Beryllium isotopes in sediments from Lake Maruwan Oike and Lake Skallen, East Antarctica, reveal substantial glacial discharge during the late Holocene

Abstract. We determined the mean crustal uplifting rate during the late Holocene along the Soya Coast, Lützow-Holm Bay, East Antarctica, by dating a marine-lacustrine transition recorded in lake sediments. We focused on temporal variations in the chemical composition of sediments recovered from Lake Skallen Oike at Skallen and Lake Oyako at Skarvsnes. Both sets of lake sediments record environmental changes associated with a transition from marine to lacustrine (fresh water) settings, as indicated by analyses of sedimentary facies for carbon and nitrogen contents, nitrogen isotopic compositions (15N/14N), and major element concentrations. Changes in the dominant primary producers during the marine-lacustrine transition were also clearly revealed by biogenic Opal-A, diatom assemblages, and gradient gel electrophoresis (DGGE) with 16S rRNA gene analysis. Geochronology based on radiocarbon dating of acid-insoluble organic carbon suggested that the environmental transition from saline to fresh water occurred at 2940±100 cal yr BP at L. Skallen and 1060±90 cal yr BP at L. Oyako. Based on these data and a linear approximation model, we estimated a mean crustal uplifting rate of 3.6 mm yr−1 for the period since the marine-lacustrine transition via brackish condition; this uplift is attributed to glacial-isostatic rebound along the Soya Coast. The geological setting was the primary factor in controlling the emergence event and the occurrence of simultaneous changes in sedimentary and biological facies along the zone of crustal uplift.

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Holocene glacial discharge fluctuations and recent instability in East Antarctica

Earth and Planetary Science Letters ◽

10.1016/j.epsl.2014.03.009 ◽

2014 ◽

Vol 394 ◽

pp. 38-47 ◽

Cited By ~ 15

Author(s):

Julien Crespin ◽

Ruth Yam ◽

Xavier Crosta ◽

Guillaume Massé ◽

Sabine Schmidt ◽

...

Keyword(s):

East Antarctica ◽

Discharge Fluctuations ◽

Glacial Discharge

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Iron in ice cores from Law Dome, East Antarctica: implications for past deposition of aerosol iron

Annals of Glaciology ◽

10.3189/s0260305500017742 ◽

1998 ◽

Vol 27 ◽

pp. 365-370 ◽

Cited By ~ 24

Author(s):

R. Edwards ◽

P. N. Sedwick ◽

Vin Morgan ◽

C. F. Boutron ◽

S. Hong

Keyword(s):

Southern Ocean ◽

Late Holocene ◽

Ice Core ◽

Iron Concentration ◽

Ice Cores ◽

Snow Accumulation ◽

East Antarctica ◽

Iron Deposition ◽

Past Century ◽

Preliminary Estimate

Total-dissolvable iron has been measured in sections of three ice cores from Law Dome, East Antarctica, and the results used to calculate atmospheric iron deposition over this region during the late Holocene and to provide a preliminary estimate of aerosol iron deposition during the Last Glaciol Maximum I LGM). Ice-core sections dating from 56-2730 BP (late Holocene) and ~18000 BP (LGM) were decontaminated using trace-metal clean techniques, and total-dissolvable iron was determined in the acidified meltwatcrs by flow-injection analysis. Our results suggest that the atmospheric iron flux onto the Law Dome region has varied significantly over time-scales ranging from seasonal to Glaciol-interglaciol. The iron concentrations in ice-core sections from the past century suggest (1) a 2 4-fold variation in the atmospheric iron flux over a single annual cycle, with the highest flux occurring during the spring and summer, and (2) a nearly 7-fold variation in the annual maximum atmospheric iron flux over a 14 year period. The average estimated atmospheric iron flux calculated from our late-Holocene samples is 0.056-0.14 mg m a−1, which agrees well with Holocene flux estimates derived from aluminium measurements in inland Antarctic ice cores and a recent order-of-magnitude estimate of present-day atmospheric iron deposition over the Southern Ocean. The iron concentration of an ice-corc section dating from the LGM was more than 50 times higher than in the late-Holocene ice samples. Using a snow-accumulation rate estimate of 130 kg m −2 a−1 for this period, we calculate 0.87 mgm −2 a−1 as a preliminary estimate of atmospheric iron deposition during the LGM, which is 6-16 times greater than our average late-Holocene iron flux. Our data are consistent with the suggestion that there was a significantly greater flux of atmospheric iron onto the Southern Ocean during the LGM than during then Holocene.

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A geochemical study of marine sediments from the Mac. Robertson shelf, East Antarctica: initial results and palaeoenvironmental implications

Annals of Glaciology ◽

10.3189/1998aog27-1-268-274 ◽

1998 ◽

Vol 27 ◽

pp. 268-274 ◽

Cited By ~ 7

Author(s):

P. N. Sedwick ◽

P.T. Harris ◽

L. G. Robertson ◽

G. M. Mcmurtry ◽

M. D. Cremer ◽

...

Keyword(s):

Organic Carbon ◽

Late Holocene ◽

Sediment Accumulation ◽

Transport Processes ◽

East Antarctica ◽

Outer Shelf ◽

Geochemical Data ◽

Accumulation Rates ◽

Inner Shelf ◽

The Holocene

Sediments from the Antarctic continental margin may provide detailed palaeoenvironmental records for Antarctic shelf waters during the late Quaternary. Here we present results from a palaeoenvironmental study of two sediment cores recovered from the continental shelf off Mac. Robertson Land, East Antarctica. These gravity cores were collected approximately 90 km apart from locations on the inner and outer shelf. Both cores are apparently undisturbed sequences of diatom ooze mixed with fine, quartz-rich sand. Core stratigraphies have been established from radiocarbon analyses of bulk organic carbon. Down-core geochemical determinations include the lithogenic components AÍ and Fe, biogenic components opal and organic carbon, and palaco-redox proxies Mn, Mo and U. We use the geochemical data to infer past variations in the deposition of biogenic and lithogenic materials, and the radiocarbon dates to estimate average sediment accumulation rates. The Holocene record of the outer-shelf core suggests three episodes of enhanced diatom export production at about 1.8, 3.8 and 5.5 ka BP, as well as less pronounced bloom episodes which occurred over a shorter period. Average sediment accumulation rates at this location range from 13.7 cm ka−1 in the late Pleistocene early Holocene to 82 cm ka−1 in the late Holocene, and suggest that the inferred episodes of enhanced biogenic production lasted 100-1000 years. in contrast, data for the inner-shelf core suggest that there has been a roughly constant proportion of biogenic and lithogenic material accumulating during the middle to late Holocene, with a greater proportion of biogenic material relative to the outer shelf. Notably, there is an approximately 7-fold increase in average sediment accumulation rate (from 24.5 to 179 cm ka−1) at this inner-shelf location between the middle and late Holocene, with roughly comparable increases in the mass accumulation rates of both biogenic and lithogenic material. This may represent changes in sediment transport processes, or reflect real increases in pelagic sedimentation in this region during the Holocene. Our results suggest quite different sedimentation regimes in these two shelf locations during the middle to late Holocene.

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Relative sea-level history from the Lambert Glacier region, East Antarctica, and its relation to deglaciation and Holocene glacier readvance

Quaternary Research ◽

10.1016/j.yqres.2004.09.005 ◽

2005 ◽

Vol 63 (1) ◽

pp. 45-52 ◽

Cited By ~ 49

Author(s):

Elie Verleyen ◽

Dominic A. Hodgson ◽

Glenn A. Milne ◽

Koen Sabbe ◽

Wim Vyverman

Keyword(s):

Sea Level ◽

Late Holocene ◽

East Antarctica ◽

Relative Sea Level ◽

Larsemann Hills ◽

Melting Event ◽

Ice Retreat ◽

Vestfold Hills ◽

A Site ◽

Lambert Glacier

We present a relative sea-level (RSL) history, constrained by AMS radiocarbon-dated marine–freshwater transitions in isolation basins from a site adjacent to the Lambert Glacier, East Antarctica. The RSL data suggest an initial ice retreat between c. 15,370 and 12,660 cal yr B.P Within this period, meltwater pulse IA (mwp IA, between c. 14,600–14,200 and 14,100–13,700 cal yr B.P.) occurred; an exceptionally large ice melting event, inferred from far-field sea-level records. The RSL curve shows a pronounced highstand of approximately 8 m between c. 7570–7270 and 7250–6950 cal yr B.P. that is consistent with the timing of the RSL highstand in the nearby Vestfold Hills. This is followed by a fall in RSL to the present. In contrast to previous findings, the isolation of the lakes in the Larsemann Hills postdates the isolation of lakes with similar sill heights in the Vestfold Hills. An increase in RSL fall during the late Holocene may record a decline in the rate of isostatic uplift in the Larsemann Hills between c. 7250–6950 and 2847–2509 cal yr B.P., that occurred in response to a documented mid-Holocene glacier readvance followed by a late-Holocene retreat.

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Glacial Crooked Lake, Vestfold Hills, East Antarctica

Polar Record ◽

10.1017/s0032247400027637 ◽

1996 ◽

Vol 32 (180) ◽

pp. 19-24 ◽

Cited By ~ 4

Author(s):

D.B. Gore ◽

J. Pickard ◽

A.S. Baird ◽

J.A. Webb

Keyword(s):

Lake Level ◽

Late Holocene ◽

East Antarctica ◽

Maximum Height ◽

Alluvial Fans ◽

Vestfold Hills

AbstractGlacial Crooked Lake was an ice-dammed impoundment in Vestfold Hills, East Antarctica, that had a volume of (250 ± 45) × 10 m. The impoundment is inferred to have existed during deglaciation following the Late Holocene Chelnok Advance of Sørsdal Glacier. The dam released water incrementally, allowing the formation of four major series of shorelines with a maximum height of 24 m above the current lake level of 22 m asl. Water from Glacial Crooked Lake overflowed into Watts Lake downstream, allowing saltwater there to mix, dilute, and be transported to the sea via Ellis Rapids. In this way water in Watts Lake became fresh, and alluvial fans consisting of cobbles and boulders formed below Crooked Lake and Ellis Rapids.

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