Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 2 of 2
Full-Text Articles in Earth Sciences
Unconformities And Age Relationships, Tongue River And Older Members Of The Fort Union Formation (Paleocene), Western Williston Basin, U.S.A., Edward S. Belt, Joseph H. Hartman, John A. Diemer, Timothy J. Kroeger, Neil E. Tibert, H. Allen Curran
Unconformities And Age Relationships, Tongue River And Older Members Of The Fort Union Formation (Paleocene), Western Williston Basin, U.S.A., Edward S. Belt, Joseph H. Hartman, John A. Diemer, Timothy J. Kroeger, Neil E. Tibert, H. Allen Curran
Geosciences: Faculty Publications
An unconformable relationship is observed within the Paleocene Fort Union Formation in the western Williston Basin at the contact between the Tongue River Member and the underlying Lebo and Ludlow Members. Isotopic dates and pollen biozone data reported here are integrated with previously published data. A new correlation of these facies results in a revised history of localized depositional and tectonic events. One unconformity occurs at this lithological contact in the Pine Hills (PH), Terry Badlands (TB), and Ekalaka (E) areas west of the Cedar Creek anticline (CCA), and another unconformity occurs at the same lithological contact in the Little …
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 …