Geology of New Mexico -- PFF

This week I went through my unfiled papers drawer in my office and dug deep and found, yes, more geology postcards! After going through the west of the USA, we'll have to head east again for CT and VT. Anyway...
Welcome to Postcard Friendship Friday, hosted by Marie at the French Fractrice.

This is an oversized postcard (6 by 8 inches) published by the New Mexico Bureau of Mines and Mineral Resources, 801 Leroy Place, Socorro, NM. I have scanned it at a higher resolution than usual so there should be detail visible if you double-click on the image.

The back has a good summation of the general geologic history and so I will quote it here, with my comments in [ and ] brackets.

"The rocks of New Mexico reveal a long and complex of deposition, volcanic eruptions, structural deformation [due to plate tectonics as described in earlier posts], and climatic extremes -- from intensely folded Precambrian cores of mountain ranges more than 600 million years old to black basalts that flowed across the landscape as recently as 900 AD. White sand dunes today move slowly across the world's largest gypsum [a calcium sulfate mineral] desert, where waves of water once broke upon the shores of vanished lakes. New Mexico's extensive mineral and energy resources are a result of this colorful history -- petroleum and natural gas, coal, copper, uranium, gold, silver, molydenum [used for specialty steel] , lead, zinc, barite [a source of barium], fluorite [mined for fluorine, used in industry], gypsum [mined for drywall, aka sheetrock], perlite [see Wikipedia entry] , potash [used in fertilizer], and sand and gravel."
A Virtual Geologic Tour of New Mexico from the Bureau.

Major cities shown on the map are Farmington, Santa Fe (the capital), Albuquerque, Socorro, Las Cruces, and of course, Roswell.

Viridian

Sentimental Landscape

This card is Tuck's card, mailed from London Jan. 23 1907 (and postmarked 10 AM!) to Littehampton. It is part of the series "Picturesque England" and depicts Hayes Common near Bromley.
The cryptic message is:
"I feel very selfish about Nell, really the time flies so quickly & I am afraid that Local work takes up more of my time than it should, however, I have written asking her about a trip to town, which we arranged for at Christmas. Writing later about steamer (?) A."

"Town" would be London, and steamer refers to a ship, but beyond that.....
We'll just have to let the veil fall between us and the past.

viridian

Geology of Nevada: Postcard Friendship Friday

I have already blogged about my Geology of Utah postcard (on July 3!), so it's time to move on to Nevada. Utah is to the east, Idaho to the north, California to the West. the large areas of orange to the north of Nevada are fairly young volcanic rocks that extend into Idaho. there are some orange blotches to the south too. Note the pink, purple and blue bands oriented north-south, with pale yellow in between. This is the Basin and range part of the North American continent.

[The following information is from a remote sensing tutorial published by NASA.]


Major C.E. Dutton, an early explorer of the American West, described these mountains as they appeared on a map as resembling "an army of caterpillars crawling northward out of Mexico".

Hmm, I see what he's saying. Below is a color - coded relief map (relief: the ups and downs of the landscape) of NV.

The mountains are uplifted parts of older continental crust. This area was being pulled apart, slowly, and the pieces in-between sank lower. The valleys are filled with a lot of sediment that has eroded from the ranges and partially filled them up. This is what the area looks like from the air.
[End quoting]
Some of these peaks are significant. Wheeler Peak in Great Basin National Park is about 13,000 ft (4000 m) tall. What little rain or snow there is falls on these peaks and so the heights are green with pine trees, even white with snow. It is quite different from the dry, hot, desert valleys in between!

There is a wonderful part of the East Humboldt Range where erosion had sculpted the ridges in amazing ways, and the ridge is so thin that there is a hole right through it! This, of course, is called the Hole-in-the-Wall (or Lizzie's Window), near Hole-in-the-Wall Mountain. Please see this website for hiking in the area. The photos are amazing, but copyrighted, so I am not going to reproduce them here.

Las Vegas is way to the south of the state. Many areas in the middle of the state are very sparsely populated. With renewed gold mining in some areas in the north, population has grown somewhat.
Much more detail from about.com: http://geology.about.com/library/bl/maps/blnevadamap.htm
Nevada Bureau of Mines and Geology: http://www.nbmg.unr.edu/

Viridian

Geology of Wyoming: Postcard Friendship Friday

Welcome to Postcard Friendship Friday, hosted by the lovely Marie at http://www.cpaphilblog.com/

"Geology - interpreting the past to provide for the future"

From the back of this postcard.
"This Geologic Map of Wyoming was reproduced from a part of Geological Highway map n. 5 (1972), Northern Rocky Mountain Region, published by the American Association of Petroleum Geologists, P.O. Box 979, Tulsa, Oklahoma 74101. For a free publications list or for information on geologic and topographic map coverage of Wyoming, contact the Wyoming State Geological Survey at 307-766-2286."

Oh boy, now we are getting into complex geology. And some fantastic scenery.

The big red blob in the northwest corner of the state is Yellowstone National Park, worthy of many postcards and blog posts. South of there is Jackson Hole.

The large oval-ish brown blobs (one is under the "W" in Wyoming) are large blocks of continental crust that have been thrust upwards by plate tectonics, often bending the flat-lying surface rocks above them. The dark green and other colored rocks in the northeast corner are the WY part of South Dakota's Black Hills. Devil's Tower is also nearby. Cheyenne, the capital of WY is in the south east corner and Interstate 80 meanders across southern Wyoming.

Wyoming has many natural resources, including oil (in the aformentioned bent rocks), natural gas, coal, and uranium. A shot from NASA, showing the mountain ranges topped with snow (and portions of other states):

viridian

PFF: Geology of Montana

Nothing too creepy from me, but see Postcard Friendship Friday for more from our hostess Marie and other people playing along. I'll skip the catacombs of Paris, thank you.

Today, the big wonderful state of Montana. Haven't been to the Big Sky country? Please go, for it's really beautiful. Yellowstone is in that inside corner. Glacier National Park is not to be missed.

The legend shows igneous rocks in red and pink. Very old rocks (over 1,000,000,000 years old) are in deep orange. Lighter orange is a formation called the Belt Supergroup. This is a very thick layer of different sedimentary rocks, some with pretty coarse (boulder-sized) stream sediments. Big mountains had been uplifted nearby and were eroding in a hurry.

The blues and greens are younger, Cretaceous or the time of the dinosaurs. There are some famous fossil localities in the general area of Great Falls.

Much later, bits and pieces of the Western USA came crashing into the North American continent. In a previous post I had described mountain building as a process similar to a carpet on a hardwood floor rumpling. Here, the push was so hard and so sustained, the rocks broke along faults and slivers were pushed up on top of other pieces. Think of how you can bend a piece of wood, but if you keep bending it, it will break. The faults are shown as thin black lines, esp. in northern Montana.

The other thing to note is the white line with hash marks along it. This is the extent of continental glaciation at the height of the last Ice Age, a pretty recent event in geologic time.

Ok, enough geology, I can see your eyes glazing over. Remember, there's a quiz next Friday! ;-)

Montana Bureau of Mines and Geology (MBMG)

USGS links for Montana

Glacier National Park

viridian

Postcard Friendship Friday - Postcard of Bedrock of Nebraska

Hello everyone to one of my favorite memes, hosted by our wonderful leader Marie, at Vintage Postcards.

Remember I am going through the USA from generally east to generally west, so hold on please for Montana and California.

We have the cut away block diagram and the legend or key on the right side, with youngest rocks (yellow orange) on top and older rocks (greens, then blues) on the bottom. Gee, just like the rock layers in Nebraska.

From the back:

"Block diagram of Nebraska Geology, on front, is available in The Groundwater Atlas of Nebraska from the Conservation and Survey Division, as is the Geological Bedrock Map of Nebraska and other maps and publications.

Nebraska Geological Survey

Conservation and Survey Division

113 Nebraska Hall

University of Nebraska-Lincoln

68588-0517"

Well! In the center of the continent there are many layers of flat-lying rocks. The bright pink at the bottom represents the old old basement rocks of the Precambrian. The thick gray layer is the Pierre (pronounced 'peer') Shale, named after the city in South Dakota, which after all is the state just north of Nebraska.

The state website is: http://www.nebraska.gov/dynamicindex.html.

The rolling plains of the American West is here, especially in the Sandhills region of north-central Nebraska. See these beautiful photos of this area. I have driven through here, and it is a beautiful place, empty of humans, but full of grass, sky, and wind.

And FYI: Willa Cather spent her formative years in Red Cloud, Nebraska.

Bedrock geology of Wisconsin PFF

With our lovely hostess Marie at Vintage Postcards. Her postcard and story this week ... Shocking!


Not so shocking: Bedrock Geology of Wisconsin

From the back: :An example of one of many maps available from the Wisconsin Geological and Natural History Survey. Write to the M.A.P.S. Office for a free list of publications.
Geological and Natural History Survey, 3817 Mineral Point Road, Madison, Wisconsin. "

Here in Wisconsin there are older flat-lying layers of sedimentary rocks of Devonian and Ordovician in age, but also some much older rocks. See the geologic time scale on this web page. There is also a PDF (handy when reading my blog ;-) )

Those purple and lavender rocks in northern Wisconsin are about 1000 million years old! The patches of orange are even older, about 2500 million years old! These rocks have been metamorphosed and folded - hard to escape that when you have been around so long.

There is an area in west-central Wisconsin that was not covered by ice during the last glaciation event in the Ice Ages. How do they know? because there are no piles of glacial sediments as there are in most parts of North America, and Northern Europe and Asia too. This is still pretty difficult to explain.

Catch up on your geology postcards:

Illinois

Florida

Oklahoma

Alabama

Tennessee

Kentucky

New Jersey

New Hampshire

Massachusetts

Utah

Viridian