TY - JOUR

T1 - Anatomy of a platform margin during a carbonate factory collapse

T2 - implications for the sedimentary record and sequence stratigraphic interpretation of poisoning events

AU - Andrieu, Simon

AU - Krencker, François-Nicolas

AU - Bodin, Stéphane

N1 - Funding Information: This study was conducted within the framework of research project9040-00188B funded by the Danmarks Frie Forskningsfond (Natur og UniversProgram) and granted to Stéphane Bodin and research project DISED (19 CARN0003 01) funded by the French National Research Agency and granted to SimonAndrieu. Acknowledgments: We are grateful to Thin Section Lab for the high-quality thin sections. The authors thank the reviewers Dan Lehrmann and EliasSamankassou and the editor Gene Rankey for their constructive comments, whichgreatly contributed to improving the quality of our paper.

PY - 2022/8/23

Y1 - 2022/8/23

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=85142256680&partnerID=8YFLogxK

U2 - 10.1144/jgs2022-005

DO - 10.1144/jgs2022-005

M3 - Article

VL - 179

JO - Journal of the Geological Society

JF - Journal of the Geological Society

SN - 0016-7649

IS - 6

M1 - jgs2022-005

ER -