INVESTIGADORES
ORIA jimena
congresos y reuniones científicas
Título:
A Holocene lake-margin aeolian sequence from interior Tierra del Fuego,
Autor/es:
FANNING, PATRICIA; CORONATO, ANDREA; SALEMME, MÓNICA; PICKARD, JOHN; ORÍA, JIMENA; PONCE, FEDERICO
Lugar:
Bern
Reunión:
Congreso; XVIII INQUA Congress; 2011
Institución organizadora:
INQUA
Resumen:
A 20 m thick sequence of aeolian deposits and palaeosols, deposited above Tertiary marine
sediments adjacent to the shallow, saline, ephemeral Laguña Arturo in interior Tierra del Fuego,
is described. The sequence of nine aeolian units, including eight palaeosols and capped by the
contemporary soil, provides evidence of environmental changes which have occurred during the
Holocene in the cold Fuegian steppe, beginning as early as the Late Glacial-Early Holocene
transition. A chronostratigraphy is provided by guanaco and Canidae sp. bones embedded
within palaeosols, and organic matter content, radiocarbon dated from 9,951+/-59 y BP
(11,304 cal BP) at the base of the sequence to 434 +/- 43 y BP ( 471 cal BP) near the top. A
tephra layer between palaeosols 4 and 5 is interpreted from its geochemical fingerprint as the
product of one of the mid-Holocene eruptions of Mt Burney, located in the Southern Patagonian
Andes. The evidence suggests that accumulation of the aeolian sediments occurred throughout
most of the Holocene, and were sourced from deflation from the intermittently dry lake bed, as
well as deposition of material transported by wind from more distant sources. Local acquisition
of fine particles derived from the weathering and erosion of the basal Tertiary marine sediments
may also have occurred. The orientation of the aeolian deposits suggests a more northwesterly
wind direction instead of the present westerlies. Weakly developed A-horizons capping each of
the aeolian units suggest that the landscape was sensitive to environmental change, from more
arid conditions when the aeolian deposits accumulated to brief periods of landscape stability
when topsoil development occurred. Evidence of human occupation in Laguña Arturo 1 (stone
artefacts and animal bones) is confined to the upper part of the sequence, and is interpreted as
a place for primary butchering and raw material acquisition.