LUPO liliana concepcion
Palynological evidence of the geoecological belts dynamics from Eastern Cordillera of NW Argentina (23° S) during the Pre-Last Glacial Maximum
GONZALO R. TORRES; LILIANA C. LUPO; JULIO JOSÉ KULEMEYER; CLAUDIO PEREZ
SERVICIO NACIONAL GEOLOGIA MINERVA
Año: 2016 vol. 42 p. 151 - 165
This paper presents the first palynologycal evidences that provide paleoenvironmental data of the geoecological belts of the Eastern Cordillera in Northwestern Argentina during the millennia prior to the Last Glacial Maximum (LGM). The study was carried out on a 5-m deep sedimentary core raised at Laguna Blanca (23°09?S, 65°12?W; 4256 masl), province of Jujuy. The geochronology was based on three C14 dating by AMS method. Results show the sensitive response of the geoecological belts to temperature and effective moisture variations from ca. 29,000 cal years BP to ca. 25,000 cal years BP. The High Andean belt probably suffered an altitudinal descent forced by intense cold climate conditions ca. 29,000 cal years BP, and may have reached a distribution comparable to the present one on 26,300 cal years BP, favored by a less cold and dry climate than the former phase. The Puna belt did not suffer great changes, since it remained with low representation in the pollen spectrum. A noteworthy regional biogeographic aspect is the presence of high pollen percentages of the Yungas arboreal species ca. 29,000 cal years BP. Probably this is a response to the intensification of the anabatic winds that ascend the slope of the Sierras Subandinas towards the Eastern Cordillera. These results represent an important contribution to the paleoenvironmental discussion of the Upper Pleistocene for the Argentine Northwestern region, where the available information on vegetation history is scarce.