Fire-cracked rock features on sandy landforms in the Northern Rocky Mountains: Toward establishing reliable frames of reference for assessing site integrity

In cool coniferous forest settings of the Northern Rocky Mountains, well-preserved fire-cracked rock (FCR) features within 30 cm of the surface on ostensibly stable, sandy upland landforms date to the last six millennia. Isolated FCR and artifacts sometimes extend a meter or more below surface, which is suggestive of in situ burial. A paucity of intact features in the lower solum, however, is consistent with the downward migration of deeply buried artifacts by biomechanical processes, especially floralturbation. Moreover, an absence of credible sediment source areas usually precludes colluvial deposition, and results of grain-size analysis reported herein are inconsistent with eolian deposition. Site disarticulation rates tend to be faster on landforms in warmer forested regions of south-central North America, given that most intact FCR features there date only to the last two millennia. The very presence of millennia-old FCR features in these diverse settings, however, is a testament to their durability and utility as measures of site integrity. © 2007 Wiley Periodicals, Inc.