Lost cold Antarctic deserts inferred from unusual sulfate formation and isotope signatures.
Nat Commun
; 6: 7579, 2015 Jun 29.
Article
em En
| MEDLINE
| ID: mdl-26119082
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.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Nat Commun
Assunto da revista:
BIOLOGIA
/
CIENCIA
Ano de publicação:
2015
Tipo de documento:
Article
País de afiliação:
Estados Unidos