Radiocarbon dating marine sediments

Posted by / 25-Nov-2017 01:43

Statistical analysis on an a posteriori design indicates that geographic area is the major cause of variability; there is a difference in mean surface sediment age of nearly 2000 yr between sites in the western Ross Sea and sites east of Ross Bank in south-central Ross Sea. The systematic variability in surface age between areas may be attributed to: (a) variable sediment accumulation rates (SAR) (surface age is inversely related to SAR), (b) differences in the percentage of reworked (dead) carbon between each area, and/or (c) differences in the CO2 exchange between the ocean and the atmosphere.

The systematic variability in surface age between areas may be attributed to: (a) variable sediment accumulation rates (SAR) (surface age is inversely related to SAR), (b) differences in the percentage of reworked (dead) carbon between each area, and/or (c) differences in the COTY - JOURT1 - Problems and possible solutions concerning radiocarbon dating of surface marine sediments, Ross Sea, Antarctica AU - Andrews, John T. AB - Radiocarbon accelerator mass spectrometric (AMS) dates on the acid-insoluble fraction from 38 core tops from the western Ross Sea, Antarctica, are used to address these questions: (1) What are the apparent ages of sediments at or close to the present sediment/water interface?

Until recently, there were no radiocarbon dates from late Quaternary sediments of this location.

Eight samples from the Ulleung Basin cores were accelerator mass spectrometry (AMS) -values as 400 yr.

Chironomids, leaves produce the most consistent results.

Sedimentological and physical properties of the core suggest that three meltwater events with high sedimentation rates are superimposed on a long-term trend with glacier retreat between 97 cal BP.

Radiocarbon accelerator mass spectrometric (AMS) dates on the acid-insoluble fraction from 38 core tops from the western Ross Sea, Antarctica, are used to address these questions: (1) What are the apparent ages of sediments at or close to the present sediment/water interface? PY - 1999/9Y1 - 1999/9N2 - Radiocarbon accelerator mass spectrometric (AMS) dates on the acid-insoluble fraction from 38 core tops from the western Ross Sea, Antarctica, are used to address these questions: (1) What are the apparent ages of sediments at or close to the present sediment/water interface?

The timing and duration of Holocene environmental changes is estimated using 38 AMS radiocarbon dates on terrestrial macrofossils, insects and chironomids covering the time period from 9750 to 1180 cal BP.

As part of a wider paleoclimate and paleoceanographic study of Holocene–upper Pleistocene laminated sediments from the eastern equatorial Pacific and Peru continental margin, we completed 32 accelerator mass spectrometry (AMS) C dates from cores recovered during Ocean Drilling Program (ODP) Leg 201.

Sample preparation and measurement were carried out at the ANTARES AMS facility, Australian Nuclear Science and Technology Organisation (ANSTO), in Sydney, Australia (Lawson et al., 2000; Fink et al., 2004).

Two different trends can be seen in the tree ring series.

First, there is a long-term oscillation with a period of about 9,000 years, which causes radiocarbon dates to be older than true dates for the last 2,000 years and too young before that.

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Ages of core top sediments range from 2000 to 21,000 14C yr B. Some 'old' core top dates are from piston cores and probably represent the loss of sediment during the coring process, but some core top samples 6000 14C yr B. Statistical analysis on an a posteriori design indicates that geographic area is the major cause of variability; there is a difference in mean surface sediment age of nearly 2000 yr between sites in the western Ross Sea and sites east of Ross Bank in south-central Ross Sea.

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