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While walking along the beach, I discovered a prominent fault exposed in the rocks along the buff. The sedimentary layers are offset with the thin-bedded grey shales on the left side dropping down in relation to the thick-bedded orange sandstone on the right side.
The San Andreas Fault, here exposed on the floor of the Carrizo Plain in one of the most desolate and least-visited regions of California. Note the offset streams cutting across the fault. On the far side is the Pacific plate and on the near side the North American. It's a right-lateral fault, meaning the other side of it is moving to the right, on whichever side you stand. The Pacific side is moving to the northwest in a motion geologists call "right step." Streams that once flowed straight across the fault now step to the right before they continue. These steps are recent. The plate below has moved hundreds of miles in the last two dozen million years. One study says stream channels were offset up to 50 feet in the 1857 Fort Tejon quake, one of the largest in historic time. This section of the fault raises the Elkhorn Scarp through the Elkhorn Hills. The most spine-like segment is also called Dragon's Back.
Here you can see the marks made by rocks sliding along a fault. These features, called slickensides, are polished striated rock surfaces caused by one rock mass moving across another on a fault. The quarter is there for scale.
Looking down toward the entrance of Arches National Park, a couple miles north of Moab. The Moab Fault runs along the road, and over the course of a few hundred thousand years, the cliffs on the near side of the road have sunk nearly 200 metres below the equivalent rock layers on the far side of the road.
Thrust faults are low-angle reverse faults, involving upward movement of the hanging wall and downward movement of the footwall. The fault planes of thrust faults are supposed to be less than 30 degrees from the horizontal, as seen in cross-section. Thrust faults, and reverse faults in general, form by compressional stress - they are common in mountain belts.
The light-colored rocks in the upper thrust plate are part of the basal Dunham Dolostone (upper Lower Cambrian). The gray-colored rocks in the lower thrust plate are part of the Iberville Formation (Middle Ordovician). The rocks look like shales, but they're not - they're intensely calcite-veined, dark gray lime mudstones (probably argillaceous).
Normally, one would not expect older rocks above younger rocks - that's an apparent violation of the Principle of Superposition. However, the principle only applies to non-disturbed/deformed rocks.
The Champlain Thrust Fault was active during the Taconic Orogeny, an Ordovician to Silurian mountain-building event involving the collision of a volcanic island arc with Laurentia (= the North American paleocontinent). The fault zone was also active during the subsequent Acadian Orogeny (Silurian to Devonian).
Locality: lakeshore cliff in small cove north of Lone Rock Point, northwestern side of the town of Burlington, northwestern Chittenden County, northwestern Vermont, USA (44° 29' 41.33" North latitude, 73° 14' 49.46" West longitude)
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Sergipe Alagoas Basin, Laranjeiras, SE , Brasil. Bleaching probably due to reduction from deeper fluids
Taken and originally posted in 2015.
Fissures and faults (often water-filled) in Iceland's Thingvellir National Park. The North American and Eurasian tectonic plates are pulling apart here, creating the rift valley we were crossing. Hence the fissures, which they've built bridges over. Seen on our Golden Circle tour from Reykjavik.
I was told the other day that I'm the cause of the world's problems... so, instead of solving said problems... I just drew a comic about it.
While walking along the beach, I discovered a prominent fault exposed in the rocks along the buff. The sedimentary layers are offset with the thin-bedded grey shales on the left side dropping down in relation to the thick-bedded orange sandstone on the right side.
Dalradian Quartzites form fault scarp against which Kingshouse Breccias have accumulated. Waterslide Slab, Buachaille Etive Mor.
The Wellington Fault in the Totara Park area of Upper Hutt.
The fault runs along the central reservation of the road in the background, and then through this reserve. Movement of the fault over time means that the land on right (NW) side is higher than that on the left (SE), forming this "scarplet".
This photo is on mainly to show River Ankh in her old weathered livery. She derailed after running over a nettle!
At the Bridge between Continents which spans this fault between the Eurasian and North American tectonic plates.
Visual Fault Locator Fiber Optic Laser Tester 30km is specially designed for field personnel who need an efficient and economical tool for fiber tracing, fiber routing and continuity checking in an optical network during and after installation.
Features:
Easy to check fiber faults with visual red laser light
FC, SC, ST General interface
Sturdy and durable shell
Constant output power
Long inspection distance
Operates in either CW (Continuous wave) or pulse (Both modes are available)
Pen pattern design, convenient for use and carry
Compact in size, light in weight, red laser output, both SM and MM available