Comparative analysis of cladoceran microfossils in the Don and Scarborough Formations, Toronto, Canada
Tóm tắt
Pleistocene deposits at Toronto, consisting of Don Formation (considered to be of Sangamonian interglacial age) and Scarborough Formation (interpreted to be Early Wisconsinan, >50 000 years B.P.) were examined at three sites: Don Valley Brickyard, Leaside, and at the south end of Brimley Road at the foot of the Scarborough Bluffs. Comparison of the cladoceran microfossil assemblages described from these sites has enabled reconstruction of the lacustrine environment of the region. Cladoceran microfossil evidence from each site confirmed the disparity in community composition and structure, and in environmental conditions that existed during deposition of the Don and Scarborough Formations. Cladocera community composition averaged 40–45% remains of littoral species in the warmer Don interval at all three sites. The Scarborough Formation contained a more homogeneous cladoceran assemblage, with higher community similarity across sites than observed in the Don Formation. However, there was greater variation in the littoral: planktonic ratio among sites, ranging from >0.90 at Leaside to <0.10 at Brimley Road. Stratigraphically constrained cluster analysis of cladoceran microfossil assemblages clearly separated the communities in the Don Formation from those in the Scarborough Formation at each site. During the interglacial, the Don Brickyard site appears to have been a shallow, protected embayment on the lake shore, whereas the other sites are more distinctly lacustrine. The Scarborough assemblage at each site is representative of deeper, oligotrophic, subarctic lakes.
Tài liệu tham khảo
Chengalath, R. & B. J. Hann, 1981. Two new species ofAlona (Chydoridae, Cladocera) from western Canada. Can. J. Zool. 59: 377–389.
Dean, W. E., Jr., 1974. Determination of carbonate and organic matter in calcareous sediments and sedimentary rocks by loss on ignition: comparison with other methods. J. Sediment. Petrol. 44: 242–248.
Duthie, H. C. & R. G. Mannada Rani, 1967. Diatom assemblages from Pleistocene interglacial beds at Toronto, Ontario. Can. J. Bot. 45: 2249–2261.
Eyles, N. & B. M. Clark, 1986. The significance of hummocky and swaley cross-stratification in Late Pleistocene lacustrine sediments of the Ontario Basin, Canada. Geology 14: 679–682.
Eyles, N. & B. M. Clark, 1988. Last interglacial sediments of the Don Valley Brickyard, Toronto, Canada, and their paleoenvironmental significance. Can. J. Earth Sci. 25: 1108–1122.
Eyles, N. & B. M. Clark, 1989. Last interglacial sediments of the Don Valley Brickyard, Toronto, Canada, and their paleoenvironmental significance: Reply. Can. J. Eart Sci. 26: 1083–1086.
Eyles, N. & N. E. Williams, 1992. The sedimentary and biological record of the last interglacial transition at Toronto, Canada. Geol. Surv. Am. Spec. Pap. 270: 119–137. IN: Clark, P. U. & P.D. Lea (eds). The last interglacial-glacial transition in North America. Geol. Surv. Am., Boulder, Colorado.
Flössner, D., 1990. Die Geschichte der Cladocerenfauna des Kleinen Barsch-Sees, eines sauren, kalkarmen Moorweihers im mitteleuropäischen Flachland. Limnologica (Berlin) 21: 125–135.
Frey, D. G., 1959. The taxonomic and phylogenetic significance of the headpores of the Chydoridae (Cladocera). Int. Revue ges. Hydrobiol. 44: 27–50.
Frey, D. G., 1960. The ecological significance of cladoceran remains in lake sediments. Ecology 41: 684–699.
Frey, D. G., 1962. Cladocera from the Eemian Interglacial of Denmark. J. Paleontol. 36: 1133–1154.
Frey, D. G., 1976. Interpretation of Quaternary paleoecology from Cladocera and midges and prognosis regarding usability of other organisms. Can. J. Zool. 54: 2208–2226.
Frey, D. G., 1988. Littoral and offshore communities of diatoms, cladocerans and dipterous larvae, and their interpretation in paleolimnology. J. Paleolimnol. 1: 179–192.
Goulden, C. E., 1969. Developmental phases of the biocoenosis. Proc. natl. Acad. Sci. USA 62: 1066–1073.
Goulden, C. E. & D. G. Frey, 1963. The occurrence and significance of lateral head pores in the genusBosmina (Cladocera). Int. Rev. ges. Hydrobiol. 48: 513–522.
Grimm, E., 1987. CONISS: a Fortran 77 program for stratigraphically constrained cluster analysis by the method of incremental sum of squares. Comp. Geosci. 13: 13–35.
Hammond, P., A. Morgan & A. V. Morgan, 1979. On thegibbulus group ofAnotylus, and fossil occurrences ofAnotylus group of Anotylus, and fossil occurrences ofAnotylus gibbulus (Staphylinidae). Syst. Entomol. 4: 215–221.
Hann, B. J., 1989. Methods in Quaternary Ecology #6. Cladocera. Geosci. Can. 16: 17–26.
Hann, B. J. & P. F. Karrow, 1984. Pleistocene paleoecology of the Don and Scarborough Formations, Toronto, Canada, based on cladoceran microfossils at the Don Valley Brick-yard. Boreas 13: 377–391.
Hofmann, W., 1978. Analysis of animal microfossils from the Grösser Segeberger See (F.G.R.). Arch. Hydrobiol. 82: 316–346.
Kalas, L., 1975. Malacological evidence of interglacial environments at Toronto, Ontario, Canada: a quantitative approach. Quaternary Non-Marine Paleoecology Conference, Program with Abstracts, Waterloo, Ontario.
Karrow, P. F., 1967. Pleistocene geology of the Scarborough area. Ontario Dept. of Mines, Geological Report 46, 108 pp.
Karrow, P. F., 1969. Stratigraphic studies in the Toronto Pleistocene. Proc. Geol. Assoc. Can. 20: 4–16.
Karrow, P. F., 1989. Last interglacial sediments of the Don Valley Brickyard, Toronto, Canada, and their paleoenvironmental significance: Discussion. Can. J. Earth Sci. 26: 1078–1082.
Karrow, P. F., 1990. Interglacial beds at Toronto. Geographic physique et Quaternaire 44: 289–297.
Karrow, P. F. & S. Occhietti, 1989. Quaternary geology of the St. Lawrence Lowlands of Canada. In Fulton, R. J. (ed.), Quaternary Geology of Canada and Greenland. pp. 319–389. Geological Survey of Canada, Geology of Canada No. 1. (also Geological Society of America, The Geology of North America, V. K-1).
Kelly, R. I. & I. P. Martini, 1986. Pleistocene glaciolacustrine deltaic deposits of the Scarborough Formation, Ontario, Canada. Sediment. Geol. 47: 27–52.
Kerr-Lawson, L. J., P. F. Karrow, T. W. D. Edwards & G. L. Mackie, 1992. A paleoenvironmental study of the molluscs from the Don Formation (Sangamonian?), Don Valley Brickyard, Toronto, Ontario. Can. J. Earth Sci. 26: 2406–2417.
Korhola, A., 1992. The early Holocene hydrosere in a small acid hill-top basin studied using crustacean sedimentary remains. J. Paleolimnol. 7: 1–22.
Korhola, A. & M. Tikkanen, 1991. Holocene development and early extreme acidification in a small hilltop lake in southern Finland. Boreas 20: 333–356.
Martinson, D. G., N. G. Pisias, J. D. Hays, J. Imbrie, T. C. Moore & N. J. Shackleton, 1987. Age dating and the orbital theory of the Ice Ages: development resolution 0 to 300 000-year chronostratigraphy. Quat. Res. 27: 1–29.
Megard, R. O., 1967. Three new species ofAlona (Cladocera, Chydoridae) from the United States. Int. Rev. ges. Hydrobiol. 52: 37–50.
Morgan, A., 1972. The fossil occurrence ofHelophorus arcticus (Coleoptera: Hydrophilidae) in Pleistocene deposits of the Scarborough Bluffs, Ontario. Can. J. Zool. 50: 555–558.
Patalas, K., 1975. The crustacean plankton communities of fourteen North American great lakes. Verh. int. Ver. Limnol. 19: 504–511.
Patalas, K., 1990. Patterns in zooplankton distribution and their causes in North American great lakes. In Tilzer M. & Serruya, C. [eds.], Ecological structure and function in large lakes. pp. 440–458. Science-Techn. Publ., Madison, Wisconsin.
Pielou, E. C., 1977. Mathematical ecology. John Wiley & Sons, NY, 385 pp.
Poplawski, S. & P. F. Karrow, 1981. Ostracodes and paleoenvironments of the late Quaternary Don and Scarborough formations, Toronto, Ontario. Can. J. Earth Sci. 18: 1497–1505.
Smol, J. P., 1981. Problems associated with the use of ‘species diversity’ in paleolimnological studies. Quat. Res. 15: 209–212.
Terasmae, J., 1960. Contributions to Canadian palynology No. 2. Part II. A palynological study of Pleistocene interglacial beds at Toronto, Ontario. Geol. Surv. Can. Bull. 56: 23–40.
Uimonen-Simola, P. & K. Tolonen, 1987. Effects of recent acidification of Cladocera in small clear-water lakes studied by means of sedimentary remains. Hydrobiologia 145: 343–351.
Warner, B. G. & P. J. Barnett, 1986. Transport, sorting, and reworking of late Wisconsinan plant macrofossils from Lake Erie, Canada. Boreas 15: 323–329.
Warner, B. G. & B. J. Hann, 1987. Aquatic invertebrates as paleoclimatic indicators? Quat. Res. 28: 427–430.
Williams, N. E. & A. V. Morgan, 1977. Fossil caddisflies (Insecta: Trichoptera) from the Don Formation, Toronto, Ontario, and their use in paleoecology. Can. J. Zool. 55: 519–527.
Williams, N. E., J. A. Westgate, D. D. Willams, A. Morgan & A. V. Morgan, 1981. Invertebrate fossils (Insecta: Trichoptera, Diptera, Coleoptera) from the Pleistocene Scarborough Formation at Toronto, Ontario, and their paleoenvironmental significance. Quat. Res. 16: 146–166.