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The influence of metamorphic deformation on graphitization process

Domenii publicaţii > Ştiinţele pământului şi planetare + Tipuri publicaţii > Articol în revistã ştiinţificã

Autori: Barzoi, S.C., Ciobanu, D. Ramona, Guy, B., Seclaman, M.

Editorial: Journal of Science Politics and Scientometry - Special Number, ISSN-1582-1218, 2005.

Rezumat:


The research completed within the grant „The Influence of Metamorphic Deformation on Graphitization Process” has evidenced by field works and laboratory studies, optical microscopy and X-ray diffractometry, a relationship between the metamorphic strain and the carbonaceous material crystallinity from the Schela Formation (the northern part of the Parang Mountains, Romania).

Based on its results, this research work has been appreciated as an original and valuable scientific achievement to the research on the metamorphic rocks from Carpathian Mountains, and especially to a better understanding of the graphite genesis.

Founded on this grant researches, it has been proved that the metamorphic stress, evidenced by a more intense deformation and quantified by the foliation planes frequency, influences the carbonaceous material crystallinity. Both, the isotropic quartzite and the anisotropic schist from Schela Formation contain the carbonaceous material but with a different degree of graphitisation, graphite-d2 in the quartzite and graphite-d1 in the schist.
Using the X-ray diffractometry and a strain estimation method, it has been observed that the degree of crystallinity increases proportionally with the metamorphic deformation.

Furthermore, it has been shown that the carbonaceous material crystallinity could be used as a geothermometer only whether the deformation had an essential role during the metamorphism. The concepts described by Stach et al. (1982) and Pasteris & Wopenga (1991) in their articles might conduct to aberrant temperatures in case that a rock is not considerably deformed. Therefore, it should be previously studied the degree of deformation of the rock and, only after that, it could be decided whether or not the graphite can be used in geothermometry.

Cuvinte cheie: metamorphic strain, carbonaceous material crystallinity, graphite genesis, geothermometer