SciELO - Scientific Electronic Library Online

 
vol.29 número2Variabilidad y simetría de una cucaracha (Blattida: Raphidiomimidae) depredadora nocturna del JurásicoEstudio gravimétrico de la estructura cortical en la cuenca de Grenada y las Antillas Menores índice de autoresíndice de materiabúsqueda de artículos
Home Pagelista alfabética de revistas  

Revista mexicana de ciencias geológicas

versión impresa ISSN 1026-8774

Resumen

CHAVEZ-LARA, Claudia M. et al. Lacustrine ostracodes from the Chihuahuan Desert of Mexico and inferred Late Quaternary paleoecological conditions. Rev. mex. cienc. geol [online]. 2012, vol.29, n.2, pp. 422-431. ISSN 1026-8774.

The abundance and distribution of ostracodes in the upper 865 cm of a sediment core recovered from Babícorapaleolake allows reconstruction of paleoecological conditions in the western Chihuahuan Desert by inferring variations in temperature and salinity of the lake water over the last ca. 72 cal kyr BP. The ostracode assemblage consists of five species (Candona patzcuaro Tressler, Cypridopsis vidua Brady, Limnocythere bradburyi Forester, L. platyforma Delorme andL. Ceriotuberosa Delorme), and its abundance varies between 0 and 1441 valves/g. Low ostracode abundance suggests the presence of dilute lake water (salinity>100 ppm) with abundant fresh water inflow into the basin prior to ca. 57 cal kyr BP. During ca. 57-49 cal kyr BP salinity remained low (>100ppm), but the water column was characterized by cold temperatures (>4 °C). Sediments of this zone have higher organic carbon content. Conditions were optimal for ostracode productivity (abundance of44-1441 valves/g) during ca. 49-29 cal kyr BP, and this zone indicates fluctuating temperature (5-32 °C) and salinity (100-100,000 ppm). A warm water column (>13 °C) and salinity of >500 ppm are inferred during ca. 29-12 cal kyr BP. Sediments of the last 12 cal kyr BP lack preserved ostracodes, and precipitation of authigenic calcite indicates periodic desiccation of the lacustrine basin during the Holocene. The inferred paleoecological conditions in the western Chihuahuan Desert are synchronous with other proxy-based late Quaternary paleohydrological and paleoclimatic information obtained from southwestern USA and northern Mexico.

Palabras llave : ostracode; paleoecology; Late Quaternary; Chihuahuan Desert; Mexico.

        · resumen en Español     · texto en Inglés     · pdf en Inglés