Late Precambrian crustal evolution in NE Sudan: isotopic and geochronologic constraints

Abstract:

The continental crust of NE Africa and Arabia was formed or modified during the late Precambrian (ca. 900-550 Ma) Pan-African orogenic cycle. The relationship between juvenile crust of the Arabian-Nubian shield (formed by accretion of ensimatic terranes) and older rocks of the Nile craton to the west (thermally reworked at the same time), is poorly understood. A regional geochronologic and isotopic study indicates that the crust of NE Sudan formed between about 810 and 580 Ma. The ages and isotopic characteristics are indistinguishable from those of adjacent juvenile terranes in Arabia and Egypt but contrast markedly with samples along and west of the Nile near the eastern margin of the Nile craton. The ages and isotopic signatures of rocks north of the Nakasib suture seem distinctly younger and derived from a more depleted mantle source than those from south, suggesting that this is one of the most important terrane boundaries in the Arabian-Nubian shield. -from Authors

Año de publicación:

1993

Keywords:

Fuente:

scopus