Changes

==Morphometric procedure==

==Morphometric procedure==

Morphometric analysis involves collecting the measurements of two or three dimensions of fossil form, typically either an outline (silhouette) or the coordinate positions of a morphologic “landmark.” Once a sufficient data set is collected, multivariate methods are used to break out fossil “shape components” statistically and to relate component variability to chronostratigraphic or paleoenvironmental indices.<ref name=ch17r29>Davis, J., C., 1986, Statistics and data analysis in geology: New York, John Wiley, 646 p.</ref> When the relationship between change in fossil shape and environmental and stratigraphic data is established, fossil morphology can increase confidence in geologic correlation and paleoenvironmental inference.<ref name=ch17r73>Reyment, R., A., Blackith, R., E., Campbell, N., A., 1984, Multivariate Morphometrics, 2nd ed.: London, Academic Press, 233 p.</ref><ref name=ch17r74>Rohlf, F., J., Bookstein, F., L., eds., 1990, Proceedings of the Michigan Morphometrics Workshop: University of Michigan Museum of Zoology Special Publication 2, 380 p.</ref>

Morphometric analysis involves collecting the measurements of two or three dimensions of fossil form, typically either an outline (silhouette) or the coordinate positions of a morphologic “landmark.” Once a sufficient data set is collected, multivariate methods are used to break out fossil “shape components” statistically and to relate component variability to chronostratigraphic or paleoenvironmental indices.<ref name=ch17r29>Davis, J., C., 1986, Statistics and data analysis in geology: New York, John Wiley, 646 p.</ref> When the relationship between change in fossil shape and environmental and stratigraphic data is established, fossil morphology can increase confidence in geologic correlation and paleoenvironmental inference.<ref name=ch17r73>Reyment, R., A., Blackith, R., E., Campbell, N., A., 1984, Multivariate Morphometrics, 2nd ed.: London, Academic Press, 233 p.</ref><ref name=ch17r74>Rohlf, F., J., Bookstein, F., L., eds., 1990, Proceedings of the Michigan Morphometrics Workshop: University of Michigan Museum of Zoology Special Publication 2, 380 p.</ref>

==Applications==

==Applications==

Morphometric analysis of microfossils from stratigraphic sections can augment the resolution of existing biostratigraphic zonations.<ref name=ch17r72>Reyment, R., A., 1980, Morphometric methods in biostratigraphy: London, Academic Press, 168 p.</ref> The illustration to the right shows changes vs. age in the average morphometrically defined shape of tests in populations of the planktonic foraminifera ''Globoquadrina altispira''.

Morphometric analysis of microfossils from stratigraphic sections can augment the resolution of existing biostratigraphic zonations.<ref name=ch17r72>Reyment, R., A., 1980, Morphometric methods in biostratigraphy: London, Academic Press, 168 p.</ref> [[:file:applied-paleontology_fig17-33.png|Figure 1]] shows changes vs. age in the average morphometrically defined shape of tests in populations of the planktonic foraminifera ''Globoquadrina altispira''.

Data for the illustration were compiled from cores taken in the DeSoto Canyon area, eastern Gulf of Mexico. Significant shifts in shape (such as at {{Ma|7.5}}) can augment the resolution of existing biostratigraphic zonations. In addition to analysis from stratigraphic sections, refined paleoenvironmental interpretations can be obtained by comparing morphometric results from fossil populations (e.g., benthic foraminifera) with results obtained from analysis of existing species from known environments.

Data for the illustration were compiled from cores taken in the DeSoto Canyon area, eastern Gulf of Mexico. Significant shifts in shape (such as at {{Ma|7.5}}) can augment the resolution of existing biostratigraphic zonations. In addition to analysis from stratigraphic sections, refined paleoenvironmental interpretations can be obtained by comparing morphometric results from fossil populations (e.g., benthic foraminifera) with results obtained from analysis of existing species from known environments.

[[file:applied-paleontology_fig17-33.png|thumb|{{figure number|17-33}}Printed with permission of N. Healy-Williams, University of South Carolina.]]

[[file:applied-paleontology_fig17-34.png|thumb|{{figure number|2}}After .<ref name=ch17r41>Gary, A., C., Healy-Williams, N., Ehrlich, R., 1989, Water–mass relationships and morphologic variability in the benthic foraminifer Bolivina albatrossi Cushman, northern Gulf of Mexico: Journal of Foraminiferal Research, vol. 19, no. 3, p. 210–221., 10., 2113/gsjfr., 19., 3., 210</ref> Copyright: Journal of Foraminiferal Research.]]

==Systematic changes vs. water depth==

==Systematic changes vs. water depth==

The illustration below shows systematic changes vs. water depth in the outline shape (lobateness) of the benthic foraminifera ''Bolivina alhatrossi'' as defined by morphometric analysis. Data for this illustration were collected from a transect of bottom samples from the present-day Gulf of Mexico. Similar analyses of ''B. alhatrossi'' specimens from Neogene sections can be compared with the modern relationship to obtain paleobathymetric estimates.

[[:file:applied-paleontology_fig17-34.png|Figure 2]] shows systematic changes vs. water depth in the outline shape (lobateness) of the benthic foraminifera ''Bolivina alhatrossi'' as defined by morphometric analysis. Data for this illustration were collected from a transect of bottom samples from the present-day Gulf of Mexico. Similar analyses of ''B. alhatrossi'' specimens from Neogene sections can be compared with the modern relationship to obtain paleobathymetric estimates.

 

==Particle analysis==

==Particle analysis==