CIG   05423
CENTRO DE INVESTIGACIONES GEOLOGICAS
Unidad Ejecutora - UE
artículos
Título:
Archaeocyaths from South America: review and a new record.
Autor/es:
GONZÁLEZ PABLO DIEGO; TORTELLO, FRANCO; DAMBORENEA, SUSANA; NAIPAUER MAXIMILIANO; SATO ANA MARÍA; VARELA RICARDO
Revista:
GEOLOGICAL JOURNAL (CHICHESTER)
Editorial:
JOHN WILEY & SONS LTD
Referencias:
Lugar: Chichester; Año: 2011
ISSN:
0072-1050
Resumen:
In South America, autochthonous archaeocyathan fauna contained in Early Cambrian limestones have not been found yet, despite the fact that there are rocks of the right age and lithology. Nevertheless, few well-documented occurrences of these organisms in allochthonous clasts contained in psephytic rocks of a wide age range were made known in recent years. Limestone erratic blocks within the Late Carboniferous-Early Permian Fitzroy Tillite Formation in the Malvinas (Falkland) Islands yielded three archaeocyath taxa and, most recently, seven taxa were reported from archaeocyathan limestone clasts in a metaconglomerate of the Cambro-Ordovician El Jagüelito Formation in northern Patagonia. To these, a new record from the Late Carboniferous-Early Permian Sauce Grande Formation diamictites in Sierras Australes, Buenos Aires Province, Argentina, should now be added. Preservation of this scarce new material is poor, but at least three different taxa can be distinguished. The most likely source of all archaeocyathan limestone clasts found up to now in southern South America is the Shackleton Limestone from the Transantarctic Mountains in East Antarctica. The new record from the Sauce Grande Formation and the inferred clast provenance strengthen the correlation between this unit, the Dwyka Tillite (South Africa) and the Fitzroy Tillite Formation (Malvinas/Falklands), suggesting a very wide distribution of these Antarctic materials during the Late Carboniferous-Early Permian Gondwana glaciation (Episode III). Thus, even though being allochthonous, Archaeocyaths are emerging as a new key biological feature for Gondwana palaeogeographic reconstructions.