Role of metamorphic strain in the cristallinity of graphite: the example of the graphitic schists from the Lotru valley (Carpathians, Romania)

Role of metamorphic strain in the cristallinity of graphite: the example of the graphitic schists from the Lotru valley (Carpathians, Romania). The study of the schists from Lotru valley (Carpathians mountains, Romania) shows the role of stress in graphite crystallinity. The carbonaceous material was separated and studied by X-ray diffraction and Raman microspectrometry. There exists a clear contrast between the crystallization degree of graphite found in the quartz- muscovite schists (good) and that found in the quartzites (poor). This observation is in conformity with a clear differentiation of fabric. The graphite suffered an anisotropic deformation in the graphitic schists, whereas it was protected from deformation by quartz in the quartzites. In this last case, the development of graphite from the organic material took place with a volume decrease, protected by the surrounding quartz. (C) 2002 Academie des sciences/Editions scientifiques et medicales Elsevier SAS.