Preservation of Mesoproterozoic age deep burial fluid signatures, NW Scotland

Parnell, J., Blamey, N. J.F., Costanzo, A., Feely, M. and Boyce, A. J. (2014) Preservation of Mesoproterozoic age deep burial fluid signatures, NW Scotland. Marine and Petroleum Geology, 55, pp. 275-281. (doi: 10.1016/j.marpetgeo.2013.11.018)

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Abstract

Bedding-parallel fibrous calcite is a widely developed feature of mudrock successions, reflecting conditions of fluid overpressure (Stoneley, 1983, Parnell et al., 2000 and Cobbold et al., 2013). The calcite preserves signatures of fluids developed during deep burial, including hydrocarbons. Most studied examples are of Phanerozoic (<540 Ma) age. This study reports well-preserved fibrous calcite in the Mesoproterozoic (∼1180 Ma) Stoer Group, NW Scotland. The fibrous calcite occurs immediately above a unit of carbonaceous black shale. If hydrocarbons were generated from the black shales, they could have contributed to the development of fluid overpressure, but there is no direct evidence for this. The calcite reflects the original deep burial fluid, rather than a later overprint, because (i) it has a distribution related to stratigraphy, (ii) the bedding-parallel fibres have not been recrystallized, and (iii) later veining is at high angles to bedding. The calcite contains fluid inclusions, and has yielded stable isotope and entrained volatile data, indicating the potential to record diagenetic processes over one billion years ago.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Boyce, Professor Adrian
Authors: Parnell, J., Blamey, N. J.F., Costanzo, A., Feely, M., and Boyce, A. J.
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Marine and Petroleum Geology
Publisher:Elsevier Ltd
ISSN:0264-8172
ISSN (Online):1873-4073

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