Data di Pubblicazione:
2010
Citazione:
Upper Permian Brachiopods from the Nesen Formation, North Iran / L. Angiolini, L. Carabelli - In: Evolution and development of the brachiopod shell / [a cura di] F. Alzarez, G. Curry. - [s.l] : The Palaeontological Association, 2010 Nov. - ISBN 9781444339376. - pp. 41-90 [10.1111/j.1475-4983.2010.00989.x]
Abstract:
The two members of the Nesen Formation in
North Iran are very rich in brachiopods, which, collected
bed-by-bed along six sections and in two localities, comprise
48 species of 31 genera of the orders Productida, Orthotet-
ida, Orthida, Rhynchonellida, Athyridida, Spiriferida, and
Terebratulida. One subfamily (Transcaucasathyriinae) and
three species are new. Brachiopod settling preferences show
a significant change through the formation, with semi-infau-
nal productids dominating in the lower member and more
diversified pedicle attached and cemented taxa increasing in
the upper member. This suggests a shallowing upward trend
from settings below storm-wave base in the lower member
to shallow water, higher nutrient substrates around fair-
weather wave base in the upper member, in agreement with
lithological and sedimentological data. The two biozones of
the lower member, the Tyloplecta persica and Araxilevis inter-
medius Biozones, are Wuchiapingian in age and can be cor-
related with the Araxilevis Biozone of Transcaucasia. More
difficult is the correlation of the biozones of the upper
member, the Permophricodothyris ovata and Enteletes latero-
plicatus Biozones, which are Changhsingian in age and more
diversified than the Changhsingian ‘Comelicania’(= Gruntal-
lina) beds of Transcaucasia. This may be related to a palaeo-
ecological control, as the North Iran sediments were
deposited at shallow water depths, whereas the Transcauca-
sian succession records a shift to deeper water settings. How-
ever, the two biozones of the upper member show a
significant generic similarity with the Changhsingian shal-
low-water brachiopod faunas of South China. The Nesen
brachiopod fauna disappears about twenty metres below the
Permo ⁄ Triassic boundary, with a single occurrence of a spe-
cies of Ombonia in this almost barren interval. This pattern
has been recorded in many other locations in the western
Tethys and it contrasts with the brachiopod distribution pat-
tern of South China, which has more diverse and abundant
faunas up to the end-Permian extinction crisis and even in
the survival interval.
Tipologia IRIS:
03 - Contributo in volume
Keywords:
Biostratigraphy; Brachiopod systematics; Correlation; End-Permian faunal change; Palaeoecology
Elenco autori:
L. Angiolini, L. Carabelli
Link alla scheda completa:
Titolo del libro:
Evolution and development of the brachiopod shell