辽河裂谷盆地地幔热流

辽河盆地是一个在前中生代基底上发展起来的裂谷盆地,实测大地热流平均值为65mW/m²,变动于44-83mW/m²之间。在给出地壳结构模型并确定各岩层放射性生热率的基础上,采用“剥层”法从地表开始,自上而下,由浅及深地扣除各岩层所提供的热量,从而得出地幔热流值。结果表明,辽河裂谷盆地地幔热流为41mW/m²,占整个地表总热流量的63％。可见,本区热量大部分来自地幔。与世界上其它地质构造单元相比,辽河裂谷盆地无论地幔热流绝对值或其与地表热流之比值,都具有介于稳定地区和构造活动区之间的特点。作者认为,辽河裂谷盆地地幔热流的上述特点,乃是中、新生代以来本区长期地质历史发展的产物。

MANTLE HEAT FLOW OF LIAOHE RIFTED BASIN IN NORTH CHINA

Liaohe Basin is a Mz-'Cenozoic rifted basin, developed on the Pre-Mesozoic basement. Observed heat flow in Liaohe Basin is about 65 mW/m², ranging from 44 to 83 mW/m². On the basis of the determination of radiogenic heat productivity for different rock strata of the Basin and crustal models, mantle heat flow was calculated by means of "stripping" method. Results indicalte that mantle heat flow for Liaohe rifted basin is about 41mW/m², which amounts to 63% of the total surface heat flow. Consequently, the heat observed at the surface of Liaohe Basin is believed to come mostly from the upper mantle at depth. Furthermore, Liaohe Basin is characterized by relatively high mantle heat flow value and high ratio of mantle to surface heat flow, characteristic for the area in-betweeh tectonically stable and active units in other part of the world. This feature may be considered to be the product of the history of geological evolution in the region studied.