Proceedings of the Ocean Drilling Program, 145 Scientific Results

Rea, David K.; Basov, La.; Scholl, David W.; Allan, James F.

doi:10.2973/odp.proc.sr.145.1995

Cited by 17 publications

(1 citation statement)

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“…Alpine glaciation along the margin may have initiated as early as ~7 Ma (Lagoe et al, 1993) and was well under way by 5.5 Ma (Lagoe et al, 1993;Rea and Snoeckx, 1995;White et al, 1997), when elevation of the Chugach-St. Elias mountain belt was sufficient to trap precipitation from storms generated in the Gulf of Alaska. Initial onset of tidewater glaciation, Lagoe et al's (1993) "Glacial Interval A," is linked to the appearance of ice-rafted debris (IRD) in the Yakataga Formation at the Yakataga Reef outcrop at 5.5 Ma and at Site 887 from ~5 Ma (Krissek, 1995) to 4.3 Ma (Rea and Snoeckx, 1995) (Fig. F3).…”

Section: Northwestern Cordilleran Ice Sheet Dynamicsmentioning

confidence: 99%

Untitled

2011

IODP Scientific Prospectus

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Section: Northwestern Cordilleran Ice Sheet Dynamicsmentioning

confidence: 99%

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2011

IODP Scientific Prospectus

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Gulf of Alaska continental slope morphology: Evidence for recent trough mouth fan formation

Swartz

Gulick

Goff

2015

Geochem Geophys Geosyst

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Glaciated continental shelves are host to numerous morphologic features that help understand past glacier dynamics. Southeastern Alaska is home to the St. Elias mountains, an active orogen that also hosts temperate marine glaciers. During glacial periods ice streams advance across the continental shelf, carving shelf-crossing troughs that reach the shelf edge. We use high-resolution multibeam data to develop the relationship between the Yakutat and Alsek Sea Valleys and the resulting continental slope morphology. The shelf and slope geomorphology can be divided into statistical groupings that relate to the relative balance of erosion and deposition. Our analysis indicates that only the Yakutat system has been able to build an incipient trough-mouth fan. The extreme sediment supply from this region was able to overwhelm the steep initial topography of the transform margin while further to the east sediment slope-bypass dominates. This analysis provides an extreme end member to existing studies of temperate glaciation along continental margins. The unique interplay between rapid uplift due to ongoing collision and the massive erosion caused by temperate glaciers provides for sedimentary flux far above most other systems.

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Nutrient leakage from the North Pacific to the Bering Sea (IODP Site U1341) following the onset of Northern Hemispheric Glaciation?

März

Schnetger²,

Brumsack³

2013

Paleoceanography

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Intergrated Ocean Drilling Program Expedition 323 recovered a sediment record covering the last ~4.3 Ma from the Bering Sea (Integrated Ocean Drilling Program Site U1341, Bowers Ridge, 2177 m water depth). To resolve Pliocene‐Pleistocene paleoenvironmental changes in this marginal basin, ~190 sediment samples were analyzed for their bulk element composition. Aluminium contents in Bowers Ridge sediments are variable but overall higher toward younger sediments, probably related to the intensification of the Northern Hemispheric Glaciation and increasing sea ice transport in the Bering Sea. The gradual increase of terrigenous input is mirrored by decreasing SiO2 and excess Si (Sixs) contents, but the overall Si enrichment of the deposits reflects continuous opal deposition since the Pliocene at Bowers Ridge. Unlike in the North Pacific, the Sixs record at Site U1341 does not support a dramatic decrease in opal export following the onset of the Northern Hemispheric Glaciation around 2.7 Ma, but SiO2xs have higher accumulation rates (up to ~8 g/cm2/ka) between ~2.6 and ~1.8 Ma BP. During this period, the major oceanic opal deposition centers shifted globally from open marine high latitude regions to upwelling areas. We here discuss how the onset of North Pacific stratification at ~2.7 Ma BP may have caused leakage of nutrient‐rich deep/intermediate North Pacific water into the Bering Sea via the deep Kamtchatka Strait, leading to increased opal deposition—and likely reactive organic matter export—at Bowers Ridge. As a result, magnetic and geochemical records were overprinted by intensified diagenesis, significantly affecting their applications as paleoceanographic proxies.

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Proceedings of the Ocean Drilling Program, 145 Scientific Results

Cited by 17 publications

References 0 publications

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Untitled

Gulf of Alaska continental slope morphology: Evidence for recent trough mouth fan formation

Nutrient leakage from the North Pacific to the Bering Sea (IODP Site U1341) following the onset of Northern Hemispheric Glaciation?

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