Eleven sedimentary and volcanic rock units are mapped and described in the thesis area, and chronicle the dynamic geologic history of the Tillamook embayment from the Oligocene through the middle Mlocene. The
oldest unit is the Zemorrian to early Saucesian Smuggler Cove formation, a bathyal tuffaceous mudstone with some thin-...
Two ash-flow tuff units of the late Miocene-early Pliocene Deschute Formation in central Oregon were studied in detail because of the widespread distribution, diverse compositions, and stratigraphic importance.
The Lower Bridge tuff is a double-flow simple
cooling unit that is poorly welded. The upper flow grades from rhyolite in the...
Four formations of the Cretaceous Nanaimo Group crop out on Galiano Island and on Parker and Gossip Islands, nearby. These formations are: early Campanian Geoffrey Formation which encloses a tongue of the Northumberland Formation; early Campanian to late Maestrichtian Spray Formation; and Maestrichtian Gabriola Formation. The stratigraphic succession has a...
The thesis area is located in the southeastern corner of Harney County, Oregon. This portion of Oregon is situated in the northern part of the Basin and Range province, and is characterized by both mafic and silicic extrusives, and localized nonmarine sediments and
tuffs ranging in age from middle (?)...
The Virgin Valley-McGee Mountain area is located in the northwest
corner of Nevada in the northwestern part of the Basin and
Range structural province.
Rocks within the area consist predominantly of Miocene to
Pleistocene volcanic rocks and volcanic derived sedimentary rocks.
The volcanic rocks include rhyolite, rhyolite welded tuffs, and...
Steens Mountain is a major horst block near the northern terminus of the Basin and Range geomorphic province of southeastern Oregon. A section of Miocene volcanic rocks totaling 5000 feet in thickness are exposed in a fault escarpment on the eastern side of Steens Nountain. These include: the Pike Creek...
In the South Fork of the Clearwater River area, the Salmon River suture (Lund and others, in prep.) is defined by an abrupt change in lithology, structure, initial strontium isotope ratios (Fleck and Criss, 1985), and rare earth element signatures. These changes occur across a narrow, structurally complex zone (less...
Surface and subsurface data indicate that Cretaceous strata
in the southern Ventura basin are part of the northward prograding
Chatsworth submarine fan. The fan extends westward as far as
Trancas Beach in the Santa Monica Mountains and wells in the
Oxnard Plain and on Oak Ridge. The eastern edge of...
Several uranium anomalies, with concentrations of U₃0₈ that
average below 0.003 percent and reach maximums of 0.069 percent,
are associated with black, fossiliferous, pyritic parts of the Ordovician
Ledbetter Slate in northern Stevens County, Washington. The most
uraniferous parts of the slate occur in small (average of 5 by 30...
About 225 lava flows and ash-flow tuffs of the Deschutes Formation (DF) were mapped at Green Ridge. The units fill east-trending paleovalleys which "sky-out" westward and dip east; the eastward dip of the units decreases
as they are traced eastward. The source of the units was west of Green Ridge...
Volcán Miño (21°11'S) is located on the westernmost periphery of a longlived complex of stratovolcarioes and domes called the Aucanquilcha Complex. The Aucanquilcha Complex ranges in age from 11 Ma to 1-lolocene and lies along the main N-S trending axis of Quaternary volcanoes in the Andean Central Volcanic Zone (CVZ)....