A hydrohalite spring deposit in the Canadian high Arctic: A potential Mars analogue

摘要

On Axel Heiberg Island in the Canadian High Arctic, low temperature perennial saline springs occur despite thick permafrost and cold polar desert conditions marked by a mean annual air temperature close to -20 degrees C. We present the first comprehensive geomorphic study of the Stolz Diapir Spring (79 degrees 04'30 '' N; 87 degrees 04'30 '' W), a unique groundwater system due to its known fresh water source and sodium chloride dominated chemistry. During winter, spring discharge precipitates hydrohalite (NaCI.2H(2)O) by freezing fractionation that forms a pool and barrage system morphologically similar to carbonate travertines and tufas found in temperate climates. The deposit is the largest hydrohalite accumulation on Earth based on published sources. This system experiences dramatic seasonal differences in hydrology and mineralogy marked by a switch from winter regime of salt deposition and cascading surface flow from pool to pool to a summer regime marked by chemical and mechanical erosion and deposit subsurface flow. The warmer temperatures also cause the decomposition of hydrohalite to halite. Accordingly, this site is a useful analogue for similar structures identified on Mars located in areas rich in evaporite minerals and lacking evidence of volcanic activity. (C) 2018 Elsevier B.V. All rights reserved.