Mineral magnetic record of paleoclimate variation in loess and paleosol from the Buenos Aires formation (Buenos Aires, Argentina)

Environmental magnetic techniques were applied to a loess-paleosol sequence of the Chacopampean plain (Buenos Aires, Argentina). Mineral magnetic carr iers and their grain size were identified in order to detect magnetic miner al fluctuations associated with climatic changes. Multidomain magnetite of detrital origin dominates the record. In paleosols, a high coercivity fract ion was identified. Horizons with no Visual evidence of pedogenesis, but sh owing magnetic behavior analogous to that of paleosols were observed and ar e thought to represent environmental conditions similar to those prevailing during paleosol formation. The results suggest that the magnetic signal yielded by paleosols in these South American loess deposits is different from that in the Chinese loess. This may be due to differences in parent materials, diagenetic processes an d/or differences in paleoclimatic conditions in both regions. (C) 1998 Else vier Science Ltd. All rights reserved.