Subsurface Geology of the Fenton Hill Hot Dry Rock Geothermal Energy Site

[摘要] The Precambrian rock penetrated by wells EE-2A and -3A belongs to one or more granitic to granodioritic plutons. The plutonic rock contains two major xenolith zones of amphibolite, locally surrounded by fine-grained mafic rock of hybrid igneous origin. The granodiorite is cut by numerous leucogranite dikes that diminish in abundance with depth. The most prominent structural feature is the main breccia zone, in which the rock is highly fractured and moderately altered. This zone is at least 75 m thick and is of uncertain but near-horizontal orientation. Fracture abundance decreases with increasing depth below the main breccia zone, and fractures tend to be associated with leucogranite dikes. This association suggests that at least some of the fractures making up the geothermal reservoir are of Precambrian age or have long-range orientations controlled by the presence of Precambrian-age granitic dikes.

[发布日期] 2010-12-01

[学科分类] 再生能源与代替技术

[关键词] ABUNDANCE;FRACTURES;GEOLOGY;GEOTHERMAL ENERGY;GRANODIORITES;ORIENTATION;ORIGIN;PLUTONIC ROCKS