Climatological, Implications of Microparticle Concentrations in the Ice Core From “Byrd” Station, Western Antarctica

Thompson, Lonnie G.; Hamilton, Wayne L.; Bull, C.

doi:10.3189/s0022143000021948

Cited by 26 publications

(30 citation statements)

References 15 publications

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“…The detection of stable oxygen-isotope or micro particle variations (Johnsen and others, 1972;Thompson and others, 1975) requires that the snow of a particular season be present. The oxygen-isotope method may require, for example, that each summer snow layer be present.…”

Section: Discussionmentioning

confidence: 99%

Surface Mass-Balance Variability Near “Byrd” Station, Antarctica, and its Importance to Ice Core Stratigraphy

Whillans

1978

J. Glaciol.

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ABSTRACT. The local variability in surface mass bal a n ce (net snow accumulation) up-glacie r from " Byrd" station, Antarctica, is due to the combined effects of year-to-year " climate" variations and of th e surface microrelief due to snow drifts and sastrugi. These variabilities are consistent with the variability in surface mass balance obtained from core str atigraphy (Gow, 1968), a nd are used in a discussion of the difficulties encountered with the deep " Byrd " station core in detecting annual layering by the stable oxygen-isotope ratio and thc microparticle concentration techniques. The recognition of annual layers by these techniques req uires tha t the snows of certain seasons be present in the measured section, but near "Byrd" station the microrelief is su c h that summer snow layers a re not horizontally con tinuous and may be absent from a given section . At other sites on ice sheets, where the mi crorelief is less (less wind acti vity) or where the surface mass ba lance is large r, or both, less difficulty is a nti cipated in using the stable oxygen-isotope ratio and microp a rticle-concentration techniques to identify annual layers.R ESUME. Variabilile des bilalzs sup erjiciels pres de la station "Byrd" en Anlarctique et SOIl importance pour le stratigraphie des carot/es. La varia bilite locale des bilans supe rficiels (accumulation nette de neige) du gl acier superieur d e la station " Byrd" dans I' Antarctique est due it I'effet com bine d es variations du " climat" d'une annee a l'autre e t du mi cro-relief superficiel engendre par les congeres et les zastrougi . Ces variabilites sont coherentes avec la variabili te d ans les bilans superficiels obtenus par stratigraphie des carottes prelevees (Gow, 1968) ; o n les utilise pour discuter les difficultes re ncon trees dans les carottes profondes d e station " Byrd " pour detecter la stratifi ca tion a nnuelle par les techniques de la te ne ur e n oxygene stable isotopique et de la concentration en micropa rticul es. La reconnaissance des couch es a nnuelles par ces techniques necessite que les neiges de certa in es saisons soient reelle m en t presentes da ns la section mesuree, m a is pres de la station " Byrd ", le microrelief es t tel que les couches de neige de I'e te ne son t pas con tinues horizontalemen t et peuvent e tl"e a bsentes de certa ins points. Sur d'autres sites de calottes glaciaires dont le mic ro relief est moindre (moindre activite du vent) ou dont le bilan superficiel est plus fort, o u les deux , o n escompte moins d e difficultes pour utiliser les techniques de la teneur e n oxygene isotopique stable ou de la concentration en microparticul es pour identifier les couches a nnuelles.ZUSAMMENFASSUNG. Schwankungell der Massenbilan z all der Oberjliiche bei der "Byrd"-Station, Alltarktika. Die lokal en Schwankungen der Massenbilanz (Netto-Schneeakkumulation) an d er OberAache gl e tsch e ra ufwarts von der " Byrd " -Station, Antarktis, werden durch die kom binierte Wirkung von ja hrlichen Klimaunterschieden und der Schneedrif...

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Section: Discussionmentioning

confidence: 99%

Surface Mass-Balance Variability Near “Byrd” Station, Antarctica, and its Importance to Ice Core Stratigraphy

Whillans

1978

J. Glaciol.

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“…by identification of total ~-activity reference horizons. This is undoubtedly what Thompson and others (1975) have in mind, when stating on p. 441: "In the 1973-74 Antarctic field season one of us (L.C.T.) collected samples for microparticle analysis from areas near 'Byrd' station where the snow stratigraphy and chronology are well known".…”

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“…We feel this problem should b e solved prior to discussing flow patterns or time scales based on any interpretation of dust profiles. It is true that there is some degree of similarity between the dust and 8( IB O ) variations in (according to Johnsen and others, 1972 ) a 15500 year old increm ent (Thompson and others, 1975, fig. I ), but it is difficult to accept as "strong presumptive evidence", because the 8 oscillation is short and obviously atypical, while the dust profile is disturbed by numerous volcanic ash bands.…”

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“…Furthermore, Marshall ( 1962 ) suggested seasonal dust variations at 2 I m d epth, but he analysed only 0.65 m of firn comprising two annual layers as determined by visual stratigraphy observations. And, tru e enough, if seasonal dust variations are recognizable at Pole of Relative Inaccessibility, they may also b e so at "Byrd" that has twice as much accumulation; on the other hand, the meteorological regimes at the two stations are quite different , and midway between them, at the South Pole, "there are difficulties in determining the annual layering" (Thompson and others, 1975) , may be because the fall-out in this area (and at "Byrd"?) simply does not vary r egularly with the seasons in an interpretable way.…”

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Microparticles in “Byrd” station ice core: further comments on the paper by L. G. Thompson, W. L. Hamilton and C. Bull

Johnsen¹,

Hammer²,

Reeh³

et al. 1977

J. Glaciol.

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Once again, we agree with some of the viewpoints put forward by Thompson and others ( 1977). For example, we agree that the ice flow in the "Byrd" area must be of quite unusual character if the layer thicknesses claimed were true. Also we agree that detection of seasonal variations in the microparticle concentration in an ice core is not just a matter of increasing the sampling frequ ency. The appropriate sampling frequ ency must in any given case depend upon the signal-to-noise ratio. Using the minimum of 3 or 4 samples per annual layer is justified only in high accumulation areas with particularly favourable wind, fall-out and d eposition conditions.In our opinion, the authors' new figure I (above) suggests that this does not hold true for the "Byrd" area. In fact, it stresses the authors' statement that "conclusive proof is lacking that the short-period variations in micropartide concentration are annual". We feel this problem should b e solved prior to discussing flow patterns or time scales based on any interpretation of dust profiles. It is true that there is some degree of similarity between the dust and 8( IB O ) variations in (according to Johnsen and others, 1972 ) a 15500 year old increm ent (Thompson and others, 1975, fig. I ), but it is difficult to accept as "strong presumptive evidence", because the 8 oscillation is short and obviously atypical, while the dust profile is disturbed by numerous volcanic ash bands. Furthermore, Marshall ( 1962 ) suggested seasonal dust variations at 2 I m d epth, but he analysed only 0.65 m of firn comprising two annual layers as determined by visual stratigraphy observations. And, tru e enough, if seasonal dust variations are recognizable at Pole of Relative Inaccessibility, they may also b e so at "Byrd" that has twice as much accumulation; on the other hand, the meteorological regimes at the two stations are quite different , and midway between them, at the South Pole, "there are difficulties in determining the annual layering" (Thompson and others, 1975) , may be because the fall-out in this area (and at "Byrd"?) simply does not vary r egularly with the seasons in an interpretable way.H ence, we consider a feasibility study as particularly important in areas like "Byrd", closer to active volcanoes than to potential sources of continental dust. Marshall's excellent pilot study should be followed up by measuring a detailed dust-concentration profile through th e upper firn from the surface down to strata that can b e safely dated, e.g. by identification of total ~-activity reference horizons. This is undoubtedly what Thompson and others (1975) have in mind, when stating on p. 441: "In the 1973-74 Antarctic field season one of us (L.C.T.) collected samples for microparticle analysis from areas near 'Byrd' station where the snow stratigraphy and chronology are well known". In several respects these analyses will render much more information than the new figure I above.Finally, a short remark about matching the Camp Century and "Byrd" time scales. The technique used ...

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“…Moreover, grain size and mineral composition of IM are often applied for source discrimination. Thompson et al [8] found that grain size distributions of IM can dis-tinguish the origin of regional and global dust. Studies on the mineral composition in Vostok ice cores suggested that southern Australia dust sources have been of major importance, indicating that the Vostok glacial areas might have been affected by air masses differently from other Antarctic regions [9].…”

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Magnetic characteristics of insoluble microparticles in ice core (Nojingkangsang) from the southern Tibetan Plateau and its environmental significance

Duan

Gao

Liu

et al. 2011

Sci. China Earth Sci.

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Insoluble microparticles in ice cores are related closely to the transportation of eolian dust, and thus are important natural media to reconstruct climate change. In this study, we conducted a systematic mineral-magnetic investigation of insoluble microparticles in the Nojingkangsang ice core (29°2.1′N, 90°11.88′E, 5950 m) from the Southern Tibetan Plateau. Results indicate that the dominant magnetic mineral is magnetite, and its concentration has grown significantly since the 1980s, which coincides with trends in climate warming of the Tibetan Plateau. Influenced by regional warming, the glacial recession around Nojingkangsang shortens the distance between the dust source and glacial areas and thus increases the concentration of coarse-grained magnetic minerals in ice cores. However, the frequency of dust storms, associated with annual precipitation, could play only a regulatory role on the magnetic content over yearly (or seasonal) time scales. Therefore, using a new approach, the magnetic index of insoluble microparticles in ice cores of this region is seen as mainly reflecting trends in climate warming. Nojingkangsang, insoluble microparticles, rock magnetism, SIRM, climate warming Citation:Duan Z Q, Gao X, Liu Q S, et al. Magnetic characteristics of insoluble microparticles in ice core (Nojingkangsang) from the southern Tibetan Plateau and its environmental significance.

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Climatological, Implications of Microparticle Concentrations in the Ice Core From “Byrd” Station, Western Antarctica

Cited by 26 publications

References 15 publications

Surface Mass-Balance Variability Near “Byrd” Station, Antarctica, and its Importance to Ice Core Stratigraphy

Surface Mass-Balance Variability Near “Byrd” Station, Antarctica, and its Importance to Ice Core Stratigraphy

Microparticles in “Byrd” station ice core: further comments on the paper by L. G. Thompson, W. L. Hamilton and C. Bull

Magnetic characteristics of insoluble microparticles in ice core (Nojingkangsang) from the southern Tibetan Plateau and its environmental significance

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