The Paleogeographic Atlas Project (PGAP has existed as research enterprise at The University of Chicago since 1975 when Shell Oil offered initial funding to Alfred (Fred) M. Ziegler. A number of the most dramatic indications of larger international warmth throughout these periods embrace evidence for Late Cretaceous dinosaurs on the North Slope of Alaska and Eocene proof of alligators on northern Canada’s Ellesmere Island. Research of this kind has been performed by the Soviet paleontologist R. F. Gekker.
Clues from the geologic file can be used to find out the posistions of continents, in addition to how sea stage has changed throughout time. The continents can, though, be dismembered into microcontinents, and maps adjusted by proof of connections and splits between organisms, climate as indicated by attribute rocks (e.g., coal, or fossil sand dunes), and geological activity.
The Cenozoic paleogeographic maps of North America above are from Dr. Ron Blakey- ~rcb7/ ), that are based mostly on observations and interpretations from the geologic file. Word that Nebraska was almost fully inundated by marine water throughout this time interval. Amongst these are mosses and ferns, fern-related vegetation corresponding to horsetails, seed-producing vegetation such as conifers and ginkgoes, and flowering vegetation.
Organic indicators of climate will be both megafossils or microfossils and are interpreted in two basic methods. The terrigenous mineralogical faculty (V. P. Baturin) of paleogeography makes use of the composition of heavy and light fractions of accessory minerals (quartz, feldspar) in correlating sedimentary strata.
To supply paleogeographic maps, the age of rock layers must be accurately dated. Dimension, shape, and texture of fossil leaves, for example, provide general climate data as a result of bushes in numerous climates have distinctive leaves. As collections and lineages of plants turned higher understood, it is useful to look at the fossil knowledge with the geological and paleogeographical knowledge related to these fossils.