南海中央海盆热流特征及成因

    CHARACTERISTICS AND GENESIS OF GEOTHERM IN THE CENTRAL BASIN OF SOUTH CHINA SEA

    • 摘要: 对南海中央海盆70个热流观测值的统计结果表明,南海中央海盆属于高热流区,热流平均值可达89.9 mW/m2。其中西南次海盆热流平均值为96.6 mW/m2,东部次海盆热流平均值为86 mW/m2,西南次海盆比东部次海盆更"热"。高热流值的主要原因是岩石圈的构造拉张减薄以及壳内高导层埋深较浅。而局部存在的热流高值异常其根本原因是断裂和岩浆活动的结果。通过对研究区热流分布以及高值特征的分析,不仅可以对洋壳年龄和扩张年代进行估算,还可以对构造特征以及沉积环境进行有效推测。

       

      Abstract: The 70 heat flow data collected from the Central Basin of South China Sea reveals that it is a high heat flow region with an average value of 89.9 mW/m2. The average heat flow is 96.6mW/m2 in the southwest subbasin, but 86 mW/m2 in the east subbasin. It means that the southwest subbasin is "hotter" than the east subbasin. It is believed that the high heat flow value is an indication of lithospheric stretching and thinning in addition to the occurrence of shallow high conductivity layer in earth crust. Faulting and magmatic activities might be the main reasons for the high local heat flow anomaly. The distribution pattern of the high heat flow is not only a useful tool to estimate the oceanic crust age and expansion period, but also an effect mean for study of structural features and sedimentary environment.

       

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