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The Spatial And Temporal Evolution Of The Portland And Tualatin Basins, Oregon, Usa, Darby Patrick Scanlon
The Spatial And Temporal Evolution Of The Portland And Tualatin Basins, Oregon, Usa, Darby Patrick Scanlon
Dissertations and Theses
The Portland and Tualatin basins are part of the Puget-Willamette Lowland in the Cascadia forearc of Oregon and Washington. The Coast Range to the west has undergone Paleogene transtension and Neogene transpression, which is reflected in basin stratigraphy. To better understand the tectonic evolution of the region, I modeled three key stratigraphic horizons and their associated depocenters (areas of maximum sediment accumulation) through space and time using well log, seismic, outcrop, aeromagnetic, and gravity data. Three isochore maps were created to constrain the location of Portland and Tualatin basin depocenters during 1) Pleistocene to mid-Miocene (0-15 Ma), 2) eruption of …
Stratigraphy And Sedimentology Of Paleogene Arkosic And Volcaniclastic Strata, Johnson Creek-Chambers Creek Area, Southern Cascade Range, Washington, Warren Jon Winters
Stratigraphy And Sedimentology Of Paleogene Arkosic And Volcaniclastic Strata, Johnson Creek-Chambers Creek Area, Southern Cascade Range, Washington, Warren Jon Winters
Dissertations and Theses
Over 1150 m of middle to late Eocene nonmarine arkose, lithic arkose, mudstone, and siltstone, referred to here as the Chambers Creek beds, are int~r.stratified with, and overlain by over 1600 m of late Eocene-Oligocsne(?) andesitic volcaniclastic and subordinate volcanic rocks assigned to the Ohanapecosh Formation, in a dissected structural high in the southern Washington Cascade Range, about 18 km south-southeast of the town of Packwood.