|Paleo Slide Set: Packrat Middens: Vegetation & Climate Variability in the Southwestern United States|
|Bristlecone pine needles from late glacial age packrat midden; Ladder Cave in eastern Nevada.|
| The macrofossils found
in this late glacial midden from Ladder Cave in eastern Nevada provide evidence
for the low elevation occurrence of what are now high elevation plants.
This difference in elevation range indicates that the mean annual temperatures
of Ladder Cave during the last glacial period were possibly as much as 10C
below modern temperatures. In most cases the excellent preservation of biological
remains from packrat middens permits identification to the species level
as demonstrated by the bristlecone pine (Pinus longaeva) needles
shown in this slide. This is the same pine that produces 7,000-year-old
living individuals and climate-sensitive tree-ring chronologies in the White
Mountains of eastern California and western Nevada.
Robert S. Thompson & Robert S. Webb
U. S. Geological Survey & NOAA National Geophysical Data Center
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