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Table of Contents - Special Paper 495

Mesozoic Assembly of the North American Cordillera

By Robert S. Hildebrand


Abstract 1
Introduction 2
Problems with the Existing Back-Arc Model 3
A Segmented Orogen 8
Laurentian Passive Margin 9
Great Basin Sector 11
Sevier Fold-Thrust Belt 11
The Hinterland Belt 19
Central Nevada 20
White-Inyo Range 20
Death Valley 21
Western Sierra Nevada Metamorphic Belt 22
Klamath Mountains 24
Jurassic Magmatic Rocks 27
Sierran Region 27
Northwestern Nevada 30
Mojave Desert Region 31
Cretaceous Batholithic Rocks 33
Sierra Nevada Batholith 34
Salinian Block 37
Great Valley Sedimentation and Deformation 37
Coast Range Ophiolite 40
Franciscan Complex 41
Late Cretaceous Deformation and Metamorphism 42
Rand-Pelona-Orocopia-Swakane Subduction Complex 43
Sonoran Sector 44
Transverse Ranges 44
Southern Arizona 45
Mexican Sonora 47
Baja California 47
San Gabriel–Caborca Block 47
Guerrero and Other Mexican Terranes 48
The Great Arc of the Caribbean 49
Peninsular Ranges Batholith 50
Cretaceous Magmatism in the Mojave and Sonoran Deserts 50
Subduction and Fore-Arc Complexes 51
Late Cretaceous Deformation and Metamorphism 51
Canadian Sector 52
Passive Margin 52
Foredeep 53
Canadian Terranes and Superterranes 53
Belt-Purcell-Windermere Supergroups 54
Selwyn Basin 54
Omineca Belt Magmatism 56
Kootenay Terrane 56
Yukon-Tanana Terrane 57
Slide Mountain Terrane 57
Stikinia and Quesnellia 57
Cache Creek Terrane 58
Triassic Overlap Sequence 58
Coast Range Plutonic Complex 58
Cretaceous Overlap Sequence 59
Late Cretaceous–Early Tertiary Magmatism 62
North Cascades 62
Idaho Batholith 62
Blue Mountains Terranes 64
Alaskan Sector 64
Brooks Range, North Slope and Alaskan Orocline 64
Wrangellia Composite Terrane 66
Orogenic Basins in Central Alaska 67
The Chugach Accretionary Complex 68
Discussion 69
Paleozoic Events within the Great Basin and Canadian Sectors 69
Upper Triassic to Middle Jurassic Arcs and Collisions 71
Talkeetna Arc 71
Bonanza Arc 71
Quesnellia-Kootenay-Belt-Purcell-Windermere 72
Black Rock Arc 72
Klamath Arcs 72
Lake Combie–Slate Creek Arc 74
Smartville Arc 74
Sierran Jurassic Arc 75
Slab Break-Off 77
Jurassic Slab-Failure Magmatism 77
Blue Mountains Assembly 78
Jurassic Amalgamation of Rubia 78
Subduction on the Western Side of Rubia 78
Arctic Alaska–Angayucham Collision in Alaska 79
Sevier Fold-Thrust Belt and Early Collision on Western North America 80
Effects of Sevier Collision on the Franciscan Complex and Great Valley Group 81
Plate Reorganization Due to Collision 81
Great Basin Slab-Failure Magmatism and STEP Faults 81
Cretaceous Cordilleran Batholiths 82
Mid-Cretaceous Transpressional Deformation in Batholithic Terranes 84
Folding of Sierra Nevada 88
Doubling of Cordilleran Batholiths in the Canadian Sector 95
The Laramide Event: ~80–75 Ma Deformation and Metamorphism 98
Laramide Collision along the Orogen 99
Cretaceous–Early Tertiary Slab Failure Magmatism 100
Shutdown of Franciscan Subduction 103
Exhumation of Franciscan Complex 105
Northward Migration of Terranes 107
Colorado Plateau and the Laramide Grand Canyon 111
Metamorphic Core Complexes and Hinterland Duplexes 112
Basin and Range Extension 114
Summary of Cordilleran Assembly 114
Carrying the Orogen Southward 119
Problems and Direction for Future Research 120
Acknowledgments 121
References Cited 123