Pliocene Climatic and Glacial History of Antarctica As Revealed by Southeast Indian Ocean Deep-Sea Cores

Blank, Richard G.; Margolis, Stanley V.

doi:10.1130/0016-7606(1975)86<1058:pcagho>2.0.co;2

Cited by 28 publications

(11 citation statements)

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“…Such a setting is likely for that time. A greater influx of ice-rafted debris into the oceans at this time has also been found in the southwest Atlantic Ocean (Bornhold, 1983) and in the southeast Indian Ocean (Blank and Margolis, 1975). …”

Section: Early Pliocene To Late Pliocene Transitionmentioning

confidence: 95%

Late Miocene to Holocene Glacial History of East Antarctica as Revealed by Sediments from Sites 745 and 746

Ehrmann¹,

Grobe²,

Fütterer³

1991

Proceedings of the Ocean Drilling Program

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The sediments recovered at ODP Sites 745 and 746 in the Australian-Antarctic Basin are characterized by cyclic fades changes between clayey diatom oozes and diatomaceous clays ranging in age from late Miocene (about 10 Ma) to Quaternary.The gravel and terrigenous sand content of the sediments is used as an indicator of the intensity of ice rafting through time. Maxima are recorded at 8.7-7.9, 6.6-6.0, 5.0-4.4, and 4.0-3.2 Ma. The maxima in more recent times are much less pronounced and occur at 2.4-1.6 and 1.4-1.0 Ma. All sand-and gravel-sized terrigenous sediment particles are of gneissic or granitic origin and originated from the East Antarctic continent. The maxima of ice rafting recorded at Sites 745 and 746 do not appear to represent local phenomena. Rather they document major advances and decays of the Antarctic ice shelves and glaciers and therefore represent events of great importance for the reconstruction of the paleoceanography of the Southern Ocean and the glacial history of Antarctica. In general, ice rafting was pronounced in the late Miocene and early Pliocene epochs, which are characterized by repeated ice advances and retreats. Ice rafting was less intensive during the late Pliocene to Quaternary time period, when ice shelves remained relative stable.The clay minerals indicate the fluctuating influence of different source areas on the delivery of fine-grained terrigenous sediment components. Part of this material may have been delivered from the Permian Amery Formation or from equivalents of this formation.

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Section: Early Pliocene To Late Pliocene Transitionmentioning

confidence: 95%

Late Miocene to Holocene Glacial History of East Antarctica as Revealed by Sediments from Sites 745 and 746

Ehrmann¹,

Grobe²,

Fütterer³

1991

Proceedings of the Ocean Drilling Program

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“…Although ice-rafted sediment has all grain-size classes represented in roughly equal parts, most studies have used only the concentration of terrigenous sand or gravel as a measure of the ice-rafting intensity (e.g., Blank and Margolis, 1975;Bornhold, 1983;Grobe, 1986). The clay and silt fractions of sediments are not commonly used as an indicator of ice rafting, because this material could also originate from other sources, such as wind transport, turbidity currents, and bottom currents and because they are prone to postdepositional redistribution by current activity.…”

Section: Ice Rafting On Southern Kerguelen Plateaumentioning

confidence: 99%

Implications of Sediment Composition on the Southern Kerguelen Plateau for Paleoclimate and Depositional Environment

Ehrmann¹

1991

Proceedings of the Ocean Drilling Program

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Cretaceous to Quaternary sediments recovered at Leg 119 Sites 738 and 744 on the southern tip of the Kerguelen Plateau were studied in order to determine the depositional environment and the paleoceanography of the southern Indian Ocean and especially the long-term glacial history of East Antarctica. Emphasis is given to bulk-sediment composition, grain-size data, and clay mineralogy.The sediment sequence at the two sites is generally of a highly pelagic character, with nannofossil oozes, chalks, and limestones dominant from the Turanian to upper Miocene and diatom oozes dominant within the uppermost Miocene to Holocene interval.The first indication of glaciation at sea level is the occurrence of isolated gravel and terrigenous sand grains, which indicate ice rafting in the middle Eocene interval of 45.0-42.3 Ma. A major intensification of glaciation, probably the onset of continental East Antarctic glaciation, is recorded in sediments of early Oligocene age (36.0 Ma). All major sediment parameters document this event. The clay mineralogy changes from smectite-dominated assemblages, typical of moderately warm and humid climatic conditions in which chemical weathering processes are prevalent, to illite-and chlorite-dominated assemblages, indicative of cooler climates and physical weathering. Ice-rafted debris of both gravel and sand size occurs in large quantities in that interval and coincides with a change in the mode of carbonate deposition. Carbonate contents are relatively high and uniform (90%-95%) in strata younger than early Oligocene; in Oligocene to upper Miocene strata they fluctuate between 65% and 95%.Oligocene and Neogene hiatuses reflect an intensification of oceanic circulation and the increased erosional force of Circumpolar Deep Water. The long-term Cenozoic cooling trend was interrupted by a phase of early Miocene warming indicated by maximum Neogene smectite concentrations. Although ice-rafted debris is present only in minor amounts and mainly in the silt fraction of early Oligocene to late Miocene age, it shows that glaciers advanced to the East Antarctic shoreline throughout that time. Ice-rafting activity drastically increased in latest Miocene time, when carbonate deposition decreased and diatom ooze sedimentation started. This suggests a pronounced intensification of Antarctic glaciation combined with a northward migration of the Polar Front.

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“…Based on stable isotopic records, Shackleton and Kennett (1975) suggested that a cooling trend occurred in the Southern Hemisphere during this time period. However, the Blank and Margolis (1975, fig. 6) study of Southeast Indian Ocean cores suggested that a fairly warm climatic trend occurred from the Gauss through early Matuyama (3.4-0.8 Ma).…”

Section: Late Pliocenementioning

confidence: 99%

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

James¹

1992

Proceedings of the Ocean Drilling Program

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Pliocene Climatic and Glacial History of Antarctica As Revealed by Southeast Indian Ocean Deep-Sea Cores

Cited by 28 publications

References 0 publications

Late Miocene to Holocene Glacial History of East Antarctica as Revealed by Sediments from Sites 745 and 746

Late Miocene to Holocene Glacial History of East Antarctica as Revealed by Sediments from Sites 745 and 746

Implications of Sediment Composition on the Southern Kerguelen Plateau for Paleoclimate and Depositional Environment

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

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