Abstract
Melt droplets formed by the impact of a large meteorite impact event(s) have been found in upper Eocene marine sediments from the Atlantic, Pacific, and Indian oceans. The number of discreet impacts that occurred to form these melt droplets can be gleaned by compositionally analysing the droplets and establishing the number of distinct groups. Previous studies have inferred two, three, or more source impact events, although we believe the statistical techniques used to distinguish the groupings are open to criticism. Multivariate and univariate analysis (including discriminant analysis) of the major-element composition of an increased data set of impact melt ejecta droplets have been performed. The results demonstrate that the uppermost ejecta layer is geochemically distinct from other late Eocene melt ejecta. Our statistical analysis suggests two underlying, purportedly stratigraphically separate ejecta layers, possess minimal differences that cannot be distinguished clearly from one another by discriminant analysis, which adds to the plausibility that they have a common source. Finally, our results reveal apparent disparities between the new major-element data from this study and data compiled from existing sources.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
REFERENCES
Aitchison, J., 1986, The statistical analysis of compositional data: Monographs on applied statistics and applied probability: Chapman and Hall, London, New York, 416 p.
Aitchison, J., 1992, Oncriteria for measures of compositional difference: Math. Geol., v. 24, p. 365–379.
Anderson, T. W., 1984, An introduction to multivariate statistical analysis, 2nd edn.: Wiley, New York, 675 p.
Barnes, V. E., 1963, Tektite strewn fields, in O'Keefe, J. A., ed., Tektites: University of Chicago Press, Chicago, IL, p. 477–582.
Bottomley, R., Grieve, R., York, D., and Masaitis, V., 1997, The age of the Popigai impact event and its relation to events at the Eocene/Oligocene boundary: Nature, v. 388, p. 331–365.
D'Hondt, S. L., Keller, G., and Stallard, R. F., 1987, Major element compositional variation within and between different late Eocene microtektite strewn fields: Meteoritics, v. 22, p. 61–79.
Glass, B. P., and Burns, C. A., 1987, Late Eocene crystal-bearing spherules: Two layers or one?: Meteoritics, v. 22, p. 265–279.
Glass, B. P., Burns, A., Crosbie, J. R., and DuBois, D. L., 1985, Late Eocene North American microtektites and clinopyroxene-bearing spherules: J. Geophys. Res., v. 90, p. D175–D196. Proc. 16th lunar planet. sci. conf.
Glass, B. P., and Koeberl, C., 1998, Spherules from upper Eocene sediments at ODP hole 689B, Maud Rise, in Antarctic. proc. 29th lunar planet. sci. conf., Abstract 1679, Lun. Planet. Inst., Houston, TX. (CD-ROM)
Glass, B. P., Koeberl, C., Blum, J. D., Senftle, F., Izett, G. A., Evans, B. J., Thorpe, A. N., Povenmire, H., and Strange, R. L., 1995, A Muong Nong-type Georgia tektite: Geochim. Cosmochim. Acta, v. 39, p. 4071–4082.
Glass, B. P., and Zwart, M. J., 1979, North American microtektites in Deep Sea Drilling Project cores from the Caribbean Sea and Gulf of Mexico: Geol. Soc. Am. Bull., v. 90, p. 595–602.
Grieve, R., Rupert, J., Smith, J., and Therriault, A., 1995, The record of terrestrial impact cratering: GSA Today, v. 5, p. 193–196.
Hazel, J., 1989, Chronostratigraphy of upper Eocene microspherules: Palaios, v. 4, p. 318–329.
Johnson, R., and Wichern, D., 1992, Applied multivariate statistical analysis, 3rd edn.: Prentice Hall, New York, 642 p.
Kaye, A. C., Schnetzler, C. C., and Chase, J. N., 1961, Tektite from Martha's Vineyard, Massachusetts: Geol. Soc. Am. Bull., v. 72, p. 339–340.
Keller, G., D'Hondt, S. L., Orth, C. J., Gilmour, J. S., Oliver, P. Q., Shoemaker, E. M., and Molina, E., 1987, Late Eocene impact microspherules: Stratigraphy, age and geochemistry: Meteoritics, v. 22, p. 25–61.
Koeberl, C., and Glass, B. P., 1988, Chemical composition of North American microtektites and tektite fragments from Barbados and DSDP Site 612 on the continental slope off New Jersey: Earth Planet. Sci. Lett., v. 87, p. 286–292.
Mak, E. K., York, D., Grieve, R. A. F., and Dence, M. R., 1976, The age of the Mistastin Lake crater, Labrador, Canada: Earth Planet. Sci. Lett., v. 31, p. 345–357.
Melosh, H. J., 1989, Impact cratering: A geologic process: Oxford University Press, New York, 245 p.
Mungall, J. E., and Martin, R. F., 1994, Severe leaching of trachytic glass without devitrification, Terceira, Azores: Geochim. Cosmochim. Acta, v. 58, p. 75–83.
Obradovich, J. D., Snee, L. W., and Izett, G. A., 1989, Is there more than one glassy impact layer in the late Eocene?: Geol. Soc. Am. Abstr. Prog., v. 21, p. A134.
Poag, C.W., Powars, D. S., Poppe, L. J., and Mixon, R. B., 1994, Meteoroid mayhem in Ole Virginny: Source of the North American tektite strewn field: Geology, v. 22, p. 691–694.
Sanfilippo, A., Riedel, W. R., Glass, B. P., and Kyte, F. T., 1985, Late Eocene microtektites and radiolarian extinctions on Barbados: Nature, v. 314, p. 613–614.
Saunders, J. B., Bernoulli, D., Müller-Merz, E., Oberhansli, H., Perch-Nielsen, K., Riedel, W. R., Sanfilippo, A., and Torrini, R., 1984, Stratigraphy of the late Middle Eocene to Early Oligocene in the Bath Cliff section, Barbados, West Indies: Micropaleontology, v. 30, p. 390–425.
Stecher, O., Ngo, H. H., Papanastassiou, D. A., and Wasserburg, G. J., 1989, Nd and Sr isotopic evidence for the origin of tektite material from DSDP Site 612 off the New Jersey coast: Meteoritics, v. 24, p. 89–98.
Steiger, R. H., and Jäger, E., 1977, Subcommission on geochronology: Convention on the use of decay constants in geo-and cosmochronology: Earth Planet. Sci. Lett., v. 36, p. 359–362.
Swinski, M. B., and Glass, B. P., 1979, North American tektites from the Pacific and Indian Oceans: EOS, Trans. Am. Geophys. Union, v. 60, p. 308.
Walden, J., Smith, J. P., and Dackombe, R. V., 1992, The use of simultaneous R-and Q-mode factor analysis as a tool for assisting interpretation of mineral magnetic data: Math. Geol., v. 24, p. 227–247.
Wang, X., and Zhang, J., 1992, Two methods of orthogonally stepwise discrimination and their applications: Math. Geol., v. 24, p. 203–218.
Whitehead, J., Papanastassiou, D. A., Spray, J. G., Grieve, R. A. F., and Wasserburg, G. J., 2000, Late Eocene impact ejecta: Geochemical and isotopic connections with the Popigai impact structure: Earth Planet. Sci. Lett., v. 181, p. 473–487.
Winzler, S. R., Lum, R. K. L., and Schumann, S., 1976, Rb, Sr and strontium isotopic composition, K-Ar age and large ion lithophile trace-element abundances in rocks and glasses from the Wanapitei Lake impact structure: Geochim. Cosmochim. Acta, v. 40, p. 51–57.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Marchand, E., Whitehead, J. Statistical Evaluation of Compositional Differences Between Upper Eocene Impact Ejecta Layers. Mathematical Geology 34, 555–572 (2002). https://doi.org/10.1023/A:1016094928524
Issue Date:
DOI: https://doi.org/10.1023/A:1016094928524