Wolfgang Frisch/Martin Meschede / Ronald Blakey Plate ...978-3-540-76504-2/1.pdfFrom continental...
Transcript of Wolfgang Frisch/Martin Meschede / Ronald Blakey Plate ...978-3-540-76504-2/1.pdfFrom continental...
Wolfgang Frisch /Martin Meschede /
Plate TectonicsRonald Blakey
Wolfgang Frisch /Martin Meschede /
Plate TectonicsRonald Blakey
123
Continental D riftand Mountain Building
ISBN 978-3-540-76503-5 e-ISBN 978-3-540-76504-2DOI 10.1007/978-3-540-76504-2Springer Heidelberg Dordrecht London New York
c© Springer-Verlag Berlin Heidelberg 2011This work is subject to copyright. All rights are reserved, whether the whole or part of the mate-rial is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation,broadcasting, reproduction on microfilm or in any other way, and storage in data banks. Dupli-cation of this publication or parts thereof is permitted only under the provisions of the GermanCopyright Law of September 9, 1965, in its current version, and permission for use must alwaysbe obtained from Springer. Violations are liable to prosecution under the German Copyright Law.The use of general descriptive names, registered names, trademarks, etc. in this publication doesnot imply, even in the absence of a specific statement, that such names are exempt from the rele-vant protective laws and regulations and therefore free for general use.
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Prof. Dr. Wolfgang FrischDepartment of GeosciencesUniversity of Tü[email protected]
Prof. Dr. Martin MeschedeUniversity of GreifswaldInstitute of Geography and GeologyFriedrich-Ludwig-Jahn-Str. 17AD-17487 [email protected]
Prof. Dr. Ronald BlakeyNorthern Arizona UniversityDept. GeologyCenter for EnvironmentalSciences & EducationPO Box 409986011-4099 Flagstaff [email protected]
Content
Preface XII
1 Contractional theory, continental drift and plate tectonics 1
Plate tectonics – a change in the paradigm of the geosciences 1
Early history of geodynamic thought 1
From continental drift to plate tectonics 2
Th e plate tectonic concept 4
Th e pattern of magnetic polarity stripes 8
Plate motions and earthquake zones 8
Two kinds of continental margins 11
Magmatism and plate tectonics 11
What drives the plates and what slows them down? 12
Collision and mountain building 12
2 Plate movements and their geometric relationships 15
Helpful transform faults 15
Relative movements and triple junctions 16Two RTF triple junctions off North America 18
Relative plate velocities – past and present 20
Direct measurement of plate movements 21
Apparent contradictions in the plate motion pattern 22
Fault-plane-solutions of earthquakes 23Seismic tomography 25
3 Continental graben structures 27
Active and passive graben structures 28Symmetric and asymmetric crustal extension 28
Sediments and ore deposits in graben structures 29
Volcanism in graben structures 30
Th e Upper Rhine Graben in Germany 31
Th e history of the Upper Rhine Graben 32Th e Upper Rhine Graben in the Middle European stress fi eld 33
Magmatism and heat fl ow in the Upper Rhine Graben 34
Th e large East African rift system 34
Th e Afar Depression 37Th e Red Sea – from rift to drift 37Th e extensional area of the Basin and Range Province 39
Th e development of metamorphic domes 40
A brief history of the Basin and Range Province 41
4 Passive continental margins and abyssal plains 43
Continuous subsidence of the continental margins 43
Th e sedimentary trap at a passive continental margin 44
Tracts of sequence stratigraphy 45Processes on continental margins 46
Petroleum deposits – the economic signifi -cance of passive continental margins 48
Th e Atlantic – an ocean opens in an intricate manner 48
Pangaea and Panthalassa 49Th e large abyssal plains 51
Sediments of the abyssal plains 52Manganese nodules from the deep sea 54
Facies changes on the large oceanic conveyor belt 55
Th e Bengal deep sea fan 56
VI
5 Mid-ocean ridges 59
Topography of the ridges 59
Generation of oceanic lithosphere 60
Rocks of the oceanic crust 61Pillow lavas 62Seismic layers 64
Basalts of mid-ocean ridges 65
Fast and slow spreading ridges and rocks of the lithospheric mantle 65
Segmentation of ridges by faults 67
Graben formation in the Atlantic 67An oceanic crustal profi le in the Atlantic Ocean 68
Black and white smokers 68
Ocean fl oor metamorphism 70
Chromite deposits 71
Ophiolites 71
Th e ophiolite of the Semail Nappe in Oman 72Metamorphic sole 72
Alpine-Mediterranean ophiolites 72
6 Hot spots 75
Hot spots and mid-ocean ridges 77
Th e mysterious D'' layer and the dented Earth 77
Hot spots of Pangaea 78Hot spot tracks in the ocean 80
A guyot evolves 82Hot spot tracks on the continent 82
Flood and trap basalts 84
Th e Azores – hot, cold or wet spot? 85
Hawaii – a typical oceanic hot spot 86
Iceland 87
Yellowstone 87
Th e superplume event in the Cretaceous 88
7 Subduction zones, island arcs and active continental margins 91
Structure of plate margin systems with subduction zones 91Spontaneous and forced subduction: Mariana- and Chile-type subduction 93
Deep sea trenches as sediment traps 96
Accretionary wedge and outer ridge 97Th e accretionary wedge of the Sunda Arc 99
Subduction erosion instead of accretion 100
Th e forearc basin 103Earthquakes and Benioff zones 103
Th e secret of deep earthquakes 107
High-pressure or subduction metamorphism 109
Ultrahigh-pressure meta morphic rocks 111Rapid burial, rapid uplift 112
Subduction-related magmatism – a paradox? 113
Rocks of the magmatic zone 114
Zonation of magmas in space and time 116Explosive stratovolcanoes as indicators for subduction magmatism 117
Metamorphism in the magmatic belt 119Paired metamorphic belts 119
Ore deposits in the magmatic belt 120
Th e backarc basin 120Splitting of intra-oceanic island arcs 122
Gravity and heat fl ow 122
Subduction and collision 122
What is the reason for the arcuate shape of island arcs? 94
Mud volcanoes 101
Th e Shigatse Flysch in Tibet 104
Isotopic signatures and the infl uence of continental crust 118
VII
8 Transform faults 123
Oceanic transform faults 123
Fracture zones in the ocean fl oor 123
Continental transform faults 125
San Andreas – the infamous transform fault of California 127
Th e North Anatolian Fault in Asia Minor and the Alpine Fault in New Zealand 129
9 Terranes 131
Documenting terranes 132
Terranes in the North American Cordillera 134
Suspect terranes in Mexico and Middle America 138
10 Early Precambrian plate tectonics 139
Th e oldest rocks and minerals 140Greenstone-granite belts 141Granulite-gneiss belts 143
Towards an Archean plate tectonic model 145
Th e growth of continents 146Possible younger equivalents of greenstone-granite belts 147
11 Plate tectonics and mountain building 149
Types of active continental margins within orogenic styles 149
Continent-continent collision 152
Uplift , erosion, and elevation of mountains 154
Collapse and crustal escape 158
12 Old orogens 1592500–2000 million years old ophiolites 159
Th e Wopmay orogen in Canada 160
Th e Grenville orogenic cycle and the formation of the supercontinent Rodinia 160
Th e Panafrican orogeny and the formation of Gondwana 160
Th e Caledonides – a Wilson cycle around the Iapetus Ocean 161
Th e signifi cance of Scotland and the Greek mythology 162
Th e Variscides – a broad mountain belt in central Europe 163
A Variscan suture in the southern Black Forest 165
Th e Variscan orogen in the Alps 165
Paleozoic mountain building in eastern and southern North America 167
How many orogenies? 169
13 Young orogens – the Earth’s loftiest places 171
Th e Himalayas – a mountain range with superlatives 172
Tectonic history of the Himalayas 172Nanga Parbat and Namche Barwa syntaxis 174
Th e Alps – an untypical but classic orogen 174
Brief history of Alpine evolution 176Lateral tectonic extrusion in the Alps 178
Th e North American Cordillera – a diff erent style of orogen 179
Laramide Rocky Mountains – an orogenic mystery solved 185
Epilog 187
Glossary 189References 199Keyword Index 207
Komatiites 144
Th e Great Dike of Zimbabwe 147
VIII
Preface
I n the late 1960’s, Wegener’s theory of continental drift , originally conceived fi ft y years earlier, was merged with the theory of plate tectonics and the
concepts gained global acceptance among geosci-entists. For the fi rst time, a unifying concept, plate tectonics, could reconcile and unify all phenomena in geoscience into a common synthesis. Th e basic tenants have not changed since the 1960’s, although many corrections and refi nements have been added regarding questions of detail. Th e impact of the theory of plate tectonics cannot be overestimated – its importance to geoscience is as basic as Darwin’s theory of evolution is to the biological sciences.
Earth is subject to steady change. Th is can impres-sively be realized in volcanic bursts and earthquakes around the Pacifi c Ocean or in the grandeur of young mountain ranges. Whilst new parts of plates are created along the mid-ocean ridges, older parts of plates disappear in subduction zones. Mountain chains arise from the collisions of plates. Th ese dy-namic processes are driven by the heat that is released from the interior of the Earth; this is what keeps the dynamo running. Continental drift , mountain build-ing, volcanism, earthquakes, and in consequence of quakes, sea waves like the devastating tsunami of 26th December 2004 in the Indian Ocean – all this is the expression of the dynamics of the Earth.
Th is book presents an introduction in the wide fi eld of plate tectonics and is dedicated to a broad audience interested in natural sciences, and students and professionals in geosciences and related subjects. Expertise in tectonics is not a pre-condition; the tech-nical terms and geological processes are explained and reviewed in adequate detail. Many terms are defi ned in the glossary at the end of the book and a keyword index enables quick location of topics and terms in the text. Figures at the inside front-end and back-end covers present concise overviews of the geologic timescale and critical events in Earth history as well as the classifi cation of magmatic and metamorphic rocks. More than 200 references en-able the studious reader to gain deeper insight into special topics.
Th e book begins with an historical introduction concerning early ideas of continental drift and Earth
dynamics that leads into discussion and considera-tion of plate motions and geometry. Th is is followed by several chapters that defi ne, describe in detail, and illustrate the various features, processes, and settings that comprise the plate tectonic realm: graben structures, passive continental margins, ocean basins, mid-ocean ridges, subduction zones, and transform faults. Th e remaining chapters deal with mountain-building processes as a consequence of plate tectonics and the collision of terranes and large continents. Th ese chapters illuminate plate tectonic processes from the early history of the Earth to the present. We examine how plate tec-tonics played a role in the construction of ancient Archean continents and then built large volumes of Proterozoic crust via “modern” plate-tectonic processes. Following the late Proterozoic break-up of the supercontinent Rodinia, we follow the plate tectonic events that generated older and deeply eroded Paleozoic mountains and the formation of Pangaea to the more recent Mesozoic and Ceno-zoic mountains that remain the pinnacles of our modern planet. Examples from across the Earth are presented, including the young and loft y mountain ranges of the Himalayas, the Alps, and the North American Cordilleras. We relate the concepts, pro-cesses, and examples from the earlier chapters of the book to the plate-tectonic evolution discussed in the latter part of the book. In this way the book not only describes the plate tectonic phenomena, but also focuses on the processes behind them and how they have worked in concert to produce the present plate confi guration. Th roughout the book, we strive to communicate to the reader an understanding that the Earth is a body in constant motion and change
– a tectonic machine.Th e present edition has evolved from an earlier
German edition, Plattentektonik (Wissenschaft liche Buchgesellschaft , Darmstadt) by Wolfgang Frisch and Martin Meschede (2005). Although largely a translation of the German edition, it also contains a number of new contributions by Ron Blakey, who especially enriched the text with geological examples from North America and upgraded the English text from an earlier translation.
Wolfgang Frisch, Ron Blakey, and Martin MeschedeVienna, Sedona, and Greifswald, May 2010