GeoSleuthing 101 – A Mancos Murder Mystery

I have to apologize to the WoGE community for not posting WoGE #60 sooner – it’ll be up in short order as soon as I’ve got this one posted.

The reason for my delay is mainly because it’s been a busy week of teaching. I’m finally getting a break now that it’s Friday afternoon evening. But in a larger sense, the delay stems from the fact that I was really challenged by Active Margin‘s Where on Google Earth #59, so solving it was really satisfying for me – especially when I discovered that it was in a location that I, too, know and love. I figured my fellow WoGEers might appreciate a little insight into how I went about the task, so I’m writing this post to explain the method behind my madness.

Kurtz: Are my methods unsound?
Willard: I don’t see any method at all, sir.

On many Where on Google Earth challenges having a general sense of the geologic feature in question and its orientation will give one a fairly small portion of the world to search. This is especially true for sites with structural features and only slightly less so for features such as rivers and glaciers. I benefit greatly from the use of my SpaceNavigator in solving such challenges because it gives me the ability to scan large areas very efficiently. (If you use Google Earth on a any sort of a regular basis I highly recommend purchasing one!) This advantage is minimized to some degree when the total field of view is down to a few kilometers or less as it has been on a few recent challenges.

I’ll come back to the use of geology in solving WoGE challenges, but first a couple of general strategy tips. One of the obvious ones is to consider the nature of the imagery itself. Because of the patchwork nature and diverse sources of the satellite coverage in Google Earth it is possible to narrow some searches based on the resolution of the imagery and its general hue. I was able to do this, for example in solving WoGE #48 – the Swiss and German imagery has a rather unique green hue to it. (Some of the western US states have similarly distinctive hues.) Very few WoGE challenges span high and low resolution imagery because these seams are generally easy to recognize and tend to disrupt the feature in question, anyhow. (Someday we’re gonna have a real interesting challenge if someone captures imagery for a site and then Google updates the imagery of that site before the challenge is solved.) Another valuable non-geological tool is shadows. Look for them being cast from clouds and/or steep topography. Shadows cast to the east or west only tell you the time of day the imagery was taken (generally not helpful for this sort of challenge) but shadows cast to the north or south can give you important information about the hemisphere in which the imagery was taken. Shadows cast to the north at midday indicate illumination from the south, and thus a northern hemisphere location and vice versa for shadows cast to the south. (Technically you need to know the season to invoke this rule between the Tropics of Capricorn and Cancer, but as a practical matter this rarely comes into play.)

None of this was much help for me on WoGE #59. The area was small, there were no data seams, the hue did not jump out at me (though perhaps it should have in hindsight), and illumination was from the east, so no info on the hemisphere. In a situation like this I actually didn’t spend much time on this challenge in the first day or so after it was posted. That’s partly attributable to the Schott Rule, but also partly because I figure this might just be in someone else’s back yard and as small as the area is I wouldn’t stand a chance if that were the case. When nobody got posted any comments after a day or so, I decided to give it a closer look. The first thing I did was to try to get a sense of the scale of the meander bends and the ridges. Clearly these were not large rivers, so their orientation didn’t mean quite as much – if you look around the region where I ultimately found it you can find similar drainages in many different orientations. Anyhow, the orientation of the rivers was turning out to be a dead end in terms of locating a general region for the imagery.

The next clue I followed up turned out to be more fruitful. There’s absolutely no vegetation in the imagery – something you’d normally see in an image of this resolution and zoom level. Now that immediately gets me thinking about deserts, but it turns out most deserts have more vegetation than this and/or more prominent wind-related features (of which I could detect none in this image). I spent a lot of time searching the Atacama Desert in South America because it was the bleakest (least vegetation) I could think of, but alas – no matches for the hue of the imagery nor the sharpness of the ridgelines. Frustrated, I gave up for another day or two.

On Oct. 8 Jim dropped the hint about the ammonites and inoceramus. Living, as I do, in a former Cretaceous seaway I immediately understood the significance of the age and depositional setting implied by the clue. My first thought was the chalk beds of western Kansas – was it possible this WoGE was in my own backyard? Well, no, because the chalk beds out here have very distinctive bedding, which would be easily recognizable in this sort of high resolution imagery. And then it began to dawn on me… I hadn’t seen any bedding at all! Sometimes the lack of evidence is as important a clue as the one that is covered in oyster shells. What sort of rock would be deposited in an Upper Cretaceous seaway that wouldn’t display obvious bedding? The Mancos Shale! My attention immediately turned to eastern Utah. (In hindsight, the hue of the imagery might have suggested this, as well.) I first searched the area just south of the Book Cliffs in the eastern half of the area of WoGE #7. I found some really promising drainages there, but none that matched the challenge. After that it was a matter of searching for other properly oriented drainages in flat lying Mancos. It didn’t take too long to find my way down toward Caineville, Utah. Bingo!!! Just south of Factory Butte on the east flank of North Caineville Mesa…

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The actual WoGE #59 spot is somewhere in the middle ground of the left side of this image. I’ve been though this area as recently as 2005, when I took some of these photos in the area.

Back in my first season of graduate field work (summer 1992) I came through this area for the first time on my way back to Wisconsin from California. My field assistant and I had just spent three days in Escalante, UT waiting for the mechanics to fix a busted water pump and serpentine belt on my Jeep. My field assistant was coming down with walking pneumonia from Valley Fever which he had contracted in California – though we didn’t know that until we finally got him treated at the emergency room in Grand Junction, Colorado (almost makes this a “How the Earth Can Kill You” entry). We stopped for a quick dinner at a little place called the Luna Mesa Cantina (below). On their lunchboard they inform their patrons that the restaurant is located at the Ferron Sandstone member of the Mancos Shale. It is the unvegetated and otherworldly Mancos that gives the Luna Mesa its very fitting name. On learning that we were geologists the proprietor gave us a large selenite crystal from the Mancos as a parting gift. I’ll never forget it. I highly recommend stopping by if you’re ever headed through.

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Thanks for the memories, Jim!

Where on (Google) Earth #55?

Apparently Kent has given up on blogging, if not solving WoGEs. That’s too bad – we need all the geology bloggers we can get, IMHO.

With all of the Where on (Google) Earth’s I’ve won and posted, some think I might have seen it all. Not so. I never thought I’d see pink imagery in Google Earth, nor did I expect to find this particular geologic feature in the place I found it. Who knew?

I’ll invoke the Schott Rule (Post time: 23:55 CDT), though I suspect it won’t be necessary this time.

For the newbies: Identify the location of the feature (latitude and longitude will do) and describe the geology as best you can. We’re pulling for you!

Where on (Google) Earth #55

Where on (Google) Earth #54?

I found Brian’s Chinese folds, so it’s again my pleasure to send you off to the far corners of the (Google) Earth. Coastlines are pretty easy to recognize in traditional map view, so I’m showing this one obliquely. It’s still probably not gonna be too hard to find, so I’ll invoke the Schott Rule (post time: 1:20 am CDT), in hopes of giving the newbies a chance.

What do you suppose came out of that hole in the foreground? Find the location and the answer will be as plain as the noses on their faces.

Where on (Google) Earth #54

Where on (Google) Earth #51?

After two volcanoes, it’s time for a river…

I intend the following quote as a (slightly misleading) clue to the location of WoGE #51, rather than a political statement: “The conquest of the earth, which mostly means the taking it away from those who have a different complexion or slightly flatter noses than ourselves, is not a pretty thing when you look into it too much.” Take from it what you will.

Identify the location to claim the right to post WoGE #52, the geology to demonstrate your understanding of the Earth, and explain the multilayered nature of the clue to establish that your grasp of literature is on a par with your knowledge of current events.

Old school map view…

Where on (Google) Earth #51

…or is it?

Using Google Earth to Teach Geology

I first discovered Google Earth back when it was still Keyhole and Google had just bought them up. For the past couple of years I’ve had a free academic license for Google Earth Pro and it has become one of my favorite teaching tools. I regularly use it during lectures to illustrate landforms, discuss geologic events in the news (earthquakes, volcanoes, etc.), and to simply enhance the geographic context of photos. This year, as part of the license renewal process, Google has requested that I share some of my successes with the Google Earth user community. I’m pleased to have the opportunity to do so. What follows are just a couple of the ways I’ve used Google Earth to teach geology.

My idealized use case for Google Earth is one that I’ve yet to actually achieve, though there’s a good chance I’ll be able to finally realize it this semester. My Intro Geology classes generally follow a traditional lecture format, though I often try to mix it up with videos, clickers, and other innovative interactive techniques I’ve learned in large part through the excellent NAGT Cutting Edge workshops. Normally when I teach about geologic process and landforms such as alpine glaciation my lecture will include plenty of photos and a good deal of arm waving, but has traditionally included no significant student interaction beyond my conversational lecture style. What I’m hoping to do this semester, now that a significant number of students are bringing wireless enabled laptops and tablets to class, is to limit my traditional description of alpine glacial features to the first 35-40 minutes of class and then use the final 15 minutes to ask students to go out in Google Earth and find these alpine glacial features for themselves. It’s a very simple exercise, but it requires students to synthesize the material that I’ve been discussing in order to know where to go looking for these features and then recognize the different elements when they find them. Ideally I’d end the class by asking students to each e-mail me a placemark of an alpine glacial feature of their choice, using the description box of the placemark to give a brief account of geologic origin of the landform they’ve identified. In addition to enhancing student engagement with the topic by invoking an active learning style, students would get a chance to experience the joy of discovery in a virtual field experience that I cannot otherwise duplicate here on the high plains of western Kansas. Alpine glaciers are almost the ideal scale of geologic feature to explore in Google Earth, though they are by no means the only one. One could easily adapt this exercise to river systems, coastal features, volcanoes, and regional geologic structures such as anticlines and synclines, to name just a few.

I have also begun employing Google Earth as a component of a number of the “GeoChallenges” that I’ve begun offering this semester. The very first GeoChallenge of this semester offers students credit for solving one of the ongoing “Where on (Google) Earth?Google Earth Placemark” challenges that were pioneered by Brian at his Clastic Detritus blog. Already this semester I’ve had two Intro Geology students successfully solve the Where on (Google) Earth challenge in (relatively) open competition with the general geoblogosphere. Another GeoChallenge invokes Google Earth to get students to explore the geology of their hometown. I expect to offer many more GeoChallenges this semester that involve Google Earth in some way.

Finally, I also used Google Earth extensively last spring in teaching an upper level geomorphology class. Students were given weekly assignments to investigate different types of landforms and I strongly encouraged them to cite examples using placemarks in Google Earth. Although student response to the use of Google Earth in this class was not as enthusiastic as I had hoped, I believe that with refinement this class could make excellent and extensive use of the Google Earth platform.

I’ve certainly got other ideas for using Google Earth for teaching geology (virtual field tripsGoogle Earth Placemark, for example), but it’s time for me to listen now. How are you using Google Earth to teach geology (or any other course)? Got any other ideas for using it that you’d like to bounce off the community before putting into practice? I’d love to hear your ideas and questions.