Open AccessStable isotope geochemistry of siderite concretions from Jurassic sedimentary rocks on Bornholm (Denmark)
Author(s) -
Nis Brorson Christensen
Publication year - 1995
Publication title -
bulletin of the geological society of denmark
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.674
H-Index - 28
eISSN - 2245-7070
pISSN - 0011-6297
DOI - 10.37570/bgsd-1995-42-05
Subject(s) - siderite , concretion , geology , geochemistry , diagenesis , sedimentary rock , maghemite , carbonate , weathering , brackish water , mineralogy , magnetite , calcite , paleontology , chemistry , oceanography , organic chemistry , salinity
The diagenetic history of siderite concretions in Mesozoic sedimentary rocks on the islandof Bornholm has been investigated using stable isotope-, AAS- and XRD-analysis anddetermination of carbonate content. Siderite concretions and bands, found in non-marineas well as marine environments, are investigated. The siderite concretions were precipitatedfrom fresh to brackish pore-water prior to compaction.8'3CPDB values from -14.2 to +1.4 o/oo indicate ne ar-surface precipitation affected bybacterial oxidation of organic matter. 8180 values between +22.1 and +28.7 o/oo 5180SMOWindicate concretion precipitation in pore-water of fresh to brackish origin. Weatheringeffects are seen, but temperature fractionation is not observed.