Lately, this blog has been focusing a lot on a subduction zone complex in Turkey, the Tavşanlı Zone. Much of the geologic appeal of that complex is its profusion of high-pressure, low-temperature metamorphic rocks, those in the blueschist metamorphic facies. From the last location visited on the Tavşanlı Zone field trip, I collected this fine … Read more
Part 5 of the Tavşanlı Zone field trip left us eating lunch amid some fine blueschists. Of course, nothing tops off a blueschist lunch like… more blueschist. So after our meal, we took another stroll through the countryside in search of more interesting subduction zone rocks… I’;ve got a bunch more photos for you today. … Read more
After our mind-boggling encounter with the limestone strata turned lurid pink by their high-pressure encounter with subduction, our band of merry geologists set off for a stroll: We began the walk in greenschist + blueschist mélange, as seen here with a Turkish 1-lira coin (26 mm diameter; about the same size as a U.S. quarter) … Read more
Picking up where we left off… I was telling you about the field trip I took through Turkey’s Tavşanlı Zone, a tectonic suture zone between fragments of continental crust that accreted during the closure of the Tethys Ocean. Day 2 of the trip dawned and we broke fast, and then headed out to a bizarre … Read more
Happy Saturday morning, everyone. I’m on my way down to the National Mall for fellow Tribesman Jon Stewart’s “Restoring Sanity” rally, but I thought I would just quickly post a little geological treat for Mountain Beltway readers. These are pisolites (basically like a big oolite, but without the biological component that would qualify them as … Read more
Highly contorted laminations in a blueschist-grade marble, Sivrihisar massif, Turkey.
Picking up where we left off last time, we were in some partly-serpentenized peridotite, part of the Burham Ophiolite in Turkey’s Tavşanlı Zone, an ancient tectonic suture. Our next stop on the field trip allowed us to visit some diabase dikes: Here’s a close-up of the right contact of the dike with the host peridotite: … Read more
Yesterday, I shared a few thoughts about the first couple of stops on the field trip I took earlier this month from Istanbul to Ankara, prior to the Tectonic Crossroads conference. Today, we’ll pick up with some images and descriptions from the next few stops. After lunch, our next stop brought us to a relatively … Read more
Before the Tectonic Crossroads conference two weeks ago, I had the good fortune to participate in a Istanbul-to-Ankara geology field examining the Tavşanlı Zone, a tectonic suture zone where a portion of the Tethys Ocean basin closed. This paleo-convergent boundary is marked by a suite of interesting rocks, including blueschists, ophiolites, and eclogites. I’d like … Read more
Right after I got to Istanbul on this most recent trip, I took a taxi from my hotel down to the Bosphorus, to check out the Rumeli Hisarı, a fort complex built in 1452 by Sultan Mehmet the II in anticipation of the following year’s siege of Constantinople. It’s constructed at the narrowest point on … Read more