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Quaternary Chronology Of The Palouse Loess Near Washtucna, Eastern Washington, Lucy L. (Lucy Louglin) Foley

WWU Graduate School Collection

Four roadcuts in the Palouse loess near Washtucna, southeastern Washington, expose a thick sequence of buried calcic soils and tephra layers which span more than the last 730,000 years. The identification of four tephra layers of known age in the upper part of the loess sequence

(Mazama, Mt. St. Helens Set S, and two separate layers of Mt. St. Helens Set C) allow the formulation of a soil chronology for the last 40,000 years. Paleomagnetic stratigraphy resulted in the identification of the Brunhes Normal-Matuyama Reversed polarity epoch boundary in one roadcut, thereby establishing an age of at least 730,000 years …