Saturday, May 1, 2010

Meteor Crater!

I've been remiss in posting the last few days, but it is time to wrap up our trip to Northern Arizona last weekend. Partially because Melinda had never been there, and also because it had been 15 years since my visit, we toured Meteor Crater on the way back to Tucson.

Meteor Crater was the first crater determined to be from an impacting body. It was just 100 years ago this was first suggested, and it was proven less than 50 years ago by geologist Eugene Shoemaker. Before then it was considered of volcanic origin, not a stretch by any imagination because the area around Flagstaff has hundreds of volcanic vents from the now-extinct San Francisco Peaks. The crater lies about 40 miles east of Flagstaff and about 6 miles south of I-40. As I mentioned 2 posts back, the crater is easily visible if you know to look for the raised rim. In fact, we first spotted it from 20 miles away when we first left the conifer forest out of Flagstaff! These two images show it from near the first time we spotted it, and again about 3 miles as we approached it from the north. In the rightmost picture, the visitor center built into the north rim is visible as a dark silhouette towards the left. Click on the pictures to load the full-size image.

While Meteor Crater is a well preserved artifact, probably from a combination of it's recent occurrence (50,000 years) and the dry climate minimizing erosion, it is a relatively small impact crater. Interestingly, one of the largest in North America is in my home state of Iowa. The Manson, Iowa crater is 24 miles (40km) in diameter, and about 74 million years old. It might have been quite impressive, though it was filled in with glacial till during the last ice age.

This is still an impressive hole in the ground! It is about 4,000 feet across (1.2 km), and nearly 600 feet deep (170 m). The crater was excavated in a few seconds by a meteoric body only 50 yards across, the energy provided by it's extreme motion estimated at 8 miles per second.

The last time I was visiting, high winds kept visitors from the outer viewpoints, so with the excellent Spring weather we enjoyed, we got to take the only walking tour they offer as part of admission - a 1 mile out-and-back tour that takes just under an hour. Our guide, John Bacon, did a great job talking about the crater, the mining efforts of Barringer (whose estate still owns the crater and runs the tourist operation), and the natural history of the area. The trail follows the raised rim west from the visitor center and provides great views not only of the crater and surrounding plain, but in good weather like we had, views of the San Francisco Peaks 40 miles to the WNW.

The hike for us ended at "Photo Point", a great viewpoint of the Crater, and John offered to take our pictures with our own photo equipment. How could we turn down such an offer? My question was how do we get permits or permission to continue to walk around the entire crater. The answer is to register for the 3-mile hike which is offered twice a month or so for $50 per person. One needs to contact the office to schedule or join a scheduled tour. Perhaps when we are better organized!

I thought it was a great tour! I took lots of pictures of moderate quality as the sun was high and not providing many shadows. With my growing interest in stereo images, I also took lots of pairs, but I found that it is hard to get much stereo effect of the crater when you are on the edge of the crater... One needs a little more separation from the subject. We'll be back, likely before another 15 years pass!


Andrew Cooper said...

$50/person? Yikes!

When I hiked it a few years back, well... actually like 15 years back, you could hike around it for free. A nice walk, there are a bunch of ruined buildings from the mining activities on the backside.

Dean said...

Hi Andrew-
That is what the guide told me, evidently they don't let you out unescorted, so one naturally would have to pay for a guide. There might be a group discount - I'll confirm when the offices open during the week.


Dean said...

Confirmed today:

A full rim walk is $50 (one time fee) on top of the normal entrance fee ($15 per person) for up to 10 people (you are effectively paying a guide $20/hr). Allow about 3 hours, schedule at least 2 weeks in advance to arrange an off-duty guide to come in.

No unescorted rim hikers...