L.A. Morgan, K.L. Pierce and W.C. Pat Shanks
The Geological Society of America Field Guide, 2008
Abstract
This field trip highlights various stages in the evolution of the Snake River Plain–Yellowstone Plateau bimodal volcanic province, and associated faulting and uplift,
also known as the track of the Yellowstone hotspot. The 16 Ma Yellowstone hotspot
track is one of the few places on Earth where time-transgressive processes on continental
crust can be observed in the volcanic and tectonic (faulting and uplift) record
at the rate and direction predicted by plate motion. Recent interest in young and
possible renewed volcanism at Yellowstone along with new discoveries and synthesis
of previous studies, i.e., tomographic, deformation, bathymetric, and seismic surveys,
provide a framework of evidence of plate motion over a mantle plume.
This 3-day trip is organized to present an overview into volcanism and tectonism
in this dynamically active region. Field trip stops will include the young basaltic
Craters of the Moon, exposures of 12–4 Ma rhyolites and edges of their associated
collapsed calderas on the Snake River Plain, and exposures of faults which show an
age progression similar to the volcanic fi elds. An essential stop is Yellowstone National
Park, where the last major caldera-forming event occurred 640,000 years ago and
now is host to the world’s largest concentration of hydrothermal features (>10,000
hot springs and geysers). This trip presents a quick, intensive overview into volcanism
and tectonism in this dynamically active region. Field stops are directly linked
to conceptual models related to hotspot passage through this volcano-tectonic province.
Features that may refl ect a tilted thermal mantle plume suggested in recent tomographic studies will be examined. The drive home will pass through Grand Teton
National Park, where the Teton Range is currently rising in response to the passage of
the North American plate over the Yellowstone hotspot.
Keywords: Yellowstone, hotspot, track, volcanism, faulting, uplift.
NOTE: the article text supplied here is for educational purposes only.
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