The structural and diagenetic evolution of injected sandstones; examples from the Kimmeridgian of NE Scotland

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doi: 10.1144/0016-764902-091
Authors:Jonk, R.; Duranti, D.; Parnell, J.; Hurst, A.; Fallick, A. E.
Author Affiliations:Primary:
University of Aberdeen, Department of Geology and Petroleum Geology, Aberdeen, United Kingdom
Other:
Scottish Universities Environmental Research Centre, United Kingdom
Volume Title:Journal of the Geological Society of London
Source:Journal of the Geological Society of London, 160(6), p.881-894. Publisher: Geological Society of London, London, United Kingdom. ISSN: 0016-7649
Publication Date:2003
Note:In English. 51 refs.; illus., incl. 2 tables, geol. sketch map
Summary:Injected sandstones occurring in the Kimmeridgian of NE Scotland along the bounding Great Glen and Helmsdale faults formed when basinal fluids moved upward along the fault zones, fluidizing Oxfordian sands encountered at shallow depth and injecting them into overlying Kimmeridgian strata. The orientation of dykes, in addition to coeval faults and fractures, was controlled by a stress state related to dextral strike-slip along the bounding fault zones. Diagenetic studies of cements allow the reconstruction of the fluid flow history. The origin of deformation bands in sandstone dykes and sills was related to the contraction of the host-rocks against dyke and sill walls following the initial stage of fluidized flow, and these deformation bands are the earliest diagenetic imprint. Early non-ferroan calcite precipitated in injection structures at temperatures between 70 and 100°C, indicating that it precipitated from relatively hot basinal fluids that drove injection. Coeval calcite-filled fractures show similar temperatures, suggesting that relatively hot fluids were responsible for calcite precipitation in any permeable pathway created by dextral simple shear along the faults. During progressive burial, percolating sea water was responsible for completely cementing the still relatively porous injected sandstones with a second generation of ferroan calcite, which contains fluid inclusions with homogenization temperatures below 50°C. During this phase, depositional host sandstones were also cemented.
Sections:Petrology
Subsections:Sedimentary petrology
Subjects:Calcite; Carbonates; Cement; Cementation; Clastic dikes; Clastic rocks; Deformation; Diagenesis; Faults; Jurassic; Kimmeridgian; Mesozoic; Sandstone; Sedimentary rocks; Sedimentary structures; Shear; Soft sediment deformation; Stress; Strike-slip faults; Structural analysis; Upper Jurassic; Europe; Great Britain; Moray Firth; Scotland; Scottish Highlands; Scottish Northern Highlands; United Kingdom; Western Europe; Eathie Scotland; Helmsdale Scotland; Northeastern Scotland; Port an Righ Scotland
Coordinates:N573000 N580000 W0033000 W0040000
Abstract Numbers:04M/668
Record ID:2004011327
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from The Geological Society, London, London, United Kingdom
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