This book presents a comprehensive overview of Australian impact structures and related mineralization, including a discussion of the significance of many of these structures for crustal evolution. The book focuses in particular on Archaean impact ejecta/fallout units in the Pilbara Craton of Western Australia, large exposed and buried impact structures, and on the geophysical evidence for possible to probable impact structures.
Thanks to their long-term geological stability, Precambrian and younger terrains in the Australian continent contain 38 confirmed impact structures and 43 ring and dome structures, many of which constitute possible to probable asteroid impact structures. The impact structures have been the subject of more than half a century of studies and range from several tens of meter-large craters to buried structures larger than 100 km in diameter. Discoveries of impact fallout units in the Pilbara Craton have defined the Pilbara as one of the two best documented terrains where Archaean impact ejecta/fallout deposits are identified, the other terrain being the Kaapvaal Craton in southern Africa. A synthesis of evidence from both cratons indicates periods of large asteroid bombardments during ~3.47 – 2.48 billion years-ago, including peak bombardment about 3.25—3.22 billion years-ago. The latter period coincides with an abrupt transformation of an early Archaean granite-greenstone crust to mid to late Archaean semi-continental crustal regimes, underpinning the significance of heavy asteroid impact events for crustal evolution. Apart from proven impact structures, Australian terrains display a range of circular features, including morphological and drainage rings, circular lakes, volcanic craters, tectonic domes, oval granite bodies, mafic igneous plugs, salt diapirs, and magnetic, gravity and seismic anomalies, many of which are of a likely impact origin. Thermal and hydrothermal processes associated with impact cratering bear important consequences for the formation of mineral deposits, such as Ni at Sudbury, Pb-Zn at Siljan and Kentland. Impact structures may also provide sites for the accumulation of hydrocarbons, whereas in some instances fracturing associated with impact structures allows outward migration of oil and gas.
Автор: Guo-Neng Chen; Rodney Grapes Название: Granite Genesis: In-Situ Melting and Crustal Evolution ISBN: 9048174694 ISBN-13(EAN): 9789048174690 Издательство: Springer Рейтинг: Цена: 18284.00 р. Наличие на складе: Есть у поставщика Поставка под заказ.
Описание: This book reviews current ideas explaining the formation of granite in terms of melting, segregation, ascent and emplacement. It introduces an alternative hypothesis that granites are endogenic in that they essentially form and remain at melting sites in the middle-upper crust under conditions of abnormally high heat flow.
Автор: Jakob Deller Название: Hyper-Velocity Impacts on Rubble Pile Asteroids ISBN: 3319479849 ISBN-13(EAN): 9783319479842 Издательство: Springer Рейтинг: Цена: 19564.00 р. Наличие на складе: Есть у поставщика Поставка под заказ.
Описание:
The thesis presents a tool to create rubble pile asteroid simulants for use in numerical impact experiments, and provides evidence that the asteroid disruption threshold and the resultant fragment size distribution are sensitive to the distribution of internal voids. This thesis represents an important step towards a deeper understanding of fragmentation processes in the asteroid belt, and provides a tool to infer the interior structure of rubble pile asteroids.
Most small asteroids are 'rubble piles' – re-accumulated fragments of debris from earlier disruptive collisions. The study of fragmentation processes for rubble pile asteroids plays an essential part in understanding their collisional evolution. An important unanswered question is “what is the distribution of void space inside rubble pile asteroids?” As a result from this thesis, numerical impact experiments can now be used to link surface features to the internal structure and therefore help to answer this question.
Applying this model to asteroid ?teins, which was imaged from close range by the Rosetta spacecraft, a large hill-like structure is shown to be most likely primordial, while a catena of pits can be interpreted as evidence for the existence of fracturing of pre-existing internal voids.
Автор: D. Vielzeuf; Ph. Vidal Название: Granulites and Crustal Evolution ISBN: 9401074224 ISBN-13(EAN): 9789401074223 Издательство: Springer Рейтинг: Цена: 54504.00 р. Наличие на складе: Есть у поставщика Поставка под заказ.
Описание: Proceedings of the NATO Advanced Research Workshop on Petrology and Geochemistry of Granulites, Clermont-Ferrand, France, September 5-9, 1988
Introduction.- Geological background.- Neoarchean basement rock assemblage, crust-mantle interactions and crustal evolution of Western Liaoning Province.- Paleo- to Mesoproterozoic magmatic rock assemblage and crust-mantle geodynamic processes.- Precambrian crustal evolution, lithospheric mantle evolution and crust-mantle geodynamics of Western Liaoning-Northwest Hebei Provinces.- Concluding remarks.
Описание: This thesis presents geological, petrological, geochemical, and zircon U–Pb–Lu–Hf isotopic field data for representative Precambrian lithologies in the Western Liaoning-Northeastern Hebei Provinces along the northern margin of the North China Craton (NCC). It describes late Neoarchean (2.64–2.48 Ga) supracrustal metavolcanic rocks and granitoid gneisses; late Paleoproterozoic (1.72–1.68 Ga) Jianping alkaline plutons and Pinggu alkaline volcanic rocks; and newly discovered ~1.23 Ga mafic dykes. The nature of magma sources and genesis of each magmatic episode are investigated, and the Precambrian (~2.6–1.2 Ga) lithospheric mantle evolution and crust-mantle interaction processes are established for the first time –aspects that provide important constraints in our understanding of the Precambrian crustal evolution and geodynamic processes in the region studied.
Автор: A. J. Tankard; S. C. Eriksson; Martin Martin; K. A Название: Crustal Evolution of Southern Africa ISBN: 1461381495 ISBN-13(EAN): 9781461381495 Издательство: Springer Рейтинг: Цена: 12157.00 р. Наличие на складе: Есть у поставщика Поставка под заказ.
Описание: Syntheses of the geology of major areas of the Earth`s crust are increasingly needed in order that the features of, and the problems associated with, the secular evolution of the continents can be understood by a wide audience.
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