Where on (Google) Earth #179?

Where on (Google) Earth has been locked in a deep freeze for the last couple of weeks. But now that it’s been released from Antarctica’s icy grip, let’s see if we can’t shake things up a bit and get it rolling again.

For those of you who may be unfamiliar with WoGE I’d point out that it’s currently just shy of its third birthday – perhaps the longest continuously running social game in the geoblogosphere. The object is to search Google Earth until you find the tract of land pictured below. Once you’ve found it, identify its latitude and longitude in the comments to this post and do what you can to describe the geological significance of this area. The winner (first person to post the correct location and geology) will have the honor of hosting the next WoGE competition on their own Geoblog. If you haven’t won (recently) or have just been thinking about starting your own geology blog it’s a great chance to win a little exposure among your colleagues and the bragging rights that go with that.

In order to level the playing field a bit, we often invoke the Schott Rule, meaning previous winners (it’s fixed!) must wait one hour per previously solved WoGE before submitting an answer. I’ll invoke the Schott Rule this time with a posting time of 9:00 am CST (15:00 GMT).

Where on (Google) Earth #179.

Good Luck!

Day #15 Deskcrop: Labradorite in Ilmenite Ore

We’re back to the Adirondacks to close out this week’s deskcrops. Today’s sample is one of my prized finds. The sample comes from the Tahawus mine dump on the south side of the High Peaks Region, not far from the Mount Marcy trailhead. Large labradorite crystals originating from the Marcy Massif Anorthosite here float in a matrix of magnetite-ilmenite ore. This suggests that the ilmenite-magnetite ore was a liquid phase, presumably immiscible and consanguinous – if not comagmatic – with the parent magma of the labradorite crystals. Elsewhere anorthositic and ferrodioritic dikes crosscut the ilmenite-magnetite orebody.

IMG_7290
Plagioclase Megacrysts in Ilmenite-Magnetite Ore

Upon closer examination of this sample, one can also observe garnet coronas at the contact of the plagioclase and oxide minerals. These little garnet “necklaces” presumably formed during granulite facies regional metamorphism.


Garnet Coronas Surround the Plagioclase Pheno(Xeno?)crysts