High-temperature silicified zones as potential caprocks of supercritical geothermal reservoirs

We examined the silicification zone in a granite-porphyry system in order to investigate the caprocks in a supercritical geothermal system. At the top of the granite intrusion, a high-temperature silicification zone contains three generations of quartz. The earliest generation formed at higher temperatures and has bright luminescence and high Ti contents. This quartz is the phenocryst that formed in the granitic magma. The second and third generations formed at lower temperatures and have weak to dark luminescence and low Ti contents. This quartz is formed as replacement and in microfractures and cavities in the earlier quartz, suggesting it is a caprock for a supercritical geothermal reservoir.

Automated summary

By examining the silicification zone, we discovered three generations of quartz in a granite-porphyry system. The earliest generation formed at higher temperatures and has bright luminescence and high titanium contents, indicating it is a phenocryst formed in the granitic magma. The second and third generations formed at lower temperatures and have weak to dark luminescence and low titanium contents, suggesting they are replacement products of the earlier quartz and potentially caprocks for a supercritical geothermal reservoir.