THE METAMORPHISM OF SIERRAS AUSTRALES. BUENOS AIRES PROVINCE. ARGENTINA.

Authors

  • María A. Leguizamon
  • Mario Egidio Teruggi

Keywords:

Petrography, Metamorphism, Buenos Aires,

Abstract

Through a through petrographical research it has been recognized that part of the Sierras Australes sequence shows the effects of a bimetamorphism overimposed on diagenesis: a dynamic metamorphism due to folding and its shear stresses with development of rhomb-cleavege and anastomocleavage, and a regional metamorphism of a very low grade (green Schists) which caused the development of a microfabric of the crenellated-edge type, constituted by muscovite and quartz. On the basis of this interpretation, a possible thermic curve of the evolution of the Sierras Australes is offered and as aresult the Paleozoic sequence is divided into two large sections: a lower one, bimetamorphic, and an upper one, monometamorphic to simply diagenetic.

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