March 29, 2011

Field photo Set #2

Late March - early April is the end of semester period, thus I'm swamped with term papers, labs, and presentations. I'm not one to procrastinate, since I've been burned by it in the past and learned my lesson. But activities like blogging must take a back seat, and I'm sure most reading this blog are experienced in what the last month of a semester is like.

So to keep things simple, for me and for you, but mostly for me, I have another pair of field photos to show, replete with explanation for the features' what/when/where/how. This time, a pair of volcanically-derived features in Oregon, both derived from eruptive activity from the legendary Mt. Mazama complex in what is today Crater Lake National Park.

The Pinnacles fumarole features, looking west.
The V-shape valley shows river erosion exposing them
To the right is a snapshot of the elegant Pinnacles, located just a couple of kilometers to the east of Crater Lake. These spires were ancient fumarole conduits of Mazama's gaseous content (SO2, CO2, H2S), exposed by fluvial erosion from a radial stream, but remaining resistant to that erosive force. Prior to the finale of Mazama's VEI 7 eruption 7.7 Ka ago, a nuée ardente flowed down Mazama's east flank, carrying scoria. Gasses escaped from the settling scoria through fumarole vents, and the mineral content, given the extreme heat, welded loose pumice to the sides of the fumaroles. Thus the pinnacles seen to the right are hollow, and are resistant to erosion from the inside-out, which is atypical of common geologic thought.

When viewing the pinnacles along the 2-3 km path (42° 51.056'N 122° 0.558'W), I noticed that some of the spires had puncture holes in them, in which I could see through. The keen eye will also notice that the base the pinnacles stand on is a lighter color, which is due to the more silica-rich rhyodacite ash falls that preceeded the scoria-laden pyroclastic flow.

This field photo is of a roadcut along the North Umpqua highway, not far from Watson Falls (43° 14.553'N 122° 21.486'W). Catching this roadcut out of the corner of my eye made me glad my car has a low center of gravity. This hillface, ~35km from Crater Lake, showcases silica-rich ashfall from Mazama during its major eruptive phase 7.7 Ka ago. The several-meters thick deposit is a testament to the volume of tephra ejected by the monster eruption (~60 km3), and its coverage across the northwest is found much further afield as well (Mount Baker slopes have a few cm thick of Mazama ash deposit, and it's over 600km from Crater Lake). Tephrochronology analyzes in the region are easily guided by Mazama ash, as the distribution of the ash from the centroid is quite ideal, making it a prime stratigraphic marker for 7.7 Ka.

The white color stems from sanidine feldspar content within the silica-rich ash, and darker grey portions contain a greater percentage of ferromagnesian minerals. The grainsize is quite fine, looks & feels almost silty, with a gritty abrasiveness, but not too harsh and not as hard as sheer-faced plutonic rocks. You can jab this rockface and it feels somewhat padded.

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March 24, 2011

A glance at Saskatchewan Potash mining

Saskatchewan might not at first seem like a province that can build itself up as a preeminent world-class supplier of any resource. The population is only 1 million, spread out over a large area, and the climate has inhospitable extremes in the summer and winter. Yet Saskatchewan has built itself up as a leading supplier of a rare-earth salt called potash. Potash is essentially a water-soluble potassium-rich mineral that is often combined with chloride or carbonate, and it has coalesced in abundance underneath the sedimentary platform that defines the geology of Saskatchewan's prairie-lands. The industrial heart of the province has utilized this abundance to strike at rich in a world market where potash is an excellent & cost effective fertilizer for crops, and markets in India, China and Brazil have made it lucrative for the monopoly that Potash Corp. has created.

Why is Saskatchewan so rich in potash? 

That question can be answered by looking at the historical geology of the province. During the Devonian period 390 million years ago, southern Saskatchewan was inundated by a restricted inland sea. The equator was also located close to the province, thus the conditions were ripe for evaporation of water in the ancient sea, and thus the leftover mineral content collected and formed what are called evaporite beds. These beds were subsequently covered by later horizontal sedimentary deposits. The capping layers were not too thick, on the order of a thousand meters, thus drilling and mining access to the potash using modern techniques is cost & technically feasible.
World potash reserves, top ten states (left); cross-section of Saskatchewan strata with sylvinite beds (right)
Types and uses of Potash

Potash occurs when Potassium binds with another compound or element to produce a salt. Such compounds include Potassium Chloride (KCl), Potassium Sulphate (K2SO4), Potassium Carbonate (K2CO3), and Potassium nitrate (KNO3), all of which have varying uses and grades of quality. Potash has general uses as a bleaching agent, a soap, and a de-icer, and technological uses in computer screens, but the majority industrial use of the compound is as a fertilizer of plant crops. The variations of potash mentioned above are all effective as fertilizers, because plants soak up the nutrients provided by potash when they are dispersed and allowed to percolate into the soil (after being soaked by irrigation). Potash's water-solubility allows this to occur effortlessly, and thus crops will soak up the nutrient content as they soak up water.

Not many countries produce and export commercial-grade potash, and Canada is by far #1 among the ones that do. Importers tend to be heavily populated countries that rely on extensive agriculture to feed their people.

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March 19, 2011

Earth Story: The Beeb's forgotten geology gem

I love it when I'm made aware of a documentary or TV miniseries about geology that I hadn't known existed, and I was just recently introduced to the BBC series called "Earth Story", an 8-parter released in the late 90's. A professor showed it in my historical geology class, using an old VHS tape of the program from the university archives. He used it to bring attention to such features as Banded Iron Formations and Stromatolites, and such events as the Rodinian Snowball Earth and ELE's. It's a perfect fit for a class on the evolution of the planet, and certain episodes would fit well in structural geology, geomorphology, paleontology, and geophysics classes, among others.

Naturally, I looked up the rest of the documentary on youtube, and lo and behold found a user's channel with virtually all of them available for ready consumption. I get easily addicted to geo-documentaries that are well presented, and Earth Story has an eloquent Englishman (zoologist Aubrey Manning), beautiful locations and brilliant animations, all prerequisites for a good doc. The series is well structured, with each part highlighting a piece of a particular whole of the history of Earth in geological terms, whilst building a story around revelations about certain phenomena. It has something for everyone, be you a geoscientist of one of the 4 major spheres, or an interdisciplinary. Without further ado, below is a sampling of the available episodes:

This part on Climate change examines Pleistocene glacial advances. Some of the interesting things you'll be informed about include coral reef terraces, foraminifera, smoothed tillite, Carbon cycle & the Carboniferous, Milankovitch cycles, and my favorite of using ice-core samples to reveal Pb atmo concentration during Roman times.

This part on Deep time discusses topics such as unconformities, geothermal gradient, ammonites, radioactivity's role in geochronology, pre-Earth meteorites, Archaean cratonic pillow basalts, lithified mud pools.

This part about volcanoes and the lithosphere examines mantle plumes, plate tectonics, seismic anisotropy, isostatic depression & rebound, mantle mineralogy, mantle convection, the Deccan Traps, Curie point.

This part on mountain formation looks into sea floor uplift, buoyant crust, slickensides, Gondwana's breakup, crustal thickening/thinning, geodesy, lithospheric flexure, serrate/entire leaf edges.

Above is just a small sample of the entire series. Thanks to Kurdistan Planetarium for supplying the videos online. Readers, enjoy!

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March 15, 2011

My day @ The Western Division of the Canadian Association of Geographers

On Saturday, March 12 I attended an interesting conference, the Western Division of the Canadian Association of Geographers, with plenty of excellent presentations that both faculty and grad students from a multitude of BC universities. There were plenty of interesting topical presentations to choose from, and with only an 8 hour stretch to fit in nearly 80 presentations, I had to choose 1 out of a possible 6 for every 20 minute time slot. Thus I'm having to send a lot of follow-up emails to those presenters I missed but wanted to hear their findings. One regret is that I wasn't able to catch much of the presentations on BC cordilleran glaciation, but luckily the lunch intermission allowed me to chat with some students on their findings and field experiences.
Figure showing hydrologic response in a coastal western hemlock
watershed. John Martin's investigations found that infiltration of
precipitation is excellent, as the nature of the soil allows for a high
hydraulic conductivity & porosity. Thus heavy rainfall doesn't result
in much overland flow, at least not until the subsurface reaches
saturation, and shallow depressions overtop.

I was able to catch presentations on GIS modeling of landslides, soil loss, and slope mapping of rugged terrain, in addition to my boss's talk on the decrease of agricultural land in Surrey, BC. He showed some maps I digitized, contrasting 30 years of shifting and merging agricultural lots and their tangible erosion in favor of RCI development. Most of the others I attended were on wetland hydrology and lotic ecosystems. The hydro presentations were quite technical in terms of highlighting their results, and quite advanced in terminology, but amazingly I found myself understanding most of what was said. That I attribute to my excellent Hydrology professor (who was one of the presenters), plus the presenters ability to define the important elements in their work. The only one that threw me for a loop was the aeolian physics of sand particles of a vegetated dune, and the subsequent quadrant mapping of their behavior during microclimate wind eddies & gusts.

Thanks to my university's geography department, the cost of the conference was covered, and I will direct the reimbursement to relief of the earthquake/tsunami disaster in Japan. Below is a list of the presentations I attended with, of course, my university profs in bold (gotta represent the alma mater):
  • Connie Chapman (University of Victoria) - Turbulent airflow and sediment transport over a vegetated foredune, PEI National Park
  • Parthiphan Krishnan (Kwantlen Polytechnic University) - A GIS for Municipally Enabled Sustainable Agriculture
  • Terence Lai (Simon Fraser University) - Simulation of Urban Landslides: Cellular Automata approach
  • Laurens Bakker (Simon Fraser University) - Spatial disaggregation of the Universal Soil Loss equation using Cellular Automata approach
  • Brandon Heung (Simon Fraser University) - Automated procedure for digital landscape classification based on DEM data
  • Sarah Howie (Simon Fraser University) - Vegetation variation across lagg forms of raised bogs in coastal BC 
  • John Martin (Kwantlen Polytechnic University) - The Hydrologic response of a small forested swamp complex, North Vancouver BC
  • Yue-Ching Cheng (Simon Fraser University) - Ins and Outs of Burns Bog: A look into the water balance of a large ombrotrophic bog in the Fraser Valley
  • Jan Thompson (Kwantlen Polytechnic University) - Management of small water storages: A case study of small farm dams in New Zealand
  • Steven Marsh et al (University of the Fraser Valley) - Variation of Fraser River, Kanaka Creek, and Silver Creek geochemistry
  • Maureen Attard (Simon Fraser University) - Progress towards acoustic suspended sediment transport monitoring: Fraser River
  • Jessica Craig (University of Victoria) - Dendroglaciological investigations at South More glacier, northern BC coast mountains
The study area in Jan Thompson's research into small farm dams in New Zealand (North Island). 39°58.218'S 176°19.850'E in Google Earth will place you around the highlighted watersheds, and by adjusting aspect you can see the drainage regime ultimately has its headwaters in the Ruahine Range foothills. Farmers with small dams (under 4m depth) gather their water mostly from first order streams, and Jan's investigations attempt to ascertain the cumulative effect these volumes will have on the larger whole downstream within the dendritic network, how they will alter the hydrology in regards to water quantity, water quality, downstream sediment transfer, and channel morphology.
I learned lots of new things, not only about technical terminology and equipment used in the field, but also on the sociopolitical state of the environment on scales small and large. With food prices increasing worldwide, food security is coming to the forefront as an increasingly acute issue. In regards to equipment I saw utilized by researchers, I had never heard of using a pharmaceutical device called a Wenglor sensor to count grains of sand, or a device called the ADCP (Acoustic Doppler Current Profiler); nor had I heard of certain equations, such as the Fernandez-Luque and van Beek equation. In essence, attending this conference has given me some extra homework to do, but that is all welcome cuisine for the cranium of this geo information junkie.

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March 2, 2011

Field photo follow-up

This is a follow-up to the field photos I posted a month ago, and my best explanation of their origins and processes.

First is a landform located in a gravel quarry in Squamish, BC (49° 43.899'N 123° 06.250'W). Access is via Sea-Sky highway #99. Take a right onto Mamquam Rd. near the Canadian Tire, and travel for 2km up to the quarry entrance, which will be on your left. The geomorphology of what you see below was created when the land in the area was much closer to sea level during the Pleistocene epoch. The environment of deposition was transitional, specifically a delta, represented by visible topsets & foresets. Bottomsets are presumably there, but have not been exposed by the quarrying. Since the region experienced glaciation during the Pleistocene, isostatic depression was the primary force for lowering the area to near sea level, and Holocene rebound has taken it up to its current 100m elevation. Evidence of glaciation is apparent from the mantle of glacial till, which overrode the underlying sedimentary structure during a later advance.
Second is an up-close shot of a granodiorite rockface that includes a granulite xenolith shaped somewhat like a tooth (49° 20.025'N 123° 07.124'W). The rockface is tremendously chemically weathered, turning it into saprolite. This chemical weathering mechanism is not indicative of the current mid-latitude temperate climate of BC, but is indicative of when BC was placed in a more equatorial latitude in its late Paleozoic-early Mesozoic paleogeography. The granodiorite is typical of so much of southwest BC, as it is a plutonic extension of the Coast Range batholith that encompasses the region, and by subsequent erosion has been thoroughly exposed. During its subduction-driven intrusion, the batholiths extensions baked overlying sedimentary & igneous units, and metamorphosed granulite 'polka-dots' became inclusions within much of the granodiorite seen at the surface. Touring Greater Vancouver, one can spot many instances of aggregate that uses the granodiorite w/ granulite xenoliths manufactured for construction and landscaping.

Access to this rockface: Follow Trans-Canada highway #1 west in North Vancouver. Take the Taylor Way exit and make a left turn onto Taylor Way. Head south for nearly a kilometer, and make a left onto Keith Rd. Follow Keith Rd all the way until you pass under the highway, then park and walk down a relatively steep trail to the Capilano riverside.
A couple more field photos will be posted soon, and this time explanations will be included forthwith. And just a small aside, a small rant: Anyone putting up paleogeographic maps on the web please, for the love of god, include major demarcations of latitude (equator, 30°, 60°, poles). It makes a world of difference in deducing paleoclimates.

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