| Magnetostratigraphic evaluation of a well-exposed stratigraphic section in northeast Montana has been undertaken to expand upon and better understand the timing of the deposition of Hell Creek and Fort Union Formations. Characteristic remnant magnetizations show clear magnetostratigraphic patterning of chrons C28n, C28r, C29n, C29r, C30n, and possibly C30r. Differentially corrected GPS coordinates, including elevation, were recorded at each sample site allowing the magnetostratigraphic framework to be precisely relocated in the field and traced laterally across the landscape. Localities in Montana that have been sampled for fossil studies have been mapped and correlated to the same stratigraphic sections as the magnetostratigraphy, and so can be compared directly to the geomagnetic polarity time scale. The new magnetostratigraphy can also be used to relate to other basins of Cretaceous and Paleogene age using information independent from biostratigraphic zonation, making it possible to directly compare the composition of coeval faunas from significantly different latitudes. |
