Sunday, April 1, 2012

WOGE 339

I had to go way, way south to find WOGE 338 at Cape Royds in Antarctica. This was a bit confusing at first because the shadows would normally suggest a northern hemisphere location, but the snow has clearly been sculpted by strong, persistent south winds.  After I checked a few areas near Greenland I realized that if you went far enough south and took a picture in the summer the sunlight might also be coming from the south. I went around Antarctica checking the scattered ice-free areas and finally found Cape Royds.

Since I was able to locate a cleverly selected location from the famous Ron Schott himself, it would be ungrateful to put any limits on this edition.  To win, just post a comment giving the coordinates of the Google Earth image and an explanation of what we are looking at (geologically speaking).  A mention of the specific rocks/minerals found here might be nice this time.  Also, extra credit if you can figure out how this location is a first for WOGE.

4 comments:

  1. 35.905N 109.101W - Buell Park Pipe belonging to the Navajo volcanic field in northeastern Arizona. Here, ultrapotassic minette diatreme is nested within a genetically related kimberlitic breccia, both emplaced at the end of Oligocene (~25 Myr ago) in Permian sandstones near the axis of the Defiance Uplift. The maar-like structure (now significantly eroded) is the result of a phreato-magmatic eruption. The breccia hosts abundant typical kimberlite indicator minerals, dominated by olivine and garnet, but also Cr-diopside, enstatite, and Ti-clinohumite. Microscopic diamond is also present. In addition to these minerals, the minette also contains phlogopite and sanidine, as well as a wealth of mantle xenoliths (peridotites and eclogites).

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  2. ps. No idea what kind of answer you'd expect for the "extra credit" :-)

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  3. Congratulations to Peter. I had a feeling this location would be easy for some of the experienced players to track down. In addition to the technical details you comment on, I also found Buell Park mentioned as a minor source of gem-quality peridot and garnet. The "extra credit" would have been for noticing that this is the first time that a location in the state of Arizona has been used in WOGE.

    We look forward to seeing what you have in store for edition #340.

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  4. WoGE#340 is now open and restriction-free. Enjoy the quest!

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