Collaborative Research: Uncovering the Ross Ocean and ice Shelf Environment and Tectonic setting Through Aerogeophysical surveys and modeling of the Ross ICE Shelf (ROSETTA-Ice)
Colorado College is one of four institutions to come together for investigation of the world’s largest ice shelf, the Ross Ice Shelf in Antarctica. The Ross Ice Shelf consists of continental ice that has flowed off-land and floats upon seawater. Still connected to ‘land ice’ behind and is anchored to coastal rock alongside, the Shelf has long buttressed the West Antarctic ice sheet, holding it in place, but there is concern over the that the Shelf may be weakened by the warming of atmosphere and ocean. To characterize the ice-ocean-continent system, airborne geophysical surveys are underway for collection of gravity, magnetics, radar, and LiDAR data, using LC-130 aircraft flown by the New York Air National Guard, and supported by McMurdo Station personnel and logistics. The progress of the current data collection in Antarctica is being logged semi-regularly in on-Ice team reports .
Alec Lockett, a senior geology major at Colorado College, is participating in the 2016 field data collection. He is making regular blog posts during his weeks based out of McMurdo Station. Scott Springer, of Earth Space Research, also has an informative and entertaining blog: first-timers to the Ice, both of them are offering a fresh and inquisitive view of Antarctica!
The integrative system model that will be produced by the investigators from four institutions will be used to address questions such as: : What are the geological controls upon the bathymetry of the sub-RIS seafloor? Is there channeling of seawater flow by sculpted bedrock ribs that project up from the Ross Sea floor? Is the Ice Shelf likely to weaken and thin along linear trends parallel to these bedrock features, rather than broadly, uniformly across its width?
The seabed beneath the Ross Ice Shelf is formed by extended continental crust that is inundated by seawater, upon which the RIS floats. Inaccessible beneath the thick shelf ice and the ocean water, the geology of the bedrock is not directly known. Limited geophysical and remote sensing data do indicate, however, that the crust beneath the RIS is contiguous with the crust beneath Marie Byrd Land —where rock exposures in mountain ranges protrude through the West Antarctic Ice Sheet. ROSETTA-Ice PI Christine Siddoway has worked and traveled throughout these mountains (Ford Ranges; Rockefeller and Alexandra Mountains) for over 16 months during five field expeditions between 1998 and 2012. This regional knowledge has been expanded through use of geospatial data and spectral analysis, with the support of the Polar Geospatial Center.
In 2015-16, Christine Siddoway worked with Colorado College students to extend the surficial geological map of Marie Byrd Land into an interpretive subglacial bedrock geological map. Marie Byrd Land is the province that forms the eastern margin of the RIS, and as such it provides a geological framework to be extended to and beneath the ice shelf, across to the tectonic boundary with the Transantarctic Mountains. That work now is complete, and next stage of work will be involve joint work with colleagues from LDEO and Scripps, including team members who complete the ROSETTA-Ice field campaign, to use new geophysical data collected by LC130 overflights to map geological faults and potential zones of elevated heat flow that may influence ice sheet dynamics and future stability.
The ROSETTA-Ice Ross Ice Shelf project is funded by NSF Antarctic Integrated Systems Science [AISS] – The four-year collaboration involves earth science investigators from Colorado College, Scripps Oceanographic Institute/U. C. San Diego , Earth and Space Research Foundation and Lamont Doherty Earth Observatory of Columbia University, and affiliated institutions including Otago University. For abstract of scientific aims, click here. A primary objective is to understand the ice-ocean-lithosphere dynamics of the ice shelf system, that depends on addressing a current unknown: the extent and characteristics of ocean current circulation along and beneath the Ross Ice Shelf.
Future prospects for the Ross Ice Shelf and West Antarctic Ice Sheet ?
The prospects for the West Antarctic ice sheet appear to be dire, even from the standpoint of a smaller active ice shelf in the Amundsen Sea. Modeling by Feldman and Leverman (2015, doi: 10.1073/pnas.1512482112) is presented as an animation that portrays a catastrophic scenario not solely for the WAIS but for the largest Antarctic ice shelves, the Ronne-Filchner and the Ross. It is of note, however, that the Feldmann and Levermann model does not include any degree of sub-ice-shelf melting beneath the large Ronne-Filchner and Ross Ice Shelves. The Rosetta-Ice Ross Ice Shelf Project will help to determine this parameter for the Ross Ice Shelf.