Lake records of Paleoindian and Archaic environments of the Northern Plains: The “park oasis” hypothesis
Catherine H. Yansa
Fossil pollen and other proxies from lake sediments are used
to reconstruct past dynamics in vegetation, climate and local availability of
potable water for the Northeastern Plains, thereby providing a landscape context
to re-assess local Paleoindian and Early Archaic subsistence strategies and
settlement patterns. Presented are pollen and plant macrofossil data from two
lakes in North Dakota and discussion of these results in the context of
published paleoenvironmental and archaeological data for the region. Aridity has
characterized the regional climate since deglaciation. From 12,000 to 10,000 14C
yr BP, this aridity was counter-balanced by glacial meltwater saturating much of
the landscape, which supported a vegetation of white spruce parkland. The
regional water table lowered after 10,000 14C yr BP. As some lakes went dry or
became saline others received ground-water input, thereby creating scattered
“oases” in a deciduous parkland, which would have attracted prehistoric people
and game alike. Grassland became widespread by 9,000 14C yr BP. Alternating arid
and moist intervals characterized the mid-Holocene Altithermal, but some oases
existed in the region. This paper supports the hypothesis proposed by some
archaeologists for the persistence of human occupation of the Northern Plains
during the Altithermal except, perhaps, during the severest droughts.