Stabilized sand sheets and dunes hold a remarkable amount of information on paleoenvironmental conditions under which late Quaternary landscapes evolved in northern subarctic regions. We provide the results of a project focused on understanding the development of lowland environments and ecosystems, including dunes and sand sheets, which were critical habitat for early human occupations in subarctic regions. Our study area is the Rosa-Keystone Dunes Field in the Shaw Creek Flats of the middle Tanana River basin, interior Alaska, one of the oldest continuously occupied areas in North America (14,000 cal. BP to present). The disturbance regimes of reactivated dunes and associated forest fire cycles between 12,500 and 8800 cal. BP fostered a unique early to mid-successional mixed vegetation community including herbaceous tundra, shrubs, and deciduous trees. This environment provided key habitats for large grazers and browsers, significant resources for early hunter-gatherer populations in central Alaska. After 8000 cal. BP, the expansion of black spruce and peatlands heightened landscape stability but decreased the range of local habitat for large grazers. Hunter-gatherer economic change during these periods is consistent with human responses to local and regional landscape disturbance and restructuring.

The middle Tanana Valley of central Alaska contains a well‐preserved record of human occupation and paleoenvironmental change since the Late Glacial period (c. 16,000 cal yr BP) and is a critical region for understanding human dispersal into the Americas. Micromorphology analysis of soils and sediments from six archaeological sites yields valuable information about soil formation processes and landscape evolution during the Late Glacial and into the Holocene. At the macroscale, site stratigraphies are very similar, and thin organic‐rich layers (locally known as “stringers”) are commonly interpreted as buried soils. However, at the microscale, these layers exhibit significant differences in the degree of bioturbation, organic matter humification, and boundary abruptness, indicating that pedogenesis was not the sole process at every site. In this way, our microscale analysis addresses issues of equifinality related to site formation interpretations, a persistent problem with subarctic and high‐latitude stratigraphy. Additionally, this study reveals a certain level of landform and landscape instability within a broader trend of regional increases in pedogenesis and vegetation coverage, adding to the existing model of heterogeneity across this subarctic landscape. Here we demonstrate the utility of micromorphology to test field interpretations and improve models of Late Glacial landscape evolution in high‐latitude contexts.

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