Dark humic alluvial paleosols in Central and Southern Mexico:: Micromorphological indicators of Late Pleistocene megafauna habitats.

摘要: During the Late Pleistocene, Mexico had a richer fauna than today with many different forms of megafauna that are now extinct. However, ecosystems they inhabited and particular ecological niches occupied still poorly understood. Most findings Pleistocene have been in alluvial deposits present rich opportunities for paleoecological studies using paleopedological records. Floodplain paleosols commonly developed. micromorphological analysis provides information about grade development soil at microscale, discriminating between genetic sedimentary processes; thus helping identification environmental setting which formed. We analyzed micromorphology six pedogenetic units sequences Santa Cruz Nuevo Axamilpa, south Puebla, Huexoyucan, state Tlaxcala. These pedosequences correspond to second half marine isotopic stage 3 (MIS3), MIS2 early Holocene. All studied characterized by strong pigmentation dark humus. The MIS3 reveals aquatic conditions evidence freshwater biota microlamination as well features hydrogenic carbonate precipitation redoximorphic processes. Holocene demonstrate signs stronger coprogenic aggregation, weathering fewer gleyic features. Comparison modern soils shows latter were formed under better-drained, aerated exclude We conclude colored paleosol indicative paleo-landscapes: wetlands moist meadows – swampy could play an important role habitat.