Disentangling shallow-water bulk carbonate carbon isotope archives with evidence for multi-stage diagenesis: An in-depth component specific petrographic and geochemical study from Oman (mid-Cretaceous)

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dc.identifier.uri http://dx.doi.org/10.15488/4789
dc.identifier.uri https://www.repo.uni-hannover.de/handle/123456789/4832
dc.contributor.author Huck, Stefan
dc.contributor.author Wohlwend, Stephan
dc.contributor.author Weissert, Helmut
dc.contributor.author Coimbra,Rute
dc.contributor.author Christ, Nicolas
dc.date.accessioned 2019-05-16T09:34:10Z
dc.date.available 2019-05-16T09:34:10Z
dc.date.issued 2017
dc.identifier.citation Huck, S.; Wohlwend, S.; Weissert, H.; Coimbra, R.; Christ, N.: Disentangling shallow-water bulk carbonate carbon isotope archives with evidence for multi-stage diagenesis: An in-depth component specific petrographic and geochemical study from Oman (mid-Cretaceous). In: Depositional Record 3 (2017), Nr. 2, S. 233-257. DOI: https://doi.org/10.1002/dep2.35
dc.description.abstract Disentangling shallow-water bulk carbonate carbon isotope archives into primary and diagenetic components is a notoriously difficult task and even diagenetically screened records often provide chemostratigraphic patterns that significantly differ from global signals. This is mainly caused by the polygenetic nature of shallow-water carbonate substrates, local carbon cycle processes causing considerable neritic-pelagic isotope gradients and the presence of hiatal surfaces resulting in extremely low carbonate preservation rates. Provided here is an in-depth petrographic and geochemical evaluation of different carbonate phases of a mid-Cretaceous (Barremian-Aptian) shallow-water limestone succession (Jabal Madar section) deposited on the tropical Arabian carbonate platform in Oman. The superposition of stable isotope signatures of identified carbonate phases causes a complex and often noisy bulk carbon isotope pattern. Blocky sparite cements filling intergranular pores and bioclastic voids evidence intermediate to (arguably) deep burial diagenetic conditions during their formation, owing to different timing or differential faulting promoting the circulation of fluids from variable sources. In contrast, sparite cements filling sub-vertical veins reveal a rock-buffered diagenetic fluid composition with an intriguing moderate enrichment in C-13, probably due to fractionation during pressure release in the context of the Miocene exhumation of the carbonate platform under study. The presence of abundant, replacive dedolomite in mud-supported limestone samples forced negative carbon and oxygen isotope changes that are either associated with the thermal breakdown of organic matter in the deep burial realm or the expulsion of buried meteoric water in the intermediate burial realm. Notwithstanding the documented stratigraphically variable and often facies-related impact of different diagenetic fluids on the bulk-rock stable isotope signature, the identification of diagenetic end-members defined C-13 and O-18 threshold values that allowed the most reliable primary' bulk carbon isotope signatures to be extracted. Most importantly, this approach exemplifies how to place regional shallow-water stable isotope patterns with evidence for a complex multi-stage diagenetic history into a supraregional or even global context. eng
dc.language.iso eng
dc.publisher Hoboken : Wiley-Blackwell Publishing
dc.relation.ispartofseries Depositional Record 3 (2017), Nr. 2
dc.rights CC BY 4.0
dc.rights.uri https://creativecommons.org/licenses/by/4.0/
dc.subject Arabian carbonta platform eng
dc.subject Barremian - Aptian eng
dc.subject multi stage diagenesis eng
dc.subject shallow - water chemostratigraphy eng
dc.subject.ddc 550 | Geowissenschaften ger
dc.title Disentangling shallow-water bulk carbonate carbon isotope archives with evidence for multi-stage diagenesis: An in-depth component specific petrographic and geochemical study from Oman (mid-Cretaceous)
dc.type article
dc.type Text
dc.relation.issn 2055-4877
dc.relation.doi https://doi.org/10.1002/dep2.35
dc.bibliographicCitation.issue 2
dc.bibliographicCitation.volume 3
dc.description.version publishedVersion
tib.accessRights frei zug�nglich


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