Geology Chronicles

Welcome to the blog for all things geological.

[some-1one]

[thisobscuredesireforbeauty]

“Baikal Zen”: Rocks that have fallen on the ice of Lake Baikal are heated by sunlight and emit infrared rays that melt the ice below. Once the sun is gone, the ice becomes solid again, creating a small support for the rock above.

[lsleofskye]

Montana | davidmrule

Location: Lake McDonald, USA

[odditiesoflife]

The Most Photographed Stone East of the Mississippi

Very near the Soudan Underground State Park administered by the Minnesota Department of Natural Resources is what some people call “the most photographed outcrop in the state.” This is a pavement outcrop of folded banded iron formation. The outcrop consists of metallic hematite, red jasper and white chert. These originally horizontal layers have been folded multiple times. In some areas, the jasper and chert have fractures filled with milky quartz.

[vugnasmineralblog]

Vanadinite ACF Mine, Mibladen, Midelt Province, Drâa-Tafilalet Region, Morocco      

[babyfoxcollectionthings]

[tomasorban]

Torysh, Kazakhstan

[babyfoxcollectionthings]

[geopsum]

Source: unknown.

[sedraboc]

[vugnasmineralblog]

Arsenatian Vanadinite var. Endlichite Mibladen Mine, Midelt, Khenifra Province, Meknes-Tafilalet Region, Morocco, Africa

[1five1two]

Halloysite.

[matialonsorphoto]

Argentina is okay

Prints | Instragram

[awesome-picz]

Artist  Jon Foreman Arranges Stones In Stunning Patterns On The Beach, Finds It Very Therapeutic

[geopsum]

A very happy Valentine's day to all my rock lovers. Platonic or not.

Random thought: Plate Tectonic = Platonic?

[mostly-history]

The American Niagara Falls without water (New York, 1969).

The American Falls is the second of three waterfalls that make up the Niagara Falls.  It has a massive talus (rock pile) at its base as a result of a series of natural rockslides in 1931 and 1954.  In the late 1960s, however, there were concerns that further rockslides could erode the falls entirely.  A joint American-Canadian commission decided to “dewater” the falls for five months, so that a geological survey of the rock face could be carried out.

So in June 1969, over 1,200 trucks dumped nearly 28,000 tons of rocky fill into a dam upstream of the falls [1 top right & 2], diverting the flow of the Niagara River away from the American Falls and towards the much larger Horseshoe Falls.  This process took three days.  The US Army Corps of Engineers could then begin their investigation.

The riverbed was criss-crossed with a series of cracks [4] that were examined for possible links to rockslides, and the engineers mechanically bolted and strengthened any faults that they found [7]. They drilled test-cores to check for instabilities, planted instruments to monitor rock movements in several locations, installed steel bolts and cables to stabilize the rocks around Luna Island and Bridal Veil Falls, and drilled drainage holes to relieve hydrostatic pressure at several points.

A temporary walkway was installed 6 metres from the edge of the dry falls, allowing tourists to explore the landscape.  Only two corpses were found during these five months, which was surprising given the falls’ history of accidents and suicides.

There was a plan to remove the huge mound of talus [9], but it was abandoned because of the high cost for what would be basically aesthetic reasons.

In November, the dam was dynamited in front of 2,650 observers, restoring the river’s flow to the American Falls.  Luna Island (between the American and Bridal Veil Falls) remained off-limits to the public for years, due to fears that it was unstable and could collapse into the gorge.  Erosion of the American Falls used to be about 1.2m a year, but today it is only 7.5 – 10.0cm.

[pearl-nautilus]

Quartz over Chrysocolla - Ray mine, Arizona