TY - JOUR
T1 - Preservation of Mesoproterozoic age deep burial fluid signatures, NW Scotland
AU - Parnell, John
AU - Blamey, Nigel J. F.
AU - Costanzo, Alessandra
AU - Feely, Martin
AU - Boyce, Adrian J.
N1 - Acknowledgements
We are grateful to C. Taylor, J. Still and A. Sandison for skilled technical support. P. Cobbold and an anonymous reviewer made constructive criticisms which helped to improve the manuscript. SUERC is financially supported by the Scottish Universities.
PY - 2014/8
Y1 - 2014/8
N2 - 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.
AB - 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.
KW - Calcite
KW - Diagenesis
KW - Mesoproterozoic
KW - Oxygenation
KW - Precambrian
KW - Scotland
KW - Stoer group
UR - http://www.scopus.com/inward/record.url?scp=84901670725&partnerID=8YFLogxK
U2 - 10.1016/j.marpetgeo.2013.11.018
DO - 10.1016/j.marpetgeo.2013.11.018
M3 - Article
AN - SCOPUS:84901670725
VL - 55
SP - 275
EP - 281
JO - Marine and Petroleum Geology
JF - Marine and Petroleum Geology
SN - 0264-8172
ER -