Mapping of Genetic Sequences of the Cambrian Series in the Jbel Saghro Massif, Eastern Anti-Atlas, Morocco: Implications for Eustatic and Tectonic Controls

  • Assia Idrissi Department of Earth Sciences, Faculty of Sciences, Mohammed V University, Rabat, Morocco
  • Mohamed Saadi Department of Earth Sciences, Faculty of Sciences, Mohammed V University, Rabat, Morocco
  • Yasser Astati Department of Petroleum, National Office of Hydrocarbons and Mines, Rabat, Morocco
  • Ali Bouayachi Department of Geology, Ben M’sik Faculty of Sciences, Hassan II University, Casablanca, Morocco
  • kawtar Benyas Deparement of Water and Natural Resources Analysis, Mohammadia School of engineers, Mohammed V University, Rabat, Morocco
Keywords: Sequence stratigraphy; sedimentary process; delta; tectonics; Jbel Saghro; Eastern Anti-Atlas.

Abstract

In this paper, a sedimentological and sequence stratigraphy analysis was performed on Lower and Middle Cambrian deposits of Jbel Saghro, Eastern Anti-Atlas. The field data analysis and the application of sequence stratigraphy concepts were used to classify sedimentary processes and depositional environment, and to define the Lower to Middle Cambrian basin’s detailed geometry. The Cambrian sedimentation of northeastern Saghro indicates a deltaic environment, which is composed of two depositional sequences. These sequences are made of a transgressive system tract with retrograding sediments, and a highstand system tract with prograding sediments. In response to sea-level change, these system tracts were formed by several genetic units and limited by various stratigraphic surfaces. The genetic unit stacking patterns combined with the study of synsedimentary tectonics enabled to follow the sedimentary record’s Spatio-temporal evolution and its three-dimensional geometry. The study area deposits display significant dissimilarities in thickness. The western part shows a Lower Cambrian hiatus and an important reduction of the thickness in the Middle Cambrian deposits. However, the marine trend (progradation/retrogradation) remains similar in the study area. This suggests the same eustatic origin of all genetic sequences and variations in their preservation rate. This configuration is the result of differential subsidence that affected the Anti-Atlas during the Cambrian.

Published
2022-04-23