Image of the Day
Surprisingly high geothermal heating revealed beneath West Antarctic Ice Sheet
New WISSARD science results were published this week. An investigation led by Andy Fisher at UCSC found that the amount of heat flowing toward the base of the West Antarctic ice sheet from geothermal sources deep within the Earth is surprisingly high, providing insight into mechanisms for ice sheet instability. Temperatures on the West Antarctic Ice Sheet (WAIS) can plummet below minus 50 degrees Celsius in winter. But under the ice, scientists have found geothermal heat seeping up from Earth’s interior. The heat production that they measured is nearly four times the global average and could melt up to 35 cubic kilometres of water off the bottom of the WAIS each year, according to results reported in the journal Science Advances. Read more in Scientific American.
August 28th, 2015
More than 30 WISSARDS met in Bozeman, Montana to share research results and work toward future collaborations with WISSARD data during the final WISSARD meeting held August 2nd-August 5th, 2015 at Montana State University. WISSARD's are planning a joint session at the annual American Geophysical Union meetings to discuss WISSARD findings. A number of WISSARD focused papers are in the works or cued for publication, including the recently published paper in the journal Science Advances led by Dr. Andy Fisher at USCS regarding high geothermal heat flux. Work will continue to integrate scientific results of the WISSARD Project and prepare additional scientific publications. Three short videos that provided an overview of some aspects of the WISSARD project and life on the ice were previewed and will be posted to the WISSARD webpage when finalized.
WISSARD Project Overview
Subglacial Aquatic Environments
Over the last several decades, by using ground penetrating radar and other remote sensing tools, scientists have discovered that under the massive Antarctic ice sheets there lies a vast hydrological system of liquid water. This water exists because geothermal heat flow from below, coupled with pressure, movement, and the insulating nature of the ice sheet above, is great enough to maintain some areas at the base of the ice sheet above the freezing point, even in the extreme cold of Antarctica. In topographic depressions there are hundreds of lakes, both large and small; some are isolated, but many are interconnected by water channels and large areas of saturated sediments, the water eventually running out into the Southern Ocean as the ice sheet becomes a floating ice shelf.
In order to explore one of these hydrological systems at the margin of the West Antarctic Ice Sheet, we have organized an interdisciplinary project to access the subglacial environment. The Whillans Ice Stream Subglacial Access Research Drilling project (WISSARD) is using a variety of tools and techniques to explore Subglacial Lake Whillans and the nearby grounding zone, on the southeastern edge of the Ross Sea. Radar and seismic equipment is used to profile the overlying ice sheet and the underlying water, sediments, and rock, while GPS stations accurately track ice movement.
This season our target is the grounding zone, where the massive West Antarctic Ice Sheet atop land meets the Ross Sea. This area is considered an important piece of the puzzle for our scientists interested in ice sheet dynamics. The work will help scientists assess the stability of the West Antarctic Ice Sheet, most of which sits below sea level. It is the last ice sheet on Earth resting in a deep marine basin and is the most likely player in any future, rapid sea-level rise. If the grounding zone is retreating or primed to retreat, rapid changes in ice behavior could follow over the next century. Work focused on microbial life, biogeochemical cycling, and surrounding geophysical surveys will also continue during the 2014-2015 season.
Our intentions are to have 8 days of science in the primary borehole at the Grounding Zone location mid-January. We will deploy all of the WISSARD tools during this period and recover sediment and water samples from the water cavity some 750 meters below the surface of the ice. We also hope to recover about 5 meters of basal ice cores at another borehole very near the primary hole. Image: Rachel Xidis/NIU.