Penetration depth of meteoric water in orogenic geothermal systems

Diamond, Larryn William; Wanner, Christoph; Waber, Niklaus (2018). Penetration depth of meteoric water in orogenic geothermal systems. Geology, 46(12), pp. 1063-1066. Geological Society of America 10.1130/G45394.1

[img]
Preview
Text
Diamond Wanner Waber 2018 Penetration depth of meteoric water in orogenic geothermal systems.pdf - Published Version
Available under License Creative Commons: Attribution (CC-BY).

Download (616kB) | Preview

Warm springs emanating from deep-reaching faults in orogenic belts with high topography and orographic precipitation attest to circulation of meteoric water through crystalline bedrock. The depth to which this circulation occurs is unclear, yet it is important for the cooling history of exhuming orogens, for the exploitation potential of orogenic geothermal systems, and for the seismicity of regional faults. The orogenic geothermal system at Grimsel Pass, Swiss Alps, is manifested by warm springs with a clear isotopic fingerprint of high-altitude meteoric recharge. Their water composition and their occurrence within a 3 Ma fossil upflow zone render them particularly favorable for estimating the temperature along the deep flow path via geochemical modeling. Because the background geotherm has remained stable at 25 °C/km and other heat sources are unavailable, the penetration depth can be derived from the deep-water temperature. We thus estimated the base of the Grimsel system to be at 230–250 °C and 9–10 km depth. We propose that deep temperatures in such systems, particularly those with normal background geotherms (<30 °C/km), have been systematically underestimated. Consequently, far more enthalpy may be accessible for geothermal energy exploitation around the upflow zones than previously thought. Further, the prevalence of recent earthquake foci at ≤10 km beneath Grimsel suggests that meteoric water is involved in the seismicity of the host faults. Our results therefore call for reappraisal of the heat budget and the role of meteoric water in seismogenesis in uplifting orogens.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Other Institutions > Teaching Staff, Faculty of Science
08 Faculty of Science > Institute of Geological Sciences

UniBE Contributor:

Diamond, Larryn William; Wanner, Christoph and Waber, Niklaus

Subjects:

500 Science > 550 Earth sciences & geology

ISSN:

0091-7613

Publisher:

Geological Society of America

Language:

English

Submitter:

Larryn William Diamond

Date Deposited:

19 Nov 2018 15:46

Last Modified:

23 Oct 2019 11:23

Publisher DOI:

10.1130/G45394.1

BORIS DOI:

10.7892/boris.121206

URI:

https://boris.unibe.ch/id/eprint/121206

Actions (login required)

Edit item Edit item
Provide Feedback