The dominant unit mapped is a drumlinized diamicton correlated to the Two Rivers glacial advance
. That glacial advance
also built the Manistee moraine, which is lobate due to being directed into preexisting valleys.
In the last 650,000 years, there have been seven cycles of glacial advance
and retreat, with the abrupt end of the last ice age about 7,000 years ago marking the beginning of the modern climate era--and of human civilisation.
Oxygen enrichment can be attributed to air entrapment in ice during periods of the glacial advance
. During melting of an ice sheet entrapped air maybe released into meltwater under elevated hydraulic head conditions, explaining the enriched dissolved [O.sub.2]-concentrations [2, 20].
Earth's climate is constantly changing, with alternating cycles of glacial advance
They repeat a disproven claim that the Toba eruption 74 ka BP caused a glacial advance
. And in another section on volcanic activity, they several times talk about dust emitted by eruptions rather than explaining that it is actually sulfate aerosols.
It's also a cautionary tale for those who rely almost exclusively on cycles of glacial advance
and retreat to study sea-level changes.
Additionally carbonate content was used to assign samples to a particular glacial advance
using data summarized in Szabo (2006b).
Rampton (1982) assigned the "Buckland Glaciation," the single glacial advance
on the Yukon Coastal Plain that formed the ice-thrust ridge of Herschel Island, to the Early Wisconsinan interval (Fig.
However, during times of peak glacial advance
, the inhabitable latitudinal span of North America was tightly constricted.
As the woody debris in the present study dates from 30,070 [+ or -] 240 y BP, the Newport sample predates the Wedron Formation and, thus, the glacial advance
of the Late Wisconsinan (i.e., Woodfordian Substage).