Right in Portland, Oregon's backyard, Mt. Hood offers some spectacular glimpses into textbook glacial geomorphic features. In the top left picture we can see some little ice age moraines. In the rest of the pictures we can see the transition into crevassing on the increase in slope. In the photo below, we can see where the glacier become debris covered in the transition from exposed ice on the left to covered on the right. There is ice below the debris all the way off of the end of this photo!!
The geology of the Eastern Sierra is that of the start of the basin and range system, it is the story of the creation of the Sierra Nevada, the movement of a subduction zone northward and the loss of rock from Pleistocene Ice caps. It is the steep mountains of White and Inyo Ranges towering over Owens and Death Valley. And the smashing of shallow water carbonates into folded messes like the Poleta folds.
First of all, if you have not been there already, go to this website, it will change your life for the better because it provides answers to any questions you have ever had about humans and climate change and the science behind it. I especially like the science explanations of the top 100 myths that a lot of people keep mistaking as real arguments.
It is called skeptical science and it can really help educate you on the science behind the issues.
The main point of this post is to say that humans are warming the planet through the rapid release of CO2 (there is no question there) and that even if we stop all CO2 emissions right now (which we are actually exponentially increasing) the planet's mean annual surface temperature and the mean ocean surface temperature (important in terms of Antarctica and Greenland) will rise enough for us to take notice in the next 80 years.
Solar seems to be the next logical step, we just need to improve our solar capture and energy storage. Perhaps that will happen in 100 years when we run out of oil, coal and gas, and the world's ice sheets disappear faster than they have done since they have been around.
Even assuming that everything we are doing has zero effect on temperature, sea level etc. (which is obviously false), we should be yearning to clean up our act as a group (country, species, town, state, community, citizen of the universe etc.) no matter what. The pollution alone should be reason enough to not want to be burning coal. We should not want plastic bags on our beaches. Or need to not go outside on certain days because we made our air poisonous. It seems sort of silly if we end up only taking action about deforestation, pollution and loss of biodiversity once the sea level has risen by two meters.
One obvious response to this is the fact that the reason a lot of this happens is because there are so many people in the world where price outweighs being environmentally conscious. If a country can't afford as a government to pick up trash, it is just not going to offer that to it's citizens. If a country keeps having babies, it needs electricity now, and can't afford to research solar energy for 15 years and stop burning coal.
This all comes back to money like most things do. A carbon tax seems like the only way to incentivize people to stop using fossil fuels. If solar is cheaper than fossil fuels people will use it, thats all there is to it, in the end people will use what is cheaper. The only way to really achieve that right now is through a carbon tax. This is not new stuff, but the problem is that the changes that we are making to climate, though extremely rapid (like bullet out of a gun fast in terms of the geologic time scale), are slow on the human time scale. So we can't watch the ocean rise, because it rises by 5-10 mm a year give or take, and not the same around the globe (for example). I think the problem is how to get people to feel like they need to do something now for a change they won't be able to really see except for a snapshot comparing 2000 to 2100. I suppose the answer to this is the whole pollution thing I mentioned before. If people start making changes based on not wanting to make the world dirty (which is a change that is very observable in the week to week basis) that that will have the built in effect of mitigating the problems of the next 100 years. To me it makes sense that we should be wanting to be less of a dirty species regardless of the climate consequences (but we still get to address the climate problems). But if that doesn't work, people are easily driven by cost, so let's make solar cheaper and fossil fuels more expensive.
Glacial valleys as well as fjords have a U-shaped cross sectional profile. For the most part this stems from the fact that energetically it is easiest for ice to flow down and get channelized in a pre-existing river valley. Once in those valleys, ice is proficient at tearing apart the landscape underneath and moving large portions of the landmass. In these pre-existing v-shaped river valleys, the glaciers act as widening, straightening, and overdeepening (cutting down vertically) agents. The steep walls in a U-shaped valley come from the fact that the glacier flowing downslope is grinding the sidewalls as it moves downhill. U-Shaped valleys have wide bases because of the widening effect of a flowing glacier and its resistance to flow and shear stress (high viscosity). Simplified, this means that ice, being a solid, (but still acting as a fluid, important distinction) does not get channelized as highly as the water did in the valley before. It follows that the bases of U-shaped valleys become even more flat because of sediment infilling. With sediment infilling, what would have been a more parabolic shape, gets its trough filled in by sediment because the glacier is doing so much grinding of the preexisting valley to deepen, widen and straighten it, that there is bound to be a large sediment flux. Also, that 'overdeepening' is why you usually have glacial lakes sitting in a u-shaped valley after the glacier has receded, because there are low spots conducive to have meltwater and runoff sitting in them.
Standing on a glacier, seeing the foot of a glacier oozing down the slope of a mountain or even seeing a photo of a glacier online there are a lot of cool things to notice that can tell you about that glacier.
This is a photo from the Matanuska Glacier in the Chugach Mountains of Alaska. What you are looking at is a small crevasse in the glacier, which is filled with meltwater. What I think is most interesting here is the glacial debris. As a glacier flows and deforms downslope under its own weight, it crushes and entrains the material below it. I like this picture because it shows how a glacier could come to have rock debris on top of it. If you look into the wall of that crack, you get to see a vertical cross-section of the glacier in which you see other entrained debris. As the glacier thins, the debris that was sparse in the glacier, piles up on top as the ice around it turns into meltwater. This is how you may come to have a glacier topped by a pile of glacial debris. This debris absorbs more short-wave solar radiation and reflects less long-wave radiation back to space, multiplying the melting, adding more debris creating a positive-feedback.
Have you ever bent something like a stick of gum and seen cracks form on the surface of the convex side of where it was being bent. That is essentially what is going on in crevasse formation, you have brittle deformation at the surface from shear stress in the interior of the glacier. This photo is of the Portage Glacier in Alaska. Glaciers in southern Alaska flow relatively fast downslope, which means there is more shear stress, which is why you generally see a lot of crevasses in Alaskan glaciers. What one can notice looking on at glaciers like these are where all of the crevasses are being formed. All of the dark ridges are places of high crevasse formation due to three main factors: steeper slopes, faster glacial flow and where ice is being stretched over larger basal topography.
I really liked this scene I came upon on Battle Island, Newfoundland, Canada. It caught my eye because it really encapsulates differences in resistance to erosion and weathering. Also, this is a classic case of who cut who. The Psammite (which I'm pretty sure isn't a term used that much anymore, it is actually probably called a quartzite or a metamorphosed quartz arenite) is ~1200 million years old. That was then cut by the granitic intrusion injecting in fractures ~1000 million years ago (called Pegmatite). Both were subjected to intense regional force from orogenic events in the Pre-Cambrian which is why you see that big buckle in the pegmatite. These both were then cut by the basaltic dyke about ~570 million years ago. Both of the suites of minerals that the basalt dyke cut were felsic containing mostly quartz and are very stable at earth's surface. The basalt dyke contains a lot more olivine, pyroxene, and amphibole, which are all less stable at earth's surface and go into solution readily. This leads the basalt dyke to get eroded faster than the quartz (this is why you see quartz sand beaches and not green olivine sand beaches). You can see the basalt dyke sitting about a meter below everything thing else, pretty awesome.
you could skip to 0:44 for the start of the good stuff
it shows you how seemingly impossible things are very possible and can be comprehended better when you scale them down
Laurentia was the portion of Laurasia now known as North America and Gondwana was Africa, South America etc. as you can see in the reconstruction to the left. The main place these two supercontinents impacted during the Alleghanian orogeny was at present day northern Africa eastern Canada.
I traveled to the coast of Newfoundland for my field camp and I saw the remnant of the rift of this boundary. When Gondwana and Laurentia began to break apart during the late Triassic it was not a clean break and the remnant of Africa on North America is a very distinct difference in lithology that you can see in the picture that I took below:
Hello! I am extremely excited about this blog. Anytime I experience any new geology from now on I will be putting it up here fully explained to the best of my ability as a geology grad student. This is where I will also put up stuff for my Ph.D. research updates as well.
In the meantime I will be putting up some stuff from my past geologic picture collection to explain some of the stuff that I have seen that I think is particularly amazing.
Hi my name is Nilo Bill and I am a graduate student in Geology at Oregon State University College of Earth Ocean and Atmospheric Science