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Sedimentological Evolution of the Late Emsian to Early Givetian Carbonate Ramp in the Mader (Eastern Anti-Atlas, SE-Morocco)

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Sedimentological Evolution of the Late Emsian to Early Givetian Carbonate Ramp in the Mader (Eastern Anti-Atlas, SE-Morocco) 1 Sedimentological evolution of the late Emsian to early Givetian carbonate ramp in the Mader (eastern Anti-Atlas, SE-Morocco) Dissertation zur Erlangung des Grades eines Doktors der Naturwissenschaften der Geowissenschaftlichen Fakultät der Eberhard-Karls-Universität Tübingen vorgelegt von Sascha DÖRING aus Wetzlar 2002 2 Tag der mündlichen Prüfung: 30.7.2002 Dekan: Prof. Dr. Dr. hc. Muharrem Satir 1. Berichterstatter: Prof. Dr. Jobst Wendt 2. Berichterstatter: Prof. Dr. Thomas Aigner 3 Contents ABSTRACT............................................................................................................................. 5 KURZFASSUNG .................................................................................................................... 6 1 INTRODUCTION............................................................................................................... 9 2 GEOLOGICAL SETTING ................................................................................................. 9 2.1 Basin evolution at the northwestern margin of the Sahara Craton....................................................... 9 2.2 Regional geological setting (Devonian - Carboniferous) ......................................................................10 3 DATABASE AND METHODS........................................................................................ 13 3.1 Stratigraphic sections ...............................................................................................................................13 3.2 Thin section analysis and charting .........................................................................................................13 3.3 Stratigraphy ..............................................................................................................................................14 3.3.1 Sequence stratigraphy .......................................................................................................................14 3.3.2 Lithostratigraphy ...............................................................................................................................17 3.3.3 Biostratigraphy...................................................................................................................................17 3.4 Reconstruction of the depositional geometry and facies relationships ...............................................18 4 LITHOFACIES AND PALAEOENVIRONMENT OF EMSIAN TO GIVETIAN ROCKS OF THE MADER............................................................................................... 19 4.1 Shales and marls (LF 1) ...........................................................................................................................19 4.2 Nodular limestones (LF 2) .......................................................................................................................19 4.2.1 Palaeoenvironment of lithofacies 2a, b.............................................................................................19 4.3 Micritic limestones and dolostones (LF 3) .............................................................................................19 4.3.1 Palaeoenvironment of lithofacies 3a .................................................................................................19 4.3.2 Palaeoenvironment of lithofacies 3b .................................................................................................19 4.3.3 Palaeoenvironment of lithofacies 3c .................................................................................................23 4.3.4 Palaeoenvironment of lithofacies 3d ................................................................................................25 4.4 Bioclastic limestones (LF 4) .....................................................................................................................25 4.4.1 Palaeoenvironment of lithofacies 4a .................................................................................................25 4.4.2 Palaeoenvironment of lithofacies 4b .................................................................................................26 4.4.3 Palaeoenvironment of lithofacies 4c .................................................................................................26 4.5 Crinoid limestones (LF 5) ........................................................................................................................28 4.5.1 Palaeoenvironment of lithofacies 5a, b.............................................................................................28 4.5.2 Palaeoenvironment of lithofacies 5c .................................................................................................28 4.5.3 Palaeoenvironment of lithofacies 5d ................................................................................................28 4.6 Peloid limestones (LF 6) ..........................................................................................................................29 4.6.1 Palaeoenvironment of lithofacies 6a .................................................................................................29 4.6.2 Palaeoenvironment of lithofacies 6b .................................................................................................29 4.7 Coral-stromatoporoid limestones (LF 7) ................................................................................................33 4.7.1 Palaeoenvironment of lithofacies 7a .................................................................................................33 4.7.2 Palaeoenvironment of lithofacies LF 7b ...........................................................................................33 4.7.3 Palaeoenvironment of lithofacies LF 7c............................................................................................33 4 4.7.4 Conclusions on the palaeoenvironment of lithofacies 7a, b, c ........................................................33 4.7.5 Palaeoenvironment of lithofacies LF 7d ...........................................................................................34 4.8 Conglomerates and breccias (LF 8) .........................................................................................................38 4.8.1 Palaeoenvironment of lithofacies LF 8a ...........................................................................................38 4.8.2 Palaeoenvironment of lithofacies LF 8b ...........................................................................................38 4.9 Dacryoconarid limestones (LF 9) ............................................................................................................40 4.9.1 Palaeoenvironment of lithofacies LF 9 .............................................................................................40 4.10 Partially laminated sandstones and siltstones (LF 10) ........................................................................40 4.10.1 Palaeoenvironment of lithofacies LF 10 .........................................................................................41 4.11 Brachiopod-mollusc coquinas (LF 11) ..................................................................................................41 4.11.1 Palaeoenvironment of lithofacies LF 11 ..........................................................................................41 5 SEQUENCE STRATIGRAPHIC FRAMEWORK ......................................................... 43 5.1 Depophase 0, Emsian (excavatus - serotinus Zone) ..............................................................................43 5.1.1 Depophase 0a, Emsian (”Emsien calcaire” sensu Massa 1965, Emsian limestones) .....................43 5.1.2 Depophase 0b, Emsian (”Emsien argilo-silteux” sensu Massa 1965) .............................................43 5.2 Depophase 1, late Emsian (serotinus Zone) ............................................................................................48 5.2.1 Depophase 1a .....................................................................................................................................48 5.2.2 Depophase 1b .....................................................................................................................................49 5.3 Depophase 2, late Emsian - early Eifelian (patulus - lower part of the costatus Zone) ........................51 5.4 Depophase 3, early Eifelian (costatus Zone) ...........................................................................................55 5.5 Depophase 4, early - late Eifelian (costatus - upper part of the kockelianus Zone) ...............................56 5.6 Depophase 5, early Givetian (Lower varcus Zone) ................................................................................58 5.6.1 Depophase 5a .....................................................................................................................................60 5.6.2 Depophase 5b .....................................................................................................................................61 5.6.3 Depophase 5c, d, e .............................................................................................................................64 5.7 Synsedimentary deformation during depophase 4 and 5 ....................................................................66 5.7.1 Boulchral area.....................................................................................................................................66
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