局部热膨胀产生的重力异常及其构造意义

GRAVITY ANOMALIES CAUSED BY HEAT EXPANSION IN PART OF THE CRUST AND ITS TECTONIC SIGNIFICANCE

地热梯度的增加不仅引起地壳的体积变化，而且使地壳的荷载发生变化。定量计算表明，在均衡深度以上，局部地壳地热梯度的增加将产生重力负异常。随之而来的地壳均衡运动会造成２ｋｍ左右的地壳上升，用以补偿膨胀后地壳的质量亏损。

The increase of the heat gradient in part crust can cause the change not only in volume of the crust,but also in the load. The calculation shows that the increase of heat gradient,over the depth of isostasy, will cause the negative gravity anomaly.Then,the crust will lift about 2 km by the isostasy to compensate the crust for a loss of mass after thermal expansion.