摘要
本文报道新编比例尺为1:1500000的华北平原新生界盖层地温梯度图。该图以近4000口钻井的温度资料和对地温场控制因素的分析为基础,并结合地温场数学模拟计算结果编制而成。圈定全区地温梯度G>4℃/100m及大地热流q>62mw/m^2的局部地热异常区44片,总面积为25000km^2,为地热能勘探、开发远景规划提供了重要的科学依据。
A new map of geothermal gradient of Cenozoic cover in the North China Plain on scale of 1:1500000 is reported in this paper. This region geologically is a very large-seall Mz + Kz sedimentary basin of faulting-depression which developed on the Palaozoic and Precambrian basement. This Basin is bounded on the piedmonts by Yanshan, Taihungshan, Funiushan, Da-bieshan and Taishan mountains with whole area of 3.4℃ 105 km2 Based upon the temperature data of about 4000 boreholes and analysis for main control factors of geothermal field as well, as the results of mathematical simulation of regional geothermal field, the map has been com-pilel. The geothermal gradients (G) of Cenozoic cover are divied into six grades, namely G<3, 3.0-3.5, 3.5-4.0, 3.5-4.5, 4-5, >5℃/100m.The distribution and variation of the geothermal gradients are closely related to relief of basement and form of tectonic framework, exhibiting a low-high-low pattern Regional and local ground woter activity also may significanly influence the geothermal fields in piedmont plain and at some fault zones, respectively.The local geothermal anomalies occurring in the basement uplift areas are caused by the great variation of the thermal properties of rocks in vertical and horizontal directions. This phenomenon can be regared as the result of redistribution of heat flow in the upper-most part of the crust by condutions from deep Earth's crust. When thermal water upwelling along the open fractures the convective heat transfer superposes on the condutive portion, giving rise to a even more intensive anomaly in some locations. Whereas, in the piedmont plain owing to the effect of cool ground water movement the geotemperature exhibits obviously low features.The geothermal anomaly area with G>4℃/100m and heat flow q>62mW/m2 accounts to 25000km2 including 44 areas in North China Plain. It provided important scientific basis for long term planning of the exploration and exploitation of geothermal energy sources.
出处
《地质科学》
CAS
CSCD
北大核心
1990年第3期269-277,共9页
Chinese Journal of Geology(Scientia Geologica Sinica)
关键词
新生界盖层
地温梯度图
局部地热异常
华北平原
地热能
Cenozoic cover, the map of geothermal gradient, local geothermal ano-maly, long term planning of the exploitation of geothermal energy, the North China Plain
