Scientific results from the deepened Lopra-1 borehole, Faroe Islands: A reconnaissance study of fluid inclusions in fracture-filling quartz and calcite from the Lopra-1/1A well, Faroe Islands

• Main Author: Konnerup-Madsen, Jens
• Format: Article in Journal/Newspaper
• Language: English
• Published: Geological Survey of Denmark and Greenland 2006
• Subjects: Basalts; Faroe Islands; fluid inclusions; hydrocarbons; veins; zeolites; Geology; QE1-996.5; Geophysics. Cosmic physics; QC801-809; Lopra; Geological Survey of Denmark and Greenland Bulletin
• Online Access: https://doaj.org/article/11f7a1ba02ca450eb9dba16170dbfc77

Fracture-filling calcite and quartz from the Lopra-1/1A well (at 2380 m and 3543 m depth) contains both aqueous low-salinity fluid inclusions and hydrocarbon-dominated fluid inclusions. Microthermometry indicates that the aqueous fluids contain 0.2 to 1.4 equivalent weight% NaCl and occasionally contain traces of hydrocarbons. Homogenisation to liquid occurred between 90°C and 150°C. Modelling based on these fluid inclusion observations indicates that during burial the basaltic section was subjected to temperatures of 160°C and 170°C, occasional pressures of 600–700 bars and the simultaneous percolation of aqueous and hydrocarbon fluids. These fluid conditions may also be relevant to the formation of zeolite observed in the Lopra-1/1A well.