High-Resolution Study of Neogene Ice-Rafted Debris, Site 751, Southern Kerguelen Plateau

James, R. Breza

doi:10.2973/odp.proc.sr.120.136.1992

Cited by 16 publications

(9 citation statements)

References 22 publications

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“…A third factor is the latitude at which the icebergs melt and hence where the IRD is deposited. It is unlikely that the icebergs melted further north than Site 1165, because early Miocene IRD is found only in trace amounts at Site 744 (61.6°S) and not at all at Site 751 (57.7°S) on the Kerguelen Plateau to the northeast of Site 1165 [ Ehrmann and Grobe , 1991; Breza , 1992]. In the present day, icebergs generally travel westward parallel to the coast just to the south of Site 1165 under the influence of the Polar Current and the prevailing winds; it is possible that a weaker current during Facies 2 deposition allowed more icebergs to drift northward over the site than during Facies 1 deposition.…”

Section: Discussionmentioning

confidence: 99%

“…Site 274, west of the Ross Sea, contains IRD back to the Oligocene/Miocene boundary [ Piper and Brisco , 1975], and Site 693 on Maud Rise [ Grobe et al , 1990] and Site 744 on the southern Kerguelen Plateau [ Ehrmann , 1991] contain trace levels of IRD from the late Oligocene, but these sites do not have high enough sedimentation rates or core recovery to trace the detailed evolution of the IRD record through time. No IRD older than 10 Ma was found at Site 751, approximately 400 km north of Site 744 [ Breza , 1992]. In general, IRD appears earlier at sites which are closer to the continent, reflecting the location of iceberg melting, probably because sea surface temperatures fell and the polar front moved northward through time [ Handwerger and Jarrard , 2003].…”

Section: Introductionmentioning

confidence: 99%

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A high‐resolution record of early Miocene Antarctic glacial history from ODP Site 1165, Prydz Bay

Williams

Handwerger

2005

Paleoceanography

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[1] ODP Site 1165, located 400 km northwest of Prydz Bay, contains a high-resolution early Miocene record of pulses of ice-rafted debris (IRD) originating from the ancestral Lambert Glacier system and the Antarctic coast to the east. The 520 m of early Miocene sediments consist of dark gray claystone with silt laminae (contourites) alternating with decimeter-scale layers of greenish-gray bioturbated claystone that commonly contain ice-rafted debris. Downhole logs also record the alternations between the two facies: the IRD-bearing greenish-grey claystone corresponds to high resistivity and density values because of increased cementation by silica, and corresponds to lower natural gamma radiation values because of diluted clay content. The downhole logs thus allow a continuous and detailed stratigraphic record of the IRD-bearing layers to be obtained. The IRD-bearing layers represent deglaciations and interglacials, when a high flux of icebergs with incorporated material were melting out over the site; the contourite-rich layers represent glacials, when the Polar Current over the site was relatively strong. The sequence is dated by magnetostratigraphy, and the timing of the major IRD pulses is paced by orbital eccentricity, indicating that the volume of the East Antarctic ice sheet also fluctuates on this timescale. After 19.7 Ma, minor precessional and subprecessional IRD layers appear in the record, indicating that the ice sheet becomes more prone to deglaciation through this interval, perhaps associated with the gradual warming trend through the early Miocene.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A high‐resolution record of early Miocene Antarctic glacial history from ODP Site 1165, Prydz Bay

Williams

Handwerger

2005

Paleoceanography

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“…There is no consistent relationship between ice rafted debris (IRD) deposition and SST in early Pliocene strata from the Southern Ocean [ Bohaty and Harwood , 1998; Anderson , 1999]. IRD deposition was consistently high throughout the Southern Ocean ∼4.5 Ma to 4.2 Ma [ Hodell and Warnke , 1991; Breza , 1992]; a period that spans both warm and cool silicoflagellate events identified at Kerguelen Plateau Site 751 [ Bohaty and Harwood , 1998]. A warm event at Site 751, ∼3.7 Ma, is also associated with high IRD [ Bohaty and Harwood , 1998].…”

Section: Discussionmentioning

confidence: 99%

“…Iceberg calving can increase during both ice sheet growth and retreat. Calving, dispersal, and drift trajectory are also dependent on sea‐ice condition, ocean currents, and wind [ Anderson , 1986; Breza , 1992; Anderson , 1999]. Altered sediment deposition rates and erosion (i.e., winnowing) can also concentrate IRD [ Whitehead and McMinn , 2002], which may be misinterpreted as increased iceberg calving.…”

Section: Discussionmentioning

confidence: 99%

Pliocene summer sea surface temperature reconstruction using silicoflagellates from Southern Ocean ODP Site 1165

Whitehead

Bohaty

2003

Paleoceanography

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In the modern marine environment the silicoflagellate genus Dictyocha is rare, or absent, south of the Antarctic polar front (APF); the genus Distephanus, in contrast, is dominant. In sediments recovered from ODP Site 1165, 1600 km south of the front, however, three intervals where Dictyocha is abundant are interpreted to represent Pliocene warm events. Comparison of our data with Ciesielski and Weaver's [1974] modern core top silicoflagellate relationship with sea surface temperature (SST) indicates that at Site 1165 mean annual SST was approximately 5°C at 3.7 Ma (event I), and approximately 4°C at 4.3–4.4 Ma (event II) and 4.55–4.8 Ma (event III). Event I represents a 5.5°C warming, and events II and III represents a 4.5°C warming relative to modern mean annual SST. Dictyocha is absent from other Site 1165 Pliocene intervals, which suggests that cooler SST (<2°C) prevailed. The warm events detected at Site 1165 may represent times when North Atlantic Deep Water production and ocean heat transport into the Southern Ocean exerted maximum influence.

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“…A significant Antarctic iceberg calving event occurred at 36 Ma, depositing ice rafted debris (IRD) on the Kerguelen Plateau, ~1200 km north of Prydz Bay (Breza & Wise 1992). IRD deposition did not occur here again until the Late Miocene (Breza 1992).…”

Section: Late Eocene-early Oligocene Glacial Retreat and Marine Deposmentioning

confidence: 99%

A review of the Cenozoic stratigraphy and glacial history of the Lambert Graben—Prydz Bay region, East Antarctica

et al. 2006

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Abstract:The Cenozoic glacial history of East Antarctica is recorded in part by the stratigraphy of the Prydz Bay-Lambert Graben region. The glacigene strata and associated erosion surfaces record at least 10 intervals of glacial advance (with accompanying erosion and sediment compaction), and more than 17 intervals of glacial retreat (enabling open marine deposition in Prydz Bay and the Lambert Graben). The number of glacial advances and retreats is considerably less than would be expected from Milankovitch frequencies due to the incomplete stratigraphic record. Large advances of the Lambert Glacier caused progradation of the continental shelf edge. At times of extreme glacial retreat, marine conditions reached > 450 km inland from the modern ice shelf edge. This review presents a partial reconstruction of Cenozoic glacial extent within Prydz Bay and the Lambert Graben that can be compared to eustatic sea-level records from the southern Australian continental margin.

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High-Resolution Study of Neogene Ice-Rafted Debris, Site 751, Southern Kerguelen Plateau

Cited by 16 publications

References 22 publications

A high‐resolution record of early Miocene Antarctic glacial history from ODP Site 1165, Prydz Bay

A high‐resolution record of early Miocene Antarctic glacial history from ODP Site 1165, Prydz Bay

Pliocene summer sea surface temperature reconstruction using silicoflagellates from Southern Ocean ODP Site 1165

A review of the Cenozoic stratigraphy and glacial history of the Lambert Graben—Prydz Bay region, East Antarctica

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