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The smectite to corrensite transition: X-ray diffraction results from the MH-2B core, western Snake River Plain, Idaho, USA

Published online by Cambridge University Press:  02 January 2018

Jeff Walker  and
Joseph Wheeler
Jeff Walker*
Affiliation:
Department of Earth Science and Geography, Vassar College, Poughkeepsie, NY 12604, USA
Joseph Wheeler
Affiliation:
Department of Earth Science and Geography, Vassar College, Poughkeepsie, NY 12604, USA
*
*E-mail: jewalker@vassar.edu
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Abstract

The MH-2B borehole, a part of Project HOTSPOT, was drilled to a depth of 1821 m in late Cenozoic basalts, hyaloclastites and interbedded lake sediments, on the Mountain Home Air Force Base in southern Idaho, USA. Drillers encountered hot water (145°C) under artesian pressure at 1745 m in a narrow zone of highly fractured rock associated with a major sub-surface fault. X-ray diffraction (XRD) analysis identified corrensite (with and without smectite) between 1700 and 1800 m, but only smectite above 1700 m and below 1800 m. This corrensite horizon contains a relatively narrow zone of fracturing and hot artesian water near its centre but for the most part occurs in relatively massive basalt flows. No evidence was found for randomly interstratified chlorite-smectite.

Keywords

smectitecorrensiteMH-2B boreholeXRD
Type
Short Note
Information
Clay Minerals , Volume 51 , Issue 4 , September 2016 , pp. 691 - 696
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2016

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Footnotes

†

This work was originally presented during the session ‘The many faces of chlorite’, part of the Euroday 2015 conference held in July 2015, in Edinburgh, UK.

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