Sequence stratigraphic interpretations face limitations in predicting the sedimentary architecture and sea-level change in systems characterized by marked fluctuations in sediment supply, particularly in carbonate-dominated environments. Scenario of 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 have studied the impact of this event on sedimentation and stratal stacking patterns in the Moroccan central High-Atlas. We reconstruct the lateral variations of 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 difficulty of sequence stratigraphy interpretations in cases of neritic carbonate factory collapse without assessing the shoreline movement, as stacking patterns in open marine environments do not necessary reflect regional base level variation in disturbed carbonate systems. This study also emphasizes uncertainties associated with focusing solely on lower offshore strata for assessing the history and causes of paleoenvironmental perturbations, as decreases in the rates of carbonate production dampens neritic carbonate shedding and therefore favors the creation of hiatus in deep-water settings.

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