TY - JOUR

T1 - Tracking a drowning unconformity up to the peritidal zone: proximal expression of the early Bajocian carbonate crisis in Morocco

AU - Danisch, Jan

AU - Krencker, Francois-Nicolas Frédéric

AU - Malte, Mau

AU - Mattioli, Emanuela

AU - Fauré, Philippe

AU - Alméras, Yves

AU - Nutz, Alexis

AU - Kabiri, Lahcen

AU - El Ouali, Mohamed

AU - Bodin, Stéphane

N1 - Funding information: This research was financed by the Aarhus Universitets Forskningsfond (grant n° AUFF-E-2015-FLS-8-77 ) and the Independent Research Fund Denmark ( DFF , grant n° 9040-00188B ) to SB. We thank Sara Tomás and an anonymous reviewer for their constructive comments on an earlier version of this manuscript.

PY - 2021/10

Y1 - 2021/10

N2 - The early Bajocian environmental crisis is marked by floral and faunal turnovers, and a positive carbon excursion recognized in both marine and continental archives. In the basinal setting of the Central High Atlas Basin, it is concomitant to a drastic drop of carbonate content, interpreted as a result of a severe carbonate demise event in neritic settings. In order to provide a carbonate platform perspective of this demise event, we have investigated a proximal–distal transect consisting of five sections of the Errachidia Platform, which represents upper neritic settings on the southern margin of the basin. New nannofossils and brachiopod findings, supported by organic matter carbon isotope chemostratigraphy, allow for the establishment of a high-resolution chronostratigraphic framework of the Errachidia Platform and a detailed reconstruction of carbonate factory evolution during the late Aalenian to middle Bajocian interval. The early Bajocian (Propinquans Zone) environmental crisis triggered a severe demise event which restricted carbonate production to supra-to intertidal settings, where microbial and peloidal limestones are the only trace of carbonate production. As a consequence, most of the platform is dominated by extended marl deposits that are usually interpreted as hemipelagic deposits. This observation demonstrates that caution must be exerted when interpreting the depositional environments of marl-dominated successions during time of neritic carbonate factory demise.

AB - The early Bajocian environmental crisis is marked by floral and faunal turnovers, and a positive carbon excursion recognized in both marine and continental archives. In the basinal setting of the Central High Atlas Basin, it is concomitant to a drastic drop of carbonate content, interpreted as a result of a severe carbonate demise event in neritic settings. In order to provide a carbonate platform perspective of this demise event, we have investigated a proximal–distal transect consisting of five sections of the Errachidia Platform, which represents upper neritic settings on the southern margin of the basin. New nannofossils and brachiopod findings, supported by organic matter carbon isotope chemostratigraphy, allow for the establishment of a high-resolution chronostratigraphic framework of the Errachidia Platform and a detailed reconstruction of carbonate factory evolution during the late Aalenian to middle Bajocian interval. The early Bajocian (Propinquans Zone) environmental crisis triggered a severe demise event which restricted carbonate production to supra-to intertidal settings, where microbial and peloidal limestones are the only trace of carbonate production. As a consequence, most of the platform is dominated by extended marl deposits that are usually interpreted as hemipelagic deposits. This observation demonstrates that caution must be exerted when interpreting the depositional environments of marl-dominated successions during time of neritic carbonate factory demise.

KW - Brachiopods

KW - Carbonate platform demise

KW - Central High Atlas Basin

KW - Chemostratigraphy

KW - Middle Jurassic

KW - Nannofossils

UR - http://www.scopus.com/inward/record.url?scp=85107803932&partnerID=8YFLogxK

U2 - 10.1016/j.jafrearsci.2021.104300

DO - 10.1016/j.jafrearsci.2021.104300

M3 - Article

VL - 182

JO - Journal of African Earth Sciences

JF - Journal of African Earth Sciences

SN - 1464-343X

M1 - 104300

ER -