Orthogneiss at Trent & Harvard
Faculty Sponsor
Andy Buddington (andy.buddington
@scc.spokane.edu)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
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.
