Monday, March 16, 2009

Ted Talk...

Callan's post on the TED talks reminded me that I wanted to post a TED talk I thought was very interesting. Despite living in the Rocky Mnt Region, I do on occassion scuba dive. I only have my open water certification, but I was enthralled with the development of this new technology to go deeper with minimal risk of oxygen/nitrogen toxicity.
Now, the development of this new technology opened up a whole new level of the ocean for exploration. Go check out Richard Pile's TED talk. Well worth the 17 minutes.

10 Things every geology major should know...

Callan at NOVA Geoblog has started a new meme. “What are ten things that every geology major ought to know about? The only restriction is you're not allowed to list anything that has already been listed by a previous geoblogger. You don't have to list everything, just ten important things.”

Mel’s Ten Things a Geology Major Should Know
1. Evolution.
2. Evidence for plate tectonics.
3. That fossils (and trace fossils) can provide more information about the rocks they reside in - depositional environment, chronology and correlation, water temperature, stratigraphic up, relative rate of deposition, water depth, etc.
4. And vice versa, the rocks can tell you a lot about the fossils that are contained within them - geography, taphonomy, chronology and correlation, etc.
5. The relationship between sediment production --> sediment transport --> sediment deposition.
6. How to identify minerals.
7. Differentiation and fractionation and how they apply to the planet, the solar system, and isotopes.
8. How aquifers work (or don’t work if we drain them too quickly).
9. Where our energy supply comes from. All facets from petroleum products, to solar radiation, to conductive metals extraction, etc. (These are also useful for seeking gainful employment as a geologist.)
10. Pedogenesis. How it takes thousands of years of chemical reactions and transport to generate the soils we use for agriculture. (And how we should be taking better care of them.)

I know, seds and paleo heavy. I am expecting the rest of the geoblogosphere will round things out a bit… I can definitely see where my paleo and chemistry backgrounds have influenced this list. And towards the end, I got a little soap-boxy. Everyone should know these last couple, not just geologists. But, I don’t think we can limit the list to just 10. If we were, then it should be composed of things like “critical thinking” and “the scientific method” and all encompassing subjects like “plate tectonics.” If it were really only limited to 10, we should be thinking about goals as per Kim and SERC tutorial. I did find a good "subjects to know in geology" study guide here, but it's a wee bit longer than 10. So, what is on your list?

Callan Bentley’s Ten Things a Geology Major Should Know
1. The relationship between cooling rate and crystal size in igneous rocks.
2. The fact that rocks can flow, given sufficient temperature and pressure [and low strain rate, for the purists out there].
3. The idea that sedimentary rocks reflect specific depositional settings. By studying modern depositional settings and the sediments they contain, we can interpret ancient sedimentary rocks in light of the conditions under which they accumulated.
4. The fact that the chemical stability of molecular configurations (minerals) changes with different temperatures and pressures (metamorphism).
5. Large Igneous Provinces, and their potential role in tectonics and expressing mantle plumes.
6. Elastic rebound theory for the origin of earthquakes.
7. The notion of partial melting, and its relationship to Bowen's Reaction Series.
8. An understanding of the carbon cycle, and an understanding of the atmospheric physics that facilitate global warming.
9. The role that rivers play in shaping the landscape: nickpoints, terraces, quarrying, abrasion, drilling of potholes, etc.
10. The Earth is 4.6 billion years old, which is extremely old in comparison to human life -- and the reasons we think it's so old [Pb isotopes, etc.].

Thursday, March 5, 2009

The generation of giant dunes explained

Ever climbed up a 200+ ft dune (I know some of you have from your memes ...) and wondered how it formed?
Well, a new paper in Nature explains the controls on giant dune size. Andreotti et al. (2009) use a combination of field measurements and aerodynamic calculations to provide evidence that giant dunes are built of smaller dunes and their terminal height is controlled by an atmospheric boundary layer.
They show that large dunes grow by the amalgamation of superimposed dunes. Dune growth stops (assuming it's not the result of climatic change) by interaction with an inversion layer. Once the dune has grown large enough, it begins interacting with the inversion layer which confines airflow to move around the dunes rather than over them. The height of this inversion layer correlates to the variation in annual temperature. The greater the variation in annual temperature the higher the altitude of the inversion layer and the taller the giant dunes can grow. Continental dunes with larger annual temperature changes grow larger than coastal dunes which have smaller annual temperature changes moderated by their proximity to the ocean.

There is also a short piece on Ralph Bagnold and his seminal book "Physics of Blown Sand and Desert Dunes." And in case you missed it in the Carnival of the Arid #1, Through the Sandglass' Michael Welland describes the fascinating life of Ralph Bagnold.

Cool stuff!

Bozeman Building Explosion and Fire

Thank you everyone for your concern. If you haven't heard, a natural gas explosion and fire occured in downtown Bozeman this morning. Initially, no one was reported missing or injured because most if the downtown businesses were closed. However, the local officials are now reporting up to five people missing (one is officially missing, 5 are unaccounted for as of yet). For more information, our local paper is making regular updates. I'd like to extend my deepest symapthies to all the people and businesses affected by this tragedy and I appreciate the hard work of the firefighters and emergency personel.

Update: One person is officially missing and was reported to be in the building at the time. For anyone needing aid Red Cross has set up a relocation center at Grace Bible Church at 19th Street or people can call 1-800-ARC-MONT for more information.