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Key stratigraphic section that documents the abrupt arrival of the Colorado River in the Laughlin-Bullhead City area approximately 5.59 million years ago. Five strata exposed here document the transition of this basin from a hydrologically closed basin to one containing a very large, sediment laden throughgoing river. The transition involved an initial influx of water associated with an overflowing lake in the basin upstream which culminated in a catastrophic flood through a bedrock divide at the location of Davis Dam. The rapid influx of water and sediment ultimately resulted in a large, deep lake that inundated both Mohave Valley and Cottonwood Valley between 5.59 and 4.1 million years ago. The demise of this large lake preceded the arrival of the throughgoing Colorado River which initially filled the valleys with nearly 300 m of gravel and sand. |
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Detail of 30 m thick deposit of coarse fluvial conglomerate that heralded the first arrival of Colorado River water into Mohave Valley near the conjunction of Nevada, Arizona, and California |
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Collected in Owens Gorge, northwest of Bishop, California, this piece of Bishop Tuff illustrates flattening of pumice balls during initial burial. |
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Type locality(?) of the Black River Limestone. |
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Black Sand is a smaller geyser basin (relative to others in Yellowstone, that is) - the visitor boardwalk leads to two pools: this pan is taken from the boardwalk looking towards Sunset Pool.
The water draining from the pool is relatively warm, and is a great habitat for bacteria - the red and black colors are due to those organisms. The steam underneath the boardwalk is not from the pool, but from little fumaroles (steam vents) punching through to the surface - you can hear and see (yes, and smell) them from the boardwalk as you walk out to the pool. |
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This is a famous location for finding fossils on the Dorset coast. Sadly something went wrong and the image is not well-focused. If that was not enough, the white balance was set to incandescent light. I attempted to make the resulting blue image warmer but the colours are quite wrong. The sun was setting and all the rocks should have gold/rust colour.
The dark "soil" above the beach on the left is some sort of soft black rock. Erosion from the sea has cause a huge landslip here. For a much better shot and geological information see http://share.gigapan.org/viewGigapan.php?id=13305. You can see the next bay East (right) here: http://tinyurl.com/m3f8ap. |
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More geology macros coming... |
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Syenite boulders in river bed of Vitosha Mountains south of Sofia, Bulgaria.
360 panorama |
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"Broken Hill" is a weathered sandstone feature atop this small reserve's steep coastal bluffs which overlook the Pacific Ocean 10 miles north of downtown San Diego. Recent heavy rains after a prolonged drought seem to have caused fresh collapsing of the cliff face. |
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Almost to the south end of the Bryce Canyon Ampitheater (part of the northern part of the park itself), with another view of orange hoodoo formations. |