Geometry of the Butterknowle Fault at Bishop Auckland (County Durham, UK), from gravity survey and structural inversion

Westaway, R., Watson, S., Williams, A., Harley, T. and Middlemiss, R. (2019) Geometry of the Butterknowle Fault at Bishop Auckland (County Durham, UK), from gravity survey and structural inversion. Technical Report. Earth and Space Science Open Archive. (doi: 10.1002/essoar.10501104.1).

Abstract

The Butterknowle Fault is a major normal fault of Dinantian age in northern England, bounding the Stainmore Basin and the Alston Block. This fault zone has been proposed as a source of deep geothermal energy; to facilitate the design of a geothermal project in the town of Bishop Auckland further investigation of its geometry was necessary and led to the present study. We show using three-dimensional modelling of a dense local gravity survey, combined with structural inversion, that this fault has a ramp-flat-ramp geometry, ~250 m of latest Carboniferous / Early Permian downthrow having occurred on a fault surface that is not a planar updip continuation of that which had accommodated the many kilometres of Dinantian extension. The gravity survey also reveals relatively low-density sediments in the hanging-wall of the Dinantian fault, interpreted as porous alluvial fan deposits, indicating that a favourable geothermal target indeed exists in the area. This study demonstrates the value of gravity data for elucidating geological structure, even in a well-studied region such as Britain, and highlights the need to verify published structural interpretations as future deep geothermal projects are designed. Future work of this type might be undertaken more expeditiously using microelectromechanical gravimeters.

• Item Type: Research Reports or Papers (Technical Report)
• Status: Published
• Refereed: No
• Glasgow Author(s) Enlighten ID: Williams, Mr Aaron and Middlemiss, Dr Richard and Harley, Mr Thomas and Westaway, Dr Robert and Watson, Mr Sean
• Authors: Westaway, R., Watson, S., Williams, A., Harley, T., and Middlemiss, R.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering; College of Science and Engineering > School of Engineering > Systems Power and Energy; College of Science and Engineering > School of Engineering > Infrastructure and Environment
• Publisher: Earth and Space Science Open Archive
• Copyright Holders: Copyright © 2019 The Authors
• Publisher Policy: Reproduced under a Creative Commons License