کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6435452 | 1637169 | 2014 | 7 صفحه PDF | دانلود رایگان |

- Bedding-parallel fibrous calcite is preserved in Mesoproterozoic sediments, UK.
- The calcite records deep burial fluid signatures.
- The vein mineralogy indicates oxidizing conditions.
Bedding-parallel fibrous calcite is a widely developed feature of mudrock successions, reflecting conditions of fluid overpressure (Stoneley, 1983; Parnell et al., 2000; 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 (â¼1180 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.
Journal: Marine and Petroleum Geology - Volume 55, August 2014, Pages 275-281