Tripartite Stratigraphy

Stratigraphy of ENA rift basins. Ages of synrift rocks in select basins of the the eastern North American rift system and the Argana basin of Morocco. Basins are arranged from south to north; geologic age decreases to the right. The southern segment of the rift system contains only Triassic strata and no CAMP-related synrift extrusives. The central segment contains Triassic synrift rocks, CAMP-related synrift flows, and Early Jurassic-age strata. The northern segment contains Triassic synrift, Early Jurassic-age Early Jurassic-age strata, and middle Jurassic-age to Cretaceous synrift strata. The transition from continental rifting (green) to drifting / seafloor spreading (purple) is oldest for the southern segment and youngest for the northern segment. BSMA is the Blake Spur Magnetic anomaly. Magnetic anomaly M-25 is the oldest dated magnetic anomaly in oceanic crust. Additional notes: (1) CAMP activity (diabase sheets, NW-striking dikes, and possibly postrift basalt flows in southern segment; diabase sheets, NE-striking dikes, and synrift basalt flows in central and northern segments). (2) Oldest postrift strata in Morocco. (3) Strata eroded during development of Avalon unconformity. (4) Strata associated with thermal subsidence or synrift strata. (5) Synrift strata associated with rifting between the northern Grand Banks and Greenland/Europe or postrift strata associated with salt movement. Modified from Withjack & Schlische (2005), Withjack et al. (2012), and Withjack et al. (2022).

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Geology of the Newark Rift Basin