After my cousin Brad caught up with us after our Pinkham Notch roadcut excursion, we started up the trail at Tuckerman Ravine, and then detoured to go via the Lion Head. Immediately, we began to see some freaking awesome metamorphic porphyroblasts. During the Acadian Orogeny (in the late Devonian), the original muds and sands (deep … Read more
Okay, a final post (for now, anyhow) sharing some images from last Friday’s field trip to the Billy Goat Trail, in Potomac, Maryland. Yesterday we looked at lamprophyre dikes, but there are other dikes on the Billy Goat Trail, too. Like this granite pegmatite: What’s interesting to me about this is that the joint set … Read more
The Friday fold takes us to some high-grade metamorphic rocks in the Piedmont of northern Virginia.
The Friday fold visits the French Broad Massif of North Carolina’s Blue Ridge province.
Merry Christmas! Along with the red cherts of last Tuesday, enjoy today’s green rocks — serpentinite and serpentinite mélange of Marshall Beach, west of the Golden Gate Bridge in San Francisco.
The geological tour of San Francisco continues with an examination of the graywacke deposits of the
One other thing that I noticed during my visit last weekend to the Virginia Museum of Natural History in Martinsville, Virginia, was this fold. As soon as I saw it, I squealed “Oooh! That’s going to be the Friday fold!” It says something about the crowd I was traveling with that everyone (a) knew what … Read more
Part 6 of the Tavşanlı Zone field trip had us looking at some blueschists and eclogites. Today we conclude the terrific field trip with a brief look at a couple more stops.
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