是岩石热物性参数之一,也是研究岩石圈热结构和构造热演化的重要参数。针对南海海盆区缺少岩石生热率资料的实际情况,本文通过整理和分析IODP349航次中的测井资料,测试钻井岩心样品的主要放射性生热元素,通过计算得出:玄武岩样品的生热率平均值为0.28±0.07μW/m~3,沉积碎屑岩样品的生热率为1.21±0.34μW/m~3,以及3个钻井的地热流值。获得以下认识:(1)本次研究的沉积碎屑岩样品生热率与中国东南沿海的同类岩石样品的生热率值相近,而洋壳中的基性火山岩生热率明显低于大陆碱性玄武岩。(2)用新资料计算南海西南次海盆段的岩石圈热结构得出其热岩石圈厚度约为39~42 km,平均壳幔热流比值为2.4%,说明西南次海盆岩石圈薄,海底热流主要受深部的地幔热源控制。(3)U1431D和U1433A钻井的热流密度值与附近探针热流密度值相近;而U1431C的热流密度值明显偏小,属于受地下水热循环影响所致。
[Abstract]:Radioactive heat generation rate is one of the thermal physical parameters of rock, and is also an important parameter to study the thermal structure of lithosphere and tectonic thermal evolution. In this paper, by sorting out and analyzing the logging data of IODP349 voyage, the main radiogenic heat elements of drilling core samples are tested. The average heat generation rate of basalt sample is 0.28 卤0.07 渭 W / mm3, the heat generation rate of sedimentary clastic rock sample is 1.21 卤0.34 渭 W / mm3, and the geothermal flow value of three drilling wells is obtained. The calorific rate values of the similar rock samples in the southeastern coast of China are similar. The calorific rate of basic volcanic rocks in oceanic crust is obviously lower than that of continental alkaline basalt. (2) using new data to calculate the lithospheric thermal structure of the southwest subbasin of the South China Sea, the thickness of the thermal lithosphere is about 394km and the average ratio of crust-mantle heat flow is 2.4 cm. The subbasin lithosphere in the southwest of the Ming Dynasty was thin, The undersea heat flux is mainly controlled by the deep mantle heat source. The heat flux density of U1431D and U1433A drilling is similar to that of the nearby probe, while the heat flux of U1431C is obviously smaller, which is caused by the influence of groundwater thermal cycle.
【作者单位】：国土资源部海底矿产资源重点实验室广州海洋地质调查局;中国科学院大学;核工业二九0研究所;
【基金】：国家自然科学基金(91428205) 国家863计划海洋技术领域科研项目(2006AA09A203)联合资助
【分类号】：P714.6;P736

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