Research Project Title

Orthogneiss at Trent & Harvard

Session Type

Poster Presentation

Research Project Abstract

Orthogneiss at Trent & Harvard

This study examined an outcrop near the intersection of Trent and Harvard roads, in eastern Spokane County. The NNW-trending outcrop is approximately 100’ by 600’. The southern exposure was sampled for mineral and geochemical examination. The rock is medium-grained and well-foliated with a C.I. of 30-35. Identified minerals in thin section are: plagioclase, quartz, biotite, orthoclase, hornblende, titanite, allanite, opaques, apatite, and zircon. Point count analysis indicates the rock is of quartz monzodioritic composition, which is confirmed by geochemistry. Geochemically, the rock is calc-alkaline and metaluminous, with 60.07% SiO2. Based on geochemistry, this meta-igneous rock likely formed in a subduction generated, volcanic arc setting.

Session Number

PS2

Location

HUB Multipurpose Room

Abstract Number

PS2-t

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COinS
 
Apr 28th, 11:00 AM Apr 28th, 12:30 PM

Orthogneiss at Trent & Harvard

HUB Multipurpose Room

Orthogneiss at Trent & Harvard

This study examined an outcrop near the intersection of Trent and Harvard roads, in eastern Spokane County. The NNW-trending outcrop is approximately 100’ by 600’. The southern exposure was sampled for mineral and geochemical examination. The rock is medium-grained and well-foliated with a C.I. of 30-35. Identified minerals in thin section are: plagioclase, quartz, biotite, orthoclase, hornblende, titanite, allanite, opaques, apatite, and zircon. Point count analysis indicates the rock is of quartz monzodioritic composition, which is confirmed by geochemistry. Geochemically, the rock is calc-alkaline and metaluminous, with 60.07% SiO2. Based on geochemistry, this meta-igneous rock likely formed in a subduction generated, volcanic arc setting.