ESTRUTURA GEOLÓGICA DA REGIÃO DE CAJAMAR-JORDANÉSIA, SP

EDGARD SANTORO, CELSO DAL RÉ CARNEIRO, MÍRIAN CRUXEN B. DE OLIVEIRA, JORGE HACHIRO

Resumo


The geological mapping of the Cajamar-Jordanésia region (São Paulo State) is outlined in five lithological units belonging to the São Roque Group (Upper Proterozoic). Geological, structural, and stratigraphical features support the setting. The structural trend of those units is ENE, with increasing metamorphic grade southwards . Slate and meta-arenite occur at the northern portion of the area and schists at the southern. The basal units are composed by micaschists and some porfiroblastic staurolite schists. The micaschists are in gradual contact with phyllites. Small bodies of amphibolites are found in the metapelites. The intermediate level of the lithological column is constituted by a carbonatic layer with few metapelitic inclusions. The top level is formed by metapsamit es with frequent metapelitic intercalations . Three generations of folds have been recognized. The second one is impressive in any scale of analysis. It is also associated to a zonal crenulation cleavage on metapelites and responsible for the general structure outline of rocks bodies at regional scale. This paper makes reference to the soil collapses which took place in August 1986, in Cajamar town. Those collapses were related to the karstic evolution of the studied area.


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