Heat flow and thermal history of the South China Sea

A total of 589 heat flow values are available from the South China Sea. The values are widely scattered, ranging from 9 to 181 mW/m(2) with a mean of 77 MW/M-2. In the northern margin, the values are less scattered and the av erage is about 75 mW/m(2). Heat flow increases gradually from the northern margin to the central basin, in which two high heat flow centers appear, on e in the east subbasin and the other in the southwest subbasin. The souther n margin has an average heat flow of 80 mW/m 2, similar to the northern mar gin. The western margin where the Manila trench is located has an average h eat flow as low as 49 mW/m(2). In order to understand the high heat flow in the basin in the context of its tectonic history, we carried out thermal m odeling using a 2D finite-element method along a profile across the norther n margin. A theoretical thermal history has been inferred on the basis of a multistage pure-shear extension model. The result shows that, before Mioce ne, the basement heat flow showed relatively low values, ranging from 48 to 57 mW/m(2). Since Late Miocene, the basement heat flow has increased as a result of greater extension. The present-day high heat flow is primarily th e result of Pliocene extension. (C) 2001 Elsevier Science B.V. All rights r eserved.