Tag Archive for 'geology'

Amazing Geological Oddities Part II

Published
by
Fingel
on September 23, 2008
in Science
. 2 Comments

Ever since Amazing Geological Oddities was published, it has attracted quite a few comments. Most of them are useless Internet flame that you would expect to find anywhere, but several good people posted some great stuff. In this post, I will be collecting the best of the suggestions that people left on the original post. Enjoy!

Link to original Post: http://www.fingel.com/2008/04/amazing-geological-oddities/

David Keech thoguht the Wave Rock in Hyden, Western Australia was pretty cool.

This incredible rock formation, named obviously because of its wave like shape, is approximately 15 meters (about 50 feet) tall and 110 meters (360 feet) long. The shape was caused by subsurface erosion of the granite rock. After the rock was exposed, algae began to grow on its face, causing the darker streaks that add to the look of this rock.

Dave recommended the Hell Gate in Uzbekistan.

This site is truly amazing, with an incredible back story as well. 35 years ago, geologists were drilling for gas outside the small town of Darvaz. The drilling equipment unexpectedly broke through a cavern and the entire thing caved in. The gas that the geologists were looking for began to seep through the ground, and to make sure that nobody was harmed by the potentially poisonous gas, they lit it on fire. It has been burning ever since with no end in sight.

Martin told us about the Bay of Fundy in Nova Scotia.

The Bay of Fundy is not so much a marvel of geology as it a total coincidence. That doesnt mean its easy to understand how it works.  Oceanographers say that the huge tidal range, which can fluctuate an entire 17 merers (thats about 55 feet) is a result of the perfect timing of normal tides, and the amount of time a wave takes to move from the opening of the bay to the end. One thing I find funny about the Bay of Fundy is that although it has these huge tides, people still have docks with boats on them, even though half way through the day any boat will be grounded!

Bay of fundy at high tide.

Same place at low tide!

Same place at low tide!

The bay of fundy really gets its justice with a video:

Todd gave us one of my favorite reccomendations, the Devils Tower in Wyoming.

This huge rock, as there is no other way to describe it, stands tall in comparison to its surroundings. Although still disputed, the prevailing (and this writers favorite) theory is that the formation is a volcanic plug of a long extinct volcano. Magma moved up the inside of the volcano, but before it could erupt, the volcano died and the magma was left sitting inside. The hard igneous rock that the magma formed is more resiliant to erosion that the surroundig volcano which has long ago been washed away. The Devils Tower hexagonal pattern is the result of the cooling of magma. When magma cools, it shrinks, causing the cracks and pattern. This is called Jointing.  The volacano that the Devils Tower was originally formed in would have been massive.

There is a similar formation in Southern Oregon called Pilot rock that was formed the same way:

Daithi was the first, but not the last, to recommended the Giants Causeway in Northern Ireland.

Legend has it that the Giants Causeway was built by an Irish giant as a bridge to Scotland so he could fight his rival giant there. But really, the Giants Causeway was formed in much the same way as the Devils Tower and Pilot Rock. The rock is from an ancient volcanic eruption, and the cooling of the magma formed the hexagonal pillars, a phenomena called “jointing”. The Giants Causeway covers a huge area that contains about 40,000 almost perfect hexagonal columns.

Tim wanted us to know about the incredible blue holes:

Blue holes are another result of Karst topography. That is, formation by massive amounts of erosion. Blue holes are named because of the contrast between their dark, deep inner waters and the light blue water surrounding them. Many of them are hundreds of feet deep, the deepest one is 663 feet deep! The water inside is extremely anoxic (without oxegen) so they don’t support much life other than certain types of bacteria.

The Belize blue hole, close up.

The Belize blue hole, close up.

The same blue hole, but from a distance.

The same blue hole, but from a distance.

Good for swimming?

Good for swimming?

Moving Rocks?

There seemed to be some controversy over how those moving rocks really move. Here is a great video that might help clear things up. Thanks Henry!

Tony left a brilliant comment that should be quoted:

“Enjoy the awesomeness of this world; you have only one chance at life to do so as the odds of experiencing life is immeasurably billions against. Don’t waste it on negativity”

Thanks to all that enjoyed and left feedback on the original post! Hope everyone enjoys round 2!

Southern Oregon Universtity Geology 103 Field Trip

Published
by
Fingel
on May 15, 2008
in Science
. 2 Comments

On Wednesday Dr. Elliot’s geology 103 class went for a field trip. The main focus was on gathering fossil specimens from various locations. The fossils were all found in the Hornbrook formation, contained within Osberger Gulch Sandstone. The rocks were formed during the Cretaceous, which gives them and the fossils an age of approximately 95,000,000 years.

The interpretation is that the sediments were deposited from a beach or shallow marine environment. The abundance of the shells and the broken state of them suggests a high energy environment, so waves must have been present. By far the most common fossils (and original hard parts) were clams and mussels, but gastropods were also present. One lucky student even found a shrimp.

Dr. elliot and 2 students

Dr. Elliot and 2 other students climbing a tilted bed of sandstone on the side of Interstate 5, just south of Ashland.

nice specimin

A nice collection taken inches away from a fault that dampened and softened the surrounding sandstone making it easier to collect

taking notes

Identifying Fossils

scorpion

One of the many local scorpions we found. We didn’t kill it in hopes that it would die in a depositional environment somewhere and make a nice fossil.

removing a fossil

Trying to remove a fossil from the sandstone.

relic

Relic of time.

Amazing Geological Oddities

Published
by
Fingel
on April 13, 2008
in Science
. 124 Comments

Update! I’ve taken some of your suggestions and feedback and written part 2 of Amazing Geological Oddities! See it here: Amazing Geological Oddities Part II

Moving Rocks at the Racetrack Playa, Death Valley California.

Death Valley in California is home to rocks that seem to move on their own. Pebbles to Boulders are found scattered around the “racetrack” with trails that turn, loop, and zigzag behind them. Some of the Rocks move, others don’t. It was thought for some time that magnetic forces were the cause of the phenomena. Scientists now believe that the cause is wind. When there has been enough water to soak the flat clay, and temperatures lower below freezing, it causes tiny ice crystals to form. When the surface of a rock is slick enough in these conditions wind will actually have enough power to move them around, leaving a trail.

The Richat Structure, or “Eye of the Sahara.”

This spectacular landform in Mauritania in the southwestern part of the Sahara desert is so huge with a diameter of 30 miles that it is visible from space. The formation was originally thought to be caused by a meteorite impact but now geologists believe it is a product of uplift and erosion. The cause of its circular shape is still a mystery.

The driest place on Earth, Atacama Desert.

The Atacama Desert receives less than 1mm of rain per year, and at one point not a single drop of precipitation landed on its dry surface for 400 years. It’s caused by the Andes rainshadow; meaning that the trade winds moving east along South America lose all moisture when they slam against the steep slopes of the Andes Mountains. The Atacama Desert is found nestled up against the western slopes of the mountain range. Interestingly, several thousand miles south the winds change direction, and the deserts are then found on the eastern side of the Andes, such as the Monte Desert in Argentina.

The Naica Mine, Cave of Crystals, Mexico.

These caverns found in a mine in Chihuahua Mexico
are home to some of the largest crystals ever discovered and are an impressive sight. The crystals are made mainly of Gypsum, and under these extremely rare conditions were allowed to grow unimpeded.

The Curtain of Fire, Hawaii.

These amazing lava fountains erupted during the first stage of the Puu Oo eruption in January, 1983. The lava created a wall of magma 100-160 feet high along a fissure along the Eastern Rift of Mount Kilauea.

Sinkholes

What could be more terrifying than the earth opening itself and swallowing your entire home? Among other places, this can become a reality in the Southeastern United States. Sinkholes are found in regions of Karst Topography, where pockets of loose sedimentary rock found under the surface can be eroded by groundwater, leaving behind caverns and caves, some of which collapse.



Stone Forest, Southwest China.

The Shilin (Chinese for stone forest) is an impressive example of karst topography. The rocks are made of limestone and are formed by water percolating the ground’s surface and eroding away everything but the pillars.