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Titolo:
Palaeobiogeography of Early Cretaceous (Berriasian-Barremian) calcareous nannoplankton
Autore:
Street, C; Bown, PR;
Indirizzi:
Univ Coll London, Dept Geol Sci, London WC1E 6BT, England Univ Coll London London England WC1E 6BT l Sci, London WC1E 6BT, England
Titolo Testata:
MARINE MICROPALEONTOLOGY
fascicolo: 1-4, volume: 39, anno: 2000,
pagine: 265 - 291
SICI:
0377-8398(200006)39:1-4<265:POEC(C>2.0.ZU;2-F
Fonte:
ISI
Lingua:
ENG
Soggetto:
ATLANTIC-OCEAN; NANNOFOSSILS; SEA; PALEOCEANOGRAPHY; BIOSTRATIGRAPHY; PRESERVATION; BIOGEOGRAPHY; DIVERSITY; EVOLUTION; SEDIMENTS;
Keywords:
calcareous nannofossils; palaeobiogeography; Early Cretaceous; palaeoecology;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
69
Recensione:
Indirizzi per estratti:
Indirizzo: Street, C Univ Coll London, Dept Geol Sci, Gower St, London WC1E 6BT, England Univ Coll London Gower St London England WC1E 6BT 6BT, England
Citazione:
C. Street e P.R. Bown, "Palaeobiogeography of Early Cretaceous (Berriasian-Barremian) calcareous nannoplankton", MAR MICROPA, 39(1-4), 2000, pp. 265-291

Abstract

In order to assess Early Cretaceous nannoplankton biogeography, we studieda series of sites which provide a north-south transect across the AtlanticOcean, supplemented by sections from the North Sea Basin, Barents Sea, Falkland Plateau, Weddell Sea (Antarctica), Argo Abyssal Plain (NW of Australia) and Neuquen Basin (Argentina). Quantitative assemblage data were gathered from each site for seven time-slices within the Berriasian to Barremian interval, each horizon being determined by a nannofossil datum. Trends in species relative abundance and measures of diversity, evenness and richness provide revealing biogeographic information. A broad, low- to mid-palaeolatitude zone (50 degrees N-50 degrees S) is flanked in both Northern and Southern Hemispheres by distinct high-palaeolatitude zones. Major changes in assemblage abundance and composition occur across a sharp biogeographic 'front' at around 50 degrees N and S palaeolatitude. High-palaeolatitude assemblages are lower in species richness and diversity and characterised by the presence of abundant, typically bipolar, taxa (e.g. Crucibiscutum salebrosum). A less distinct biogeographic boundary at similar to 40 degrees N is distinguished by the presence/absence of rarer, but biogeographically significant, taxa, many of which have previously been assigned to Boreal or Tethyan provinces. Continental shelf sites are characterised by lower-diversity assemblages with common to dominant diagnostic taxa, which vary with palaeolatitude: Nannoconus and Micrantholithus at low palaeolatitudes, and Biscutum constans and Zeugrhabdotus spp. at higher palaeolatitudes. The latter two taxa are considered to be indicative of elevated surface-water fertility andthe former two may have been similarly adapted. The genus Watznoueria is ubiquitously dominant, giving the populations an unevenness, which appears to be a common feature throughout coccolithophore history. (C) 2000 Published by Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 11/07/20 alle ore 07:52:33