The Tasrirt structure (Kerdous inlier, Western Anti-Atlas, Morocco): a late Pan-African transtensive dome
✍ Scribed by A. Soulaimani; A. Piqué
- Publisher
- Elsevier Science
- Year
- 2004
- Tongue
- English
- Weight
- 836 KB
- Volume
- 39
- Category
- Article
- ISSN
- 1464-343X
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✦ Synopsis
New geological investigations and geochronological data from the Kerdous inlier of the Moroccan Anti-Atlas suggest that an extensional event is recorded by stratigraphic and tectonic features within the Late Proterozoic-Early Cambrian cover. The Tasrirt massif is interpreted as a Late Proterozoic diapiric gneiss dome based on the pattern of metamorphic isograds, the presence of normal ductile shear bands and kinematic criteria indicative of non-coaxial deformation. The ascent of this gneiss dome was controlled by two late Pan-African shear zones with a dominant dextral wrench component. Sedimentary basins developed simultaneously with basement uplift in a NE-SW transtensional system, followed by NE-SW to E-W pure extension. 40 K-40 Ar mica ages of 1900-1350 Ma obtained from the Palaeoproterozoic protoliths are related to a thermal rejuvenation during the late Pan-African syn-metamorphic doming events. The Tasrirt dome is thought to be the most representative of numerous domes within the Anti-Atlas and High Atlas, and is similar to related structures described along the rim of the West African craton during Late Precambrian-Lower Cambrian crustal extension.