Actualistic and statistical approaches to taphonomic interpretations in Quaternary environments

Open Access
Author:
Milideo, Lauren Elizabeth
Graduate Program:
Geosciences
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
April 29, 2015
Committee Members:
  • Russell W Graham, Dissertation Advisor
  • Russell W Graham, Committee Chair
  • Richard B Alley, Committee Member
  • MARK E PATZKOWSKY, Committee Member
  • Eric S Post, Committee Member
Keywords:
  • vertebrate paleontology
  • taphonomy
  • paleoecology
  • late Pleistocene
  • late Holocene
Abstract:
ABSTRACT This study is an examination of vertebrate taphonomy from varying perspectives. I begin with an examination of actualistic vertebrate faunal assemblages from diverse environments, and representing divergent taphonomic pathways. Next, I employ these modern paradigms to inform interpretation of a late Pleistocene large mammal fossil assemblage. I conclude my study by shifting to a more expansive analysis, exploring the relative influences of taphonomy and spatial scale on interpretations of paleoenvironments. In order to establish actualistic models for fossil assemblages, I studied modern bone assemblages from three different taphonomic pathways in varying environments (grassland/forest mosaic, deciduous forest, and tundra), representing two different ends of the taphonomic continuum. These actualistic assemblages include scavenged modern bison and deer carcasses lying on the landscape, as well as bones of hunted prey, collected from modern wolf dens. I utilize statistical comparisons of bone surface damage and skeletal element types to identify differences between these assemblages that can also be identified in fossil assemblages. I then place the late Pleistocene Heinze Cave large mammal fossil assemblage within these models, quantitatively comparing the assemblage to divergent modern analogs in order to interpret its origins and taphonomic history. Finally, I employ multivariate statistical techniques to investigate taphonomy’s effect on Late Holocene assemblages at a greater spatial scale. Specifically, I examine the influence of collection techniques on our ability to extract an environmental gradient, from single-state to multi-state scales. I find that quantifiable bone damage and element type variations do differentiate landscape and den assemblages, yielding a model that can aid in interpretation of North American late Pleistocene large mammal assemblages. This model’s application to the taphonomic features of the Heinze Cave assemblage indicate that while one level shares similarities with landscape assemblages and one with den assemblages, none is a perfect match to any actualistic paradigm, suggesting a more complex taphonomic history. Last, ordination of Late Holocene sites reveals that at a smaller spatial scale (i.e. a single state), taphonomic histories of assemblages exercise a very heavy influence over analysis, concealing environmental differences among sites; at larger spatial scales, conversely, environmental shifts are strong enough to outweigh taphonomic factors, allowing the true gradient to emerge.