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| 100 | _a20170817a2017 k y0engy50 ba | ||
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| 102 | _aDE | ||
| 135 | _adrcn ---uucaa | ||
| 181 | 0 | _ai | |
| 182 | 0 | _ab | |
| 200 | 1 |
_aThe 3.6 ka Aniakchak tephra in the Arctic Ocean: a constraint onthe Holocene radiocarbon reservoir age in the Chukchi Sea _fC. Pearce [et al.] |
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| 203 |
_aText _celectronic |
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| 300 | _aTitle screen | ||
| 320 | _a[References: p. 313-316] | ||
| 330 | _aThe caldera-forming eruption of the Aniakchak volcano in the Aleutian Range on the Alaskan Peninsula at 3.6 cal kyr BP was one of the largest Holocene eruptions worldwide. The resulting ash is found as a visible sediment layer in several Alaskan sites and as a cryptotephra on Newfoundland and Greenland. This large geographic distribution, combined with the fact that the eruption is relatively well constrained in time using radiocarbon dating of lake sediments and annual layer counts in ice cores, makes it an excellent stratigraphic marker for dating and correlating mid-late Holocene sediment and paleoclimate records. This study presents the outcome of a targeted search for the Aniakchak tephra in a marine sediment core from the Arctic Ocean, namely Core SWERUS-L2-2-PC1 (2PC), raised from 57 m water depth in Herald Canyon, western Chukchi Sea. High concentrations of tephra shards, with a geochemical signature matching that of Aniakchak ash, were observed across a more than 1.5 m long sediment sequence. Since the primary input of volcanic ash is through atmospheric transport, and assuming that bioturbation can account for mixing up to ca. 10 cm of the marine sediment deposited at the coring site, the broad signal is interpreted as sustained reworking at the sediment source input. | ||
| 330 | _aThe isochron is therefore placed at the base of the sudden increase in tephra concentrations rather than at the maximum concentration. This interpretation of major reworking is strengthened by analysis of grain size distribution which points to ice rafting as an important secondary transport mechanism of volcanic ash. Combined with radiocarbon dates on mollusks in the same sediment core, the volcanic marker is used to calculate a marine radiocarbon reservoir age offset ΔR = 477 ± 60 years. This relatively high value may be explained by the major influence of typically "carbon-old" Pacific waters, and it agrees well with recent estimates of ΔR along the northwest Alaskan coast, possibly indicating stable oceanographic conditions during the second half of the Holocene. Our use of a volcanic absolute age marker to obtain the marine reservoir age offset is the first of its kind in the Arctic Ocean and provides an important framework for improving chronologies and correlating marine sediment archives in this region. Core 2PC has a high sediment accumulation rate averaging 200 cm kyr−1 throughout the last 4000 years, and the chronology presented here provides a solid base for high-resolution reconstructions of late Holocene climate and ocean variability in the Chukchi Sea. | ||
| 461 |
_tClimate of the Past _ointernational scientific journal _d2005- |
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| 463 |
_tVol. 13, iss. 4 _v[P. 303-316] _d2017 |
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| 610 | 1 | _aэлектронный ресурс | |
| 610 | 1 | _aтруды учёных ТПУ | |
| 610 | 1 | _aАнякчак | |
| 610 | 1 | _aСеверный Ледовитый океан | |
| 610 | 1 | _aЧукотское море | |
| 610 | 1 | _aголоцен | |
| 610 | 1 | _aрезервуары | |
| 610 | 1 | _aрадиоуглерод | |
| 701 | 1 |
_aPearce _bC. _gChristof |
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| 701 | 1 |
_aVarhelyi _bA. _gAron |
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| 701 | 1 |
_aWastegеrd _bS. _gStefan |
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| 701 | 1 |
_aMuschitiello _bF. _gFrancesco |
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| 701 | 1 |
_aBarrientos _bN. _gNatalia |
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| 701 | 1 |
_aO’Regan _bM. _gMatt |
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| 701 | 1 |
_aCronin _bT. M. _gThomas M. |
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| 701 | 1 |
_aGemery _bL. _gLaura |
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| 701 | 1 |
_aSemiletov _bI. P. _cgeographer _cProfessor of Tomsk Polytechnic University, doctor of geographical Sciences _f1955- _gIgor Petrovich _2stltpush _3(RuTPU)RU\TPU\pers\34220 |
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| 701 | 1 |
_aBackman _bJ. _gJan |
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| 701 | 1 |
_aJakobsson _bM. _gMartin |
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| 712 | 0 | 2 |
_aНациональный исследовательский Томский политехнический университет (ТПУ) _bИнститут природных ресурсов (ИПР) _bКафедра геологии и разведки полезных ископаемых (ГРПИ) _h2181 _2stltpush _3(RuTPU)RU\TPU\col\18660 |
| 801 | 2 |
_aRU _b63413507 _c20170817 _gRCR |
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| 856 | 4 | _uhttp://dx.doi.org/10.5194/cp-13-303-2017 | |
| 942 | _cCF | ||