Salt basin in the Atlantic and Red Sea-Afar

Abstract

Evaporite basins in the SW Barents Sea, Southern North Sea, Central Atlantic, South Atlantic, and Red Sea-Afar largely formed at subtropical latitudes. This is consistent with classic views on development of evaporites. The SW Barents Sea and the Southern North Sea evaporite basins formed in abandoned continental rifts. The Central Atlantic salt basins (Newfoundland, Nova Scotia, eastern US, Morocco, and Seenegal\/Guines Bissau) formed in relatively confined intrarift basins, prior to continental breakup. The South Atlantic salt basins (Brasil and West Africa) formed in a wide basin during the late stage of rifting, shortly before breakup. Only minor magmatism is documented for the Late Carboniferous SW Barents Sea evaporite basin. Ther Permian North Sea evaporite basin overlies a three-armed Permian rift, which was associated with considerable magmatism. The magmatism preceded the evaporite sequence by c. 50 Ma, and the relationship between magmatism and the evaporites is indirect through thermal subsidence. Neither the SW Barents Sea nor the North Sea developed into oceanic basins. The northern Central Atlantic evaporites formed in Late Triassic - Early Jurassic rifts along the continental margins approximately synchronously with a very widespread pulse of dykeswarm injection at c. 200 Ma. However, the evaporites predate opening of the Central Atlantic by c. 20 Ma. None of the mentioned evaporite sequences can thus be related to oceanic seafloor spreading. The southern Central Atlantic salt basins have not been dated and their age is inferred from the north basins. If the age is similar, the southern basins formed at anomalously equatorial latitudes. In the South Atlantic, the continet-ocean boundary (COB) is not well established, and the relationship between the outmost limit of evaporites and the COB remains somewhat unclear. However, the preferred plate reconstructi