Megaflutes y eskers en lago Viedma, provincia de Santa Cruz

PONCE, J.F.; MAURICIO GONZALEZ GUILLOT; DÍAZ BALOCCHI, L.

Congreso; XX Congreso Geológico Argentino; 2017

Megaflutes and eskersat Lago Viedma, Santa Cruz Province. Two megaflute fields and an esker group hasbeen identified at Lago Viedma (49º 41?S, 72º 17?W). In this paper, their geomorphological and sedimentological characteristicsare identified and described. One of the megaflute field is located to the eastof lago Viedma, and is composed of 34 megaflutes and 12 drumlins. Thissubglacial landform field is part of the Post-GGP 1 ground moraines, and could havebeen generated when the Viedma Paleoglacier abandoned the valley where it wasconfined and expanded, extending eastwards as a piedmont glacier, probably inpre-LGM glacial advance. The second megaflute field is located along thesouthern margin of the lake and is composed of 92 megaflutes. This megaflutefield is interrupted by a small group of 10 eskers.  The megaflutes and eskers were developed in a glacialsuture zone, where the Río Cóndor tributary paleoglacier joined with the Viedmamain Paleoglacier.  The increase in thicknessand speed of the ice body probably in LGM times could have been responsible of thedevelopment of this second megaflute field. Full concentration of glacialdrainage systems along the suture area could have generated the eskers duringLGM Lateglacial times.