Continents and SupercontinentsTo this day, there is a great amount of controversy about where, when and how the so-called supercontinents--Pangea, Godwana, Rodinia, and Columbia--were made and broken. Continents and Supercontinents frames that controversy by giving all the necessary background on how continental crust is formed, modified, and destroyed, and what forces move plates. It also discusses how these processes affect the composition of seawater, climate, and the evolution of life. Rogers and Santosh begin with a survey of plate tectonics, and go on to describe the composition, production, and destruction of continental and oceanic crust, and show that cratons or assemblies of cratons became the first true continents, approximately one billion years after the earliest continental crust evolved. The middle part of the book concentrates on supercontinents, beginning with a discussion of types of orogenic belts, distinguishing those that formed by closure of an ocean basin within the belt and those that formed by intracontinental deformation caused by stresses generated elsewhere. This information permits discrimination between models of supercontinent formation by accretion of numerous small terranes and by reorganization of large old continental blocks. This background leads to a description of the assembly and fragmentation of supercontinents throughout earth history. The record is most difficult to interpret for the oldest supercontinent, Columbia, and also controversial for Rodinia, the next youngest supercontinent. The configurations and pattern of breakup of Gondwana and Pangea are well known, but some aspects of their assembly are unclear. The book also briefly describes the histories of continents after the breakup of Pangea, and discusses how changes in the composition of seawater, climate, and life may have been affected by the sizes and locations of continents and supercontinents. |
Contents
3 | |
2 Plate Tectonics Now and in the Past | 13 |
3 Creation Destruction and Changes in Volume of Continental Crust Through Time | 31 |
4 Growth of Cratons and their PostStabilization Histories | 50 |
5 Assembly of Continents and Establishment of Lower Crust and Upper Mantle | 66 |
6 Assembly and Dispersal of Supercontinents | 85 |
7 Supercontinents Older than Gondwana | 100 |
8 Gondwana and Pangea | 114 |
Appendix B Heat Flow and Thermal Gradients | 194 |
Appendix C Paleomagnetism | 199 |
Appendix D Isotopic Systems | 204 |
Appendix E Cratons | 211 |
Appendix F Anorogenic Magmatic Suites | 217 |
Appendix G Orogenic Belts of Grenville Age | 221 |
Appendix H Orogenic Belts of 2113Ga Age | 227 |
Appendix I Orogenic Belts of PanAfricanBrasiliano Age | 234 |
9 Rifting of Pangea and Formation of Present Ocean Basins | 131 |
10 History of Continents after Rifting from Pangea | 147 |
11 Effects of Continents and Supercontinents on Climate | 159 |
12 Effects of Continents and Supercontinents on Organic Evolution | 176 |
Appendix A Seismic Methods | 190 |
References | 243 |
Author Index | 273 |
281 | |
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Continents and Supercontinents John J. W. Rogers,M. Santosh,Madhava Warrier Santosh Limited preview - 2004 |
Common terms and phrases
accretion activity Africa Amer Antarctic appendix Archean areas Asia assembly Australia basalt basement batholiths breakup caused Cenozoic chapter climate collision complex consists continental blocks continental crust continental margins continents craton crustal deformation deposited developed discuss Earth Sci East Antarctica eastern evidence evolution extinction fault felsic Figure fluids formed fragments Geol geologists Geology glaciation gneisses Gondwana gradients granites granulite Grenville intrusion island arcs isotopic Kaapvaal craton latitudes LIL elements lithosphere lower crust mafic magmatic magnetic mantle Mesozoic metamorphism minerals Moho Mountains Neoproterozoic North America northern occurred ocean basins oceanic lithosphere older ophiolites organisms orogenic belts Pacific Paleoproterozoic Paleozoic Pan-African Pangea Phanerozoic plate plumes plutons poles Precamb Precambrian processes proposed Proterozoic province range ratios region ridges rifting rocks Rodinia Santosh SCLM sediments seismic shield South southern India suites supercontinent Superior craton supracrustal suture tectonic temperature terranes thrust tion velocities volcanic West Gondwana western xenoliths zircons zone