Holocene sequences in the Mayan Lowlands - A provenance study using heavy mineral distributions

Abstract

Heavy mineral analysis of alluvial sediments and paleosols on Holocene terraces of the Usumacinta River provided an effective tool to reconstruct sediment provenance in the Mayan Lowlands. Furthermore, the mineralogical data are useful for pedostratigraphic correlations in the region. Based on our observations from the Tierra Blanca profile, the ultrastable detrital heavy minerals assemblage (mostly zircon, tourmaline, and rutile) are the most promising mineral proxies to recognize the provenance of the sediments. Those minerals are accompanied by an intriguing variety of high density authigenic minerals (including titanite). Using the specific characteristics and the ages obtained for some layers, it may now be possible to develop a regional chronostratigraphy for the paleosols and alluvial sequences. Our data suggest that sediments were transported westward in river channels originating from the highlands of Guatemala. The studied materials also contain high amounts of volcanic minerals, most of them fresh and with angular shapes, thus indicating a proximal source, mostly likely from Tacana Volcano, Mexico/Guatemala.