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

Author(s)

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

Abstract

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(s)

Department of Palaeontology

External organisation(s)

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

Journal

Sedimentary Geology

Volume

214

Pages

74-84

No. of pages

11

ISSN

0037-0738

DOI

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

Publication date

2009

Peer reviewed

Yes

Austrian Fields of Science 2012

1060 Biology, 105118 Palaeontology, 1051 Geology, Mineralogy

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