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some of the geology we will be seeing along the way. I found this pictorial most helpful when trying to identify the geology along the way http://digsfossils.com/strataman/strata ... acier.html and this outstanding pictorial about the geology of the Park (scroll to activate the screens) https://www.arcgis.com/apps/Cascade/ind ... bfda5ddcdd
Top photos: The Grinnell formation is the red argillite shown above. The Grinnell gets its red color from high oxidation levels, much higher than that of the Appekunny. The Grinnell was deposited in shallower environmental conditions than the Appekunny and therefore, higher energy as well. However, similar to the Appekunny, the Grinnell features strands of white quartzite as seen above. Note the crossbedding in the quartzite layer in the middle that indicates the higher energy environment.
Sedimentary structures including mudcracks, raindrop impressions, and ripple marks are all also commonly found in rocks from the Grinnell Formation. Raindrop impressions (one of the rocks in the lower left photo) and mudcracks are seen in the pictures below.
A stream dumped sand onto muddy shore, ripples were created, and then mud leveled them out!
Middle right photo: Purcell lava (I can't remember if the lines are glacial or sea)
Lower right: Jeff talks about that rock in the middle in my video 1
Top photos: The Grinnell formation is the red argillite shown above. The Grinnell gets its red color from high oxidation levels, much higher than that of the Appekunny. The Grinnell was deposited in shallower environmental conditions than the Appekunny and therefore, higher energy as well. However, similar to the Appekunny, the Grinnell features strands of white quartzite as seen above. Note the crossbedding in the quartzite layer in the middle that indicates the higher energy environment.
Sedimentary structures including mudcracks, raindrop impressions, and ripple marks are all also commonly found in rocks from the Grinnell Formation. Raindrop impressions (one of the rocks in the lower left photo) and mudcracks are seen in the pictures below.
A stream dumped sand onto muddy shore, ripples were created, and then mud leveled them out!
Middle right photo: Purcell lava (I can't remember if the lines are glacial or sea)
Lower right: Jeff talks about that rock in the middle in my video 1
Aug 11 2021