Friday, November 27, 2009
Thursday, November 19, 2009
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.
Tuesday, November 17, 2009
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.
Thursday, November 12, 2009
[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.
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/
Thursday, November 5, 2009
"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."