The Ross Ice Shelf (RIS) is a floating extension of the West Antarctic Ice Sheet that occupies the southern Ross Embayment in West Antarctica, and acts as a buttress to the flowing Antarctic ice sheets. The bathymetry beneath the RIS in West Antarctica controls the circulation of sub-shelf ocean water that may warm the ice shelf from below, with consequences for shelf stability and climate warming.

Sparse depth-sounding data from the 1970’s Ross Ice Shelf Geophysical Glaciological Survey (RIGGS) provide control points, but the map produced from this survey is at 55 km resolution. ROSETTA-Ice will improve upon this, mapping the RIS using 10 km resolution.

The sub-RIS bathymetry cannot be measured directly. Whereas marine surveys might be able to map bathymetry using echo sounding or by towing a gravimeter, we cannot do that because there is a massive ice shelf in the way. The bathymetry must be determined through the use of geophysical data— gravity and magnetic data, specifically —to determine the subsurface geology, which can then be applied to interpretations of the probable bathymetry beneath the shelf. The subsurface geology can be constrained by airborne gravity and magnetic data, that reflect the size, type, and origin of geological features, such as igneous bodies or fault zones.

 

 

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Subglacial geologic map (Elkind et al., 2016) for western Marie Byrd Land and magnetic anomaly flightline data from the ROSETTA-Ice 2015 survey. Topography is vertically exaggerated.

The aim of ROSETTA-Ice (A systems approach to understanding the Ross Ocean and Ice Shelf Environment, and Tectonic setting Through Aerogeophysical surveys and modelling) is to learn more about the interactions between ice, ocean, and underlying rock.

ROSETTA-Ice uses IcePod…

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Nicholas Freason securing the IcePod to the LC-130 aircraft. The IcePod connects to a lever arm attached to an LC-130 aircraft. Picture taken last season.

…a suite of instruments that includes three gravimeters, a magnetometer, LiDar, visual and infrared camera, DICE (deep ice radar), SIR (shallow ice radar), and a PNT (position, navigation, and tracking) system that includes GNSS and IMU.

 

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Our airborne survey uses not one, not two, but THREE gravimeters!

Stay tuned to see the IcePod in action!

 

Published by Alec

Hi. My name is Alec Lockett, and I am senior, geology major. I grew up in Belmont, MA, and chose Colorado College primarily because of the block plan, the rad location, and the awesome vibes I got from the students; I cannot imagine such a wonderful four years at another school. For my senior thesis, I will use airborne gravity and magnetic data from the ROSETTA-Ice 2015-2016 surveys to investigate two cross-Ross Ice Shelf transects in West Antarctica for geophysical modeling. ROSETTA-Ice (A systems approach to understanding the Ross Ocean and Ice Shelf Environment, and Tectonic setting Through Aerogeophysical surveys and modelling) is a current project that is acquiring geophysical data over the Ross Ice Shelf through airborne collection. I have the extraordinary opportunity to participate in this field data collection. When I am not busy geologizing, I enjoy reading, watching films, spending time outside whether skiing or biking, and drinking coffee.

One reply on “Our Approach to Studying the Ross Ice Shelf”

  1. That’s incredible stuff! Can’t wait to hear how it all went – sending good vibes for many more successful trips and data collection opportunities!!

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