Sunday, July 18, 2010
A Dream Like I've Never Had Before
Saturday, July 17, 2010
Petrified Forest National Park
Thursday, July 15, 2010
Sunset Crater Volcano National Monument
Walnut Canyon National Monument
Meteor Crater
Yesterday (Wednesday) we visited another big hole in the ground, this one not formed from earth’s natural processes, but from something extraterrestrial.
Meteor crater was formed 50,000 years ago when an iron-nickel meteorite (meteors stay in the sky, meteorites hit the ground) struck what is now the Arizona desert. The meteor is estimated to have been about 150 feet across and weighed several hundred thousand tons (a 2-foot wide, 1,400-pound fragment of it is pictured, above left). It struck the land with an explosive force greater than 20 million tons of TNT. During the crater’s formation, over 175 million tons of rock were thrown out a distance of over a mile. Large blocks of limestone, the size of small houses, were heaved onto the rim and flat-lying beds of rock were overturned or uplifted as much as 150 feet.
The crater made a hole in the rocks of the Kaibab Limestone and Coconino Sandstone from 260 million years ago. The crater is over 4,000 feet across and 550 feet deep. Originally, the crater is thought to have been 700 feet deep (as tall as a 70-story building) but erosion has transferred the topsoil over time. The circumference is 2.4 miles.
How do scientists know that the crater isn’t a volcanic caldera? After all, people argued over its origin when it was first discovered in 1871. Local settlers just thought it was part of the Hopi Buttes volcanic field northeast of the site. After many years of study, scientists have concluded that it is definitely not volcanic and that it is the result of an impact. There is the presence of many meteorite fragments on the northeast side of the crater. Plus, two minerals: coesite and stishovite were present in the rocks, both high-pressure forms of quartz that were altered by the extremely high pressure of the impact. These minerals are not found in volcanic craters or rocks.
During 1964 through 1972, the US Geological Survey and NASA provided science and sampling training for the Apollo astronauts because scientists were interested in what kind of materials might lay on the moon’s surface and below.
Collisions have occurred since the beginning of the solar system and will continue to occur. Collisions the size of the one that hit Meteor Crater average every 50,000 years. It’s time for another one so luckily scientists are “looking” to the skies with their high-powered digital telescopes.
Some information came from what I learned from the museum displays and from a pamphlet handed out at the fee station called, “Meteor Crater: Brief History.”
Wednesday, July 14, 2010
The Grand Canyon in One Day
Yesterday we spent the whole day at the south rim of Grand Canyon National Park. As I mentioned in a previous blog entry, the last time I was at the Grand Canyon was 15 years ago but that time we only explored the east side of the south rim. I don’t remember whether we explored the west side of the south rim or not when I came here when I was 9, but in any case, we went al the way west to Hermit’s Rest and all the way east to Desert View this visit. We walked the rim trail as often as we could and took the shuttle bus when we didn’t.
Information on the Grand Canyon is all over the Internet and in many publications already so I won’t give an in-depth geologic history lesson here—just some basic facts.
The Grand Canyon cuts down into the Colorado Plateau that stretches north to Utah, northeast to Colorado, and east to New Mexico. At the south rim, the elevation is 7,000 feet. The Canyon spans almost 2 billion years of time from the basement rocks of the Vishnu Schist to the 270 million year old Kaibab Limestone at the top. Below the Kaibab Limestone is the same Coconino Sandstone and Hermit Shale exposed in the Sedona rocks.
Monday, July 12, 2010
Cathedral Rock
The Verde Valley and Back to Sedona
Sunday, July 11, 2010
Red Rock State Park
Saturday, July 10, 2010
Fay Canyon Trail & Cathedral Rock, Sedona
Some Sedona Geology
Rocks in Red Rock Country are old. From the bottom to the top layer, you can observe about 80 million years of sediment deposition. It's like a giant layer cake with each layer being its own type of rock (sandstone, limestone, siltstone). Each layer was deposited in its own geologic era. Some layers were deposited in shallow seas, some in river deltas and flood plains. Some layers are hardened sand dunes. All of these strata were laid down, one on top of the other, during the Paleozoic Era. During this era fishes dominated the oceans and plants and amphibians were just starting to live on land.
About 350 million years ago the area that is now Sedona was covered in an ocean. Water would fill the area and then retreat over and over again for many eras. Seashores, lake beds, and sand dunes would build up and then erode away.
The red sandstone is evidence of the old sand dunes and beach deposits from long before. Wind would shift the dunes and create patterns of lines called cross beds. Eventually the dunes were cemented into sandstone by iron oxide (causing the red color) and calcium carbonate.
About 225 million years ago the tectonic plates in the region collided and slid. To the north, the Rocky Mountains were pushed up. But in the region that is now Sedona, the Pacific and North American plates slid alongside each other (this is now evident on the southern coast of California with the San Andreas Fault). Eventually, the heavier plate sank and lifted the lighter plate up, creating the Colorado Plateau north of the region.
The Arizona portion of the plateau’s edge is called the Mogollon (MUH-gee-yon) Rim. During this tectonic ballet of sorts, volcanic activity was abundant. Eight million years ago, a volcano erupted with massive flows of lava, leaving black-gray basalt over the red sandstone.
I can’t wait to explore the area and discover the different rock formations with creative names such as “Coffee Pot,” “Snoopy,” and “Bell Rock.” There is something truly relaxing about looking at rock formations and finding shapes within them.
Friday, July 9, 2010
Some Sedona History
Monday, July 5, 2010
Sedona's Vortexes
"There are four main energy vortexes in Sedona. The subtle energy that exists at these locations interacts with who a person is inside. The energy resonates with and strengthens the Inner Being of each person that comes within about a quarter to a half mile of it. This resonance happens because the vortex energy is very similar to the subtle energy operating in the energy centers inside each person. If you are at all a sensitive person, it is easy to feel the energy at these vortexes."