Heat Flux Distribution of Antarctica Unveiled

Abstract

Antarctica is the largest reservoir of ice on Earth. Understanding its ice sheet dynamics is crucial to unraveling past global climate change and making robust climatic and sea level predictions. Of the basic parameters that shape and control ice flow, the most poorly known is geothermal heat flux. Direct observations of heat flux are difficult to obtain in Antarctica, and until now continent‐wide heat flux maps have only been derived from low‐resolution satellite magnetic and seismological data. We present a high‐resolution heat flux map and associated uncertainty derived from spectral analysis of the most advanced continental compilation of airborne magnetic data. Small‐scale spatial variability and features consistent with known geology are better reproduced than in previous models, between 36% and 50%. Our high‐resolution heat flux map and its uncertainty distribution provide an important new boundary condition to be used in studies on future subglacial hydrology, ice sheet dynamics, and sea level change.

Heat Flow in Southern Australia and Connections With East Antarctica

“…Additional studies have relied on the distribution of subglacial lakes across Antarctica (Siegert & Dowdeswell, ), or combined previous heat flow estimates with numerical modeling to determine continental heat flow (Pattyn, ; Pollard et al, ). The models of Shapiro and Ritzwoller (), Fox Maule et al (), An et al (), and Martos et al () will be the focus for comparison with our study (Figure ), with particular emphasis on the two most recent models that employ the highest‐resolution seismic and magnetic data.…”

“…Consequently, constraining heat flow across the Antarctic continent has been achieved by modeling, largely using data derived from continental‐scale geophysical studies. These include satellite, airborne, and ground‐sourced magnetic data (Fox Maule et al, ; Martos et al, ; Purucker, ) and seismic data (An et al, ; Shapiro & Ritzwoller, ). Additional studies have relied on the distribution of subglacial lakes across Antarctica (Siegert & Dowdeswell, ), or combined previous heat flow estimates with numerical modeling to determine continental heat flow (Pattyn, ; Pollard et al, ).…”

“…Furthermore, geophysical models use simple layered crustal models (one‐ to two‐layered crust) that field studies of heat production heterogeneity have repeatedly shown are not geologically realistic (Burton‐Johnson et al, ; Carson et al, ; Hasterok et al, ; Sandiford et al, ). The models apply either constant thermal conductivity through a single crustal layer and assume laterally uniform crustal heat production (An et al, ), or an exponential relationship of decreasing heat production with depth (Martos et al, ). In all cases, no lateral variation in crustal heat production within the Antarctic continent is accommodated.…”

“…Green rectangle indicates the conjugate alignment between the Coompana Province and Wilkes Land. (e) Heat flow model of Martos et al () superimposed in Figure b. Note that the modern coastline shown in Figures d and e is for illustrative purposes only and is not shown in a reconstructed position for the various tectonic elements of West Antarctica.…”

“…The conventional measurement of heat flow requires access to drill holes that have recovered core samples of bedrock and direct measurement of the thermal gradient downhole (Beardsmore & Cull, ). While a small number of drill holes exist in Antarctica, they are extremely sparse in their distribution (Martos et al, ) and all measure thermal parameters only within ice or subglacial sediment; none yet have intersected the bedrock beneath (Goodge, ). Some measurements exist from offshore localities that sample sediment derived from the continental margin (Decker & Bucher, ; Dziadek et al, ; Morin et al, ).…”