Radiolitid rudists

an underestimated archive for Cretaceous climate reconstruction?

authored by
Katharina E. Schmitt, Stefan Huck, Malte Krummacker, Niels J. De Winter, Alexis Godet, Philip Claeys, Ulrich Heimhofer
Abstract

Rudist shells are important archives for palaeoenvironmental reconstructions in the greenhouse world of the Cretaceous. Radiolitids, a family of rudists became very abundant dwellers of the shallow marine carbonate platforms during the Cretaceous. Still, due to the complex structure of their low-Mg calcite outer shell layer, radiolitids are often deemed unsuitable for palaeoenvironmental reconstructions. The aim of this study is to present a combination of petrographic (transmitted light microscopy and cathodoluminescence microscopy) and elemental analyses (high-resolution μXRF and stable isotope) to investigate radiolitid shells for diagenetic alteration and to make them accessible as an archive for environmental conditions during the mid-Cretaceous. Four Eoradiolitites shells were analysed in detail: two right valves (RV), a left valve (LV) with an articulated RV and an isolated LV. Three shell structure types have been identified, including a non-compact, compact and celluloprismatic types. The compact structure type was identified in the LVs while the other two types were observed exclusively in the RVs. Radiolitid shell material composed of the non-compact and the compact structure types can be used as palaeoenvironmental archives as it preserved seasonal signals in both, shell growth structure and isotopic records, while celluloprismatic shell structures are less suitable for reconstructions due to diagenetic alteration. The alternation of dark and light lamellae in both valves, RV and LV, provide information on the intertidal living habitat of the shell-producing organism and its life span.

Organisation(s)
Institute of Geology
External Organisation(s)
Johannes Gutenberg University Mainz
Spar- und Bauverein eG
Schnack Ingenieurgesellschaft mbH Co. KG
Vrije Universiteit Brussel
University of Texas at San Antonio
Type
Article
Journal
LETHAIA
Volume
55
Pages
1-21
ISSN
0024-1164
Publication date
12.2022
Publication status
Published
Peer reviewed
Yes
ASJC Scopus subject areas
Ecology, Evolution, Behavior and Systematics, Palaeontology
Sustainable Development Goals
SDG 14 - Life Below Water
Electronic version(s)
https://doi.org/10.18261/let.55.4.4 (Access: Open)