气候变化领域集成服务门户(CCPortal): Subsurface granites in the Franconian Basin as the source of enhanced geothermal gradients: a key study from gravity and thermal modeling of the Bayreuth Granite

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DOI	10.1007/s00531-019-01740-8
	Subsurface granites in the Franconian Basin as the source of enhanced geothermal gradients: a key study from gravity and thermal modeling of the Bayreuth Granite
	de Wall H.; Schaarschmidt A.; Kämmlein M.; Gabriel G.; Bestmann M.; Scharfenberg L.
发表日期	2019
ISSN	14373254
起始页码	1913
结束页码	1936
卷号	108 期号:6
英文摘要	The Franconian Basin in NE Bavaria is a region of gravity low between the Bohemian Massif in the east and the Kraichgau Terrane in the west. Borehole measurements have identified the northern part of the Franconian Basin as a regional geothermal anomaly and new heat flow calculations give values of > 100 mW/m2. Distinct negative Bouguer anomalies observed in this basin are modeled as granitic intrusions in the Saxothuringian basement that underlies the Permo-Mesozoic units. The interpretation of gravity gradients, in combination with the filtering of gravity data, gives the possible depth constraints of the intrusive bodies. The resulting depths were cross-checked using microstructural studies of quartz veins in the basement rocks (at > 1341 m depth). The quartz shows structures typical for low-temperature plasticity and we infer a deformation temperature of ca. 300 °C. This indicates a considerable pre-Permian uplift of at least 7 km for parts of the Saxothuringian basement and supports depth estimates from gravity data. The heat supply of granitic intrusions by radiogenic decay is modeled considering several scenarios for the geological conditions recovered by the Obernsees borehole (model for conductive heat transfer). The 1390 m-deep drillhole is in a marginal position to the most-pronounced negative Bouguer anomaly. It could be shown that the Saxothuringian basement, including heat-producing granites (heat production rates: 4–6 μW/m3), covered by the insulating sedimentary rocks (1.35 km of Permian to Lower Jurassic units), can account for the enhanced geothermal gradient (38 °C/km) that were measured in the borehole. © 2019, Geologische Vereinigung e.V. (GV).
英文关键词	Gravity anomalies; Quartz microfabric; Radiogenic heat; Thermal modeling; Variscan granites
语种	英语
scopus关键词	basement rock; Bouguer anomaly; geothermal gradient; granite; Hercynian orogeny; petrofabric; quartz vein; radioactive decay; temperature anomaly; Baden-Wurttemberg; Bohemian Massif; Germany; Kraichgau; Calluna vulgaris
来源期刊	International Journal of Earth Sciences
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/147800
作者单位	GeoZentrum Nordbayern, Friedrich-Alexander-Universität Erlangen-Nürnberg, Im Schlossgarten 5, Erlangen, 91054, Germany; Leibniz-Institut für Angewandte Geophysik, Stilleweg 2, Hannover, 30655, Germany; Department f. Geodynamik u. Sedimentologie, Department f. Lithosphärenforschung, Universität Wien, Althanstraße 14, Vienna, 1190, Austria
推荐引用方式 GB/T 7714	de Wall H.,Schaarschmidt A.,Kämmlein M.,et al. Subsurface granites in the Franconian Basin as the source of enhanced geothermal gradients: a key study from gravity and thermal modeling of the Bayreuth Granite[J],2019,108(6).
APA	de Wall H.,Schaarschmidt A.,Kämmlein M.,Gabriel G.,Bestmann M.,&Scharfenberg L..(2019).Subsurface granites in the Franconian Basin as the source of enhanced geothermal gradients: a key study from gravity and thermal modeling of the Bayreuth Granite.International Journal of Earth Sciences,108(6).
MLA	de Wall H.,et al."Subsurface granites in the Franconian Basin as the source of enhanced geothermal gradients: a key study from gravity and thermal modeling of the Bayreuth Granite".International Journal of Earth Sciences 108.6(2019).