Late Holocene climate change in the Big Belt Mountains, central Montana, USA

Abstract

Carroll College and the Helena National Forest are working in a 6-year research partnership designed to investigate the relationship between paleoclimate change and human adaptation in the Big Belt Mountains of central Montana, USA. This ongoing project is designed to gather archaeological and paleoenvironmental data from three diverse ecosystems within one drainage basin: high-altitude park areas (1800–2100 m), mid-altitude conifer forests (1200–1500 m), and low-altitude locales (under 1500 m) along the Missouri River. These data will represent paleoecological and archaeological changes through time and will detect synchrony and diversity across an elevation gradient. Thus far, excavation of two mid-altitude sites, dating to 2400 and 4500 BP, and one high-altitude site, dated to 2400 BP, revealed evidence of a significant drought period about 2000 years ago. To date, the excavated sites evidence a shift in pollen to drier species, a shift to higher sedimentation rates, and changes in snail and vertebrate species.