Age Reassignment Using Luminescence Dating for The Mammoth Site, Black Hills, South Dakota, USA

Authors

• Shannon A. Mahan, U.S. Geological SurveyFollow
• Jim I. Mead, Mammoth Site of Hot Springs South Dakota Inc.
• P.R. Hanson, University of Nebraska - LincolnFollow
• Emma T. Krolczyk, US Geological Survey, Luminescence Geochronology Lab
• Christopher N. Jass, Hot Spring Mammoth Site

ORCID IDs

https://orcid.org/0000-0001-5214-7774

https://orcid.org/0000-0002-4975-022X

https://orcid.org/0000-0002-7163-4348

Document Type

Article

Date of this Version

8-11-2026

Citation

Mahan, S. A., Mead, J. I., Hanson, P. R., Krolczyk, E. T., & Jass, C. N. (2026). Age reassignment using luminescence dating for The Mammoth Site, Black Hills, South Dakota, USA. Quaternary Research, 1–18. https://doi:10.1017/qua.2026.10102

Comments

Published by Cambridge University Press

CC BY NC ND and used with permission

Abstract

The Mammoth Site (MS) at Hot Springs, South Dakota, provides a unique opportunity to reconstruct paleoenvironmental conditions on the Northern Great Plains of the United States. Previous radiocarbon analyses of mammoth bone apatite suggested the MS sinkhole was deposited ∼42–23 cal ka BP. However, two U-series ages and one thermoluminescence (TL) age ranged between 150 and 101 ka, suggesting the bones were considerably older. We analyzed six samples from the bone bed using infrared-stimulated luminescence (IRSL) on feldspars, because the quartz luminescence was saturated; the ages ranged from approximately 232 to 160 ka, showing better agreement with previous U-series and TL analyses. In addition, we dated three samples on two terraces that are at lower elevation than the MS. Our new IRSL ages show that the sediments of the MS were likely well bleached, derived from pond margin runoff events, and deposited as sandy-silt laminae couplets. Our chronology indicates that the 6-m-thick bone-bearing sediments accumulated at a rate of approximately 12 mm/yr and that deposition occurred during Marine Isotope Stage (MIS) 6 and MIS 7, not MIS 2 and MIS 3 as previously published.