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Table of Contents - Special Paper 341

Argentine Precordillera
Abstract 1
Introduction 3
  Argentine Precordillera 3
     Scope of the study 4
     Methods 4
Regional setting of the Argentine Precordillera 6
  Neoproterozoic-Paleozoic global paleographic reconstructions and the evolving terrane concept for the Argentine Precordillera 8
     Occidentalia terrane 9
     Texas plateau 9
     Precordillera terrane 9
     Cuyania terrane 11
  Historical review and stratigraphy of the Argentine Precordillera 11
     Cambrian 11
     Ordovician 12
     Silurian 12
     Devonian 13
     Post-Devonian 13
  Structural history of the Argentine Precordillera 13
  Subdivision of the Argentine Precordillera 13
     Western basin 14
     Eastern basin 14
Carbonate platform rocks of the Argentine Precordillera 14
  La Laja Formation and equivalents 14
     Lithofacies 15
     Facies associations and depositional environment 16
     Platform configuration 19
     Sedimentary succession of the La Laja Formation 19
     Evolution and sequence stratigraphy of the La Laja Formation 20
  Zonda Formation 23
     Lithofacies 23
     Facies associations and depositional environment 23
     Platform configuration 26
     Sedimentary succession of the Zonda Formation 26
     Evolution and sequence stratigraphy of the Zonda Formation 26
  La Flecha Formation 26
     Lithofacies: Mechanically deposited rocks 28
     Lithofacies: Microbial boundstones and stromatolites 28
     Facies associations and depositional environment 28
     Platform configuration 30
     Sedimentary succession of La Flecha Formation 30
     Evolution and sequence stratigraphy of the Zonda and La Flecha Formations 30
  La Silla Formation 32
     Lithofacies 32
     Facies associations and depositional environment 34
     Platform configuration 35
  Sedimentary succession of La Silla Formation 36
     Talacasto subbasin 36
     San Juan subbasin 36
     Evolution and sequence stratigraphy of the La Silla Formation 36
  San Juan Formation 37
     Time frame of deposition 38
     Lithofacies 38
     Facies associations and depositional environment 40
     Platform configuration 44
     Sedimentary succession of the San Juan Formation 44
     Evolution and sequence stratigraphy of the San Juan Formation 46
Rocks overlying the San Juan Formation 49
  Conformable and unconformable successions 49
     Rio Sassito section 49
     Cerro La Chilca section 50
     Las Chacritas section 50
     Las Aguaditas section 50
     Guandacol subbasin 50
     Discussion 50
  Don Braulio section 51
  Gualcamayo Formation 51
      Lithofacies and the sedimentary succession of the Gualcamayo Formation 51
  La Cantera Formation 51
     Sedimentary succession of the La Cantera Formation 51
     Discussion 53
  Don Braulio Formation 53
     Lithofacies 53
     Sedimentary succession of the Don Braulio Formation 54
     Discussion and sequence stratigraphy of the Don Braulio Formation 54
  Rinconada Formation 54
     Lithofacies 55
     Discussion 56
Continental margin sediments and allochthonous Cambrian and Ordovician rocks 56
  La Cruz limestones 56
     Discussion 56
     Lithofacies 59
     Interpretation and depositional environment 60
  Los Sombreros Formation 60
     San Isidro section 60
     Los Sombrebros section 61
     Ojos de Agua section 61
     Los Ratones section 61
     Los Túneles section 61
     Time frame of deposition of the Los Sombreros Formation 71
     Interpretation and depositional environment of the Los Sombreros Formation 73
  Empozada Formation 73
     Interpretation 74
     Discussion 75
Ordovician of Ponon Trehue 76
  Ponon Trehue Formation 76
     Lithofacies 76
     Interpretation, facies associations, and the sedimentary succession of the
   Ponon Trehue Formation		 76
     Evolution and sequence stratigraphy of the Ponon Trehue Formation 78
  Lindero Formation 79
     Lithofacies 79
     Interpretation, facies associations, and the sedimentary succession of the
   Lindero Formation		 80
Early Paleozoic evolution and paleogeography of the Argentine Precordillera — general aspects and the carbonate platform 81
  General aspects 81
     Size of the terrane 81
     Biogeographic aspects and faunal provincialism 82
     K-bentonites 84
     Heavy mineral associations 84
  Evolution of the carbonate platform 85
     Early Cambrian 85
     Middle Cambrian 85
     Late Cambrian 85
     Early Ordovician 86
     Sea-level history of the Precordillera 87
     Comparison between the carbonate platform of the Precordillera and the
   eastern margin of Laurentia		 91
Early Paleozoic evolution and paleogeography of the Argentine Precordillera —
the Middle Ordovician through Devonian siliciclastic successions		 96
  Middle Ordovician 96
  Late Ordovician 97
  Discussion of the Middle and Upper Ordovician evolution of the Argentine Precordillera 98
     Guanadacol event 98
     Silurian 99
  Discussion of the Silurian evolution of the Argentine Precordillera 99
     Devonian 101
     Discussion of the Devonian evolution of the Argentine Precordillera 102
Geodynamic evolution of the Argentine Precordillera and its parental terrane 102
  History of the Precordillera 102
     Precordillera as part of Laurentia 102
     Discussion 103
     Argentine Precordillera as a marginal plateau to Laurentia 104
     Continental breakup and the rift-drift transition 106
     Discussion 108
     Approach of the Argentine Precordillera toward Gondwana 110
     Discussion 110
Plate tectonic scenario for the evolution of the Argentine Precordillera 112
  Plate tectonic evolution of the Argentine Precordillera 112
     Precordillera as part of Laurentia 112
     Argentine Precordillera as an independent microplate 112
     Argentine Precordillera in the conservative models 114
     Argentine Precordillera as part of Gondwana: Precordillera in the alternative models 114
     Discussion 115
Epilogue 115
  Remaining questions 115
Acknowledgments 116
Appendix 117
References cited 118