Complicated pressure–temperature path recorded in the eucrite Padvarninkai

Author(s):  
Masaaki Miyahara ◽  
Akira Yamaguchi ◽  
Eiji Ohtani ◽  
Naotaka Tomioka ◽  
Yu Kodama ◽  
...  
Keyword(s):  
Geology ◽  
2003 ◽  
Vol 31 (12) ◽  
pp. 1045 ◽  
Author(s):  
Mutsuki Aoya ◽  
Shin-ichi Uehara ◽  
Masatoshi Matsumoto ◽  
Simon R. Wallis ◽  
Masaki Enami

1980 ◽  
Vol 47 (1) ◽  
pp. 35-39 ◽  
Author(s):  
Y. Weitsman

An optimal temperature path is derived for a thin viscoelastic plate which is cooled from a stress-free state against geometric constraints. The optimal path, which minimizes the final residual stress due to cool down, is shown to possess discontinuities at the initial and final times and to be smooth and continuous during all intermediate times. An iterative convergent scheme is provided for a wide class of linear viscoelastic responses and typical paths are determined for two specific cases. In addition, a time-temperature path which maintains constant stress values during cool-down is derived. The problem is motivated by the cooling process of composite materials.


2007 ◽  
Vol 71 (24) ◽  
pp. 6030-6039 ◽  
Author(s):  
Emma L. Tomlinson ◽  
Paul F. McMillan ◽  
Ming Zhang ◽  
Adrian P. Jones ◽  
Simon A.T. Redfern

1995 ◽  
Vol 117 (4) ◽  
pp. 478-482 ◽  
Author(s):  
G. Webb ◽  
S. D. Antolovich

The results from a series of elevated temperature prestrain experiments on a hypostoichiometric polycrstalline Ni3Al are presented. Experiments were conducted to examine the deformation characteristic of “thermal reversibility” or temperature path history independence (TPHI). Temperature path history independence was experimentally observed from prestraining experiments (also known as Cottrell-Stokes experiments) in which the specimen was deformed at different temperatures; the results were compared to those obtained from tests conducted at constant temperature. The purpose of such experiments was to macroscopically evaluate the effects of intrinsic dislocation mobility and dislocation substructure on deformation. These experiments provide a framework in which to evaluate fundamental characteristics of thermally activated deformation processes. The results for polycrystalline Ni3Al alloys indicate that the mechanisms responsible for thermal strengthening is independent of prior deformation history. This observation implies that the mechanism of anomalous strengthening in such alloys is fully reversible and independent of the development of a dislocation “substructure”.


2019 ◽  
Vol 483 (1) ◽  
pp. 255-279 ◽  
Author(s):  
Peter J. Treloar ◽  
Richard M. Palin ◽  
Michael P. Searle

AbstractThe Pakistan part of the Himalaya has major differences in tectonic evolution compared with the main Himalayan range to the east of the Nanga Parbat syntaxis. There is no equivalent of the Tethyan Himalaya sedimentary sequence south of the Indus–Tsangpo suture zone, no equivalent of the Main Central Thrust, and no Miocene metamorphism and leucogranite emplacement. The Kohistan Arc was thrust southward onto the leading edge of continental India. All rocks exposed to the south of the arc in the footwall of the Main Mantle Thrust preserve metamorphic histories. However, these do not all record Cenozoic metamorphism. Basement rocks record Paleo-Proterozoic metamorphism with no Cenozoic heating; Neo-Proterozoic through Cambrian sediments record Ordovician ages for peak kyanite and sillimanite grade metamorphism, although Ar–Ar data indicate a Cenozoic thermal imprint which did not reset the peak metamorphic assemblages. The only rocks that clearly record Cenozoic metamorphism are Upper Paleozoic through Mesozoic cover sediments. Thermobarometric data suggest burial of these rocks along a clockwise pressure–temperature path to pressure–temperature conditions of c. 10–11 kbar and c. 700°C. Resolving this enigma is challenging but implies downward heating into the Indian plate, coupled with later development of unconformity parallel shear zones that detach Upper Paleozoic–Cenozoic cover rocks from Neoproterozoic to Paleozoic basement rocks and also detach those rocks from the Paleoproterozoic basement.


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