Holocene paleoenvironmental reconstruction of Laguna Babícora, Chihuahua, Northern Mexico, based on Ostracode Ecology and Shell Chemistry

Resumen

Fossil ostracodes from the Las Vacas trench measured in Laguna Babícora, Chihuahua, Mexico were analyzed taphonomically,

and the shells of Limnocythere bradburyi were tested for trace-elements. Chronological control of the sediments was established using

two calibrated 14C ages placing plant material at 9250 and 990 years B.P. Ostracode association is represented by Candona caudata,

Eucandona patzcuaro, Cypridopsis vidua, Limnocythere platyforma and Limnocythere bradburyi. Population structure and taphonomy

indicate a biocenosis living in a low energy lake, fluctuating from fresh to hyposaline water. Ostracode abundances in the studied interval

ranged from 698 to 2 valves/g of sediment. Water salinity was established between 100 – 5000 ppm. Shell Mg/Ca molar ratios were

used to interpret changes in lake temperature, with calculated temperatures ranging from 11.9 °C to 7.3 °C, revealing a low-temperature

trend during the early to late Holocene. Our data contributes to the completion of the paleoenvironmental scenario for the Early to

Mid-Holocene based on evidence that is consistent with other paleoclimatic reconstructions from the Babícora area.