Paleoclimatic significance of Middle Pleistocene glacial deposits in the Kotzebue Sound region, northwest coastal Alaska

Conference · Wed Jan 01 04:00:00 EST 1992 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5688903

Roof, S R; Brigham-Grette, J ^[1]

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1. Univ. of Massachusetts, Amherst, MA (United States)

During Middle Pleistocene time, glaciers extended from the western Brooks Range in NW Alaska to the coast at Kotzebue Sound, forming Baldwin Peninsula, a 120 km-long terminal moraine. Marine, glacigenic, and fluvial facies exposed along coastal bluffs surrounding Kotzebue Sound and Hotham Inlet indicate that at least the initial stages of the glacial advance occurred while sea level was high enough to cover the shallow Bering Shelf. Although it is presently uncertain if the ice actually reached tidewater before extensive middle-latitude ice-sheet formation, the marine and glacigenic facies clearly indicate that this advance must have occurred significantly out-of-phase with lower latitude glaciation. The authors believe an ice-free Bering Sea provided the moisture for glacier growth during the waning phases of a global interglacial climate. Although the magnitude of the Baldwin Peninsula advance was large compared to late Pleistocene advances, the timing with respect to sea level is consistent with observations by Miller and de Vernal that late Pleistocene polar glaciations also occurred near the end of interglacial periods, when global sea level was high, high-latitude oceans were relatively warm, and summer insolation was decreasing. An important implication of this out-of-phase glaciation hypothesis is that the critical transition point between climate states may be earlier in the interglacial-glacial cycle than previously thought. Because it appears that climate change is initiated in polar regions while the rest of Earth is experiencing an interglacial climate, many of their climate models must be revised. The glacial record at Baldwin Peninsula provides an opportunity to test, revise, and perhaps extend this out-of-phase glaciation hypothesis to the middle Pleistocene interval.

• OSTI ID: 5688903
• Report Number(s): CONF-921058--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 24:7
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
ALASKA
BERING SEA
CENOZOIC ERA
CLIMATE MODELS
CLIMATIC CHANGE
DEVELOPED COUNTRIES
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GLACIERS
LEVELS
MATHEMATICAL MODELS
MORAINES
NORTH AMERICA
PACIFIC OCEAN
PALEOCLIMATOLOGY
PALEONTOLOGY
PLEISTOCENE EPOCH
QUATERNARY PERIOD
SEA LEVEL
SEAS
SURFACE WATERS
USA