Clay mineral genesis was studied in soils representative of several
different geomorphic surfaces in western Oregon, ranging in age from
Pliocene-early Pleistocene to late Pleistocene. Soil solution studies,
clay mineralogy, and soil raicromorphology were employed to provide
evidence of clay mineral synthesis and interpret soil genesis.
Soils at each study...
Wetland soils with complex stratigraphy and redoximorphic features occur on the
margin of the Willamette Valley, Oregon. In the Jackson-Frazier wetland, vertisols
show three distinct stratigraphic units that rest uncomformably upon each other and
correspond to the Bashaw series Bss, 2Bt and 3BC horizons. Holocene alluvium
deposited as distal alluvial...
Stratigraphic measurement of the 1,238-rn thick Cowlitz Formation in the
southwest Washington type section along Olequa and Stillwater creeks reveals complex
facies succession of wave- to tide-dominated deltaic sequences. The underlying, 625-rn
thick upper member of the McIntosh Formation (as mapped by Wells, 1981) is composed
of two units: a...
A composite 732-rn thick section in Germany Creek of middle Eocene upper McIntosh and lower Cowlitz Formations, as well as the lower Grays River Volcanics, was studied using bio-, magneto- and lithostratigraphy to construct a sequence stratigraphic framework and assess hydrocarbon exploration potential. The upper McIntosh Formation forms a complete...
Since 1979, over $114 million of natural gas has been produced at the Mist Gas Field, currently the only commercial gas field in the Pacific Northwest. In the Mist Gas Field, the sandstone-dominated Clark and Wilson member of the upper Eocene Cowlitz
Formation is the reservoir and the overlying upper...
The geology and natural gas potential of the Clatskanie 7.5-minute quadrangle in Columbia County, Oregon was studied utilizing a combination of geologic mapping, measuring of stratigraphic sections, diatom and molluscan fossil identifications, with subsurface geophysical data and petrographic and geochemical analyses. The stratigraphy of the study area consists of two...