IDEAN   23403
INSTITUTO DE ESTUDIOS ANDINOS "DON PABLO GROEBER"
Unidad Ejecutora - UE
artículos
Título:
Eolian deposits of the southwestern margin of the Botucatú paleoerg: Reconstruction of the Gondwana landscape in Central Northern Argentina
Autor/es:
M. NAIPAUER; M. PIMENTEL; V. PERI; H. BARCELONA
Revista:
SEDIMENTARY GEOLOGY
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2016
ISSN:
0037-0738
Resumen:
The Mesozoic Botucatú paleoerg at the southwestern margin of Gondwanaincludes a succession of eolian dunes cross-strata which are presently exposed inOtumpa Hills (Central Northern Argentina). Here, the architectural facies, petrology andprovenance of those rocks were studied in order to investigate depositionalenvironments and paleoclimates. The stratigraphic sequence included basal eolian twodimensionalcrescentic dunes (Slp) overlain by three-dimensional crescentic dunes ofsmaller scale (Smt). These were correlated with the Upper Member Rivera of theTacuarembó Formation (Uruguay), or its equivalent in Brazil, the Botucatú Formation.These outcrops partially mark the southwestern margin of the Botucatú paleoerg alongthe Chaco-Paraná Basin boundary. The paleocurrents from the W, NW and SW and theU-Pb ages of detrital zircons indicate a main Pampean cratonic and secondary Andeanmagmatic arc (180 Ma) source. A detrital zircon of 180 Ma by U-Pb limits a maximumdepositional age at 180 Ma (Toarcian) for facies Slp. Upwards, the phreatic silcrete andcalcrete indicate semiarid conditions during the Paleocene, which are correlated with theQueguay Formation of Uruguay. A saprolite paleoweathering profile, recording wettropical-hyper-tropical climate at the Early Eocene and representing the Gondwana landscape and climate conditions, crowns the sequence. This study represents the first provenance and surface texture analysis of minerals from the Botucatú paleoerg and wasinstrumental to unravel past environmental and sedimentary conditions.