冲绳海槽沉降和热演化模式初探

PRELIMINARY STUDY ON THE MODEL OF SUBSIDENCE AND HEATFLOW EVOLUTION IN THE OKINAWA TROUGH

分析了冲绳海槽盆地的沉降，给出了一个拉张系数的计算公式，并用它估算了冲绳海槽的拉张系数。在此基础上，利用多层、多次和有限拉张模式及有限元计算技术，定量模拟了冲绳海槽盆地的沉降过程和热演化历史。结果表明：冲绳海槽的形成先后经历了两次拉张过程，第一次拉张在北段的形成过程中占有主导地位，而南段海槽的第二次拉张较为显著。冲绳海槽南、北两段较高的热流值主要是由于海槽较为年青、热流散失较小所致。

オn this paper, we analyzed the subsidence and evaluated the extension factors of Okinawa Trough.Theoretical subsidence and heatflow evolution of Okinawa Trough Basin are calculated by multiplelayer and finiteextension model and finite element method.The result shows that twotime extension model is more suitable for describing the extension process of the Okinawa Trough.The formation of the northern Okinawa Trough was chiefly completed by first extension.On the contrary,second extension was notable in the southern Okinawa Trough.Analyzing the theoretical heatflow evolution,we have the conclusion that value of heatflow in the Okinawa Trough is high because of its young age and less heat disappearing.