Paleoenvironmental Evolution Of The Agua De Jagüel Formation (Late Carboniferous-Early Permian): An Example Of Glacial- Postglacial Transition In Open Marine Basins

CICCIOLI, P.L.; LIMARINO, C.O.; TEDESCO, A.M.; HENRY, L. C.; ISBELL, J. L.

Buenos Aires

Simposio; V Simposio Argentino del Paleozoico Superio; 2008

Museo Argentino de Ciencias Naturales

During the Late Carboniferous, glacial conditions in the western basins ofArgentina evolved, according to their paleogeographic position, into different patternsof postglacial facies. For example, in Paganzo Basin, the transition from glacial topostglacial conditions occurs as well-exposed fjord-like sequences and asglacilacustrine and glacifluvial deposits. In contrast, the Calingasta-Uspallata Basinshows a complete record of glacimarine sequences deposited in open marine settingsincluding Hoyada Verde, La Capilla and Agua de Jagüel formations. Located at thesouthernmost part of the Calingasta-Uspallata Basin, the Agua de Jagüel Formationcontains a nearly complete late Paleozoic stratigraphic record which has been dividedinto five major stratigraphic sections. Section 1 corresponds to the glacial interval, andis composed of several levels of resedimented diamictites, shales with dropstones, andshales with thin marl horizons. Section 2 comprises shales and fine-grained sandstones(Namurian postglacial transgression). Section 3 is floored by an important erosivesurface and is composed of fluvial sandstones and conglomerates. Section 4 starts in aconspicuous flooding surface and is mainly composed of shoreface sandstones as wellas offshore shales sedimented during the Late Carboniferous (307.2 ± 5.2 M.y.). Finally,a new transgressive surface defines the base of section 5 that is composed of a majorproportion of offshore deposits.