An Analysis of Organic Ice Patch Materials

Abstract

Ice patches are a unique source of information that can be used to infer past environments. With support from the Matthew Hansen Endowment for Wilderness Studies, and the Beartooth Environmental Alpine Archaeological Research Group, I was able to participate in two archaeological surveys of ice patches in the Greater Yellowstone Ecosystem in 2023. While both surveys were compromised by late lying snow, one resulted in the identification of non-rooted—and likely non-cultural—wood in association with two ice patches. Examination of Google Earth imagery indicates the presence of two small ice cores; a ca. 15 m long transverse core, as well as a less defined 10 m lateral core of ice in this location. The ice patch was identified by Lee’s 2019 revised assessment of snow and ice for the Greater Yellowstone Coordinating Committee (GYCC) as “SB1_A.” With additional support from Montana State University’s Undergraduate Scholars Program, I was able to submit samples of the three collected specimens to Paleoscapes Archaeobotanical Services Team (PAST) for genus and composition analysis. PAST’s analysis suggests that two of the samples (1A and 2A) are consistent with Picea (spruce). The composition of the samples appears to be similar, and macroscopic observations suggest they are likely fragments of branches. The third sample (3A) is a species of Abies (fir), with the generally smaller size of the tracheids suggesting it is from a branch. With the financial support noted above, a fragment of the spruce and fir were submitted for radiocarbon analysis, the result of which will be compared to extant reports on dated wood from other ice patches in the Rocky Mountains.