Genesis of Englacial Debris within the Lower Glacier De Tsidjiore Nouve, Valais, Switzerland, as Revealed by Scanning Electron Microscopy

Abstract

Previous analysis has failed to establish unequivocally the genesis of englacial debris bands within the Glacier de Tsidjiore Nouve. Although extraglacial sources were presumed to be dominant, some of the debris appeared to be derived either from a subglacial source or had not been passively transported. Evidence obtained through the application of scanning electron microscopy reinforces the view that the englacial debris was incorporated within the glacier via crevasses in the firn basin, and indicates that it is derived from (1) supraglacial debris, resulting from subaerial weathering of rock-faces above the ice in the firn basin, and (2) subglacial debris derived from the base of ice standing above these rock faces. The results of this investigation demonstrate the value of scanning electron microscopy in the study and interpretation of complex sediment assemblages on and within glaciers.