Quantitative interpretation of fossil pollen spectra: Dissimilarity coefficients and the method of modern analogs

Jonathan Overpeck, T. Webb, I. C. Prentice

Research output: Contribution to journalArticle

692 Citations (Scopus)

Abstract

Dissimilarity coefficients measure the difference between multivariate samples and provide a quantitative aid to the identification of modern analogs for fossil pollen samples. How eight coefficients responded to differences among modern pollen samples from eastern North America was tested. These coefficients represent three different classes: (1) unweighted coefficients that are most strongly influenced by large-valued pollen types, (2) equal-weight coefficients that weight all pollen types equally but can be too sensitive to variations among rare types, and (3) signal0to-noise coefficients that are intermediate in their weighting of pollen types. The studies with modern pollen allowed definition of critical values for each coefficient, which, when not exceeded, indicate that two pollen samples originate from the same vegetation region. Dissimilarity coefficients were used to compare modern and fossil pollen samples, and modern samples so similar to fossil samples were found that most of three late Quaternary pollen diagrams could be "reconstructed" by substituting modern samples for fossil samples. When the coefficients indicated that the fossil spectra had no modern analogs, then the reconstructed diagrams did not match all aspects of the originals. No modern analogs existed for samples from before 9300 yr B.P. at Kirchner Marsh, Minnesota, and from before 11,000 yr B.P. at Wintergreen Lake, Michigan, but modern analogs existed for almost all Holocene samples from these two sites and Brandreth Bog. New York.

Original languageEnglish (US)
Pages (from-to)87-108
Number of pages22
JournalQuaternary Research
Volume23
Issue number1
DOIs
StatePublished - 1985
Externally publishedYes

Fingerprint

pollen
fossil
diagram
method
Fossil
Pollen
marsh
Holocene
vegetation
lake

ASJC Scopus subject areas

  • Earth and Planetary Sciences(all)
  • Earth-Surface Processes

Cite this

Quantitative interpretation of fossil pollen spectra : Dissimilarity coefficients and the method of modern analogs. / Overpeck, Jonathan; Webb, T.; Prentice, I. C.

In: Quaternary Research, Vol. 23, No. 1, 1985, p. 87-108.

Research output: Contribution to journalArticle

@article{c85c97a6b60b4a18b081f2ab4f95ae3d,
title = "Quantitative interpretation of fossil pollen spectra: Dissimilarity coefficients and the method of modern analogs",
abstract = "Dissimilarity coefficients measure the difference between multivariate samples and provide a quantitative aid to the identification of modern analogs for fossil pollen samples. How eight coefficients responded to differences among modern pollen samples from eastern North America was tested. These coefficients represent three different classes: (1) unweighted coefficients that are most strongly influenced by large-valued pollen types, (2) equal-weight coefficients that weight all pollen types equally but can be too sensitive to variations among rare types, and (3) signal0to-noise coefficients that are intermediate in their weighting of pollen types. The studies with modern pollen allowed definition of critical values for each coefficient, which, when not exceeded, indicate that two pollen samples originate from the same vegetation region. Dissimilarity coefficients were used to compare modern and fossil pollen samples, and modern samples so similar to fossil samples were found that most of three late Quaternary pollen diagrams could be {"}reconstructed{"} by substituting modern samples for fossil samples. When the coefficients indicated that the fossil spectra had no modern analogs, then the reconstructed diagrams did not match all aspects of the originals. No modern analogs existed for samples from before 9300 yr B.P. at Kirchner Marsh, Minnesota, and from before 11,000 yr B.P. at Wintergreen Lake, Michigan, but modern analogs existed for almost all Holocene samples from these two sites and Brandreth Bog. New York.",
author = "Jonathan Overpeck and T. Webb and Prentice, {I. C.}",
year = "1985",
doi = "10.1016/0033-5894(85)90074-2",
language = "English (US)",
volume = "23",
pages = "87--108",
journal = "Quaternary Research",
issn = "0033-5894",
publisher = "Academic Press Inc.",
number = "1",

}

TY - JOUR

T1 - Quantitative interpretation of fossil pollen spectra

T2 - Dissimilarity coefficients and the method of modern analogs

AU - Overpeck, Jonathan

AU - Webb, T.

AU - Prentice, I. C.

PY - 1985

Y1 - 1985

N2 - Dissimilarity coefficients measure the difference between multivariate samples and provide a quantitative aid to the identification of modern analogs for fossil pollen samples. How eight coefficients responded to differences among modern pollen samples from eastern North America was tested. These coefficients represent three different classes: (1) unweighted coefficients that are most strongly influenced by large-valued pollen types, (2) equal-weight coefficients that weight all pollen types equally but can be too sensitive to variations among rare types, and (3) signal0to-noise coefficients that are intermediate in their weighting of pollen types. The studies with modern pollen allowed definition of critical values for each coefficient, which, when not exceeded, indicate that two pollen samples originate from the same vegetation region. Dissimilarity coefficients were used to compare modern and fossil pollen samples, and modern samples so similar to fossil samples were found that most of three late Quaternary pollen diagrams could be "reconstructed" by substituting modern samples for fossil samples. When the coefficients indicated that the fossil spectra had no modern analogs, then the reconstructed diagrams did not match all aspects of the originals. No modern analogs existed for samples from before 9300 yr B.P. at Kirchner Marsh, Minnesota, and from before 11,000 yr B.P. at Wintergreen Lake, Michigan, but modern analogs existed for almost all Holocene samples from these two sites and Brandreth Bog. New York.

AB - Dissimilarity coefficients measure the difference between multivariate samples and provide a quantitative aid to the identification of modern analogs for fossil pollen samples. How eight coefficients responded to differences among modern pollen samples from eastern North America was tested. These coefficients represent three different classes: (1) unweighted coefficients that are most strongly influenced by large-valued pollen types, (2) equal-weight coefficients that weight all pollen types equally but can be too sensitive to variations among rare types, and (3) signal0to-noise coefficients that are intermediate in their weighting of pollen types. The studies with modern pollen allowed definition of critical values for each coefficient, which, when not exceeded, indicate that two pollen samples originate from the same vegetation region. Dissimilarity coefficients were used to compare modern and fossil pollen samples, and modern samples so similar to fossil samples were found that most of three late Quaternary pollen diagrams could be "reconstructed" by substituting modern samples for fossil samples. When the coefficients indicated that the fossil spectra had no modern analogs, then the reconstructed diagrams did not match all aspects of the originals. No modern analogs existed for samples from before 9300 yr B.P. at Kirchner Marsh, Minnesota, and from before 11,000 yr B.P. at Wintergreen Lake, Michigan, but modern analogs existed for almost all Holocene samples from these two sites and Brandreth Bog. New York.

UR - http://www.scopus.com/inward/record.url?scp=0022205024&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0022205024&partnerID=8YFLogxK

U2 - 10.1016/0033-5894(85)90074-2

DO - 10.1016/0033-5894(85)90074-2

M3 - Article

AN - SCOPUS:0022205024

VL - 23

SP - 87

EP - 108

JO - Quaternary Research

JF - Quaternary Research

SN - 0033-5894

IS - 1

ER -