Holocene floodplain lake sediments in the Amazon: 14C dating and palaeoecological use

We have developed and tested a practical device for manually separating pollen from pollen concentrates in sufficient quantity for AMS 14C dating. It is a combination of standard, commercially available equipment handled in a clean room by an individual trained to recognize pollen. A typical example requires about 15–20 h of hand-picking under the microscope. We show the usefulness of this procedure with results on a mid-Holocene segment from a core from Mono Lake. Sediments from this hardwater lake contain pollen and finely disseminated organic matter, but no macrofossils. The pollen dated ca. 1000 yr younger than the bulk sediment. The sediment “date” is most likely affected by incorporation of limestone-derived carbon, and is erroneously old.

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Evaluation of the Siltation of River Taquari, Pantanal, Brazil, through 210Pb Geochronology of Floodplain Lake Sediments

Journal of the Brazilian Chemical Society ◽

10.1590/s0103-50532002000100011 ◽

2002 ◽

Vol 13 (1) ◽

pp. 71-77 ◽

Cited By ~ 16

Author(s):

José M. Godoy ◽

Carlos R. Padovani ◽

Jean R. D. Guimarães ◽

José C. A. Pereira ◽

Luis M. Vieira ◽

...

Keyword(s):

Lake Sediments ◽

Floodplain Lake ◽

210Pb Geochronology

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The use of chironomid remains for AMS 14C dating of lake sediments

The Holocene ◽

10.1177/095968369300300207 ◽

1993 ◽

Vol 3 (2) ◽

pp. 161-163 ◽

Cited By ~ 11

Author(s):

V.J. Jones ◽

R.W. Battarbee ◽

R.E.M. Hedges

Keyword(s):

Lake Sediments ◽

14C Dating ◽

Ams 14C Dating

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Responses of benthic invertebrates to combined toxicant and food input in floodplain lake sediments

Environmental Toxicology and Chemistry ◽

10.1002/etc.5620211020 ◽

2002 ◽

Vol 21 (10) ◽

pp. 2165-2171 ◽

Cited By ~ 30

Author(s):

Elske M. De Haas ◽

Bas Reuvers ◽

Caroline T. A. Moermond ◽

Albert A. Koelmans ◽

Michiel H. S. Kraak

Keyword(s):

Lake Sediments ◽

Benthic Invertebrates ◽

Floodplain Lake ◽

Food Input

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Comparing Varve Counting And 14C-Ams Chronologies In The Sediments Of Lake Żabińskie, Northeastern Poland: Implications For Accurate 14C Dating Of Lake Sediments

Geochronometria ◽

10.1515/geochr-2015-0019 ◽

2015 ◽

Vol 42 (1) ◽

Cited By ~ 15

Author(s):

Alicja Bonk ◽

Wojciech Tylmann ◽

Tomasz Goslar ◽

Agnieszka Wacnik ◽

Martin Grosjean

Keyword(s):

Lake Sediments ◽

Land Use Changes ◽

14C Dating ◽

Radiocarbon Age ◽

Varve Chronology ◽

Plant Remains ◽

Varved Lake Sediments ◽

Northeastern Poland ◽

The Difference

Abstract Varved lake sediments from Lake Zabihskie (northeastern Poland) provide a high- resolution calendar-year chronology which allows validation of 14C dating results. Microscopic analysis of the varve microfacies revealed that laminations found in Lake Zabihskie were biogenic (calcite) varves. Three independent counts indicated a good preservation quality of laminae in the 348 cm long sediment profile which contained 1000+12/-24 varves. The varve chronology was validated with the 137Cs activity peaks, the tephra horizon from the Askja eruption at AD 1875 and with the timing of major land-use changes of known age inferred from pollen analysis. 32 AMS 14C dates of terrestrial macrofossils distributed along the profile were compared with the varve chronology. After identification of outliers, the free-shape model performed with 21 14C dates provided the best possible fit with the varve chronology. We observed almost ideal consistency between both chronologies from the present until AD 1250 while in the lower part (AD 1000-1250) the difference increases to ca. 25 years. We demonstrate that this offset can be explained by too old radiocarbon ages of plant remains transported to the lake by the inflowing creek. Results of this study highlight that careful interpretation of radiocarbon age-depth models is necessary, especially in lakes where no annual laminations are observed and no independent method are used for cross-validation.

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