Age determination of the detrital zircon component of crustal slices of Ross Orogen from the Skelton Glacier and Royal Society Ranges areas

It is suggested that the Ross Orogeny is composed of a wide variety of crustal slices that are exotic to their present location and were accreted to the East Antarctic craton during the lower paleozoic Ross Orogeny. To test this hypothesis, rocks (metasedimentary rocks and granite) were sampled from crustal slices in both the Skelton Glacier and Royal Society Ranges including Renegar Glacier area, lower Radian Ridge, Rucker Ridge, Gloomy Hill, the Radian Glacier area, the upper Skelton Glacier area and Stepaside Spur. Samples were crushed and processed through heavy liquids and magnetic separation to isolate detrital grain of zircon and analysed by LAP-ICP-MS and their ages determined. The provenance, or source, of the detrital zircons can also be assessed from the specific characteristics of the age histogram. This enables (a) ready comparison between individual crustal slices to assess whether they originated in the same place prior to accretion and (b) it allows reconstruction of the terranes at the time of sedimentation and (c) it offers the possibility of determining the likely distance of travel of so called exotic terrances prior to accretion.