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aimeec3 t1_ivyaduq wrote

Reply to comment by pwdrchaser in Are there Basalts in Western Washington? by Spaceman9800

Well all of the Cascades are silica/granite. You just have to find places where the soil has eroded away or where roads have been blasted through the mountains. It's harder to find open granite formations in western Washington because of all the trees. There is Granite Mountain off of I-90 or going up past Paradise on Mt Rainier is always a good bet.

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pwdrchaser t1_ivyb1uu wrote

How about closer to Portland area? Seems like mostly basalt from what I have seen.

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aimeec3 t1_ivybzxq wrote

Portland is right on the Columbia River delta that the Eastern Washington flood basalt flowed through to get to the ocean. If you go closer to to Mt Hood there should be some outcroppings here and there along the road. But if you want to see large batholiths then NE Oregon in the Elkhorn mountains or SW Oregon near Medford and Granite pass.

Again the reason we don't see as many large granite formations are because of the trees and soil covering them up. So you have to find where it as been eroded away or where there has been massive uplift.

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