Constraining Geothermal Flux at Coastal Domes of the Ross Ice Sheet, Antarctica

The geothermal flux is an important boundary condition for ice‐sheet models because it influences whether the ice is melting at the bed and able to slide. Point measurements and remotely sensed estimates vary widely for the Ross Ice Sheet. A basal temperature measurement at Roosevelt Island reveals a geothermal flux of 84 ± 13 mW/m2. The presence of Raymond Arches, which form only at ice divides that are frozen at the bed, allows inferences of the maximum geothermal flux at two coastal domes along the Siple Coast: Engelhardt Ridge, 85 ± 11 mW/m2 and Shabtaie Ridge, 75 ± 10 mW/m2. These measurements indicate heat flows similar to measurements at Siple Dome and the Whillans grounding zone and to the continental crust average. The high values measured at Subglacial Lake Whillans and estimated from satellite observations of Curie depths are not widespread. Plain Language Summary Heat flow from the earth helps determine whether an ice sheet can slide rapidly over the bed or is frozen to it. Few direct heat flow measurements exist because they require drilling through thousands of feet of ice. We present three new inferences of the heat flow for the Ross Ice Sheet in West Antarctica, approximately doubling the number of existing measurements. The heat flow is similar to the global average for continents and shows that previous inferences of higher heat flow are not widespread. Key Points We constrain the geothermal flux for three new locations beneath the Ross Ice Sheet Geothermal flux is near the global average for continental crust, in contrast to some previous estimates Existing characterizations of basal water and its effect on ice‐flow are likely accurate