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author Langrock, Uwe
Stein, Ruediger
Lipinski, Marcus
Brumsack, Hans-Jürgen
author_facet Langrock, Uwe
Stein, Ruediger
Lipinski, Marcus
Brumsack, Hans-Jürgen
collection Datos científicos de ciencias marinas y ambientales
contents The Late Jurassic to Early Cretaceous (Volgian-Ryazanian) was a period of a second-order sea-level low stand, and it provided excellent conditions for the formation of shallow marine black shales in the Norwegian-Greenland Seaway (NGS). IKU Petroleum Research drilling cores taken offshore along the Norwegian shelf were investigated with geochemical and microscopic approaches to (1) determine the composition of the organic matter, (2) characterize the depositional environments, and (3) discuss the mechanisms which may have controlled production, accumulation, and preservation of the organic matter. The black shale sequences show a wide range of organic carbon contents (0.5-7.0 wt %) and consist of thermally immature organic matter of type II to II/III kerogen. Rock-Eval pyrolysis revealed fair to very good petroleum source rock potential, suggesting a deposition in restricted shallow marine basins. Well-developed lamination and the formation of autochthonous pyrite framboids further indicate suboxic to anoxic bottom water conditions. In combination with very low sedimentation rates it seems likely that preservation was the principal control on organic matter accumulation. However, a decrease of organic carbon preservation and an increase of refractory organic matter from the Volgian to the Hauterivian are superimposed on short-term variations (probably reflecting Milankovitch cycles). Various parameters indicate that black shale formation in the NGS was gradually terminated by increased oxidative conditions in the course of a sea-level rise.
format Dataset Open Access
id pangaea_https___doi_org_10_1594_PANGAEA_841464
institution PANGAEA
language en
publishDate 2003
publisher PANGAEA
record_format pangaea
spellingShingle (Table 1) Organic and inorganic geochemical analysis of Late Jurassic to Early Cretaceous black shale sediments from the Norwegian-Greenland Seaway
Langrock, Uwe
Stein, Ruediger
Lipinski, Marcus
Brumsack, Hans-Jürgen
AWI_Paleo; Calcium carbonate; Carbon, organic, total; Carbon, total; Carbon dioxide yield, S3, per unit sediment mass; Comment; Coulomat carbon analyzer; Depth, bottom/max; DEPTH, sediment/rock; Depth, top/min; DRILL; Drilling/drill rig; Element analyser CHN, LECO; Elevation of event; Event label; Hydrocarbon yield, S1, per unit sediment mass; Hydrocarbon yield, S2, per unit sediment mass; Hydrocarbon yield, S2/Carbon dioxide yield, S3; Hydrogen index, mass HC, per unit mass total organic carbon; IKU-13/1-U-02; IKU-6307/07-U-02; IKU-6814/04-U-02; Iron oxide, Fe2O3; Latitude of event; Longitude of event; Nitrogen, total; Oxygen index, mass CO2, per unit mass total organic carbon; Paleoenvironmental Reconstructions from Marine Sediments @ AWI; Production index, S1/(S1+S2); Pyrolysis temperature maximum; Rock eval pyrolysis (Espitalié et al. 1977); Stage; Sulfur, total; X-ray fluorescence (XRF)
The Late Jurassic to Early Cretaceous (Volgian-Ryazanian) was a period of a second-order sea-level low stand, and it provided excellent conditions for the formation of shallow marine black shales in the Norwegian-Greenland Seaway (NGS). IKU Petroleum Research drilling cores taken offshore along the Norwegian shelf were investigated with geochemical and microscopic approaches to (1) determine the composition of the organic matter, (2) characterize the depositional environments, and (3) discuss the mechanisms which may have controlled production, accumulation, and preservation of the organic matter. The black shale sequences show a wide range of organic carbon contents (0.5-7.0 wt %) and consist of thermally immature organic matter of type II to II/III kerogen. Rock-Eval pyrolysis revealed fair to very good petroleum source rock potential, suggesting a deposition in restricted shallow marine basins. Well-developed lamination and the formation of autochthonous pyrite framboids further indicate suboxic to anoxic bottom water conditions. In combination with very low sedimentation rates it seems likely that preservation was the principal control on organic matter accumulation. However, a decrease of organic carbon preservation and an increase of refractory organic matter from the Volgian to the Hauterivian are superimposed on short-term variations (probably reflecting Milankovitch cycles). Various parameters indicate that black shale formation in the NGS was gradually terminated by increased oxidative conditions in the course of a sea-level rise.
title (Table 1) Organic and inorganic geochemical analysis of Late Jurassic to Early Cretaceous black shale sediments from the Norwegian-Greenland Seaway
topic AWI_Paleo; Calcium carbonate; Carbon, organic, total; Carbon, total; Carbon dioxide yield, S3, per unit sediment mass; Comment; Coulomat carbon analyzer; Depth, bottom/max; DEPTH, sediment/rock; Depth, top/min; DRILL; Drilling/drill rig; Element analyser CHN, LECO; Elevation of event; Event label; Hydrocarbon yield, S1, per unit sediment mass; Hydrocarbon yield, S2, per unit sediment mass; Hydrocarbon yield, S2/Carbon dioxide yield, S3; Hydrogen index, mass HC, per unit mass total organic carbon; IKU-13/1-U-02; IKU-6307/07-U-02; IKU-6814/04-U-02; Iron oxide, Fe2O3; Latitude of event; Longitude of event; Nitrogen, total; Oxygen index, mass CO2, per unit mass total organic carbon; Paleoenvironmental Reconstructions from Marine Sediments @ AWI; Production index, S1/(S1+S2); Pyrolysis temperature maximum; Rock eval pyrolysis (Espitalié et al. 1977); Stage; Sulfur, total; X-ray fluorescence (XRF)
url https://doi.org/10.1594/PANGAEA.841464