Airliner geology
16 messages in this thread
Hi, folks–
As I write this, I am flying over Utah/Colorado at 40,000 feet. For the third
time in recent memory, I have gotten a good look at the Grand Canyon from high
altitude. Choosing connections that pass over the Grand Canyon and the Rockies
in daylight, and trying for a window seat have paid off again. Luck remains in
my flight not being delayed (as it was until dark on my outbound trip), clouds
not covering the interesting stuff, and in getting a window without the
corrosion (which I hear is caused by Pinatubo and other volcanic eruptions). I
had to settle for the usual corroded window, but the rest was great.
This time was unique in that snow had fallen on the tops of the mesas and some
of the slopes, but left lower areas and vertical faces bare. The color
contrasts are beautiful and help draw contours to help one understand what one
is seeing more readily. Parts of the canyon looked even more like layer cakes
than normal with snow-white alternating with rust.
I am flying from greater L.A. in Calif. to Denver and then back to OK city. The
same snow-highlighting of similar terrains of the Colorado Plateau continued as
we flew toward Utah and maybe Colorado before clouds closed in. Some of the
reds there made even more impressive contrasts with the snow – I sort of
remember being overwhelmed by redness and less impressed in past snow-less
overflights.
A short while after the Grand Canyon, I saw a fairly flat part of the Colorado
plateau with a narrow nearly-linear feature of great length prominent – it
involved sharply uptilted rock layers and did not seem to be any sort of
river-generated feature. It crossed the flight path – if no special turns were
involved (to see the canyon?), it would have been running
northwest-to-southeast. Is there a major fault thereabouts? My second guess
would be an anticline just barely peeking out of the general strata – but it
seemed rather narrow for that.
Do not let the possibility of bad weather put you off some really interesting
geological viewing when choosing your flights. A really good look may take
several tries, but it can be well worth it!
Well, I was flying yesterday, but now I am writing on the ground. I let my
battery run out before exiting OzCIS, and clobbered my forums database,
forbidding further activity until I could repair the damage using backups at
home.
–Doug
"I saw a fairly flat part of the Colorado plateau with a narrow nearly-linear
feature of great length prominent – it involved sharply uptilted rock layers
and did not seem to be any sort of river-generated feature."
The Waterpocket Fold, San Rafael Swell, and Comb Ridge are all in the general
area east of the Grand Canyon and trend in NW-SE directions.
jf
Hi, Jim–
Thanks for the candidates, now I have something to ask people about. With
names like fold and swell, they sound sort of like anticlines.
I neglected to mention that I spoke of uptilted layers because they were
jutting into the air on either side of the midline. It reminded me a bit of
Vasquez Rocks in the San Gabriel Mts. of southern Calif., which have appeared
in assorted movies and shows, including a couple of Star Trek (the Kirk/Spock
generation) episodes.
–Doug
"…including a couple of Star Trek (the Kirk/Spock generation) episodes."
That description fits about 99% of southern UT. <g>
If the ridge looked like giant flatirons or Stegasaurus plates were leaning up
against it, I'm more inclined to think it was the San Rafael Swell or Comb
Ridge.
jf
Hi, Jim–
Stegosaurus plates or flatirons make a good description of what I saw.
Southern UT may have lots of interesting and comparable topography, but Vasquez
Rocks is much more accessible to Hollywood (under an hour's drive from there),
thus it gets to be a star often. It also has (or had) a mock fort that
moviemakers find handy now and then – I recognize it in the start of the
"Arena" episode of Star Trek.
–Doug
"…I recognize it in the start of the "Arena" episode of Star Trek."
Yes, but are the rocks really made out of papre maiche(sp?)?
My wife and I are going hiking in southern UT over spring break. If you're
flying over, have the pilot dip the wings and we'll wave.
jf
Hi, Jim–
The ersatz fort is flimsy, and they might have added a papier-mache rock here
and there for any given scene, but Vasquez Rocks has lots of picturesque rocks
that a geologist would have no complaint about.
I see in my mind's eye a wild bighorn sheep leaping gracefully from rock to
rock, then … whoops, a left-over prop!
–Doug
I dunno may be we should retitle the thread movieland geology.<g>
Have you ever been to Monument Valley on the Navajo lands near Kayenta, AZ?
John Ford shot many westerns there. It is awe inspiring what a little water and
a lot of time can do. My wife and I have watched more bad movies (usually
westerns) trying to figure out where they were shot based on the rocks than I
care to remember. A car commercial in which red rocks are featured (roughly 80%
of them) will stop our channel surfing any time.
jf
Hi, Jim–
I have paid more attention to mineral collecting sites in past trips through
Arizona, but seeing the landscape on the way to Tucson shows (world's biggest
gem/mineral/fossil show, early Feb. each year) from L.A., and seeing geology
out of an airliner window (there, we are back on topic again!) has broadened my
interest in seeing geological features too big to take home. Maybe when I am
moving back to CA…
–Doug
Doug:
Your message reminds me of a flight I took in 1988 from Miami, FL to Calgary,
AB via Orlando and Salt Lake City, UT. I also got the "geologist's seat"
(window seat, ahead of the wing) and saw some remarkable scenery. By far the
most interesting sight over Florida was the abundance of perfectly circular
lakes and ponds surrounding Orlando. I presume these are the result of
karsting/sink-hole collapse in the limestone bedrock (?).
I was also astonished at the Basin-and-Range district in the Wyoming/Utah area.
My view of this area was nearly perfect, and the structure of the whole
Basin-and-Range district (including the Great Salt Lake) appeared in textbook
clarity, exactly as described in John McPhee's book "Basin and Range" (a book I
highly recommend to anyone interested in geology).
Other points of interest I remember from my flight were a set of small, perfect
cinder cones that I believe were probably in southern Idaho, and the huge,
gaping pit of the Anaconda copper mine near Helena, MT.
H.A.
PMFJI
Airline geology is vivid.
Also comfy and the best reason for planning seating.
The perspective allows a good imagination to see the sequence of events.
some favorites….
I saw an extruded vertical wall somewhere in northern mexico. It appeared to
be no more than 100 feet wide rising approximately 800 feet above the valley
floor and ran for miles in a slightly serpentine manner.
The view from Denver to Vail is the great! The flat planes are upturned Where
the upthrusts ends. The tumbled and tilted crustal sections littered in the
area between the plains and the Gore Range. Nice ride on the ground also.
Grand Canyon and others…wow what a planet!!!
Kamron
Kamron
(Excuse my newbie naivete–don't know what PMFJI means!)
Your description of the igneous dike in Mexico sounds interesting. I've never
seen anything like that.
Something you Americans probably don't see too much of is glacial landforms,
which can be pretty wild when seen from the air over much of Canada. In my
various flights over western Canada (including the arctic), I've seen textbook
examples of such landforms as drumlins, eskers, huge abandoned meltwater
channels, and fields of stabilized barchan (ie small, crescent-shaped) sand
dunes. One of the weirdest sights is fields of "prairie mounds" which are small
(maybe 20-30 feet in diameter) donut-shaped mounds supposedly caused by melting
blocks of ice in the glacial gravel deposits.
The delta of the Mackenzie River, near Tuktoyaktuk, Northwest Territories, is a
classic locality for pingos, huge blisters of permafrost swelling up on the
surface of the tundra. As well, I was amazed to see enormous areas of the
Northwest Territories (more than an hour's worth of flying time in a 737, as
far as the eye can see) covered in glacial-lineation features, such as
elongated lakes and ponds and till ridges, all oriented in the direction of
ice-flow from the last ice-age.
Howard
>> PMFJI means!)<<
I take it as Pardon Me for Jumping In.
>>Your description of the igneous dike in Mexico sounds interesting. I've
never seen anything like that.<<
>>Something you Americans probably don't see too much of is glacial landforms,
which can be pretty wild when seen from the air over much of Canada. In my
various flights over western Canada (including the arctic),<<
Only small areas in the Rockies.
>> I've seen textbook examples of such landforms as drumlins, eskers, huge
abandoned meltwater channels, and fields of stabilized barchan (ie small,
crescent-shaped) sand dunes. <<
Sounds very interesting most of my flights have been at lower latitudes. Since
you seam familiar with glaciers have you inspected the moraine often? I have a
unsettled problem with the formation of gravel. Isn't the gravel very rough
surfaced in the moraine?
>>One of the weirdest sights is fields of "prairie mounds" which are small
(maybe 20-30 feet in diameter) donut-shaped mounds supposedly caused by melting
blocks of ice in the glacial gravel deposits. <<
I have seen those in National Geographic. Is there more of an
explanation..sounds tough donut how big do they look.
Another thing I got from the air is that there must have been crustal
distension…. that is a cracking and spreading of the earth occurred that
allowed the crustal blocks to fall over.
Kamron
Kamron:
>>Since you seem familiar with glaciers have you inspected the moraine often? I
have an unsettled problem with the formation of gravel. Isn't the gravel very
rough surfaced in the moraine?<<
That depends on the moraine! Moraines in alpine glaciers generally have rough,
angular clasts, since most of the gravel is ground from rock surfaces on the
valley walls, or consists of fragments that have fallen onto the surface of the
glacier from overhanging cliffs or rock-slides. In any case, the clasts have
not been transported very far from their origin, and thus haven't been rounded.
As well, you sometimes see grooves or striations on these clasts, from their
being ground over bedrock and/or larger boulders.
On the other hand, the big continental glaciers and large valley glaciers have
been bulldozing everything in their path, including old soil and gravel
deposits that were originally rounded and reworked by pre-existing rivers.
These moraines contain a mixture of rounded and rough clasts, as well as a
great deal of very fine (to clay-sized) material. The distinctive feature of
moraine deposits is their very poor sorting–everything from house-sized
boulders, down to clay, all mixed together.
>>I have seen those in National Geographic. Is there more of an
explanation…<<
The explanation I got from my geomorphology prof. was roughly as follows: as a
big continental glacier begins to retreat due to melting at the toe of the
glacier, masses of stagnant (ie melting) ice begin to break up into discrete
blocks. Some of these blocks happen to be buried under a thin layer of till
(gravel), which begins to slump off on all sides of the ice block. The block
eventually melts completely, leaving an empty pit, surrounded by a ring of
gravel. I don't blame you if you're not totally convinced by this explanation
<G>.
Howard
>> Some of these blocks happen to be buried under a thin layer of till
(gravel), which begins to slump off on all sides of the ice block. The block
eventually melts completely, leaving an empty pit, surrounded by a ring of
gravel. I don't blame you if you're not totally convinced by this explanation
<G>. <<
a little thin but Not bad…. the infant donut pools water in its center and
freezes and thaws and slowly pushes the stones outward while ponding in the
areas between donuts corals them inward. The expanding ice moves the stone and
then releases it on thawing.
Your description of the glacial morains is much as I anticipated.
Most all gravel beds do not include the rough stones that are obviously part
of a grinding process.
When looking at landscapes I try to also invision a rapid creation cycle of
the basic components of the area…that is a cataclysmic catastrophy senario
where a uniform flat landscaped earth was hit by a huge meteor or anouther
favorite a Stellar flyby that ripped off the missing continental mass and
jumbled the remaing continetal crust into the distended tumbled domino
mountains and ripped apart fractures…the canyons and river valleys ect. The
KT boundrey marks when it occurred.
When reviewing both processes the rapid event wins most likely to me.
I love the planet earth and the story of how it all came about is carved into
her, there is more than one good answer to most geological histories.