The time for our next Accretionary Wedge is nigh. I suppose it’s about time for your host to let you know what the topic is, then, innit?
With Curiosity landing at the base of a three mile high mountain on Mars, I think we all know there’s only one sensible choice: we must head for other worlds!
Curiosity’s
first photo of Aeolis Mons (Mount Sharp). The 3 mile high mountain in
the middle of Gale Crater was named for geologist Robert Sharp, one of
the finest field geologists America ever had. He worked with NASA on
several Mars missions before his death in 2004. Image credit:
NASA/JPL-Caltech.
Mountains on Mars
Mercury Messenger’s unprecedented look at a hot planet
Io’s volcanoes
Venus’s bizarre surface
Plate tectonics on other worlds*
Hydrogeology on other planets (and if fluvial morphology is caused by liquids other than water, what do we call it?)
And more!
This
image is the first high-resolution color mosaic from NASA’s Curiosity
rover, showing the geological environment around the rover’s landing
site in Gale Crater on Mars. The images show a landscape that closely
resembles portions of the southwestern United States in its morphology,
adding to the impression gained from the lower-resolution thumbnail
mosaic released early in the week. Image credit: NASA/JPL-Caltech/MSSS
Since it’s already mid-month, I’ll give you a smidgen of extra time to explore: try to have your posts in to me by September 7th. We’ll publish the 2nd week of September.
Don’t miss the rocket – this edition’s gonna be a blast!
So here's my musings for this call.
When I first thought of what to write the first thing that popped into my mind was Meteor Crater. (here's what Wikepida has to say about it Meteor_Crater.) But then I figured lots of other people will probably think of that place too since that is a place that got hit by a meteor and when I think of 'other worldly geology places' I think of worlds covered with meteorite craters. Yet I kept on thinking about Meteor Crater and decided to look at the pictures I took of it back in 2004 just for old times sake. I was disappointed to realize I didn't get a whole lot of pictures because I had just gotten a new digital camera and was trying to figure out how it worked.
While I was flipping my photo album to those pictures I came across the ones for the petrified forest first. I remember at that time thinking how alien that place looked and how it felt like I was on some distant planet and not the planet earth. To me that meets the criteria of 'other worldly geology places.'
Now I have to just say I'm going with northern Arizona so I can cover those two areas since they both struck me as other worldly geologic places with some really neat geology and they are less than 100 miles apart on I-40, which is really nothing when you consider how big the world is.
METEOR CRATER
I first went to Meteor Crater when I was a child of about 10 which was back in 1965. I remembered being all excited about being able to see a place that had been struck by a meteor and wonder how they could tell that. I wondered was anyone hurt when that happened? I thought it was a recent event - and wanted to make sure it didn't happen to me. When we got there the viewing deck was closed to viewing but the museum was still open. I read everything I could and was very disappointed I wasn't able to see it for my self. At least I found out it would be very unlikely for me to be hit by a meteorite and my curiosity about the place was satiated since the meteor hit 50,000 years ago. I vowed to myself that some day I would come back to this place and see if for myself again. And I finally did in 2004 and it was worth coming back to for sure.
And here are the 2 images I got of the place. (the others didn't turn out)
Looking to the western side of the crater rim.
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| Meteor Crater, Arizona (April 2004) |
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| Meteor Crater Arizona (April 2004) |
Geology
The impact created an inverted stratigraphy, so that the layers immediately exterior to the rim are stacked in the reverse order to which they normally occur; the impact overturned and inverted the layers to a distance of one to two kilometers outward from the crater's edge.[22] Specifically, climbing the rim of the crater from outside, one finds:- Coconino Sandstone (sandstone formed 265 million years ago) nearest the top of the rim
- Toroweap Formation (limestone formed 255 million years ago)
- Kaibab Formation (dolomite formed 250 million years ago)
- Moenkopi Formation (mudstone formed 200 million years ago) nearest the outer foot of the rim
I also couldn't leave the place without getting something from there, so I was glad I could get a piece of meteorite oxide from the museum store. Here it is
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| Meteorite oxide from Meteor Crater, Arizona |
When I went out west the first time my family didn't have time for the petrified forest and skipped it in order to go to the four corners. I wished they did go there because once I heard about it I always wanted to see it and was surprised they didn't once I realize how close the two were to each other. Here's what Wikipedia has to say about The Petrified Forest National Park .
In April of 2004 my husband and I decide to visit Arizona. We decided to fly into Phoenix, see lake Montezuma, spend a night in Camp Verde, then go to the petrified forest, spend a night in Winslow then meteor crater, spend a night in Flagstaff and check out the San Fransisco mountains and then head up to the Grand Canyon and spend two days there and then back to Phoenix to catch our plane after he too a course for his continuing ed.. We came to the park from the south- southwest on route 180 and were purposely taking the back roads so we could see the area. My husband had never been in the area before and wanted to see it. Driving the back roads like we did gave us good feel for the place. What impressed me more than anything was driving up to it how desolate everything was. There were very few evidences of man and if it wasn't for the road we were on, I doubt that I would have ever been able to find the place, even though it covers 146sq miles of Arizona.
(in 2011 we got back to Arizona again because that one trip just wasn't long enough and there was so much more we wanted to see and this time we took a plane trip to the Grand Canyon- Here you can see how desolate things really are - we were flying from Phoenix to the Grand Canyon and this is the area the pilot called the Painted Desert. As you can see there's not much out there. Very sparse vegetation.
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| The Painted desert |
Like the meteorite I just had to buy some samples to take home.
Here you can see the edge looking like tree bark and the growth rings of a tree.
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| petrified wood from Arizona |
It is this dry arid climate that lends itself so much to it being so alien and reminding you of 'other-worldly geology places'. Because to me that is the one thing that seems to make our planet so unique - is its abundant water. Every other 'other-worldly geology' place just has the rocks but not the effects of water. Some do have weathering effects due to their unique systems but again they just don't have the same type of weathering like we do as seen on our planet due to water. That's why its was so hard for me to think of a place that reminded me of a distant place - everything I think of has some sort of effect due to water and has lush green vegetation covering it. The petrified forest surprised me at how little vegetation there was and when I did see some I took a picture of it. Enough of my babbling and now here's the pictures I took.
Just look at this log and the size of it. It amazed me that it could still be so well preserved.
Because this log didn't have branches, I could just imagine this pine tree tumbling down some huge river and having all its branches being stripped. Kinda like the logs I see floating in the Red River after a major storm (like right now with hurricane Isaac.) Then it hits the swamps of the delta and gets plopped down in gooey smelly mud. Because the deposition is so fast the environment is anoxic and the log doesn't get a chance to decompose before it is covered over with more sediment. It stays in the ground for awhile in this seal environment. Then to the west a couple of volcanoes blow their tops, kinda like what Mount St Helen's did in the 1980's. The fine ash gets transported into the atmosphere and then slowly settles down into this watershed basin. The ash is high in silica and the conditions are just right for the silicious solution to percolate into the ground and fill in the voids of the tree. Over an extended period of time eventually everything organic gets replace and the tree has now turn into a beautiful stone. Then the area as a whole got uplifted and eventually it was able to weather out of its encasing surrounding shales /sandstones.
It's hard to keep in mind that this area wasn't always so arid. That during periods of glaciation there was a lot more moister in this area and that is when these logs were most likely weathered out. Here's some more images of the arid environment that the Petrified Forest now occupies.
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| Petrified Forest National Park |
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| The Chinle Formation (Triassic) , Petrified Forest National Park. (Apr 2004) |
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| The Petrified Forest National Park |
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| The Petrified Forest national park |
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| The Petrified Forest National Park |
And finally I had to get this picture of this tree trying to grow against the odds.
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| Petrified Forest National Park |
I muse: I think the reason we probably couldn't go to the viewing area at Meteor Crater was because they were most likely training the astronauts for the moon mission. When I went again they had a whole display about it at the museum. I wish we could have seen that - I'm sure I that would have been so neat to tell people when I got back home.
I muse: You would not believe the problems I've had trying to get this post done. Needless to say hurricane Isaac is wrecking havoc on our cable system/ internet system. It keeps on knocking it out.- I was hoping by Aug 31 it would be working again but it's not. I've kept this short because of that.
I muse: At the time I took these photos I was still used to taking film photos and were used to be limited to 24-36 images at a time- I would take images sparingly so I wouldn't run out of film or in this case space. I had no idea I could get so many images on one disc. Now I take all that I want and just delete the ones I don't - and only print the ones that I really like. Oh how the times have changed in just 8 short years.
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