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Full-Text Articles in Earth Sciences
Patterns Of Early Lake Evolution In Boreal Landscapes: A Comparison Of Stratigraphic Inferences With A Modern Chronosequence In Glacier Bay, Alaska, Sherilyn C. Fritz, Daniel R. Engstrom, Stephen Juggins
Patterns Of Early Lake Evolution In Boreal Landscapes: A Comparison Of Stratigraphic Inferences With A Modern Chronosequence In Glacier Bay, Alaska, Sherilyn C. Fritz, Daniel R. Engstrom, Stephen Juggins
Department of Earth and Atmospheric Sciences: Faculty Publications
The chronosequence approach, which infers temporal patterns of environmental change from a spatial array of modern sites, has been a major tool for studying successional processes. A model of early lake ontogeny in boreal landscapes, developed from a chronosequence of lakes in Alaska, suggests that long-term soil development and related hydrological change produce a loss of alkalinity and base cations, a decrease in pH, an increase in DOC and a transient increase followed by a decrease in lakewater nitrogen concentrations over time. We compare this model of lake ontogeny with patterns of change reconstructed from diatom assemblages in 10 sediment …
Pleistocene Formations In Indiana, William J. Wayne
Pleistocene Formations In Indiana, William J. Wayne
Department of Earth and Atmospheric Sciences: Faculty Publications
The system of stratigraphic classification used in North America for all sedimentary rock units except nonmarine deposits of the Pleistocene Series established groups, formations, and smaller units based on objectively determined characteristics of the rocks and not on geomorphology or subjective features, such as geologic time. Not all students of the nonmarine Pleistocene have kept these two kinds of units distinct from each other. The Pleistocene sediments of Indiana and the surrounding States are continental in origin rather than marine, and thus they show far less lithologic homogeneity than sediments and rocks of marine origin. Nevertheless, these Pleistocene sediments can …