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Compositional variability of Pleistocene land snail assemblages preserved in a cinder cone volcano from Tenerife, Canary Islands

Bullard, Elizabeth
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1470744125

Abstract Details

2016, MS, University of Cincinnati, Arts and Sciences: Geology.
Fossil assemblage faunal compositions may vary through space and time in response to climatic and/or taphonomic factors, but these relationships can be difficult to diagnose and disentangle. Here, we investigate how to disentangle climatic and taphonomic signals of a land-snail-rich volcanic scoria sequence to asses if it was influenced by taphonomic bias, climate change, or both, using a multifaceted approach, combining taphonomic, ecological, body-size, and stable-isotope data. Fossil assemblages were sampled from two beds (Units A and B) in a Pleistocene cinder cone volcano of southern Tenerife (Canary Islands), dated to the glacial interval MIS 8 (~299-302 ka). The two units differed in taphonomy, species composition, and abundance distributions. The upper unit, B (6 species), showed higher snail diversity and shell concentration and lower taphonomic alteration than the lower unit, A (3 species). Furthermore, larger bodied species (length>10mm) dominated Unit A and were better preserved than smaller species (length<10mm), whereas smaller individuals were more abundant (and better preserved) at Unit B. These differences were likely impacted by physical differences in the matrices surrounding the fossils. Unit A is comprised of larger scoria while Unit B contains small-to-medium-sized scoria and fines upward into a paleosol. Grain size of the scoria matrix therefore seems to affect species preservation, with larger clasts exposing snails to more severe postmortem agents and thus favoring the interstitial preservation of larger-size taxa. Comparisons with modern assemblages from the coastal scrub, the plant biome in which the Pleistocene site currently resides, indicates that no modern analogue exists for these fossil assemblages. Shell oxygen isotope values reveal that the climate shifted from colder/wetter during MIS 8 to warmer/drier at present, which may explain variations in species composition and diversity through time. These data suggest that both taphonomic and climatic factors have induced these snail patterns in deep time, but quantifying which of these two mechanisms has more significantly influenced the observed results remains uncertain.
Arnold Miller| (Committee Co-Chair)
Yurena Yanes| (Committee Co-Chair)
Joshua Miller (Committee Member)
50 p.
Paleontology
Climate; Taphonomy; Land snails; Canary Islands

Recommended Citations

Citations

  • Bullard, E. (2016). Compositional variability of Pleistocene land snail assemblages preserved in a cinder cone volcano from Tenerife, Canary Islands [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1470744125

    APA Style (7th edition)

  • Bullard, Elizabeth. Compositional variability of Pleistocene land snail assemblages preserved in a cinder cone volcano from Tenerife, Canary Islands. 2016. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1470744125.

    MLA Style (8th edition)

  • Bullard, Elizabeth. "Compositional variability of Pleistocene land snail assemblages preserved in a cinder cone volcano from Tenerife, Canary Islands." Master's thesis, University of Cincinnati, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1470744125

    Chicago Manual of Style (17th edition)

ucin1470744125
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© 2016, some rights reserved.Creative Commons License Compositional variability of Pleistocene land snail assemblages preserved in a cinder cone volcano from Tenerife, Canary Islands by Elizabeth Bullard is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by University of Cincinnati and OhioLINK.