■ Describing dinosaur bone beds where hundreds of a single species of dinosaur have accumulated and comparing such monospecific assemblages with characteristics of modern occurrences of vertebrates (such as mammals or birds) and their modes and distances of transport.
FIGURE 7.8 Map view of crevasse splay laterally adjacent to stream channel (compare with Fig. 3.11).
■ Experimenting with different rates of flow and sedimentary particles (including teeth and bones) of different densities, shapes, and sizes, then comparing these results to the calculated values for dinosaur bodies or body parts.
■ Looking for evidence of abrasion (or lack of) in dinosaur skeletal material and looking for similar evidence from experimentally treated modern bones.
■ Carefully examining the sedimentary characteristics (lithofacies and ichno-facies) of the rock enclosing the dinosaur bones for evidence that argues for high flow rates, such as well-defined ripple bedding, large particle sizes, concentrations of bone material in the bases of channel fills, or a lack of trace fossils.
■ Mapping the distribution and orientation of bones in a bone bed to detect whether the bones show a preferred or random direction, which may indicate the former presence or absence of water currents.
■ Comparing the known geologic ranges of other fossil species or the radio-metric age dates of any associated volcanic ash deposits (Chapter 4) with the geologic ranges of certain dinosaur remains to see if they seem too "young." If the fossils occur in deposits stratigraphically above where they normally occur in deposits worldwide, they were likely reworked.
Hopefully, the most important point gained from the preceding section is that when a nearly complete dinosaur skeleton is found, a paleontologist should never assume that this skeletal integrity represents an autochthonous specimen. In some cases this might be a reasonably accurate assessment, but in others the dinosaur might be kilometers away from where it met its demise.
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