skip to navigation
ADS Main Website
Help
|
Login
/
Browse by Series
/
Series
/ Journal Issue
Holocene 15 (2)
Title
The title of the publication or report
Title:
Holocene 15 (2)
Series
The series the publication or report is included in
Series:
The Holocene
Volume
Volume number and part
Volume:
15 (2)
Publication Type
The type of publication - report, monograph, journal article or chapter from a book
Publication Type:
Journal
Editor
The editor of the publication or report
Editor:
John A Matthews
Publisher
The publisher of the publication or report
Publisher:
Sage Publications
Year of Publication
The year the book, article or report was published
Year of Publication:
2005
Source
Where the record has come from or which dataset it was orginally included in.
Source:
BIAB (The British & Irish Archaeological Bibliography (BIAB))
Relations
Other resources which are relevant to this publication or report
Relations:
URI:
http://hol.sagepub.com/content/vol15/issue2/
Created Date
The date the record of the pubication was first entered
Created Date:
01 May 2007
Please click on an Article link to go to the Article Details.
Article Title
Access Type
Author / Editor
Page
Start/End
Abstract
The application of local and regional transfer functions to the reconstruction of Holocene sea levels, north Norfolk, England
Benjamin P Horton
R J Edwards
216 - 228
Foraminiferal assemblages from Thornham and Brancaster marshes (Norfolk) illustrate a statistically significant relationship with elevation with respect to the tidal frame. The authors develop local (data from Thornham and Brancaster marshes) and regional (data from Thornham and Brancaster marshes combined with those from eleven other sites around the UK) predictive foraminifera-based transfer functions to reconstruct former sea levels from a Holocene sediment sequence from Holkham, north Norfolk. The two transfer functions produce similar patterns of tidal elevation change during the Holocene. The vertical error ranges of the local transfer function are smaller than those of the regional transfer function, although the difference (0.09 m) is not significant when compared to other factors affecting the reconstructed elevation. The value of the reconstructed elevations also differ between the two transfer functions (by up to 0.43 m), and this is primarily due to the lack of modern analogues in the local transfer function. The authors conclude that the reconstructions derived from the regional transfer function are more reliable than those of the local transfer function, since the latter achieves its slight increase in precision at the expense of a significant decrease in predictive power. The regional transfer function is used to construct a relative sea-level curve from fossil assemblages within a sediment core from north Norfolk. These results are consistent with existing sea-level data and geophysical model predictions, and illustrate the utility of the foraminifera-based transfer function approach.
Reconstructing fire regimes with charcoal from small-hollow sediments: a calibration with tree-ring records of fire
Philip E Higuera
Douglas G Sprugel
Linda B Brubaker
238 - 251
The authors examined charcoal records in 210Pb-dated cores from twelve small hollows and looked for evidence of twenty local fires reconstructed with tree-ring records from the surrounding forest. Using all charcoal > 0.15 mm wide they established an optimum threshold that identified charcoal peaks corresponding to known fires while minimizing charcoal peaks identified that were not associated with known fires (i.e., false positives). This threshold detected four of four high-severity fires, five of ten moderate-severity fires, and three of six low-severity fires. Analysis of larger charcoal alone (> 0.50 mm wide) yielded nearly identical temporal patterns and detection rates, but four false positives were identified, twice as many as identified using all charcoal >0.15 mm wide. Charcoal peak magnitude was highly variable within severity classes: although half of the low-and moderate-severity fires left no detectable peaks, others left peaks larger than some high-severity fires. Our results suggest that fire detection depends strongly on fire severity and that fine-scale spatial patterns of lower-severity burns play an important role in determining the charcoal signature of these events. High detection rates for high-severity fires and low false-positive rates indicate that charcoal records from small hollows will be most useful in systems where fires are large, severe and infrequent.
Minimum count sums for charcoal concentration estimates in pollen slides: accuracy and potential errors
Walter Finsinger
Willy Tinner
293 - 297
Charcoal particles in pollen slides are often abundant, and thus analysts are faced with the problem of setting the minimum counting sum as small as possible in order to save time. The authors analysed the reliability of charcoal-concentration estimates based on different counting sums, using simulated low-to high-count samples. Bootstrap simulations indicate that the variability of inferred charcoal concentrations increases progressively with decreasing sums. Below 200 items (i.e., the sum of charcoal particles and exotic marker grains), reconstructed fire incidence is either too high or too low. Statistical comparisons show that the means of bootstrap simulations stabilize after 200 counts. Moreover, a count of 200--300 items is sufficient to produce a charcoal-concentration estimate with less than +5% error if compared with high-count samples of 1000 items for charcoal/marker grain ratios 0.1--0.91. If, however, this ratio is extremely high or low (> 0.91 or < 0.1) and if such samples are frequent, the authors suggest that marker grains are reduced or added prior to new sample processing.
An improved method for quantifying sedimentary charcoal via a volume proxy
Chengyu Weng
298 - 301
In charcoal analysis, number and area of charcoal particles are the most commonly measured parameters. However, neither measurement is precise as charcoal fragments can be broken into smaller pieces during preservation and laboratory processing, and then both number and apparent area will increase. It is argued that volume is a more reliable parameter than area to represent charcoal amount, and that although this is difficult to measure, a simple approximation provides a stable and reliable proxy estimate of charcoal volume. Empirical experiments demonstrate that volume estimates reduce the error induced by fragmentation or loss of tiny pieces during processing or measuring.
