INVESTIGADORES
CISTERNA Gabriela Adriana
artículos
Título:
Palaeobiogeographic affinities of the Argentine Precordilleran Late Palaeozoic brachiopod faunas
Autor/es:
CISTERNA, G.A., ARCHBOLD, N.W. & SIMANAUSKAS, T.
Revista:
Alcheringa
Editorial:
Taylor & Francis Group
Referencias:
Año: 2006 vol. 30 p. 251 - 262
ISSN:
0311-5518
Resumen:
Precordilleran Late Palaeozoic brachiopod genera considered for this
palaeobiogeographical analysis belong to four faunal associations: the low diversity
Early Carboniferous (Tournaisian) Protocanites scalabrinii-Azurduya chavelensis Zone;
the Late Carboniferous (Bashkirian-Moscovian) Levipustula fauna, which appears in
sequences associated with glacial intervals; the latest Carboniferous-earliest Permian
(Gzhelian-Asselian) Rhipidomella-Micraphelia and Tuberculatella-Aseptella associations,
and the Early Permian (mid to late Asselian) Tivertonia jachalensis-Streptorhynchus
inaequiornatus Biozone. The brachiopod affinities of the Precordillera are compared
with the biogeographical Late Palaeozoic regions previously suggested by other authors
using cluster analysis. During the Bashkirian-Moscovian, the Precordilleran faunas show
a high affinity with the Austral Realm because of the presence of the Levipustula faunal
elements in Eastern Australia. At the same time the affinity with the central and North
American Regions is very low. The Early Permian Precordilleran faunas demonstrate
highest affinity with the Gondwanan Realm with several genera also linked to the
Tethyan and Boreal Realms. After the Late Carboniferous glacial episodes that affected
the southwestern Gondwanan margin, the Precordilleran region underwent climatic
amelioration. Subsequently, the Early Permian Precordilleran brachiopod assemblages
are characterized by typical cool to cold water genera widely developed in the core
Gondwanan Realm, with fewer genera (such as Kochiproductus, Rhynchopora and
Neochonetes) suggesting a warmer water influence. The Precordilleran faunas demonstrate
an increase in brachiopod diversity from the Carboniferous to the Permian, related to
water temperature changes and to the palaeogeographical evolution of the southwestern
Gondwanan margin and the movement of Gondwana across the South Pole.