Automation of phase classification, calculation of metastable chemical energy, and the interaction of deformational and metamorphic processes
- 出版日期：2004.
- 页数：1 v. :
- 第一责任说明：Kurt James Steffen.
- 分类号：a381 ; a626.2
- ISBN：049617617X(ebk.) :
MARC全文
02h0029452 20120614154925.0 cr un||||||||| 120614s2004 xx ||||f|||d||||||||eng | 3156705 049617617X(ebk.) : CNY371.35 NGL NGL NGL a381 ; a626.2 Steffen, Kurt James. Automation of phase classification, calculation of metastable chemical energy, and the interaction of deformational and metamorphic processes [electronic resource] / Kurt James Steffen. 2004. 1 v. : digital, PDF file. Adviser: Selverstone, Jane. Thesis (Ph.D.)-- The University of New Mexico, 2004. Previously developed methods of phase classification using the electron probe have been based on setting threshold values or relative ranks for weight percent oxide values. These methods perform poorly for minerals that have a significant solid solution, and provide no mechanism for checking the accuracy of the analysis or the accuracy of the classification. A new algorithm for phase classification using a transformation from weight percent oxide to cation and finally to additive/exchange components is introduced. The algorithm works by exploiting the least-squares nature of the transformation from weight percent oxide to additive/exchange components. Metastable chemical energy MCE) is the energy difference between an actual mineral assemblage and the equilibrium assemblage for the same bulk composition at specified external conditions P,T, externally buffered chemistry) of interest. By quantifying MCE and comparing it to other energy sources in different petrologic systems, the relative importance of mechanical and chemical energy sources can be identified. Results in the KASH and NCKFMASH systems indicate that MCE will typically be slightly higher than the metastable energy provided by surficial or plastic strain energies for systems that are slowly equilibrating. The MCE values for cases of extreme chemical disequilibrium metastable coexistence of granulite and eclogite facies metabasites from the Flatraket complex of Norway) indicate that MCE values may be one to two orders of magnitude higher than the metastable energy available from plastic strain and surficial sources. Hornblende Garbenschiefer and biotite schist samples from the Greiner shear zone in the Eastern Alps were used to study the effects of structural position, relative timing of metamorphic reactions and shearing, and operation of specific deformation mechanisms on calculated pressures and temperatures. Some of the scatter in the PT results represents real variations in the PT conditions at which equilibration occurred during interaction between shearing and metamorphism. However, at least some of the scatter represents spurious results obtained by pairing mineral compositions that were never in equilibrium with one another. Extraction of useful P-T information from sheared samples thus requires careful documentation of the relationships between deformation mechanisms and chemical zoning prior to performing thermobarometric calculations. Metamorphism (Geology) ; Metamorphic rocks ; Rock deformation Computer simulation. ; Computer simulation. ; Computer simulation. Electronic dissertations. aeBook. aCN bNGL http://pqdt.bjzhongke.com.cn/Detail.aspx?pid=O9OyV6vwemQ%3d NGL Bs1512 rCNY371.35 ; h1 bs1204