IDEAN   23403
INSTITUTO DE ESTUDIOS ANDINOS "DON PABLO GROEBER"
Unidad Ejecutora - UE
artículos
Título:
Facies analysis of a Toarcian-Bajocian shallow marine/coastal succession (Bardas Blancas Formation) in northem Neuquén Basin, Mendoza province, Argentina
Autor/es:
BRESSAN, G.S.; KIETZMANN, D.A.; PALMA, R.M.
Revista:
JOURNAL OF SOUTH AMERICAN EARTH SCIENCES
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Lugar: Amsterdam; Año: 2013 vol. 43 p. 112 - 126
ISSN:
0895-9811
Resumen:
Strata of the Bardas Blancas Formation (Lower Toarcian-Lower Bajocian) are exposed in northern Neuquen Basin. Five sections have been studied in this work. Shoreface and transition zone deposits predominate in four of the section studied exhibiting a high abundance of hummocky cross-stratified, horizontally bedded and massive sandstones, as well as massive and laminated mudstones. Shell beds and trace fossils of the mixed Skolithos-Cruziana ichnofacies appear in sandstone beds, being related with storm event deposition. Gravel deposits are frequent in only one of these sections, with planar cross-stratified, normal graded and massive orthoconglomerates characterizing fan deltas interstratified with shoreface facies. A fifth outcrop exhibit planar cross-stratified orthoconglomerates, pebbly sandstones with low-angle stratification and massive mudstones have been interpreted as fluvial channel deposits and overbank facies. The vertical analysis of the distribution of facies shows a retrogradational arrangement of facies related with a widespread transgressive period. Comparison of vertical distribution of facies also shows differences in thickness in the lower interval among the sections studied. This would be related with a control in the sedimentary deposition by the half graben structures result of the relief generated by the extensional regime of the rifting stage which act in the basin during the Rhaetian?Pliensbachian. Lateral variation of facies let recognize the deepening of the basin through the southwest.