12. Echinoderms and Oligo-Miocene Carbonate Systems: Potential Applications in Sedimentology and Environmental Reconstruction

  1. Maria Mutti3,
  2. Werner Piller4 and
  3. Christian Betzler5
  1. Andreas Kroh1 and
  2. James H. Nebelsick2

Published Online: 3 APR 2012

DOI: 10.1002/9781118398364.ch12

Carbonate Systems during the Oligocene-Miocene Climatic Transition

Carbonate Systems during the Oligocene-Miocene Climatic Transition

How to Cite

Kroh, A. and Nebelsick, J. H. (2012) Echinoderms and Oligo-Miocene Carbonate Systems: Potential Applications in Sedimentology and Environmental Reconstruction, in Carbonate Systems during the Oligocene-Miocene Climatic Transition (eds M. Mutti, W. Piller and C. Betzler), Wiley-Blackwell, Oxford, UK. doi: 10.1002/9781118398364.ch12

Editor Information

  1. 3

    Institut für Erd- und Umweltwissenschaften Universität Potsdam, Postfach 60 15 53 D-14415 Potsdam, Germany

  2. 4

    Institute for Earth Sciences (Geology & Paleontology) University of Graz, Heinrichstrasse 26, A-8010 Graz, Austria

  3. 5

    Geologisch-Palaeontologisches Institut, Bundesstr. 55, D-20146 Hamburg, Germany

Author Information

  1. 1

    Naturhistorisches Museum Wien, Geologisch-Paläontologische Abteilung, Burgring 7, A-1010 Wien, Austria

  2. 2

    Institut für Geowissenschaften, Universität Tübingen, Sigwartstrasse 10, D-72076 Tübingen, Germany

Publication History

  1. Published Online: 3 APR 2012
  2. Published Print: 5 APR 2012

Book Series:

  1. Special Publication Number 42 of the International Association of Sedimentologists

Book Series Editors:

  1. Ian Jarvis6,7

Series Editor Information

  1. 6

    School of Geography, Geology and the Environment Centre for Earth and Environmental Science Research, Kingston University London, UK

  2. 7

    Penrhyn Road, Kingston upon Thames KT1 2EE, UK

ISBN Information

Print ISBN: 9781444337914

Online ISBN: 9781118398364

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Keywords:

  • Echinodermata;
  • taphonomy;
  • palaeoecology;
  • skeletal chemistry;
  • Mg/Ca ratio;
  • Sr/Ca ratio;
  • stable isotopes

Summary

Echinoderms represent a major ecological component and contribute considerably to Oligocene–Miocene carbonate sediments, both as macrofossils and as skeletal grains. The skeletal morphology of all five extant echinoderm classes (echinoids, asteroids, ophiuroids, crinoids, holothuroids) is reviewed. Disarticulated skeletal elements are much morecommon in sediments than articulated specimens for all echinoderm classes except for echinoids; studies relying on complete specimens alone may be severely biased. The reproduction and growth of echinoderms, the composition of the skeleton, and the crystallography and diagenesis of echinoderm ossicles are reviewed. The echinoderm skeleton consists of high-Mg calcite with 3–18.5 wt% Mg. The skeleton exhibits strong interlacing of microcrystalline calcite with organic material and nonrandom orientation of crystals, achieving considerable hardness and durability. Echinoderm biostratinomy and the identification of disarticulated material are considered. The echinoderm origin of sediment particles can usually be recognised by their characteristic microstructure. Due to the high degree of specialisation, disarticulated remains can often be identified to family or genus level, leading to a more accurate picture of spatial and temporal echinoderm distributions.

Echinoderm geochemistry is reviewed with respect to the Mg-content of the skeleton as a palaeotemperature proxy, and the Mg/Ca ratio as a monitor of ancient seawater composition; Sr/Ca ratios and carbon and oxygen stable-isotopes are considered. The echinoderm skeleton is altered during diagenesis and is transformed to low-Mg calcite. The microstructure of the skeleton is largely unaffected by this process, but changes in the isotopic signature and minor/trace-element contents may occur. These factors, together with physiological effects of isotope intake, hamper geochemical applications. However, echinoderms have been used successfully in studies of Phanerozoic seawater chemistry: theMgand Sr contents of echinoderm skeletons apparently strongly correlate with temperature. Asteroids and ophiuroids are probably best suited for palaeotemperature reconstructions because of the lack of known fractionation within the skeleton and because genetic effects are less pronounced than in echinoids. Controlled laboratory experiments are needed to establish calibrations.

Echinoderm remains may account for 5–30% of the particles within specific Oligocene and Miocene carbonate facies. They seem to be more abundant in temperate shelf carbonates than in tropical settings. Diagenetic changes associated with echinoderm ossicles strongly affect the embedding sediment and promote lithification. Bioerosion by grazing echinoids is important for carbonate budgets in coral reefs and influences the modal size-distribution of sediments by the production of carbonate mud. Burrowing echinoderms may cause intensive bioturbation and reworking of sediments. Echinoderms provide valuable evidence for palaeoenvironmental reconstructions. Ecological information can both be gained by actualistic comparisons with modern echinoderms and by a functional morphological approach, allowing the detailed assessment of general life habits, substrate conditions, nutrient availability and hydrodynamic regimes.