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Diastrophic evolution of Western Papua and New Guinea.

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posted on 2023-05-27, 17:11 authored by Smith, Jan Gerald
There are four main phases in the diastrophic evolution of western Papua and New Guinea: (1) a Mesozoic phase of taphrogen6sis (geosyncline formation) characterized by the fragmentation of a pre-Mesozoic cratonic platform into a series of intrageosynclinal troughs and geanticlines which constituted the Papuan geosynclinal system. This phase was accompanied by basic volcanism and ultrabasic plutonism, (2) A Paleogene phase defined by the temporary stabilization of the geosynclinal system and the development of an extensive quasi-platform regime. (3) A lower and Middle Miocene phase of retrogressive taphrogeneds marked by remobilization of the earlier geosynclinal terrain and again by important volcanism. (4) An Upper Miocene to Recent orogenic phase dominated by the uplift of the Papuan geosynclinal system to form the New Guinea cordillera. Uplift was associated with the formation of an exogeosynclinal trough, foreland folding and andesitic volcanism. The Papuan geosynclinal system is thought to have formed primarily as the result of extensional stresses within the earth's crust, although there is strong evidence that-simple shear, translation and rotation have also contributed to the total deformation of the orogen. These fundamental horizontal movements have served as a framework for the intense vertical oscillations that characterized the development of the Papuan geosyncline and the adjacent platform. The vertical movements culminated in the uplift of the New Guinea cordillera and the formation of two distinct patterns of folding and faulting. The first type of folding is of a secular nature and is intimately linked with the uplift of the orogen. These primary folds are represented by the large horst-like anticlinoria which form the backbone of the main cordillera. The second type of folding is episodic in nature and is the secondary consequence of orogenic uplift. These are the foreland folded structures of the Papuan foothills which originated as the result of gravity sliding off the flank of the rising orogen.

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Copyright 1964 the Author - The University is continuing to endeavour to trace the copyright owner(s) and in the meantime this item has been reproduced here in good faith. We would be pleased to hear from the copyright owner(s). Thesis (Ph.D.) - University of Tasmania, 1965. Includes bibliography

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