Brief update on the Geoblogosphere

I'm still making figures and editing photos for the Hawaii post. For now, here are a few items floating about the 'tubes:

• Ron Schott's sandy meme. Ron's got some nice photographs of sand from different places. His challenge was to tell him where it came from. I left a few guesses, but perhaps you have other thoughts.


• Callan's NOVA blog. Some Q&A with Michael Welland, the author of "Sand." Callan's students have asked some interesting questions about "sand."


• Clastic Detritus: anthropogenic forcing of fluvial systems. Brian has some cool pictures and discussion about human-induced changes in a big river system. Neat stuff.


• Michael Welland's Sandglass. Speaking of "sand," author Michael Welland wrote an entire book devoted to the subject. Being a clastically trained sedimentologist, sand is near and dear to my heart. I haven't read the book yet, but Clastic Detritus has a review and interview here and here.
  

Oh, and don't forget to cruise on over to the Hairy Museum of Natural History for some kewl links about fossils...

2009 in Review

I'm back from a nice long vacation in Hawaii. My wife and I figured that since we've been married a few years and now I finished my PhD, we should take our honeymoon (she finished her PhD just after we got married). I'd be hard-pressed to think of a better geo-holiday-cation than poking around Hawai'i, Maui, and Kaua'i for two weeks.

So I have many geology-themed Hawai'i posts in the works, plus lots of warm, tropical photos to regale you with. I took about 2,500 photos over 14 days. That's nearly 179 per day. It's no small task to sort through 14 gigabytes of holiday snaps, but I'll be sure to share some of my favorites. Here's one:


It's a 5-photo stitched panoramic view of Haleakala "crater." The crater is actually two wide erosional canyons that have joined together near the summit. There are numerous cinder and spatter cones along the crater floor, which makes for an other-worldly hike through this landscape.


I figure before I get too far involved in a self-indulgent Hawai'i geology fest, I'd wrap-up the biggest geology places/events that I experienced this year. I expect that I'll post the list now, and then spend a few posts going into detail.

So here's the list, ranked somewhat by personal importance:

10. San Raphael Swell: Coyote Gulch
9. Panther Tongue
8. Western Wisconsin Trilobites
7. Porcupine Mountains, MI
6. San Raphael Swell: The Wedge
5. San Raphel Swell: Wild Horse Canyon
4. Airplane Flights over the US
3. Grand Teton NP
2. Mt. Saint Helens/GSA
1. Hawai'i

And of course, I give pride of place to the fact that I finished my PhD this year. It's such a relief to be done. I do feel some measure of pride. However, when I see the work being done by people like Dr. Steve Austin (backstory), I realize that - in the end - it's just a piece of paper. Any schmuck can get one if they stick with things long enough. It doesn't convey me some magical power, or make my ideas any better than the next person's. But it does show that I am stubborn enough to see something through to the end, and outlast my peers. So I guess that's something.

On Vacation...

I've been rather busy having fun. I have lots of photos to go through, and some good geo-rific things to share. But that will probably have to wait.

Merry New Year!

Okay, so I've got one more fantastic geology-trip to get in for 2009. Here's a clue: it's another active volcano. So things might remain quiet here until I return in a few weeks.


Mahalo.

Continuing apace, upscaling granular interactions

One of the things sedimentologists try to do is visualize how individual grains behave. This is important for things like sediment transport and deposition - it even plays an important role in things like quicksand. In some cases, it's helpful to scale a system down so that it may be observed in a lab room, under manageable timescales. I've been working on scaling things up to look at how individual grains interact with each other. A few thousand fluorescent BBs and a blacklight help bring out the details look pretty interesting with a long-exposure photograph.

Update on fractal landscapes

I had mentioned these fractal landscapes to an old college friend, and he had this to add:

With the caveat that looking *like* a fractal isn't the same as being a fractal, a fractal has organizing rules that are in a recursive relationship. So it seems to me that the two organizing rules are gravity and the electromagnetic force that holds materials together, and the 'recursion' is moving the materials around, primarily water but also wind. But I could be wrong.

I think that's an important point. A lot of fractal geology is mere "appearance," rather than true "behavior." But I think he's got a good point about the combination of gravity and the EM force. The disjunct between scales might be bound by the ability of materials to resist gravity (displayed in such things as a mineral's hardness, etc.). On top of that, there are continental-scale behaviors of crust, which allows for things like uplift and sedimentation in the first place. The reason the Sierpinski Triangle outcrop looks like it does is due in large part to the well-partitioned sedimentary cycles within the outcrop - breaking it up into nearly perfect thirds, top to bottom.

I've been doing a lot more thinking, rather than synthesizing lately, but I think the note about the EM force and gravity is an important one. Since much of what we see on the landscape is a tug-of-war between gravity, which tends to bring things towards the center of the Earth, and the EM force, which helps resist it. There's probably a bit of influence by the Strong and Weak Nuclear forces in there too. Although, I think crustal properties such as bulk modulus are more affected by the EM force, but it might be fun to look into the combination of the EM and Weak Nuclear forces, since much of our Earth's internal heat is provided by nuclear decay.

Another way to think about it: there appears to be a minimum size to silt grains generated by impacts with larger particles. At small enough scales, gravity can't generate enough energy to knock atoms apart - so there's another scale at work when it comes to very tiny silt-type grains. And don't forget the completely different behavior of clay minerals!

Of course, this EM force and the ability of minerals to resist breaking down plays a key role in any critique of a marine origin for the Coconino Sandstone. Yes there are mica grains in the sand. Yes, mica is softer than quartz. But there are more forces at work besides Moh's fancy little scale.