Lithostratigraphic framework and correlation of the Neoproterozoic northern West African Craton passive margin sequence (Siroua-Zenaga-Bouazzer Elgraara Inliers, Central Anti-Atlas, Morocco): an integrated approach

摘要

The Neoproterozoic volcano-sedimentary cover (～0.8Ga) deposited on the northern passive margin of the West African craton occurs in the central Anti-Atlas inliers and is a ～2km thick succession formally termed the Tizi n-Taghatine Group. The group comprises two sedimentary packages (lower and upper) separated by a middle volcanic unit. An integrated approach of lithostra-tigraphy, sedimentology, sequence stratigraphy and paleogeographic setting have been combined to provide well constrained correlation and lithostratigraphic organization. The Tizi n-Taghatine Group is formally subdivided into 12 Formations, 10 of which are defined in the lower sedimentary package while the middle volcanic unit and the upper sedimentary package constitute the two uppermost Formations. The lithostratigraphic organization and subdivision of the Tizi n-Taghatine Group constitutes a strati-graphic record of major paleogeographic settings and large cyclic changes in depositional system due to relative sea-level variations. The integrated approach of combination and comparison of various data provides significant information on the nature, origin and time significance of the formal unit boundaries. This leads to proposing a correlative scheme for the Tizi n-Taghatine Group across the Neoproterozoic central Anti-Atlas suture zone.