Anatomy of a platform margin during a carbonate factory collapse

implications for the sedimentary record and sequence stratigraphic interpretation of poisoning events

authored by: Simon Andrieu, François-Nicolas Krencker, Stéphane Bodin
Abstract: Sequence stratigraphic interpretations are limited in their prediction of sedimentary architecture and changes in sea-level when used in systems characterized by marked fluctuations in sediment supply, particularly in carbonate-dominated environments. Pronounced variations in sediment supply occurred during the Pliensbachian–Toarcian transition, when significant perturbations of the carbon cycle and intense environmental disturbances led to a global shutdown of carbonate production. We studied the impact of this event on sedimentation and stratal stacking patterns in the Moroccan central High Atlas. We reconstructed the lateral variations in facies and sedimentary geometries along a carbonate platform margin and slope in the field by tracking six key discontinuity surfaces covering the Pliensbachian–Toarcian transition from the platform margin to the toe-of-slope. This work highlights the difficulties in sequence stratigraphic interpretations in cases of neritic carbonate factory collapse without assessments of shoreline movement because the stacking patterns in open marine environments do not necessary reflect the regional variation in base level in disturbed carbonate systems. This study also emphasizes the uncertainties associated with focusing solely on lower offshore strata to assess the history and causes of palaeoenvironmental perturbations because decreases in the rate of carbonate production dampen neritic carbonate shedding and therefore favour the creation of a hiatus in deep water settings.
Organisation(s): Institute of Geology
External Organisation(s): Aarhus University
BRGM
Type: Article
Journal: Journal of the Geological Society
Volume: 179
No. of pages: 23
ISSN: 0016-7649
Publication date: 23.08.2022
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Geology
Sustainable Development Goals: SDG 14 - Life Below Water
Electronic version(s): https://doi.org/10.1144/jgs2022-005 (Access: Closed)