Abstract:
Objective Aiming at the unclear evolutionary law of the Waligongshan tectonic magmatic belt and its associated mechanism with the geothermal system, this study intends to reveal the multi−stage emplacement process and petrogenetic and metallogenic background of the magmatic belt, clarify its controlling effect on hot dry rock geothermal resources, and provide theoretical support for hot dry rock exploration in the Gonghe Basin.
Methods Through systematic analysis of lithological assemblages, petrological and mineralogical characteristics, combined with petrogeochemical testing of multi−stage intrusions, the evolutionary sequence and tectonic setting of the magmatic belt were analyzed. Meanwhile, based on fluid evolution of hot dry rock and deep geophysical exploration data, the deep occurrence state of the magmatic heat source was inverted.
Results The Waligongshan tectonic magmatic belt is a complex rock assemblage composed of intrusions of different periods and origins, characterized by long−term continuous activity and high diagenetic temperature. It is mainly of syntexis type, with characteristics of A−type granite, involving mantle−derived magma contamination in the early stage and dominated by anatectic granite in the late stage.The study reveals that a high−temperature asthenosphere (magmatic chamber) exists at a certain depth in the lower part of the Gonghe Basin, which is an important heat source for hot dry rocks in the area.
Conclusions This study clarifies the evolutionary law of the Walihuangshan tectonic magmatic belt and its coupling relationship with the hot dry rock heat source, providing a key theoretical basis for the optimization of exploration targets for hot dry rock geothermal resources in the Gonghe Basin.
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