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Paper No. 13-11
Presentation Time: 3:25 PM

THE MAURITANIDES: THE MISSING PIECE OF THE APPALACHIANS


LONGO, Shasta Rosa, Department of Earth Science, Montana State University, Bozeman, MT 59717, HUBBARD, Mary S., Department of Earth Sciences, Montana State University, PO Box 173480, Bozeman, MT 59717 and NDIAYE, Papa Moussa, Department of Geology, Université Cheikh Anta Diop, Dakar, Senegal

There is a missing piece of the Appalachian mountain belt in West Africa, known as the Mauritanide orogen. Both Appalachian and Mauritanide orogens developed during Late Carboniferous to Early Permian following the closure of the Iapetus paleo-ocean basin between 325 and 270 Ma. By Late Permian, a piece of the Appalachian orogen broke off with the continent of Africa when the modern Atlantic Ocean began to open at 240 Ma. This piece represents the Mauritanide orogen and is now found in the countries of Mauritania and Senegal, northwestern Africa. The aim of this pilot study is to increase the knowledge of the complex deformation phases within the Mauritinide orogen.

This study is designed to estimate the degree of deformation in gneiss and schist from the folded autochthonous rocks in the southern portion of the Mauritanides, Eastern Senegal. It tests the hypothesis that the Mauritanides experienced complex multi-stage deformation as indicated by the prior research. The study applies petrographic techniques to determine the kinematics from the textural relations among minerals in schist and gneiss, mainly composed of quartz, phyllosilicates, and garnet porphyroblasts. The five oriented samples, collected from the southern Mauritanides, were examined for shear deformation in the schists and gneisses. Preliminary results indicate strong right-lateral shear deformation. In some cases, there is evidence for dip-slip faulting or strike-slip deformation. This structural determination is consistent with observations that have been made in parts of the Appalachian mountain belt.

The current study indicates that deformation in the Mauritanides recorded a complex tectonic history. Additional data from the Southern Mauritanides coupled with similar research in the Blue Ridge portion of the Appalachian orogen would provide more information on how analogous the two orogens are to one another. While the Appalachians have been well studied, little is known about the Mauritanides.

Session No. 13

T95. Sigma Gamma Epsilon Student Research (Posters)
Monday, 26 October 2020: 1:30 PM-5:30 PM
Geological Society of America Abstracts with Programs. Vol 52, No. 6
doi: 10.1130/abs/2020AM-358561
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