Universidade de São Paulo. Faculdade de Filosofia, Letras e Ciências Humanas
Abstract
A geomorphological interpretation of the glacial geomorphology of the proglacial environments of the Buenos Aires, Kenney and Flora glaciers in Hope Bay, Antarctica, between the coordinates 63° 23'S and 63° 26'S latitude and 56° 8'W and 57° 4'W longitude. Sedimentary, granulometric and morphological analyzes were carried out on 15 samples collected in 2017 for the identification of depositional geomorphological features and subsequent geomorphological mapping. The glacier fronts were delineated from Sentinel-2 and Quickbird images of 1988, 2008 and 2017 using the ArcGIS® software to identify the landforms chronology of the shapes. The higher number of coarse grains, low selection, and high values of C40 in all samples indicate modification by erosive processes in supraglacial environment and/or transport distance after substrate quarrying process and grain fracturing by post-depositional physical weathering. The reconstruction of the Hope Bay’s Holocene landscape of indicates glaciers with tens of meters of advance compared to the current front during the Little Ice Age (LIA). The geomorphological mapping and sedimentary analyzes showed recent environmental changes in the proglacial system, with formation of hummocky moraines indicating the retreat/stabilization of the glaciers in the LIA. Furthermore, they set evidences of recent recession moraines, which prevail in the Buenos Aires Glacier predominate in the 2008-2017 phase, on the Flora Glacier in 1988-2008 period and the Kenney Glacier in the 2008-2017 period.The objective of this paper is to understand the glacial geomorphology of the proglacial environments of the Buenos Aires, Kenney and Flora glaciers in Hope Bay, Antarctica, between the coordinates 63° 23'S and 63° 26'S latitude and 56° 8'W and 57° 4'W longitude. Sedimentary, granulometric and morphological analyzes were carried out on 15 samples collected in 2017 for the identification of depositional geomorphological features and subsequent geomorphological mapping. The glacier fronts were delineated from Sentinel-2 and Quickbird images of 1988, 2008 and 2017 using the ARC GIS to identify the chronology of the shapes. The predominance of coarse grains, low selection, and high values of C40 in all samples indicate modification by erosive processes in supraglacial environment and/or transport distance after substrate peeling and grain fracturing by post-depositional physical weathering . The reconstruction of the holocene landscape of Hope Bay indicates glaciers with tens of meters of advance compared to the current front during the Little Ice Age (LIA). The geomorphological mapping and performed analyzes show recent environmental changes in the proglacial system, with formation of Hummocky moraines indicating the retraction/stabilization of the glaciers in the LIA, and recent recession moraines, which in the Buenos Aires glacier predominate in the 2008-2017 phase, on the Flora glacier in the period 1988-2008 and the Kenney Glacier in the 2008-2017 period
