I discovered an ophiolite this weekend! Of course it is already well known, but it was new to me, and I didn’t know I was there until I was standing on a ridge in the central Cascades looking at a massive dunite with serpentinized faults cutting through it.

Kelsey Jordahl

@kajord

6/27/2022, 11:44:11 AM

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Kelsey Jordahl

@kajord

It is part of the Ingalls ophiolite complex in the central Cascades, likely part of the same basin that became the Josephine ophiolite in N California / S Oregon. This view looking towards the Stuart range, a Cretaceous batholith.

6/27/2022, 11:46:35 AM

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Kelsey Jordahl

@kajord

I haven't found a good description of the specific context of this ridge yet, but a paper describing the larger ophiolite complex is Macdonald et al. (2008).
https://doi.org/10.1130/2008.2438(04)

6/27/2022, 11:52:35 AM

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Kelsey Jordahl

@kajord

A Google Earth view of the ridge:
https://earth.google.com/web/@47.43970078,-120.83702652,1437.00723941a,4278.7087029d,35y,5.40548836h,76.55431046t,-0r

6/27/2022, 11:57:33 AM

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Kelsey Jordahl

@kajord

There are also clues to the geology in the placenames of the region: https://www.summitpost.org/serpentine-hill/895184

6/27/2022, 12:07:37 PM

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