| PALEOLIMNOLOGY |
A record of climate over the last millennium based on varved lake sediments from the Canadian High Arctic.
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Besonen, M.R.,Patridge, W.,Bradley, R.S.,Francus, P.,Stoner, J.S.,Abbott, M.B. 2008 A record of climate over the last millennium
based on varved lake sediments from the Canadian High Arctic. The Holocene Vol. 18, No. 1, pp. 169-180.
| Data Coverage |
North: 81.3333 * South: 81.3333 |
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West: -69.5 * East: -69.5 |
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Altitude: 106 m |
Start Year: 1013 cal yr BP * End Year: 2004 cal yr BP
Data: Please Cite Data Contributors!
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Summary: A varved sediment record that extends back over the last millennium
was recovered from Lower Murray Lake, northern Ellesmere Island,
Nunavut, Canada (81°20'N, 69°30'W). Flatbed scan images and
backscattered electron images were analysed to provide varve
thickness and other quantitative sedimentary indices on an annual
basis. In many studies of lakes from the High Arctic, varve
thickness is a good proxy for summer temperature and we interpret
the Lower Murray Lake varves in this way. On that basis, the Lower
Murray Lake varve thickness record suggests that summer temperatures
in recent decades were among the warmest of the last millennium,
comparable with conditions that last occurred in the early twelfth
and late thirteenth centuries, but estimates based on the sediment
accumulation rate do not show such a recent increase. The coldest
conditions of the 'Little Ice Age' were experienced from ~AD 1700
to the mid-nineteenth century, when extensive ice cover on the lake
led to widespread anoxic conditions in the deepest parts of the
lake basin. An overall decline in median grain size over the last
1000 years indicates a reduction in the energy available to
transport sediment to the lake. Many of these features of the
record are also observed in other palaeoclimatic records from
the North American Arctic. The very recent appearance of the
diatom Campylodiscus, which was not observed throughout the
record of the last millennium, suggests that a new threshold
in the ontogenetic development of the lake has now been passed.
More Info on Paleolimnology |
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Complete XML Record: noaa-lake-6190
(Last Revised: 2009-02-11 )
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DOC/NOAA/NESDIS/NCDC (National Climatic Data Center, NESDIS, NOAA, U.S. Department of Commerce )
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| http://www.ncdc.noaa.gov/paleo/ |
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