热流的折射和再分配的数学模拟

目前,陆地大地热流的测量大多在1-2公里深的钻孔中进行,测量结果除受地形变化、气候变迁等因素的影响外,还受构造形态变化的影响。一般隆起区的浅部热流和地温梯度高于拗陷区的热流和地温梯度。有时在隆起的最高部位的地表热流值可高于平均热流值的30%-40%,从而形成局部的异常区。隆起区的地表热流值和地温梯度值高于拗陷区的原因是由于在热流扰动区内,热流产生折射和再分配的结果。为此,我们采用数学模拟方法,研究了在不同构造形态和岩层热导率条件下,热流折射和再分配对区域热流的影响。

MATHEMATICAL SIMULATION OF REFRACT AND REDISTRIBUTION OF HEAT FLOW

Using finite-element analysis, the mathematical simulation of refraction and redistribution of heat flow have been completed in this paper. Results obtained show that in the uppermost part of the crust, the refraction of heat flow occurs at the boundaries of rock strata with different thermal conductivity, and the "redistribution" of heat flow occurs in the so called "heat flow disturbed area". The refraction of heat flow is determined by the ratio of the thermal conductivity and the interface dip angle of different rock strata, whereas the redistribution of heat flow is controlled by the total thermal resistivity of rock strata at different parts of a structure. The extent of "heat flow disturbed area" and surface heat flow are dominated by the eonstract of thermal conductivity of different strata, the thickness of the sedimentary cover and interface dip angle of the strata. The result obtained is useful for quantitatively evaluating these effects in regional heat flow studies.