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Titolo:
A Valanginian (Early Cretaceous) 'boreal nannoplankton excursion' in sections from Romania
Autore:
Melinte, M; Mutterlose, J;
Indirizzi:
Ruhr Univ Bochum, Inst Geol Mineral & Geophys, D-44801 Bochum, Germany Ruhr Univ Bochum Bochum Germany D-44801 Geophys, D-44801 Bochum, Germany Geol Inst Romania, Bucharest 78344, Romania Geol Inst Romania Bucharest Romania 78344 ania, Bucharest 78344, Romania
Titolo Testata:
MARINE MICROPALEONTOLOGY
fascicolo: 1-2, volume: 43, anno: 2001,
pagine: 1 - 25
SICI:
0377-8398(200109)43:1-2<1:AV(C'N>2.0.ZU;2-7
Fonte:
ISI
Lingua:
ENG
Soggetto:
CRETACEOUS CALCAREOUS NANNOFOSSILS; CLIMATES; PALEOBIOGEOGRAPHY; ATLANTIC; PALEOCEANOGRAPHY; NANNOPLANKTON; BOUNDARY; DYNAMICS; ENGLAND; PACIFIC;
Keywords:
Early Cretaceous; Mediterranean; calcareous nannofossils; palaeobiogeography; floral exchange; Boreal nannofossil excursion; palaeoclimate; sea-level;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
69
Recensione:
Indirizzi per estratti:
Indirizzo: Mutterlose, J Ruhr Univ Bochum, Inst Geol Mineral & Geophys, Univ Str 150,D-44801 Bochum, Germany Ruhr Univ Bochum Univ Str 150 Bochum Germany D-44801 ermany
Citazione:
M. Melinte e J. Mutterlose, "A Valanginian (Early Cretaceous) 'boreal nannoplankton excursion' in sections from Romania", MAR MICROPA, 43(1-2), 2001, pp. 1-25

Abstract

In order to resolve both sea-level and palaeoclimatic signals for the earliest Cretaceous, 161 calcareous nannofossil samples of Berriasian to Valanginian age have been studied from Romania. These samples are derived from three biostratigraphically well-dated sections of Tethyan litho- and biofacies. The nannofossil assemblages recorded are of high diversity, reflecting stable warm water conditions typical for the earliest Cretaceous of the Tethys. The floras are characterised by abundant Watznaueria spp. and Nannoconus spp., whereas other taxa are less common. Long term trends on the scale of 1-4 my are reflected by shifts from Watznaueria spp. dominated assemblages in the Lower Berriasian to Nannoconus spp. assemblages in the Middle-Upper Berriasian, back to Watznaueria spp. in the Upper Berriasian-Lower Valanginian and again to Nannoconus spp. in the Upper Valanginian. These changes are thought to be caused by palaeoclimatic shifts. Periods, with a dominance of cosmopolitan eurytopic Watznatteria are thought to reflect cooler, humidconditions and well mixed surface waters, those with a dominance of Nannoconus warmer conditions and a rather stabile surface water stratification. Crucibiscutum salebrosum, very common at high latitudes, is extremely rarein the Romanian samples. It occurs only at one specific interval of early Late Valanginian age (Saynoceras verrucosum ammonite Zone), associated withother rare Boreal taxa, also restricted to this particular level. This 'boreal nannoplankton excursion' is believed to be controlled by sea-level rather than by climate, since simultaneously Tethyan ammonites found their wayinto the Boreal Realm. (C) 2001 Elsevier Science B.V. All rights reserved.

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Documento generato il 07/07/20 alle ore 11:19:32