Tell us about your beloved geosites

Mima Mounds near Olympia, Washington. No one has actually figured out how they came to be. Photographed here using kite aerial photography by yours truly.

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The Pinnacles near Hollister, CA is now a national park. It is a granite volcanic site that is slowly ā€œfloatingā€ north in the coastal valley of California.enter link description here

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Long Island, NY - a feature that did not exist prior to the last ice age.

Discovering that LI was a southern-melt-point for glaciers and built up as their debris came free was mind-blowing.

That and the learning about Lake Hitchcock and the change of the ancient river course from the New Haven to Old Saybrook.

Ice is pretty powerful.

Iā€™m sure there are similar stories all over the planet, but I just moved to CT 3 years ago, and learning about these features had an bigger ā€œwow factorā€ than anything I remembered from growing up in South Dakota. (Native America mound-building didnā€™t even interest me back then, and I wail and gnash my teeth that I never saw such sites when I was closer to them.)

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Iā€™m a geologist DO NOT MAKE ME PICK JUST ONE!

(So here are two)

Channeled Scablands - Eastern WA,
The most impressive thing for me is that Bretz theorized they were formed by floods without the benefit of aerial photography, and prior to the understanding of the Pleistocene glaciation as a source of the tremendous volume of water needed to create the landforms.


The Great Unconformity within the Grand Canyon - The gap in time between the rock layer Iā€™m sitting on and the layer to my back is on the order of one billion years.

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Denali (Mt. McKinley), for a few reasons:

  • it has a roof pendant, which is cool in itself; to see the contact between a batholith and the country rock, but additionallyā€¦

  • the roof pendant is made of much more erodable rock than the granite that comprises the bulk of the mountain. Despite that, itā€™s been uplifted thousands of meters over the past 7 or 6 million years probably because erosion has been slowed to nearly nil at the summit due to the consistent cold (the glacial cap on top of the rock is frozen to its bed, so there is very little to no erosion due to abrasion)

  • it owes itā€™s height, at least partially, to the fact that it sits at a kink in the arc (a syntaxis) of the Denali Fault, so itā€™s getting popped up like a grapefruit seed.

  • the Wickersham Wall on the north side has one of the highest reliefs found on Earth.

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Kata Tjuta,

https://www.flickr.com/photos/64262643@N00/3777732626/in/photolist-6KPSi9-6KQ9My-6KRhW7-6KV85R-6KZ6nu-6Rt9YU

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Chief Mountain, Montana. A rare example of older rock sitting on top of younger rock. Plus, itā€™s visible from almost 100 miles away, and is just plain awesome.

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Ditto. :smiley:

Atlanta sits on the Chattahoochee river. It is a long, straight river that cuts diagonally across the state. It is straight because it run down the Brevard fault. The Brevard fault is a suture from an old plate collision. Everything north of it is part of the North American Plate. Everything south of it now is part of North America but used to be part of northwest Africa. Nearby, you find Stone Mountain, what is left of an ancient volcanic plug. This is the only above ground part of an enormous granite formation on which the entire city sits. That granite formed from lava which cooled underground, and that lava in turn was associated with the original opening of the Atlantic Ocean 130 million years ago. The granite is iron-rich and when it weathers, it turns to red clay. A little further west, in northwest Georgia, you find the beginning of the ridge and valley system. This is a set of folds formed 480 million years ago, during the plate collision that created the Brevard fault, and the Appalachian Mountains. But before that, it was sedimentary rock from the bottom of an inland sea, the Appalachian Basin, uplifted and bent by the collision. Since this collision connected North America and northwest Africa, these Appalachians are part of the same mountain chain as the Atlas Mountains. So salutations to my brother highlanders in Moroccan Appalachia.

Thereā€™s cool geology everywhere if you know how to see.

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The John Day Fossil Beds National Monument, in eastern Oregon. Above, MarkDow has already recommended the Big Obsidian Flow in central Oregon. That area has had some crazy volcanic activity over the millennia. The John Day Fossil Beds had 3 different, and dramatic, areas. One has wildly convoluted lavender cliffs, another has hills in pure red or yellow. The third is bands of color. The landscape surrounding this is beautiful high plains desert.
Hereā€™s the park website

A lot of the Oregon coastline is dramatic cliffs, and thanks to some visionary government behavior way back when, itā€™s lined with state parks, so you have tall fir trees marching up the hillsides to the cliffs. Gorgeous. My favorite spot is Ecola Park.

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Devilā€™s Postpile Natā€™l Monument, So. Calif.

http://www.nps.gov/depo/index.htm

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Southern Illinois has very dynamic geoligy, including Liesegang Banding, here is my flicker page with some of that!

Well looky thereā€“I didnā€™t know itā€™d been designated a National Park, but good on it. Iā€™ll second Pinnacles as being a kick-ass spot on earth.

Can I just go ahead and pick the whole Sierra Nevada mountain range? Itā€™s wild, wooly, and wonderful, and itā€™s got the highest peak in the CONUS, Mt. Whitney.

The Alabama Hills, just downwind of Mt. Whitney are also beautiful in their own right.

Anything in Zion National Park is kick-ass, and really, letā€™s be honest, most of Utah could be included on this list.

The Badlands in South Dakota are awesome as well:

@leicester had it rightā€“I have to pick just one?

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Came to endorse the same. Specifically, the Dells, Devilā€™s Lake and Spring Green.

yes! iā€™ve camped on east lake (lake in the caldera on right of the image here). itā€™s an incredible place surrounded by incredible places. oregon rules.

lots of OR suggestions in here. love it. @Wooster mentioned ecola state park which is in the greater Columbia River Gorge national scenic area. favorite place to backpack, ever:

i84 is that road in the lower left: unfortunate for the scenic area, fortunate for Portlandā€™s economy.

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Iā€™d like to nominate the entire state of Hawaii. With 10 of 12 (or 13, or 14ā€¦) climate zones on just one island, how can you go wrong? Not to mention a drive-up volcano, currently active!

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Waimea Canyon at the top of that list, for sure.

ā€œPlease pull up to the second caldera to pay for your order.ā€

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