Los paleoambientes holocenicos de la laguna babicora, Chihuahua, México

Abstract

In the semi-arid region of Laguna de Babícora, northwestern State of Chihuahua, cight stratigraphic profiles havc bccn studied which cover the interval of the Isotope Stagc l. Thc rcsults of thc scdimcntological, statistical and stratigraphical analyses supported
by sevcn dates of 14C enable us to reconstruct and infer the paleoenvironments since the Late Wisconsin up to the Prc.sent. The paleoenvironmental chronology suggested in this study is: (1) from ca. 18 ky B.P. to ca. 10 ky B.P. pluvial environment or Lacustrine Optimum; (2) from ca. 10 ky B.P. to ca. 6 ky B.P. decrease in precipitation and increase in temperature with a marshtype environmcnt; (3) from ca. 6 ky B.P. to 3 ky B.P.: the arid conditions persist, but the sedimentary structures and the morphology of fluvial deposits suggest abundant occasional precipitations; ( 4) from ca. 3 ky B.P. to the Present, the scmi-arid conditions that characterize the region today become firmly established, preceded by a pcriod of soil formation as suggested by presence of paleosoil (horizon Bt). We suggest that the paleoclimatic variations of Laguna de Babícora were similar to those of the southwestern part of the United States; i.e. abundant precipitations in winter during Late Wisconsin and in summer during Holocene.