24 Undergraduate Research Posters
This poster session highlights geoscience research conducted and presented by undergraduate students. Abstracts must be written by students (but may include non-student co-authors). Research topics may include any area of the earth sciences.
Thursday, 23 April 2026
8:00 AM - 5:30 PM
LMH, 5th Floor Chapel
Describing the Structure and Contact of an Actinolite-Tremolite Outcrop NW Cascades, Darrington, WA
Paper number: 24-12
Program: Technical Sessions
Time: 8:15 AM – 8:15 AM
Authors
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George MustoeWestern Washington University, Bellingham, WA
Abstract
Actinolite-tremolite solid solution series amphibolites can be formed in two modes of occurrence, either through altering an ultramafic body with serpentinite-enriched blocks that introduce hydration to the ultramafics, destabilizing and elongating their lattice structure, or through the introduction of an intrusive silica-rich body to largely dolomitic regions, leading to Mg-rich fluids metasomatically altering the contacting silicates.
This work will focus on the texture and formation of a region of actinolite-tremolite between white and black wall rhodingite, all within a host serpentinite block of Washington’s NW Cascades. The goal is to look at the geologic setting of an outcrop east of Seattle in the Helena Ridge region of Darrington, WA, in the hopes that specific contact materials and their contexts, when studied, could be used as a systematic process of encountering actinolite-tremolite material as structural masses in serpentinite settings.
The analytical work will include some field mapping, optical petrography, microscopy, SEM-EDS, and XRD.
Geological Society of America Abstracts with Programs. Vol. 58, No. 3
doi: 10.1130/abs/2026CD-410958
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