Quaternary non-marine ostracods of Runtuyoc lake, northern Argentina: new taxonomic descriptions and the implication for Holocene paleoenvironment

D'AMBROSIO, D. SABINA; ROJO LEANDRO D.; FONTANA SONIA

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2019 vol. 98

0895-9811

We performed an ostracod taxonomic analysis on samplesfrom a shallow lake (Runtuyoc Lake) in north-western Argentina in order tocontribute to the understanding of the evolution of this waterbody through the last 5000 years. The ostracod assemblages consist of 15species, two species exclusively from modern samples (Herpetocypris helenae and Chlamydothecaincisa), 8 exclusively from Quaternary samples (Limnocythere jujunensis sp. nov., L. titicaca, L. alexanderi,L. aff. staplini, Cyprideis salebrosa,Penthesilenula incae, Cypridopsis vidua, Sarscypridopsis aculeata) and 5 from both, modern and Quaternarysamples (Ilyocypris ramirezi, Potamocypris smaragdina, Heterocypris incongruens, Heterocypris similis, Candona sp.). The lake is located in theMiraflores river course and is characterized nowadays by freshwater conditions,but a saline past is evident as it went through different periods ofdesiccation. From 5500 to 3000 cal a BP, the lake was absent, probably relatedto extreme dry conditions. Then, water inputs into the lake produced a salineshallow lake until to reach modern setting as a freshwater body basin. Runtuyoclake records, supports the regional environmental trending change for theArgentinian northwest, with wetter conditions in the early and late Holocene,and arid for the middle Holocene at least from 5500 to 3000 / 2500 cal a BP.