[Geysers] FW: UW-fac: Geologist to Talk on Yellowstone Lake

[Bruce Alan Richardson]

Hi All,

Here's a report on research that may be of interest.

Bruce Richardson

Casper, Wyoming

 

  _____  

From: Jill Meredith Lovato 
Sent: Tuesday, April 12, 2005 7:05 AM
To: uw-faculty at uwyo.edu; uwstaff-l at uwyo.edu
Subject: UW-fac: Geologist to Talk on Yellowstone Lake

 

Spring 2005 Student-Faculty Forum on the Environment and Natural
Resources

 

Sponsored by the Haub School and Ruckelshaus Institute of Environment
and Natural Resources

 

 

"Yellowstone Lake Is Anything But Quiet:  

Volcanic and hydrothermal processes in a large lake above an active
magma chamber"

 

Lisa Morgan

Geologist

U.S. Geological Survey

 

Wednesday, April 13, 2005

12:00 Noon

Union Family Room

 

 

Discoveries from recent (1999-2003) multi-beam sonar mapping and
seismic-reflection surveys of Yellowstone Lake provide new insight into
the recent geologic forces that have shaped a large lake at the active
front of the Yellowstone hot spot, a region strongly affected by young
(<2 my), large-volume (>100-1000's km3) silicic volcanism, active
tectonism, and accompanying uplift.  Specifically, our mapping has
identified the extent of postcaldera collapse volcanism and active
hydrothermal processes occurring above a large magma chamber on the lake
floor.  Multiple advances and recessions of thick glacial ice have
overlapped the volcanic and hydrothermal activity leaving a lake basin
that has been shaped predominantly by fire and ice.  Yellowstone Lake
has an irregular bottom covered with dozens of features directly related
to hydrothermal, tectonic, volcanic, and sedimentary processes.
Detailed bathymetric, seismic reflection, and magnetic evidence reveals
that rhyolitic lava flows underlie much of Yellowstone Lake and exert
fundamental control on lake morphology and localization of hydrothermal
activity in the northern, West Thumb, and central basins.  Many
previously unknown features have been identified and include over 300
hydrothermal vents, several very large (>500 m diameter) hydrothermal
explosion craters, many small hydrothermal vent craters (~1-200 m
diameter), domed lacustrine sediments related to hydrothermal activity,
elongate fissures cutting post-glacial sediments, siliceous hydrothermal
spire structures, sublacustrine landslide deposits, submerged former
shorelines, large glacial melting features, incipient faulting along the
trace of the Eagle Bay fault zone, and a recently active graben.
Sampling and observations with a submersible remotely operated vehicle
(ROV) confirm and extend our understanding of the identified features.
Faults, fissures, hydrothermally inflated domal structures, hydrothermal
explosion craters, and sublacustrine landslides constitute potentially
significant geologic hazards.  Fluids associated with active
sublacustrine hydrothermal vent activity influence the geochemical
composition of Yellowstone Lake water, which may significantly affect
the Yellowstone ecosystem.

 

 

 

 

 

Jill Lovato

Project Coordinator/Academic Advisor

Ruckelshaus Institute and the Haub School

of Environment and Natural Resources

University of Wyoming

Dept. 3971

1000 E. University Avenue

Laramie, WY 82071

Ph: 307.766.5146

www.uwyo.edu/enr/ <http://www.uwyo.edu/enr/>  

 

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