It’s all fine and good to enjoy the breathtaking geological vistas of our National Parks, but what drives the student of the Earth is reading her rocks to attempt to understand her past. So go ahead and get your noses up against this outcrop and do your best to interpret what you can see here. This is a “no hammer” outcrop. Take as much time as you need and place your answers in the comments.
Back in June 2005, before I owned a GigaPan (indeed, before GigaPans even existed), I passed through Bryce Canyon National Park just in time for an afternoon cloudburst. So for my Wednesday entry in Evelyn Mervine’s Geophoto Week I present you with some squeaky clean hoodoos.
“This color view of a mineral vein called “Homestake” comes from the panoramic camera (Pancam) on NASA’s Mars Exploration Rover Opportunity. The vein is about the width of a thumb and about 18 inches (45 centimeters) long. Opportunity examined it in November 2011 and found it to be rich in calcium and sulfur, possibly the calcium-sulfate mineral gypsum.” –NASA Image Credit: NASA/JPL-Caltech/Cornell/ASU
Back here on Earth you may be more familiar with veins filled with quartz or calcite. But make no mistake, if you find an environment on Earth that resembles Mars, you can find plenty of gypsum veins here, too. I had the good fortune to GigaPan just such an area on the south side of the San Rafael Swell two summers ago. The GigaPan below (and subsequent photographs) illustrate a variety of gypsum veins, as well as some nice faults, crosscutting the Jurassic Summerville Formation (itself composed mostly of shale and bedded gypsum evaporites).
A little over a month ago, while my geoblogging juices were really flowing, a late night rumble inadvertently inspired the theme for this month’s Accretionary Wedge. My own blogging pace has slacked off since then and perhaps yours has too, what with the pressures of the end of the semester and #AGU11. With any luck though, we’ll all have a chance to take a little time between final exams and the holidays to revisit our geoblogs and spread some geological holiday cheer.
Right, then. Your mission, should you choose to accept it, is to relate the story of the most memorable or significant geological event that you’ve directly experienced.
What we seek for Accretionary Wedge #41 is an account of a geologic event that you experienced firsthand. It could be an earthquake, a landslide, a flood, a volcanic eruption, etc. (but don’t feel compelled to stick to the biggies – weathering, anyone?) – some geologic process that you were able to directly observe and experience. The event itself need not have been dramatic or life threatening, or it may have been. The event may have taken place before you were trained as a geologist or since (or maybe you don’t have any geologic training at all). Ideally, it’s something you can describe from firsthand experience, even if you didn’t experience it at ground zero. Events that my have happened while you were at a safe distance, but of which you were able to directly experience the aftermath (while the geologic evidence was still fresh) are certainly acceptable (perhaps you’ve been involved in relief or research efforts immediately following a major geological event). And by all means, don’t limit yourself to a single event if you’ve experienced more that one!
The story you weave is, of course, up to you. Pictures are always a plus (bonus points for audio or video) – you know we’re all adrenaline junkies on one level or another. I’m posting this call during the waning hours of the Paleozoic (time’s almost up, trilobites) but you have until the beginning of the Anthropocene to get your submissions posted. I’ll do my best to gather it all together sometime before Pangea Ultima gets together.
A quickie for a Monday. Here’s the recording of today’s Geology Office Hours Hangout. I tried to prompt everyone to share a sand dune photo, but I don’t think I gave enough warning. Smaller group than usual, perhaps due to Thanksgiving week, but some good conversation, nonetheless.
I hear it’s Sand Dune Week. Far be it from me to pass up a good geomeme!
I actually thought I had some more GigaPans of sand dunes, but it turns out the only ones that were primarily dune focused were the ones I shot at White Sands National Monument on New Years Eve of 2008. That’s just as well because these are indeed some beautiful barchans not so dissimilar from the Martian examples Brian highlighted in his contribution.
One thing you won’t find on a Martian dune is the vegetation such as the yuccas seen in this photo of a slumped slipface at White Sands. It you look at the color of the sand you’ll note that as white as it is, there is a patch toward the bottom right corner of something even whiter. Yes, that’s snow.
Without a doubt, Siim Sepp‘s Sandatlas has already become one of my favorite new geoblogs. Back in the early heyday of geoblogging in 2007 it was a regular occurrence for the handful of geoblogers to highlight new geoblogs when they were discovered, and that’s something I’d like to get back into the habit of doing. Another thing that I really enjoyed in those days was when fresh geomemes would spontaneously appear and race through the geoblogosphere. It didn’t take much – an interesting post with a geologic theme that other geobloggers could echo with new variations. To some degree this sort of thing has been absorbed into the Accretionary Wedge, but often the Wedge format is too slow and cumbersome for a geomeme that ought to spread like wildfire. And so, when I saw Siim’s post about “Anorthosite and Labradorescence”this morning I knew I didn’t want to wait around for somebody to formalize this and turn it into a Wedge installment – I just wanted to post my reply right away.
And, of course, my reply comes in the form of a GigaPan three GigaPans that I shot this past August in the Adirondack Mountains of upstate New York. Back in early 2010 while I was doing a daily deskcrop/outcrop series on this blog, my ninth installment in that series was a series of photos of a roadcut along NY state highway 3 – the “Anorthosite Highway”. Those photos highlighted anorthosite and its labradorescence in its natural habitat, and, in many ways, they were the immediate precursor to my GigaPanning. Ever since I first got started using Google Earth I’ve wanted to recreate virtual field experiences through immersive photographic techniques. This began with basic panoramic photography and QTVRs and eventually came to fruition with GigaPans. Even so, GigaPans still have their own limitations. The series of GigaPans you see below would ideally be seamlessly nested into a single zoomable sequence, taking one all the way from the outcrop scale (top) to the macro scale (bottom). Unfortunately, there’s still no way to seamlessly merge GigaPan views together – at least, not yet…
There are actually lots of interesting things to see when one zooms in on these GigaPans. The focus on the Wide view is not crisp at full zoom, though one can still make out cleavage reflections on large plagioclase laths in that view. Berti and Edi stand in in the outcrop Detail view to give a sense of scale (Edi is about 10cm tall). Finally, in the Macro view one can make out many details of the mineralogy only hinted at in the previous two views. In addition to the labradorescence (or opalescence, as it’s sometimes referred to in the Adirondacks), there are some nice garnet coronas between plagioclase and pyroxene crystals to remind you that while these rocks have an igneous origin, they also experiences the joy of a good metamorphic episode in the granulite facies.
Two details from the macro GigaPan illustrating labradorescence (or opalescence).
A number of geologists have commented on the value of using Google+ Hangouts for education. Google has indicated that eventually Google+ users will have the opportunity to record and save Hangouts to YouTube, but this capability is not yet implemented as part of the Google+ platform. I’ve been contemplating how to get around this restriction for a couple of weeks and after a couple of failed attempts, I finally cracked the nut last week. Recently I was asked if I would share my method for recording Hangouts – I’m happy to oblige.
The basic method I’m using employs two Google+ accounts on two computers, and the recording is done using Camtasia Studio. From my primary computer I begin the Google+ Hangout with Extras from my primary Google+ account. On the second computer I first mute the speakers, then join the Hangout with my secondary Google+ account. As I’m joining the hangout with my secondary account, I also mute its audio and video input (in the “Green Room” screen). (Muting all of these is important to prevent echoes and feedback.) Next, I begin recording the full screen with Camtasia Studio on the secondary computer – the recorder should be set to record system audio, but not microphone input. At this point, my secondary G+ account on the recording computer is acting as a “silent partner” monitoring and recording, but not contributing to the conversation. I am now free to turn back to the first computer and my primary Google+ account to conduct the Office Hours conversation. Nothing else needs to be done until the Hangout is concluded, when I simply stop the recording and exit both hangout windows. At this point it’s just a matter of editing the recording (if necessary) and converting the recording to an mp4 file and then uploading this to YouTube. I should note that there may be other/better methods that only use a single account or computer, but I’m satisfied that the method I’ve described works well enough for me. Don’t hesitate to ask in the comments if you’ve got any questions.
Here’s a pair of GigaPans I shot this past summer at Kakabeka Falls, west of Thunder Bay, Ontario. Before I explain why I shot this scene twice, take a few minutes to explore the GigaPans and compare and contrast the two scenes. I’d be interested in your thoughts (please comment, below) on which is the more pleasing image and why you felt the way you did about them.
I’ve shot pairs of GigaPans before, but the goal previously was to combine two adjacent shots into an anaglyph GigaPan. This pair of GigaPans was shot from exactly the same spot, with a different intent. I used this pair of shots to try to expand my photography horizons, by shooting one (top) with the normal exposure settings I’d choose for most shots, but the second (bottom) with a very slow shutter speed to try to capture a more dreamy appearance in the waterfall (there’s probably a proper photographic term for that and I’d appreciate it if someone would let me know what it is). I also changed the framing a bit the second time round, to capture a slightly wider overall field of view, with the intent of doing a better job of framing the falls, as well. So the question to you, the viewer is: which do you like better? Let me know in the comments.