A multi-proxy study of Holocene environmental change recorded in alluvial deposits along the southern coast of the Pampa region, Argentina

ALDO R. PRIETO; MARIA VIRGINIA ROMERO; ISABEL VILANOVA

JOURNAL OF QUATERNARY SCIENCE

JOHN WILEY & SONS LTD

Lugar: Londres; Año: 2014 vol. 29 p. 329 - 342

0267-8179

Mollusks, C, O isotopes, diatoms and palynomorphs from dated Arroyo Claromecó alluvial deposits provide an integrated reconstruction of rapid Holocene environmental change relate to regional marine influence and paleoclimate shift in southern Pampas region, Argentina. The main forcing factors regionally include: (1) Marine influence in close proximity to the coast related to a sea-level which conditioned the marginal environments before ca. 7700 cal a BP. (2) A short-term decrease in salinity and increase in freshwater influx between ca. 7700 and 7400 cal a BP in response to eustatic adjustment of the basins during rising RSL. An increase in precipitation can not be dismissed. (3) An increasing input of marine water and physical-chemical changes related to the Holocene sea-level maximum along with some evaporative environments between 7400 and 6450 cal a BP. (4) Evaporative processes and consequent changes in water chemistry and progressive climatic variability since ca. 6000 cal a BP while sea-level decreased. The regional comparison of isotope records shows that coastal settings have a different isotopic signal than continent settings and revealed that evaporation and the negative balance of P/E ratio strongly influenced water chemistry, being as important as marine water influence during the period of maximum sea-level highstand.