Polycyclic Evolution of Paleoproterozoic Rocks in the Southwestern Part of the Mako Group(Eastern Senegal,West Africa)  

作　　者：Papa Moussa Ndiaye Edmond Dioh Famara Diatta Alassane Traore Makhoudia Fall Ousmane Balde 

机构地区：[1]Département de Géologie,Universite Cheikh Anta Diop,Dakar,Sénégal [2]Institut Fondamental d’Afrique Noire,Universite Cheikh Anta Diop,Dakar,Sénégal [3]Institut de Technologie Nucléaire Appliquée,Universite Cheikh Anta Diop,Dakar,Sénégal

出　　处：《International Journal of Geosciences》2014年第7期739-748,共10页地球科学国际期刊（英文）

摘　　要：After an extensional stage giving rise to tholeiitic basalts and gabbros, the south western part of Kédougou Kéniéba Inlier (KKI) was affected by three phases of compressionnal deformation. The first phase (D1) was related to NE-SW stress that led to northeastward thrusting. Early granitoids would be implemented during this tectonic event. The second phase (D2) was due to East-West compressional stress that created combined strike sleep faults: NNW-SSE and NNE-SSW respectively sinistral and dextral. During this phase, some volcanic rocks and gabbros were mylonitized, hydrothermalized and transformed into quartzites. These quartzites were considered as sedimentary rocks in previous studies. Granitic plutons and andesites took place during this tectonic phase. D3 deformation occurred towards the end of the Eburnean orogeny. It would be held in two episodes. In the first episode, WNW-ESE stresses created conjugate shears: sinistral NNW-SSE and dextral NE-SW. In the second episode, stresses moved toward the NE-SW direction and made the resulting brittle structures arranged in NS dextral corridors.After an extensional stage giving rise to tholeiitic basalts and gabbros, the south western part of Kédougou Kéniéba Inlier (KKI) was affected by three phases of compressionnal deformation. The first phase (D1) was related to NE-SW stress that led to northeastward thrusting. Early granitoids would be implemented during this tectonic event. The second phase (D2) was due to East-West compressional stress that created combined strike sleep faults: NNW-SSE and NNE-SSW respectively sinistral and dextral. During this phase, some volcanic rocks and gabbros were mylonitized, hydrothermalized and transformed into quartzites. These quartzites were considered as sedimentary rocks in previous studies. Granitic plutons and andesites took place during this tectonic phase. D3 deformation occurred towards the end of the Eburnean orogeny. It would be held in two episodes. In the first episode, WNW-ESE stresses created conjugate shears: sinistral NNW-SSE and dextral NE-SW. In the second episode, stresses moved toward the NE-SW direction and made the resulting brittle structures arranged in NS dextral corridors.

关 键 词：PALEOPROTEROZOIC Eastern Senegal Volcanic-Rocks Polycyclic Deformation SILICIFICATION 

分 类 号：R73[医药卫生—肿瘤]