Friday fold: snow on a roof
The weekly example of a fold is especially… “cool” this week.
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GoSF10: The San Andreas Fault & Mussel Rock
The final episode of the 10-part “Geology of San Francisco” series concludes with a visit to the spot where the San Andreas Fault runs off the edge of California and down into the sea. Mussel Rock, site of the opening vignette of John McPhee’s “Assembling California” is located there.
Friday fold: French Broad basement
The Friday fold visits the French Broad Massif of North Carolina’s Blue Ridge province.
GoSF9: Pleistocene dunes
The penultimate episode of Callan’s more-than-a-week-long series on the geology of the San Francisco region: today we briefly visit the sand dunes that covered San Francisco Peninsula during the Pleistocene.
GoSF8: Fractures
The 8th edition of the ongoing “Geology of San Francisco” series examines brittle fractures and the chemistry they host along their planar surfaces.
GoSF7: Serpentinite and mélange
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.
GoSF6: Graywacke turbidites
The geological tour of San Francisco continues with an examination of the graywacke deposits of the
GoSF4: Kirby Cove
Part 4 of the ongoing series examining the geology of the San Francisco area. In today’s post, Callan visits Kirby Cove in the Marin Headlands, where intensely deformed chert can be found on one end of the cove, pillow basalts on the other, and an “artificial dune” in the middle.
GoSF3: Chert
Episode three in the multi-part series on the geology of San Francisco. This post focuses on the chert layers of the Marin Headlands
GoSF2: Basalt
Second in the on-going series about the geology of San Francisco: this post explores the pillow basalts of the Marin Headlands Terrane.
GoSF1: Introduction and overview
The first in a multi-part series on the geology of San Francisco and the surrounding area.
Friday fold: monastery brick
Sometimes you find folds in funny places, like the side of a monastery. Guest fold from Maitri.
Faultcano
Visit the “faultcano” in the Owens Valley of eastern California: a cinder cone which has been cut and offset along a normal fault associated with Basin & Range extension.
Friday fold: sketchy syncline
For the structural geology fans among AGU’s readership, enjoy the weekly installment of the Friday fold.
Focusing on S-C fabrics
An animated image showing changing focus on a microscope camera aimed at a sample of S-C fabric is shared. Readers are encouraged to brainstorm uses for animated GIF images in the geosciences.
Gerede segment of the North Anatolian Fault
The author recounts a field trip in October along the section of Turkey’s North Anatolian Fault that last ruptured in 1944. The rock types on either side of the fault are compared, offset markers are illustrated, and several types of landforms particular to strike-slip faults are shown. The post concludes with an examination of the town of Gerede itself, which is built directly atop the fault.
Reduction rims?
Another look at Konnarock Formation diamictite, showing colorful reaction “halos” around some clasts.
The Konnarock Formation
A detailed description of one of the Virginia Blue Ridge’s most intriguing geologic formations: a maroon sedimentary sequence showing the advance of “Snowball Earth” glaciers in the Neoproterozoic.
Scenes from the Virginia Museum of Natural History
The author describes a quick visit to the Virginia Museum of Natural History in Martinsville, Virginia, on his way back to DC from Thanksgiving travel. Highlights: a dinosaur, a giant stromatolite, encrusting crinoids (they do that?) and a giant ground sloth.
Tavşanlı Zone field trip, part 7
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.