Facies and depositional processes of Lower Cretaceous carbonates, Danish Central Graben
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Facies and depositional processes of Lower Cretaceous carbonates, Danish Central Graben. / Jelby, Mads E.; Ineson, Jon R.; Thibault, Nicolas; Bodin, Stephane; Blok, Carlette N.; Edvardsen, Niklas; Clemmensen, Tatjana S.; Buls, Toms; Anderskouv, Kresten.
In: Bulletin of the Geological Society of Denmark, Vol. 71, 2022, p. 51-74.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Facies and depositional processes of Lower Cretaceous carbonates, Danish Central Graben
AU - Jelby, Mads E.
AU - Ineson, Jon R.
AU - Thibault, Nicolas
AU - Bodin, Stephane
AU - Blok, Carlette N.
AU - Edvardsen, Niklas
AU - Clemmensen, Tatjana S.
AU - Buls, Toms
AU - Anderskouv, Kresten
PY - 2022
Y1 - 2022
N2 - The Lower Cretaceous Tuxen (lower Hauterivian ??? upper Barremian) and Sola (upper Barremian ??? Albian) Formations in the Danish Central Graben (North Sea) constitute one of the oldest chalk successions recorded globally, but have received little attention with regards to sedimentary facies and depositional processes. This study presents the first comprehensive carbonate facies analysis of the succession, retrieved from seven drill cores from the Valdemar and Adda Fields. A total of 50 facies are identi-fied, based on a continuum of six lithologies ranging from chalk to marlstone and tuffaceous siltstone to sandstone that display eight different sedimentary structures or fabrics, and two redox-associated lithological color variations (green and red) in the Adda Field. The eight sedimentary structures record: (i) comprehensive biotur-bation of homogeneous sediment during fully oxygenated benthic conditions and low sedimentation rates; (ii) a similar bioturbation process but in heterogeneous sediment with lithological contrasts permitting visible burrows to form, perhaps due to rhythmic alternation between pelagic (clay-poor) and hemipelagic (clay-rich) sedimentation; (iii) pelagic to hemipelagic suspension settling in dysoxic to anoxic bottom-water conditions; (iv) patchy cementation of the shallow sea bed during incipient hardground formation; (v) reworking of bioclasts and chalk intraclasts by bottom or wave-induced currents and cohesive debris flows; (vi) pressure solution during late burial diagenesis; (vii) shear deformation by intense plastic deformation of unlithified sediment from limited lateral displacement; and (viii) silicification during burial diagenesis. The facies distribution indicates that active tectonism took place prior to the onset of anoxia that resulted in deposition of the Munk Marl Bed, which in the Valdemar Field was followed by tectonic waning and repeated anoxia. The Valdemar Field constituted a basinal depocenter and was flanked to the east by an early inversion high in the Adda Field characterized by condensation and bypass. The Fischschiefer Member represents a return to prevailing anoxia, consistent with global records of the early Aptian Oceanic Anoxic Event 1a (OAE-1a).
AB - The Lower Cretaceous Tuxen (lower Hauterivian ??? upper Barremian) and Sola (upper Barremian ??? Albian) Formations in the Danish Central Graben (North Sea) constitute one of the oldest chalk successions recorded globally, but have received little attention with regards to sedimentary facies and depositional processes. This study presents the first comprehensive carbonate facies analysis of the succession, retrieved from seven drill cores from the Valdemar and Adda Fields. A total of 50 facies are identi-fied, based on a continuum of six lithologies ranging from chalk to marlstone and tuffaceous siltstone to sandstone that display eight different sedimentary structures or fabrics, and two redox-associated lithological color variations (green and red) in the Adda Field. The eight sedimentary structures record: (i) comprehensive biotur-bation of homogeneous sediment during fully oxygenated benthic conditions and low sedimentation rates; (ii) a similar bioturbation process but in heterogeneous sediment with lithological contrasts permitting visible burrows to form, perhaps due to rhythmic alternation between pelagic (clay-poor) and hemipelagic (clay-rich) sedimentation; (iii) pelagic to hemipelagic suspension settling in dysoxic to anoxic bottom-water conditions; (iv) patchy cementation of the shallow sea bed during incipient hardground formation; (v) reworking of bioclasts and chalk intraclasts by bottom or wave-induced currents and cohesive debris flows; (vi) pressure solution during late burial diagenesis; (vii) shear deformation by intense plastic deformation of unlithified sediment from limited lateral displacement; and (viii) silicification during burial diagenesis. The facies distribution indicates that active tectonism took place prior to the onset of anoxia that resulted in deposition of the Munk Marl Bed, which in the Valdemar Field was followed by tectonic waning and repeated anoxia. The Valdemar Field constituted a basinal depocenter and was flanked to the east by an early inversion high in the Adda Field characterized by condensation and bypass. The Fischschiefer Member represents a return to prevailing anoxia, consistent with global records of the early Aptian Oceanic Anoxic Event 1a (OAE-1a).
KW - Keywords
KW - Aptian
KW - Barremian
KW - chalk
KW - marlstone
KW - Sola Formation
KW - Tuxen Formation
KW - NORTH-SEA
KW - CHALK
KW - RESERVOIR
KW - FIELD
KW - MUD
U2 - 10.37570/bgsd-2022-71-04
DO - 10.37570/bgsd-2022-71-04
M3 - Journal article
VL - 71
SP - 51
EP - 74
JO - Bulletin of the Geological Society of Denmark
JF - Bulletin of the Geological Society of Denmark
SN - 0011-6297
ER -
ID: 319790730