Ninth International Conference on Permafrost ... - IARC Research

A Provisional 1:50,000 Scale Soil Map of Wright Valley, AntarcticaM. McLeodLandcare Research, Private Bag 3127, Hamilton, New ZealandJ.G. BockheimDepartment of Soil Science, University of Wisconsin, 1525 Observatory Drive, Madison, WI 53706-1299, USAM.R. BalksDepartment of Earth and Ocean Sciences, University of Waikato, Private Bag 3105, Hamilton, New ZealandIntroductionDuring the austral summers of 2005–2007, we mappedsoils and permafrost form within Wright Valley, Antarctica,for use at a scale of 1:50,000. Wright Valley, within theMcMurdo Dry Valley region of Northern Victoria Land,extends 53 km from the Wright Lower Glacier, a lobe of theWilson Piedmont Glacier, to the Wright Upper Glacier, anoutlet glacier from the East Antarctic ice sheet. The OnyxRiver flows seasonally from Wright Lower Glacier inland 30km to Lake Vanda, which is 90 m a.s.l. The study area alsoincludes the Dais, Labyrinth and the North and South Forks.Although many soils have been described in central WrightValley, they have primarily been used to aid and interpretsurficial geologic deposits and assign ages/names to developa glacial chronology. Renewed interest in environmentalclassification in a spatial framework (Waterhouse 2001)has led to the demand for soil and permafrost maps ofAntarctica. This paper presents preliminary results fromthose investigations.MethodsStereo-pair aerial photographs of Wright Valley wereexamined with preliminary soil boundaries plotted onto aGIS-based geo-referenced satellite image (http://usarc.usgs.gov/ant-ogc-viewer/declasdownload.htm) and a hill shadeimage built from a 2 m post-processed resolution LIDARfile (http://usarc.usgs.gov/ant-ogc-viewer/lidardownload.htm) at 1:50,000 scale.Fieldwork was undertaken to validate the preliminaryboundaries and determine the nature of surface geology, soils,and permafrost. About 300 small test pits were excavated,described, and classified following Soil Taxonomy (SoilSurvey Staff 2003) and located by GPS. The soil pits werethen backfilled. Weathering stage follows Campbell andClaridge (1975), while salt stage follows Bockheim (1990).Soil boundaries were upgraded daily in the field using theGPS and soil pit information. At 118 locations larger pitswere dug to at least 70 cm (unless ice-cemented permafrostor boulders were encountered), with the soil being sampledby horizon. Both 2 mm fractions were weighed,with the