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GEOREF RECORD

Palaeogeographical homogeneity of trace-fossil assemblages in Lower Jurassic spotted marls and limestones; comparison of the Western Carpathians and the Betic Cordillera

Vladimir Simo and Matias Reolid
Palaeogeographical homogeneity of trace-fossil assemblages in Lower Jurassic spotted marls and limestones; comparison of the Western Carpathians and the Betic Cordillera (in Carbon cycle and ecosystem response to the Jenkyns event in the early Toarcian (Jurassic), M. Reolid (editor), L. V. Duarte (editor), E. Mattioli (editor) and W. Ruebsam (editor))
Special Publication - Geological Society of London (April 2021) 514 (1): 185-211

Abstract

Micritic sediments containing dark, discrete, organic-rich burrows, situated in a light grey background carbonate mud, were deposited over a broad geographical area in deep-shelf, bathyal and basinal environments in the western margin of the Tethys Ocean during the Early and Middle Jurassic. These hemipelagic deposits represent a distinct depositional regime marked by low-energy, soft-bottom and only locally dysoxic environments. Still, it is unclear whether the trace-fossil assemblages occurring in these deposits pertain to a network of several community types--the ichnotaxa differing from basin to basin--or to a single community of environmentally broad-ranging, burrow-producing species. Lower Jurassic trace-fossil assemblages are found in the Western Carpathians and in the Subbetic, Betic Cordillera: that is, in basins separated by more than 2000 km in their original palaeogeographical areas. The stereotypical Chondrites and Zoophycos trace-fossil assemblages that occur in the analysed deposits share two ichnogenera of distinctive morphology (Lamellaeichnus and Teichichnus). Agglutinated foraminifera Bathysiphon occurs together with the described trace-fossil assemblage and determines the epibenthic palaeoenvironmental conditions. In the Western Carpathians, a Lamellaeichnus-dominated assemblage alternates with a Zoophycos-dominated assemblage in small, metre-scale cycles in the upper Pliensbachian, and the proportion of the Zoophycos assemblage increases stratigraphically upwards, probably owing to reduced basin ventilation during the early Toarcian. Within the southern Iberian palaeomargin, represented by the Betic Cordillera, Zoophycos is scarce in the facies.


ISSN: 0305-8719
Coden: GSLSBW
Serial Title: Special Publication - Geological Society of London
Serial Volume: 514
Serial Issue: 1
Title: Palaeogeographical homogeneity of trace-fossil assemblages in Lower Jurassic spotted marls and limestones; comparison of the Western Carpathians and the Betic Cordillera
Title: Carbon cycle and ecosystem response to the Jenkyns event in the early Toarcian (Jurassic)
Author(s): Simo, VladimirReolid, Matias
Author(s): Reolid, M.editor
Author(s): Duarte, L. V.editor
Author(s): Mattioli, E.editor
Author(s): Ruebsam, W.editor
Affiliation: Slovak Academy of Sciences, Earth Science Institute, Bratislava, Slovakia
Affiliation: University of Jaen, Spain
Pages: 185-211
Published: 20210420
Text Language: English
Publisher: Geological Society of London, London, United Kingdom
References: 102
Accession Number: 2021-075805
Categories: General paleontologyStratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. strat. cols.
N48°00'00" - N49°00'00", E23°00'00" - E24°00'00"
N48°00'00" - N50°00'00", E17°00'00" - E21°00'00"
Secondary Affiliation: University of Jaen, ESP, Spain
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2022, American Geosciences Institute.
Update Code: 202153
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