Deformation experiments on natural and synthetic diabasic aggregates, with application to the tectonics of earth and venus
- 出版日期：2000.
- 页数：135 p. :
- 第一责任说明：Susan Beth Ginsberg.
- 分类号：a822
- ISBN：059986429X(ebk.) :
MARC全文
02h0020811 20101216111858.0 cr un||||||||| 101020s2000 xx ||||f|||d||||||||eng | 059986429X(ebk.) : CNY371.35 (UnM)AAI9980313 UnM UnM NGL a822 Ginsberg, Susan Beth. Deformation experiments on natural and synthetic diabasic aggregates, with application to the tectonics of earth and venus [electronic resource] / Susan Beth Ginsberg. 2000. 135 p. : digital, PDF file. Source: Dissertation Abstracts International, Volume: 61-07, Section: B, page: 3476. ; Adviser: David L. Kohlstedt. Thesis (Ph.D.) -- University of Minnesota, 2000. In order to obtain constitutive equations with application to the tectonics of Earth and Venus, as well as to investigate microstructural development in large-scale deformation, we have conducted four high-temperature deformation studies on diabasic materials.;To investigate rocks similar to those on the surface of Venus, we performed compressive creep experiments on dried and undried diabase sample. Increased pre-drying of these samples resulted in increased strength. In the dried samples, samples composed of pyroxene frameworks were stronger than samples composed of plagioclase frameworks, suggesting that estimates of the strength of Venus' crust are limited by our knowledge of the microstructures of the rocks at the surface.;We deformed dried and undried aggregates of plagioclase + melt in simple shear to explore the development of microstructures in large-scale deformation. Melt-rich bands developed at 20–30° to the shear plane and antithetic to the shear direction. These melt-rich bands had a wavelength that correlated with the peaks in the tungsten pistons used to grip the sample. Flow laws for these materials were determined in compressive creep experiments. Values for the stress exponents for deformation of these samples was consistently less than unity, possibly resulting from migration of melt from boundaries in relative compression to those in relative tension. Rheologies determined from these experiments are consistent with those found in other experimental studies. Results from these experiments can be applied to rocks in the Earth's middle and lower crustal regions.;Simple shear deformation experiments were conducted on dried synthetic aggregates of plagioclase + pyroxene. In a sample with pyroxene grains an order of magnitude larger than plagioclase grains, 200% shear strain resulted in shape-preferred orientation of the pyroxene grains. In a sample with grains of both phases similar in size, 300% shear strain resulted only in weak shape-preferred orientation. The viscosities of both samples were similar to previously published viscosities for dried plagioclase aggregates.;Our theological results help constrain models of deformation in the crustal regions of Venus and Earth. The microstructures which developed in our samples deformed in shear provide interesting phenomena which may have implications for modeling large-scale tectonics on both planets. Engineering. ; Materials science. aKohlstedt, David L. aCN bNGL http://proquest.calis.edu.cn/umi/detail_usmark.jsp?searchword=t_title%3DDeformation+experiments+on+natural+and+synthetic&singlesearch=no&channelid=%CF%B8%C0%C0&record=1 NGL Bs672 rCNY371.35 ; h1 xhbs1003