Open Access. Powered by Scholars. Published by Universities.®

Volcanology Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 3 of 3

Full-Text Articles in Volcanology

Magnetic Exploration Of The Crescent Formation, Washington: The Search For A Hidden Fault Near Dusk Point, Samuel G. Furmanski Jan 2019

Magnetic Exploration Of The Crescent Formation, Washington: The Search For A Hidden Fault Near Dusk Point, Samuel G. Furmanski

Summer Research

The mafic rocks of the Olympic Peninsula, Washington, are part of an accreted terrane known as Siletzia which experienced transpressional stresses as far as 50 Ma ago in the early Eocene. The Peninsula has an accretion-thrust marine sedimentary interior and a mafic volcanic periphery juxtaposed along the Hurricane Ridge fault; a terrane-scale thrust fault. The mafic Crescent Formation (CF) can be subdivided into two units: The Lower Crescent member (LC) and the Upper Crescent member (UC) as defined by Tabor and Cady (1978). The LC consists of submarine basalt flows that have composition similar to mid-oceanic ridges with zircon fission-track …


Investigating Cascade Magmatism Through Dating And Chemical Analysis Of The Hatchet Mountain And Pe Ell Formations, Sw Wa, Robyn Organ, Jeffery Tepper, Wesely Von Dassow, Tabor Reedy Jan 2019

Investigating Cascade Magmatism Through Dating And Chemical Analysis Of The Hatchet Mountain And Pe Ell Formations, Sw Wa, Robyn Organ, Jeffery Tepper, Wesely Von Dassow, Tabor Reedy

Summer Research

Modern Cascade arc magmatism began ~45 Ma, shortly after accretion of the Siletzia terrane culminated at ~50 Ma. The earliest expressions of this magmatism are several petrologically-diverse volcanic units in SW Washington including: (1) the Goble Volcanics (GV) / Hatchet Mountain Formation (HM), (2) the Pe Ell Formation (PE), and (3) scattered exposures of unnamed basalts (UB). These rocks, all dominantly subaerial lavas, occur west of the modern arc where they are interbedded with marine and deltaic sedimentary units, suggesting eruption in a forearc or volcanic front setting. Goals of this study are: (1) to characterize the elemental and Sr-Nd …


Petrology Of The Eocene Goble Volcanics, Southwest Washington: An Early Phase Of The Cascade Arc, Clara Phipps, Jeffrey H. Tepper Jan 2019

Petrology Of The Eocene Goble Volcanics, Southwest Washington: An Early Phase Of The Cascade Arc, Clara Phipps, Jeffrey H. Tepper

Summer Research

The Eocene Goble Volcanics (GV), comprised of >1000 km2 of subaerial lavas and tuffs, are one of the most voluminous igneous formations in SW WA. Whole rock K-Ar ages of 45 to 32 Ma (Beck and Burr, 1979) suggest these rocks are an early expression of the Cascade arc, but their location is anomalous, lying between oceanic Crescent Fm basalts of the Siltezia terrane to the west and younger arc rocks to the east. The goals of this research are to determine the chemical and Sr-Nd isotopic traits of the GV and better establish the tectonic setting in which …