PERCHED DUNES IN THE FUEGIAN STEPPE, SOUTHERN ARGENTINA: ARCHEOLOGICAL RESERVOIRS OF HOLOCENE INFORMATION

ANDREA CORONATO ; MÓNICA SALEMME; JIMENA ORÍA; FLORENCIA MARI; RAMIRO LÓPEZ

Advances in Geomorphology and Quaternary Studies in Argentina?,

Springer

Lugar: Ushuaia; Año: 2019

2197-9596

The description of the genesis and the geomorphological characteristicsof three perched dunes, named as O?Connor, Amalia and Arturo ispresented herein. They are located in the periphery of the shallow lakes of suchname, which have a semi-perennial nature in the Fuegian steppe (lat. 53° S).These landforms are characterized according to their location, orientation andquantity, as well by color, thickness and textural composition of the eolianorigin units and the units with soil development. These units, considered aspaleosoils, are indicators of stable environments that would have diminished theeolian accumulation which is responsible for the formation of eolian units ofvariable thickness. A chronological sequence, based upon radiocarbon dating onorganic matter belonging to each one of the units transformed into soils, fitsquite well with already published absolute dates and it allows the interpretationof the evolution of these dunes formed between the Late Glacial and the LateHolocene. An eolian accumulation rate for the Amalia and Arturo dunes issuggested, based upon the thicknesses of each unit and the obtained radiocarbondates. The tephras contained in the Amalia and Arturo dunes are described andcompared with the Middle Holocene eruption of Mt. Burney (Chile). Thecharacteristics of archeological record and its state of conservation are analyzed,whether they are lithic materials or bone remains. The chronology obtained forthe paleosoil sequence is discussed in relation to paleoenvironmental events.These events are determined on the base of certain proxies, both in the studiedsoils as in lacustrine cores obtained in shallow lakes from the surroundings. Thedevelopment of some of the paleosoils is in contrast with certain regionalexamples that appear in the literature. From the archeological point of view, thedevelopment of dune geomorphological processes such as auto-erosion or?cannibalism? and re-deposition exposed the possible existence of taphonomictraps and palimpsests is highly significant; these are generally visible in surfacecontexts, which are interpreted as archeological reservoirs. In this kind of sites,the resolution is low and usually, the degree of mixture could be high.