Abstract
Abstract. The Transantarctic Mountains (TAMs), a 3500 km long chain that subdivides East Antarctica from West Antarctica, are important for reconstructing the tectonic, glacial, and climatic history of Antarctica. With an ice-free area of 24 200 km2 (50% of the total in Antarctica), the TAMs contain an unusually high proportion of paleosols, including relict and buried soils. The unconsolidated paleosols range from late Quaternary to Miocene in age, the semi-consolidated paleosols are of early Miocene to Oligocene age, and the consolidated paleosols are of Paleozoic age. Paleosols on unconsolidated deposits are emphasized in this study. Examples are given from the McMurdo Dry Valleys (78° S) and two outlet glaciers in the central and southern TAMS, including the Hatherton–Darwin Glacier region (80° S) and the Beardmore Glacier region (85°30' S). Relict soils constitute 73% of all of the soils examined; 10% of the soils featured burials. About 26% of the soils examined are from the last glaciation (< 117 ka) and have not undergone any apparent change in climate. As an example, paleosols comprise 65% of a mapped portion of central Wright Valley. Paleosols in the TAMs feature recycled ventifacts and buried glacial ice in excess of 8 Ma in age, and volcanic ash of Pliocene to Miocene age has buried some soils. Relict soils are more strongly developed than nearby modern soils and often are dry-frozen and feature sand-wedge casts when ice-cemented permafrost is present. The preservation of paleosols in the TAMs can be attributed to cold-based glaciers that are able to override landscapes while causing minimal disturbance.
Highlights
In the soils literature, paleosols refer to buried, relict and exhumed soils with no assigned age (Ruhe, 1965; Nettleton et al, 2000) or to soils in which the chemical and physical characteristics are unrelated to the present-day climate or vegetation (Bronger and Catt, 1989)
In the Transantarctic Mountains (TAMs), drift from wet-based glaciers of Pliocene and older age is enriched in quartz of silt and very-fine sand size (100–2 μm) with few clasts, primarily from overriding outcrops of the Beacon Supergroup
Deposits of Miocene-age from wet-based glaciers include the Sirius Group at high elevations throughout the TAMs, Altar and Quartermain drifts in Arena Valley (Marchant et al, 1993a), Asgard and Sessrumnir drifts in the Asgard Range (Marchant et al.,1993b), Insel drift in Victoria Valley (Calkins, 1971), and Peleus drift in Wright Valley (Hall et al, 1993; Prentice et al, 1994)
Summary
Paleosols refer to buried, relict and exhumed soils with no assigned age (Ruhe, 1965; Nettleton et al, 2000) or to soils in which the chemical and physical characteristics are unrelated to the present-day climate or vegetation (Bronger and Catt, 1989). Valleys within the TAMs have been cut by major outlet glaciers that today are buttressed by the Ross Ice Shelf. These include, but are not restricted to, the Darwin–Byrd, Beardmore, Shackleton, Scott, and Reedy glaciers. Each of these outlet glaciers contains a chronosequence of soils that ranges from the late Quaternary to the Pliocene or Miocene in age and features relict and buried soils (Bockheim, 1990)
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