Late quaternary history of the Waco Mammoth site: environmental reconstruction and interpreting the cause of death.

The Waco Mammoth site is thought to be the largest single-herd, non-human related mammoth death site in the World. Previous research has failed to determine an undisputed age and cause of death of 22 Columbian mammoths (Mammuthus columbi) uncovered at the site. The purpose of this study is to produce the most accurate age and interpretation of the environmental events occurring before, during, and after the death of the Waco Mammoths. Soils, sediments, and allostratigraphic units were described using several vertical measured sections. Data collected from measured sections included stratal thickness, allostratigraphic boundaries, grain size, sedimentary and pedogenic features, and the spatial and temporal ordering of stratigraphic units. Particle size distribution and micromorphologic analyses were performed to create a microstratigraphic and pedologic history of the site. This study concludes that the Waco mammoths represent at least two separate death events occurring in a tributary of the ancestral Bosque River between 53 to 73 ka B.P.