22 AÑOS DE REGISTRO DEL OXÍGENO-18 Y DEUTERIO DE LA PRECIPITACIÓN EN USHUAIA, TIERRA DEL FUEGO. ARGENTINA

DAPEÑA, CRISTINA; PANARELLO, HECTOR

Quito, Ecuador

Congreso; IX Congreso Latinoamericano de Hidrología Subterránea; 2008

ALHSUD, EMAAP, GECAIH, CIGMYP (Ecuador) y Alcadía Metropolitana de Quito

The isotope composition of precipitation is a characteristic of a given region. It is generally determined by meteorological local parameters like temperature, relative humidity and rain amount. Precipitation represents one of the most important factors of recharge. The measurement and record of the isotope content of the precipitation of Argentina are being made by the stations of the National Network of Collectors. It was created by the Instituto de Geocronología y Geología Isotópica (INGEIS) within the framework of the Global for Network Isotopes in Precipitation (GNIP). In this work we present the results obtained in Ushuaia during the period 1982-2003. We analyzed the isotopic composition (2H, 18O) and its relation with the meteorological parameters (temperature and amount of precipitation) in a record of 22 years. This station is located in the mentioned city, in Tierra del Fuego, Antártida e Islas del Atlántico Sur province at 54º 47´ S and 68º 17´W, 10m above the sea level. It is operated by the Centro Austral de Investigaciones Científicas (CADIC) of the Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). It was installed by initiative of the INGEIS and the CADIC and began to work in October, 1981. The weighted average of the precipitation corresponds to d18O = -11.1‰ and   d2H = -84‰ and deuterium excess equal to 4‰. With these data we have elaborated the local meteoric line for the region, i.e.: d2H = (7.60 ± 0.19) d18O - (0.69 ± 2.14). A large precipitation record at Ushuaia station as well as in others localities of Argentina is a fundamental objective to bring scientific tools for environmental isotope studies