Elsevier

Chemical Geology

Volume 41, 1983, Pages 57-64
Chemical Geology

The origin of salts on Mount Erebus and along the coast of Ross Island, Antarctica*

https://doi.org/10.1016/S0009-2541(83)80005-9Get rights and content

Abstract

Salt deposits in the form of crusts and efflorescences are a common feature of rock exposures along the coast of Ross Island and on the summit of Mt. Erebus, an active volcano that dominates the island. The 87Sr/86Sr ratios of salts from coastal sites decrease with increasing elevation from 0.70861 at Cape Royds to 0.70344 at the top of Castle Rock on Hut Point peninsula, only 413 m above sea level, but may also vary along the coast in response to the seasonal duration of open water. The variation of 87Sr/86Sr ratios can be attributed to mixing of marine Sr with Sr derived from the volcanic rocks and confirms the importance of chemical weathering as a source of Sr in these secondary salts. Yellow salts of complex mineralogical composition from the summit of Mt. Erebus have 87Sr/86Sr ratios whose average is 0.70345. This value is consistent with the hypothesis that these salts formed both from the plume of volcanic gases emanating from a convect-ing lava lake of phonolitic composition and by chemical weathering of the volcanic rocks. One sample of white salt from ice caves at the summit has an anomalously high 87Sr/86Sr ratio of 0.70460 perhaps because it contains a component of marine Sr released by melting of large quantities of snow in the ice caves.

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*

Laboratory for Isotope Geology and Geochemistry (Isotopia) Contribution No. 60.

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