Mechanisms controlling the localisation of fault-controlled hydrothermal dolomitisation, Derbyshire Platform, UK



Breislin, Catherine J, Banks, Vanessa J, Crowley, Stephen F, Marshall, Jim D, Millar, Ian, Riding, James B and Hollis, Cathy E
(2022) Mechanisms controlling the localisation of fault-controlled hydrothermal dolomitisation, Derbyshire Platform, UK. DEPOSITIONAL RECORD, 9 (3). pp. 734-758.

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Abstract

<jats:title>Abstract</jats:title><jats:p>The Derbyshire Platform is a Mississippian aged flat‐topped, steep sided platform that forms the westernmost expression of the Derbyshire‐East Midlands Platform. On the south‐east platform margin, 60 km<jats:sup>2</jats:sup> of Visean limestone has been dolomitised, forming two distinct bodies. One of these bodies forms along a major NW–SE trending basement fault and smaller, associated, N–S trending faults and fractures. This study uses outcrop, petrographic and geochemical analysis to better constrain the timing and mechanism for this fault‐controlled dolomitisation. Field relationships demonstrate dolomitisation was multi‐phase and initiated after the main phase of matrix pore‐occluding calcite cementation on the Derbyshire Platform and terminated prior to the main phase of mineralisation. Fluids are interpreted to have fluxed from adjacent basins, primarily along strike‐slip crustal faults that were reactivated during basin inversion at the onset of the Variscan Orogeny. Fluid supply was episodic and progressively confined to fractures as matrix porosity became occluded. The study demonstrates the complex interplay between basin kinematics, host rock permeability and timing of fluid supply through seismic valving along faults that connect the carbonate platform to basin compartments. This ultimately controlled the position of dolomite geobodies along faults and provides a record of fluid flow during the transition from thermal subsidence to post‐rift basin inversion. The findings have implications for the exploration of both minerals and hydrocarbon within dolomitised host rocks and can inform studies of fluid transfer and reaction on carbonate platforms within the burial realm.</jats:p>

Item Type: Article
Uncontrolled Keywords: dolomite, fault, structural diagenesis, Visean
Divisions: Faculty of Science and Engineering > School of Environmental Sciences
Depositing User: Symplectic Admin
Date Deposited: 09 Mar 2023 09:45
Last Modified: 04 Sep 2023 03:20
DOI: 10.1002/dep2.214
Open Access URL: https://doi.org/10.1002/dep2.214
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3168873