title: Lost cold Antarctic deserts inferred from unusual sulfate formation and isotope signatures.
abstract: The Antarctic ice cap significantly affects global ocean circulation and climate. Continental glaciogenic sedimentary deposits provide direct physical evidence of the glacial history of the Antarctic interior, but these data are sparse. Here we investigate a new indicator of ice sheet evolution: sulfates within the glaciogenic deposits from the Lewis Cliff Ice Tongue of the central Transantarctic Mountains. The sulfates exhibit unique isotope signatures, including δ(34)S up to +50‰ for mirabilite evaporites, Δ(17)O up to +2.3‰ for dissolved sulfate within contemporary melt-water ponds, and extremely negative δ(18)O as low as -22.2‰. The isotopic data imply that the sulfates formed under environmental conditions similar to today's McMurdo Dry Valleys, suggesting that ice-free cold deserts may have existed between the South Pole and the Transantarctic Mountains since the Miocene during periods when the ice sheet size was smaller than today, but with an overall similar to modern global hydrological cycle.
authors.affiliation: 1] Louisiana State University, Baton Rouge, Louisiana 70803, USA [2] NASA Johnson Space Center, Houston, Texas 77058, USA.
authors.forename: Tao
authors.initials: T
authors.lastname: Sun
authors.affiliation: ESCG, NASA Johnson Space Center, Houston, Texas 77058, USA.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Socki
authors.affiliation: Indiana University, Bloomington, Indianapolis 47405, USA.
authors.forename: David L
authors.initials: DL
authors.lastname: Bish
authors.affiliation: Case Western Reserve University, Cleveland, Ohio 44106, USA.
authors.forename: Ralph P
authors.initials: RP
authors.lastname: Harvey
authors.affiliation: Louisiana State University, Baton Rouge, Louisiana 70803, USA.
authors.forename: Huiming
authors.initials: H
authors.lastname: Bao
authors.affiliation: NASA Johnson Space Center, Houston, Texas 77058, USA.
authors.forename: Paul B
authors.initials: PB
authors.lastname: Niles
authors.affiliation: University of New South Wales, Sydney, New South Wales 2052, Australia.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Cavicchioli
authors.affiliation: Upstream Technology, BP America, Houston, Texas 77079, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Tonui