Microdistribution of foraminifera in a single bed of the Monterey formation, Monterey County, California

Related Titles

Series: Smithsonian contributions to paleobiology, no. 60

By

Smith, Roberta K., 1931-

Buzas, Martin A.

Type

Book

Material

Published material

Publication info

Washington, Smithsonian Institution Press, 1986

Notes

While several papers exist on the small scale spatial distribution of living foraminifera, almost no work exists on the small scale spatial distribution of fossils. The present study took 24 (5 ml) replicates 10 cm apart along one bed of the Monterey Formation in California.The mean density for all replicates is 6084.96 with a standard deviation of 8776.95. Both inspection and a cluster analysis of the data indicate replicates 20-24 have a much higher density and different rank order of abundance than replicates 1-19. The mean density for the total of all species in replicates 1-19 is 2387.47 with a standard deviation of 1175.58. For replicates 20-24 the mean density is 20135.40 with a standard deviation of 11181.40. The spatial variability is so great that four replicates (more than commonly taken) would only allow us to be 95% confident that we are within 50% of the true mean. Because age determination is based on presence of particular taxa rather than on densities, stratigraphic assignment would still be possible.The three species dominating the 1-19 group make up from 86% to 99% of the fauna. The three species dominating the 20-24 group make up from 77% to 85% of the fauna. Two of these are also dominant in the 1-19 group, but the most dominant species in the 20-24 group constitutes only <1% to 8% in the 1-19 group.The greatest number of species (22) occurs in the 20-24 group, as would be expected from the densities. The 1-19 group has 16 species. The information function is also highest in the 20-24 group.An attempt was made to achieve the faunal composition of the 1-19 group for replicates 20-24 by removal of percents of small-sized taxa. Comparable relative abundances are best achieved by removing 100% of Epistominella subperuviana and 95% of Bolivina brevior and other significant small-sized species. Total specimen numbers for both small- and large-sized species remains higher in replicates 20-24 than in 1-19, however. Thus, analysis of species percentages

Subjects

California , Foraminifera, Fossil , Monterey County , Paleontology

BHL Collections

Unearthed! Smithsonian Libraries' Paleo Collection

Call Number

QE701 .S56 no. 60

Language

English

Identifiers

DOI: https://doi.org/10.5479/si.00810266.60.1
LCCN: https://lccn.loc.gov/85600357
OCLC: 13092474