MULTI-PROXY ANALYSIS OF LATE QUATERNARY SEDIMENTS IN THE LOWER BASIN OF THE QUEQUÉN SALADO RIVER (BUENOS AIRES PROVINCE, ARGENTINA): AN UPDATE
description: Abstract. Two fossil sections (Late Quaternary), and a group of modern samples analyzed through pollen and non-pollen palynomorphs, enabled the reconstruction of the palaeoclimatic and palaeoenvironmental conditions of the lower basin of the Quequén Salado River (Buenos Aires Province). The study was complemented with analysis of sedimentology, malacofauna, ostracods, diatoms, and mammal and archaeological remains. For the Late Pleistocene, the scarce presence of microfossils, associated with eolian palaeoenvironments, allowed inferring arid/extremely arid climate conditions. In the Pleistocene/Holocene boundary, evidence of a pedogenetic event suggests a brief lapse of climatic stability. Pollen indicates the development of a halophyte steppe, which remained in the area until the Middle Holocene. During the Early Holocene (8,173 cal. yr B.P.) the sedimentology, malacofauna and microfossils evidenced a sea level rise. This event ended with the establishment of a brackish lacustrine body towards the Middle Holocene. After that, a pulse characterized by high humidity levels, indicate the replacement of the halophyte steppe by a gramineous steppe. Following that pulse during the 6,799 cal. yr BP‑ 5,603 cal. yr BP lapse, the microfossils showed considerable variability, thus reflecting an alternation between relatively more humid and dry pulses. Evidence indicates that during the Late Holocene (~ 1,000 yr. BP) modern ecosystems began to settle in the lower basin of the Quequén Salado River. Two global climate changes, the Medieval Climate Optimum (823 cal. yr B.P.‑ 690 cal. yr B.P.) and the Little Ice Age (389 cal. yr B.P.) were inferred through pollen and faunistic remains at QS1 Archaeological Site. KEY WORDS. Palaeoenvironmental-palaeoclimatic changes. Late Quaternary. Quequén Salado River. Argentina. Resumen. ANÁLISIS MULTI-PROXY DE SEDIMENTOS DEL CUATERNARIO TARDÍO EN LA CUENCA INFERIOR DEL RÍO QUEQUÉN SALADO (PROVINCIA DE BUENOS AIRES, ARGENTINA). UNA ACTUALIZACIÓ…
creator: Silvia C. Grill, Ana L. Fernández
source: Publicación Electrónica de la Asociación Paleontológica Argentina
publisher: Asociación Paleontológica Argentina
date: 2016
relation: https://www.peapaleontologica.org.ar/index.php/peapa/article/view/84
coverage: Paleontology, Fossil man. Human paleontology