High geothermal heat flux measured below the West Antarctic Ice Sheet
نویسندگان
چکیده
The geothermal heat flux is a critical thermal boundary condition that influences the melting, flow, and mass balance of ice sheets, but measurements of this parameter are difficult to make in ice-covered regions. We report the first direct measurement of geothermal heat flux into the base of the West Antarctic Ice Sheet (WAIS), below Subglacial Lake Whillans, determined from the thermal gradient and the thermal conductivity of sediment under the lake. The heat flux at this site is 285 ± 80 mW/m(2), significantly higher than the continental and regional averages estimated for this site using regional geophysical and glaciological models. Independent temperature measurements in the ice indicate an upward heat flux through the WAIS of 105 ± 13 mW/m(2). The difference between these heat flux values could contribute to basal melting and/or be advected from Subglacial Lake Whillans by flowing water. The high geothermal heat flux may help to explain why ice streams and subglacial lakes are so abundant and dynamic in this region.
منابع مشابه
Evidence for elevated and spatially variable geothermal flux beneath the West Antarctic Ice Sheet.
Heterogeneous hydrologic, lithologic, and geologic basal boundary conditions can exert strong control on the evolution, stability, and sea level contribution of marine ice sheets. Geothermal flux is one of the most dynamically critical ice sheet boundary conditions but is extremely difficult to constrain at the scale required to understand and predict the behavior of rapidly changing glaciers. ...
متن کاملSensitivity of Cenozoic Antarctic ice sheet variations to geothermal heat flux
The sensitivity of long-term Cenozoic variations of the East Antarctic ice sheet to geothermal heat flux is investigated, using a coupled climate–ice sheet model with various prescribed values and patterns of geothermal heat flux. The sudden growth of major ice across the Eocene–Oligocene boundary (~34 Ma) is used as a test bed for this sensitivity. A suite of several million year-long simulati...
متن کاملSensitivity of the Frozen/Melted Basal Boundary to Perturbations of Basal Traction and Geothermal Heat Flux : Isunnguata Sermia, Western Greenland
A full-stress, thermomechanically coupled, numerical model is used to explore the interaction between basal thermal conditions and motion of a terrestrially terminating section of the west Greenland ice sheet. The model domain is a two-dimensional flowline profile extending from the ice divide to the margin. We use data-assimilation techniques based on the adjoint model in order to optimize the...
متن کاملInferring surface heat flux distributions guided by a global seismic model: particular application to Antarctica
We present a method that uses a global seismic model of the crust and upper mantle to guide the extrapolation of existing heat-flow measurements to regions where such measurements are rare or absent. For any chosen spatial point on the globe, the procedure generates a histogram of heat-flow values determined from existing measurements obtained from regions that are structurally similar to the t...
متن کاملSources of Water for Groundwater-fed Outflow Channels on Mars: Implications of the Late Noachian “icy Highlands” Model for Melting and Groundwater Recharge on the Tharsis Rise
IMPLICATIONS OF THE LATE NOACHIAN “ICY HIGHLANDS” MODEL FOR MELTING AND GROUNDWATER RECHARGE ON THE THARSIS RISE. J. P. Cassanelli, J. W. Head, J. L. Fastook, Brown University Department of Earth, Environmental and Planetary Sciences, Providence, RI 02912 USA, University of Maine, Orono, ME 04469 USA. ([email protected]). Introduction: During the Late Noachian (LN), Hesperian, and ear...
متن کامل