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The Calaveras Fault is an offshoot of the San Andreas Fault system in west-central California. The Calaveras Fault connects the San Andreas Fault to the Hayward Fault which cuts up the east side of San Francisco Bay. The fault is right-lateral strike-slip, meaning that offset appears to shift ground to the right. Right-lateral offset is apparent on the sidewalk and retaining wall, where aseismic creep has gradually offset the pavement!
Fault in ribbon cherts in the Mesozoic of California, USA.
These rocks are tectonically tilted layers of chert. The color is from hematite (Fe2O3 - iron oxide). Weathering of these chert beds results in a ribbon-like appearance, hence the term ribbon chert. Chert is a siliceous sedimentary rock, composed of cryptocrystalline quartz (SiO2). These particular cherts have abundant microfossils of radiolarians, a group of marine, unicellular, non-photosynthesizing protists that make tiny skeletons of opal (SiO2·nH2O). Burial and diagenesis of radiolarian-rich sediments results in the formation of radiolarian cherts. These rocks are part of the Franciscan Complex (Jurassic) and were deposited on an ancient deep seafloor. The rocks got scraped from the top of a subducting slab of oceanic crust (the Farallon Plate) along coastal California.
The ~up-and-down fracture that offsets the beds is a minor fault.
Locality: Rodeo Lagoon North Quarry - small inactive quarry on the northern side of Bunker Road, northern side of Rodeo Lagoon, southwestern Marin Peninsula, western-coastal California, USA (37° 49' 56.57" North latitude, 122° 31' 44.99" West longitude)
Flying over the deserts of Arizona, you find yourself taking a lot of "interesting pictures" when you sit by the wing and emergency exit for the long duration of a 45 minute flight.
Detail of fracturing and shifts in a vertical beach cliff in Port Townsend Washington.
Hat is roughly at cliff base. The round yellow dot on the hat furthest to the lower right is approx 0.9 cm across.
Direction is looking S. The large throw is roughly 8.7 cm to upper right, the smaller throws are roughly 1.2 cm to upper right and 0.7 cm to lower left.
Did about an hour geology review with Bruce of places we have been together in the Grand canyon
USGS Geologic Map of the Eastern Part of the Grand Canyon - 1986 edition
A more recent version:
Geologic Map of the Grand Canyon 30' x 60' Quadrangle, Coconino and Mohave Counties, Northwestern Arizona By George H. Billingsley 2000 38" x 42" PDF file
A great site with multiple Grand canyon 3D visualizations www.cherba.com/wcs/features/030420/index.html by R. Scott Cherba
gc 656
Formed from the Bungarider Fault, one of three large faults in a NW-SE direction on the proprerty.
PS Breccia is an Italian word with the 'cc' presumably pronounced as in capuccino (which would have been nice in the remote location!)
another take on the same parking lot where my dentist's office is (was).
iPhone
stripes: www.flickr.com/photos/guyr/sets/72157627235289373/with/69...
Coal with fault slickenside (SDSMT 868, South Dakota School of Mines and Technology Museum of Geology, Rapid City, South Dakota, USA)
Faults are quite common in orogenic belts. Faults are defined as fractures in rocks along which differential displacement has occurred. Dip-slip faults are those involving movement of rocks in non-horizontal directions. Strike-slip faults involve movement of rocks in horizontal directions.
The two common types of dip-slip faults are normal faults and reverse faults. Normal faults form by extensional stress. Reverse faults form by compressional stress.
The coal sample shown above has a fault plane surface facing the viewer. Click on the photo to zoom in and look around - the fine top-to-bottom lines and striations are slickenlines, which indicate fault movement direction.
The coal is likely Cretaceous or Tertiary in age.
Locality: undisclosed/unrecorded site at or near the town of Rock Springs, southwestern Wyoming, USA
Fault cutting through Pennsylvanian rocks in Ohio, USA.
"Lowellville Shale" is the nickname used here for dark-colored mudshales overlying the Lowellville Limestone in the Pottsville Group of northeastern Ohio, USA.
Just above the Lowellville Limestone at the Beach City Dam outcrop, the Lowellville Shale is fissile to flaggy, fossiliferous, black calcareous shale. Above that is non-flaggy, sparsely-fossiliferous, incompetent, black calcareous shale. Observed fossils include Posidonia bivalves, Trepospira gastropods, crinoid stem columnals, straight-shelled nautiloid cephalopods, coiled cephalopods, plants, and horizontal burrows.
The Lowellville Shale and underlying Lowellville Limestone are part of the Pottsville Group, a Pennsylvanian-aged cyclothemic succession in eastern Ohio that contains nonmarine shales, marine shales, siltstones, sandstones, coals, marine limestones, and chert ("flint"). The lower Pottsville dates to the late Early Pennsylvanian. The upper part dates to the early Middle Pennsylvanian. The Lower-Middle Pennsylvanian boundary is apparently somewhere near the Boggs Member (?).
The outcrop shown above is dominated by black shales. The lighter-colored material is part of a laterally-discontinuous, micritic limestone nodule horizon. The left side of this nodule has been truncated by a fault. Faults are fractures in rocks along which differential displacement has occurred. Dip-slip faults are those involving movement of rocks in non-horizontal directions. The two common types of dip-slip faults are normal faults and reverse faults.
Stratigraphy: Lowellville Shale, just above the Lowellville Limestone, Pottsville Group, upper Lower Pennsylvanian
Location: Beach City Dam outcrop - exposure on the southern side of Sugar Creek, immediately downstream from Beach City Dam, northern Franklin Township, northwestern Tuscarawas County, northeastern Ohio, USA (40° 38’ 06.71” North latitude, 81° 33’ 21.80” West longitude)
Crystal Springs and San Andreas lake visible in the distance. Los Trancos is an unusually high spot along the fault line.
In places, the collision of the two plates that created the San Andreas Fault is clearly visible as it traverses California, as shown in this photo of the Carrizo Plain 100 m north of Los Angeles.
La Falla de San Andrés
En algunos lugares, la colisión de las dos placas que creó la Falla de San Andrés es claramente visible, atravesando California. La falla se muestra aquí, en la Llanura Carrizo, 100 millas al norte de Los Ángeles.
Author: John Wiley, via Wikipedia