Ambiente de formación de la rampa carbonática en la Precordillera Central, Formación Zonda (cerro La Silla Dto. Jachal, prov. de San Juan) evidenciado por estudios microfaciales e isotópicos.

ARMELLA, C.; CABALERI, N.; VALENCIO, S. A.; PANARELLO, H.0.

Revista de La Asociación Geológica Argentina

Asociación Geológica Argentina

Lugar: Buenos Aires, Argentina; Año: 1995 vol. 50 p. 219 - 228

0004-4822

ABSTRACT. Lithofacics and stable isotopes of the Zonda Formation (Upper Cambrian) from cerro La Silla, San JuanPrecordillera. The Zonda Formation (Upper Cambrian) is constituted by alternating layers of dolomitic limestones and dolostones. Six litofacies have been recognized in this paper LF1: Mudstone with discontinuous banding, from subtidal intertidal  environment with restricted circulation on;LF2: Microbialitic mudstone, with peloidal irregular layered microstructure.characteristic of shallow intertidal environment; LF3: Bioturbated mudstone, deposited on a subtidal environment; LF4: Mudstone with cross lamination, from intertidal environment; LF5: Microbialitic mudstone, fenestral texture, intercalated with intraclastic packstone from peritidal environment, with episodic of increase of energy, and LF6: Intraclastic floatstone, forming ephemeral channel deposits. Carbonates have been developed on a tidal flat with restricted water circulation. The isotopic results, confirm this hypothesis by revealing the existence of conditions leading to the water evaporation when the carbonates precipitated.