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Seven centuries of taphonomic variation in Eocene freshwater fishes preserved in varves: paleoenvironments and temporal averaging

Published online by Cambridge University Press:  08 April 2016

Mark V. H. Wilson
Affiliation:
Department of Biological Sciences and Laboratory for Vertebrate Paleontology, University of Alberta, Edmonton, Alberta, T6G 2E9 Canada
Douglas G. Barton
Affiliation:
Department of Biological Sciences and Laboratory for Vertebrate Paleontology, University of Alberta, Edmonton, Alberta, T6G 2E9 Canada

Abstract

Eocene lake beds of Horsefly, British Columbia, are preserved in varves, or discrete yearly layers representing seasonal changes in the lake. These varves allow study of temporal variation and rates of change in morphological and ecological characters on a very short time scale. One of the most sensitive indicators of the paleoenvironmental conditions on the floor of the lake may be the taphonomic condition of the fishes, which vary between perfectly articulated and completely disarticulated skeletons. Patterns of disarticulation correspond to those produced by scavengers. The taphonomy supports the hypothesis that the lake was warm monomictic, circulating in the winter, at which time scavengers could gain access to the bottom of the lake. Larger-scale environmental events (on the order of hundreds of years) are suggested by the fact that the proportion of well-preserved specimens reached two peaks within the seven centuries of deposition, one peak during the second century and another during the fifth and sixth centuries. These results clearly demonstrate two principles: that taphonomy can be a sensitive indicator of paleoenvironmental conditions, and that temporal averaging can affect the taphonomic properties of this fossil site, and presumably of others with equal or lower time resolution.

Type
Articles
Copyright
Copyright © The Paleontological Society 

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References

Literature Cited

Anderson, R. Y, and Dean, W. E. 1988. Lacustrine varve formation through time. Palaeogeography, Palaeoclimatology, Palaeoecology 62:215235.Google Scholar
Bell, M. A., Sadagursky, M. S., and Baumgartner, J. V. 1988. Utility of lacustrine deposits for the study of variation within fossil samples. Palaios 2:455466.CrossRefGoogle Scholar
Elder, R. L., and Smith, G. R. 1988. Fish taphonomy and environmental inference in paleolimnology. Palaeogeography, Palaeoclimatology, Palaeoecology 62:577592.Google Scholar
Fisher, D.C. 1990. Rates of evolution—living fossils. pp. 152159In Briggs, D. E. G. and Crowther, P. R., eds. Palaeobiology: a synthesis. Blackwell Scientific, London.Google Scholar
Gingerich, P. D. 1983. Rates of evolution: effects of time and temporal scaling. Science 222:159161.Google Scholar
McGrew, P. O. 1975. Taphonomy of Eocene fish from Fossil Basin, Wyoming. Fieldiana (Geology): 33:257270.Google Scholar
O'Sullivan, P. E. 1983. Annually-laminated lake sediments and the study of Quaternary environmental changes—a review. Quaternary Science Reviews 1:245313.Google Scholar
Schäfer, W. 1972. Ecology and palaeoecology of marine environments. Oertel, I., transl. University of Chicago Press, Chicago.Google Scholar
Sheldon, P. R. 1990. Microevolution and the fossil record. pp. 106110In Briggs, D. E. G. and Crowther, P. R., eds. Palaeobiology: a synthesis. Blackwell Scientific, London.Google Scholar
Smith, A. G., Smith, D. G., and Funnell, B. M. 1994. Atlas of Mesozoic and Cenozoic coastlines. Cambridge University Press, Cambridge.Google Scholar
Smith, G. R., and Elder, R. L. 1985. Environmental interpretation of burial and preservation of Clarkia fishes. pp. 8593in Smiley, C. J., ed. Late Cenozoic history of the Pacific Northwest. Pacific Division, American Association for the Advancement of Science and California Academy of Sciences, San Francisco.Google Scholar
Velleman, P. F. 1992. Data desk statistics guide. Data Description, Inc., Ithaca, N.Y.Google Scholar
Wetzel, R. G. 1983. Limnology, 2d ed.Harcourt Brace College Publishing, Forth Worth, Tex.Google Scholar
Wilson, M. V. H. 1977. Paleoecology of Eocene lacustrine varves at Horsefly, British Columbia. Canadian Journal of Earth Sciences 14:953962.Google Scholar
Wilson, M. V. H. 1980. Eocene lake environments: depth and distance-from-shore variation in fish, insect, and plant assemblages. Palaeogeography, Palaeoclimatology, Palaeoecology 32:2144.CrossRefGoogle Scholar
Wilson, M. V. H. 1984. Year classes and sexual dimorphism in the Eocene catostomid fish Amyzon aggregatum. Journal of Vertebrate Paleontology 3:137142.Google Scholar
Wilson, M. V. H. 1988. Reconstruction of ancient lake environments using both autochthonous and allochthonous fossils. Palaeogeography, Palaeoclimatology, Palaeoecology 62:609623.Google Scholar
Wilson, M. V. H. 1993. Calibration of Eocene varves at Horsefly, British Columbia, Canada, and temporal distribution of specimens of the Eocene fish Amyzon aggregatum Wilson. Kaupia: Darmstädter Beiträge zur Naturgeschichte 2:2744.Google Scholar
Wilson, M. V. H., and Bogen, A. N. 1994. Tests of the annual hypothesis and temporal calibration of a 6375-varve fish-bearing interval, Eocene Horsefly beds, British Columbia, Canada. Historical Biology 7:325339.Google Scholar