2015 GSA Annual Meeting in Baltimore, Maryland, USA (1-4 November 2015)

Paper No. 226-9
Presentation Time: 9:00 AM-6:30 PM


CHRISTENSEN, Hilary1, BARTLEY, Julie K.2, DELMONT, Dominic2 and ROSENBERG, Brooke C.2, (1)Department of Biological Sciences, Moravian College, 1200 Main St., Bethlehem, PA 18018, (2)Geology Department, Gustavus Adolphus College, 800 W. College Ave, St. Peter, MN 56082, christensenh@moravian.edu

Bone beds in active rivers frequently contain diverse assemblages of modern to fossil remains, providing a valuable resource to the study of vertebrates in a local geographic area over time. One such collection, of skeletal remains from the Des Moines River outside of Jackson, MN, reflects diverse taphonomic histories. Species range from fish, birds, and small mammals such as beaver to coyotes, horses, bison, elk, and domestic cattle. All species are common in the area today with the exception of bison and elk, which were extirpated in southern Minnesota prior to European settlement (<200 years BP). In addition to modern elements in the collection bison remains returned radiocarbon ages between ~200 to 1000 years BP, and horse remains (horses existed in the area pre- and post-settlement) from ~225 to 80 years BP. Differences in degree of rounding, surface weathering, and evidence for scavenging indicate substantial differences in post-mortem history. Human butchering traces are also diverse, and include modern carcass processing via electric saw as well as potentially pre-Columbian knife/hatchet marks and splitting of long bones for marrow access. Results indicate an association between evidence for butchering and age of the cattle and bison remains (most are sub-adult), suggesting targeted selection of animals used for food. Taken together, the data reflect a time-averaged, likely successively reworked, fluvial bonebed that includes natural attritional wildlife mortality as well as elements recording a thousand years of human use of animals for food.