Paleolake and Paleoclimate Research - Taylor Valley, Antarctica

Soluble Salt Distributions

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Figure 1 We study salt distributions across Taylor Valley.  This map is a synthesis of soluble salt data from this study, and data from Bockheim available online (http://nsidc.org/data/ggd221.html).

We are working in Taylor Valley to study the glacial history of this region during the Last Glacial Maximum (LGM) by looking at salt accumulations in the soil.  Salt is a fragile soil component that can be disturbed by climate changes, landscape instability, glacial advances, and inundation by lakes. This makes salt a sensitive indicator of relative surfice age with respect to local climate and glacial history.

Salts found in the soils of Taylor Valley are thought to have been affected by the growth of West Antarctic Ice Sheet (WAIS) and proglacial Lake Washburn during the LGM. It is speculated by several authors that WAIS blocked the mouth of Taylor Valley, forming a large valley-wide paleolake, proglacial Lake Washburn, to a maximum elevation of 350 m. The extent and timing of Lake Washburn in Taylor Valley has important implications for the paleoclimate both during and after the LGM, the response of WAIS to deglacial sea level rise, and past hydrologic regimes in Taylor Valley. 

Our research on the distribution of salts in Taylor Valley suggests that Lake Washburn was much less extensive than previously thought, filling the valley to a maximum elevation of 120 m, and was controlled by major valley thresholds at 80 and 120 m elevation.  In contrast to previous authors, we believe that a lobe of WAIS entered deep into Taylor Valley, as far as the present location of the Suess Glacier, and that proglacial Lake Washburn formed well into deglaciation.

Site map
Figure 2 Above is a satalite image of Taylor Valley, showing pits sampled during the 2006-2007 Antarctic field seasons.

More About Salts

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Figure 3 In Bonney Basin, spikes in salt content indicate evapoconcentration of lake water near paleolake margins.  Similar spikes are found in Fryxell Basin at 80 and 120 m.

The extremely arid climate in the McMurdo Dry Valleys makes it possible for salt to accumulate in soils.  These salts come from a varriety of sources: atmospheric precipitation blown off the East Antarctic Ice Sheet, snowfall, marine sea spray, and weathering of primary minerals. Salts occur as Chlorides, Nitrates, Sulphates, and Carbonates, and virtually every crystalline phase of these salts in combination with Calcium, Magnesium, Sodium, and Potassium has been found. Soils with high concentrations of salt typically show visible accumulations of salt as encrustations under surface clasts, nodules, disseminated as salt flecks, or salt pans. Extremely high salt accumulations, such as those that typically occur in Wright, Victoria, and Beacon Valleys, are rare in Taylor Valley.

Salt can also be redistributed across the landscape though wind-blown material, leaching, and evapoconcentration at the margins of lakes.  This work indicates that these reditribution processes produce regional diferences in salt content.


Wind-Blown Material