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

Physical Sciences and Mathematics Commons

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

Geology

PDF

Western Washington University

2023

Geology

Articles 1 - 2 of 2

Full-Text Articles in Physical Sciences and Mathematics

An Analysis Of Clinopyroxene Reaction Rims As Assimilation Chronometers At Cinder Cone Volcano, Lassen National Volcanic Park, California, Annabelle Carozza Oct 2023

An Analysis Of Clinopyroxene Reaction Rims As Assimilation Chronometers At Cinder Cone Volcano, Lassen National Volcanic Park, California, Annabelle Carozza

WWU Honors College Senior Projects

Cinder Cone is a monogenetic cinder cone volcano located in Lassen National Volcanic Park, California. It erupted in 1666 CE and had three eruptive phases, each producing tephra and lava flows that ranged in style from Hawaiian (low explosivity) to Strombolian (moderate to high explosivity). This eruptive style variability at Cinder Cone was not caused by viscosity or volatile differences, and ascent rate has been proposed as a causal factor in the observed explosivity difference between phases. Ubiquitous quartz crystals are entrained within tephra and lava and were likely sourced from the assimilation of a granitic basement rock underlying the …


U-Pb Zircon Geochronology And Structure Of Regional Blueschist Units In The Easton Metamorphic Suite, Northwest Cascades, Wa, Katherine Lang Jan 2023

U-Pb Zircon Geochronology And Structure Of Regional Blueschist Units In The Easton Metamorphic Suite, Northwest Cascades, Wa, Katherine Lang

WWU Graduate School Collection

The Easton metamorphic suite of the Northwest Cascades Thrust System (NWCS) is a well-preserved subduction accretion complex in Washington State. The regional blueschist units of the Easton metamorphic suite include the Mt. Josephine semi-schist, Darrington Phyllite, and Shuksan greenschist/blueschist and all are interpreted to have accreted after the onset of Jurassic subduction beneath North America. This study uses zircon U-Pb geochronology, structure, and field observations to test the regional correlations between units in the Easton metamorphic suite and address models for the timing of subduction accretion along the North American margin in the Late Jurassic – Early Cretaceous. The results …