河南平原区天然地热流体同位素特征对其成生环境的揭示

河南省东部平原地区蕴藏着丰富的地热资源,不同构造单元、不同时代的天然地热流体,其水化学特征及成生环境有较大差异。本次采用稳定同位素数据研究地热流体来源、迁移特征;采用放射性同位素数据,研究地热流体年龄。结果表明:①河南平原区地热流体主要源于大气降水且多为滞留古水;②不同时代热储之间水力联系微弱;③同时代热储赋存的地热流体年龄,山前区远小于平原区,揭示其由山前向平原迁移。

Isotopic Characteristics and Forming Environment of Natural Geothermal Fluids in the Plain Area of Henan Province

The geothermal resource is abundant in the eastern plain of Henan Province. The hydrochemical characteristics and forming environment of natural geothermal fluids is greatly different in different tectonic units and in different geological period. The stable isotope data is applied to study the source and migration characteristics of geothermal fluids. The radioisotope data of 14C is used to identify the age of geothermal fluids. The results are showed as follows. Firstly, the source of the geothermal fluids in plain area of Henan Province is mainly atmospheric precipitation and the geothermal fluids are mainly ancient water. Secondly, the hydraulic connection between thermal reservoirs of different ages is weak. Thirdly, the age of contemporary geothermal fluids in front of mountains is far less than that in the plain area. The results revealed that the geothermal fluids are migrating from the front of mountains to the plain areas.