Present-day and fossil rhodolith pavements compared: Their potential for analysing shallow-water carbonate deposits

Autor(en)

Davide Bassi, James H. Nebelsick, Alessio Checconi, Johann Hohenegger, Yasufumi Iryu

Abstrakt

Coralline red algae represent the main biogenic components in most shallow-water carbonate successions

from the Eocene to the Recent. They contribute signi.cantly to sediment production on open platforms.

Carbonate sediments formed by unattached coralline algae include rhodolith pavements (RPs) which

represent dense accumulations of rhodoliths, as well as maërl which is composed of rhodoliths, coralline

algal branches and their detritus. Recent RPs sampled off Sesoko-jima (Okinawa-jima, southern Japan) occur

at depths of 50-70 m on a submarine terrace. The taxonomic coralline composition is dominated by

melobesioids associated with minor amounts of mastophoroids and sporolithaceans. The rhodoliths are

characterised by various nuclei, an encrusting inner arrangement, encrusting to warty outer growth-forms

and sub-spheroidal shapes. Bioerosion, encrustation and abrasion are the most prevalent taphonomic

features. Possible fossil counterparts were identi.ed in Chattian and Priabonian RPs from middle-ramp

depositional systems from the Venetian area, north-east Italy. A direct comparison between Recent and fossil

RPs is possible by contrasting the constituent rhodolith characteristics including taxonomic composition,

nature of the nucleus, inner arrangement, outer growth-forms, size and shape as well as taphonomic

signatures. This allows factors controlling rhodolith formation and growth in RPs to be compared especially

with respect to hydrodynamic regimes and substrate type.

Organisation(en)

Institut für Paläontologie

Externe Organisation(en)

Universitá degli studi di Ferrara, Eberhard Karls Universität Tübingen, Università degli Studi di Perugia, Tohoku University

Journal

Sedimentary Geology

Band

214

Seiten

74-84

Anzahl der Seiten

11

ISSN

0037-0738

DOI

https://doi.org/10.1016/j.sedgeo.2008.03.010

Publikationsdatum

2009

Peer-reviewed

Ja

ÖFOS 2012

1060 Biologie, 105118 Paläontologie, 1051 Geologie, Mineralogie

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