Friday, 31 October 2008
The geo-blog sphere meme du jour is "Rainbows", so I thought I'd share this one. This was taken in 1995 from somewhere along the Dalton Highway, Brooks Range, Alaska, not far from Galbrith Lake, as I was returning from my field area. As much as I loved my two months in the Brooks Range, it was a joy to be heading home at the end of the season, looking forward to a mosquito-free winter.
Thursday, 30 October 2008
Tuesday, 28 October 2008
Saturday, 25 October 2008
eThe theme that is currently spreading its branches across the geoblog sphere is “trees”. My field area for my Master’s project was in the Brooks Range, Alaska, where there was 97% outcrop, but no trees. However, I was more than a bit amused by this sign, posted along the Dalton Highway, which runs between Fairbanks and the North Slope of Alaska, pointing out that this is the furthest north tree along that route, and admonishing us to not cut it down. It has been more than a decade since I was up that way, I wonder if the tree and its sign are still there?
Tuesday, 21 October 2008
Some people are motivated by financial gain; they chose their uni course based on the question “will this get me a good job when I am done?” and race through their classes with the end goal fixed ever in their thoughts. These people tend to be successful in their chosen fields, if “success” is measured in their local currency. But are they happy?
Other people are goal-oriented in all aspects of their lives, and financial considerations are only a component. One of my sisters is a good example of this sort. When she was young she struggled, as many do, to lose weight, or to keep it off once she lost it. Then she started running. These days she runs the occasional marathon. For her the goal of the upcoming marathon is what drives her daily fitness routine. She understands just what she needs to do each day to prepare her body for the upcoming event, and she does it. However, after one marathon is over, and before she schedules the next, she finds that it is easy to cut back on her fitness regime because there is not a goal towards which she is striving. Needless to say, for her, another race of some sort, even if not a full marathon, gets added to her calendar fairly often, so that she has the impetus to keep pushing herself.
I, on the other hand, am a process oriented person. To me the most important thing in life is the enjoyment of life. Rather than focusing upon end goals, I focus upon enjoying what I am doing at the moment, and choose to do things which I will enjoy. This was a large factor in my extended time as an undergraduate student. Because I wasn’t focused upon a long-term goal such as “what sort of job will this get me”, or “will this lead to fame” I focused upon “what will I enjoy learning this semester?” As a result, I didn’t complain about my homework the way some of my classmates did. They were focused on the end goal, and saw the work as an obstacle to be overcome on their race to the finish line. I saw each assignment as a tool for learning, now, and enjoyed the process of the assignment. This doesn’t mean that I always did all of my assignments. Well do I remember the semester I took calculus, physics, and structural geology in the same semester! Calculus had assignments which needed to be turned in daily, structure had assignments which needed to be turned in twice a week, and physics had “suggested homework” which would be “counted” only if our grade from the exams was “borderline”, in which case the homework could push it up if done well, or pull it down if done poorly or not at all. There being only so many hours in a day, and life holding more of interest to a student than course work, the physics homework didn’t often get done as I focused upon getting everything turned in for the other two. As I result I only managed to pull a “C+” for the physics class. However, I have often thought that it might be nice to go back and take the class again when I didn’t have so many other demands upon my time, because, actually, the story problems are kind of fun.
Monday, 13 October 2008
I wonder if it would be any easier if I had only *one* direction in which I wished to go? Is it better to spend my precious time allotted for “job search” looking for one, specific, thing, or to send out many e-mails of inquiry in a variety of fields? I have no idea where on the planet I shall be next year, nor what I will be doing, but, given how very many things sound like fun, I suspect that I will enjoy it, whatever, wherever it may be!
But I hope that it is in mountainous area…
Sunday, 12 October 2008
The geo-metamorphism e-mail list seems to be a very good resource for answers to questions on any number of technical topics. I also note that there are a number of other geology (and other sciences) e-mail lists on that server (click on the "Email Lists button in the upper left corner).
Monday, 6 October 2008
I have been using the program suite Perplex to do “garnet isopleth thermobarometery” as part of my PhD project. This program uses the command prompt as the user-interface into which one enters answers to questions before it does the calculations. I have been using this program on a very regular basis, for a couple of years now. Very early on I figured out that one does not have to wait for it to actually ask the next question before answering it, and for those calculations which I perform over and over for a variety of different samples I soon memorized the sequence of questions/answers so that I could save time by simply typing in the sequence of key strokes needed and thereby get to the part where it does the calculations sooner. However, there were occasions wherein I’d hit an incorrect key, and then I’d have to start the sequence over again. Now, that my project is nearing the end, and I’m meant to be only writing up the thesis (but, of course, I keep doing an occasional bit of calculations too; I just can’t help myself!) I have finally stumbled upon A Better Way (TM). Instead of answering the questions each time I do the calculations, I’ve set up a Word document into which I’ve typed all the key strokes needed for each of the tasks I do, starting with typing the name of the program. Now, instead of typing:
2 1 5 1 7 1 8 1
every time I wish for it to calculate the isopleths for the pyrope end-member of garnet, I simply click on the heading “XPrp” in the word document, copy, and paste the lot of it into the command prompt. I then enter only the three numbers needed to answer the final question (and which will be different for every sample) and I’m ready to import the graph into CorelDraw and see how it looks. I have these set up for all four garnet end-members, and an additional sequence for just the “pscontor” portion of the process, because I create two graphs for each end member—one showing all of the isopleths in the range of the graph using a 0.01 contour interval, and one showing only the one corresponding to the composition I measured in my garnet core.
It is truly amazing how much easier this process is since it occurred to me to set up this time-saving device! The wonder is that it took me so long of doing this before I came up with the idea. How many of you stumbled upon a brilliant way to save yourself much time/energy/frustration for a task you have performed 1000’s of times before? Or does everyone else think of these things within the first half a dozen times they repeat the task?
Sunday, 5 October 2008
Last week I was introduced to the joys of separating zircon crystals from their host rock so that they can be analyzed with a Laser-ICPMS to determine how old they are (why we’d want to know that may well be the topic of another post one of these days).
I accomplished the first two easiest steps the week before:
(1) Crush rock into small bits with a hydraulic crusher
(2) Put small bits into the ring-mill for five seconds to make sand
On Friday I was taught how to do the next steps. The next few were also reasonably easy:
(3) Put sand into a plastic pan with ridges on one side, add water, shake, and pour off muddy water. Repeat as many times as needed to separate the mud from the sand and wash the mud away.
(4) Add more water, using a back and forth motion, start washing out the lighter weight bits of sand. The zircons, being heavy for their size, sink to the bottom of the pan with a few other heavy minerals. Repeat this step till most of the sand has been washed away, being careful not to disturb the area at the bottom of the pan where the heavy stuff is collecting. (Note: this process is done over a tub, so that the sand is collected, and *not* washed down the sink! Not only is this better for the plumbing, but if accidents happen and you wash away everything, you can start over with step three, and not have to go crush a new bit of rock. This can be very important, if the sample comes from *A Long Way Away* or you have *A Limited Suply*.)
(5) Now that there is just a little (~ 2 tablespoons worth) of sand left (of the ~2 cups of starting material) carefully submerge the pan into some clear water and tilt and shake to get most of the rest of the large, light weight, grains to separate out from the tiny, heavy, grains.
(6) Carefully pour the tiny bit of remaining sand into the tiny glass plate (~ 5 cm wide) and use the same sort of panning technique as you've been using, only scaled down, to make the heavy grains sink to the bottom, and wash away the last of the light weight grains.
(7) Check it, using a microscope--yup, some of the remaining grains are zircon! You can tell because of the bright colours it has due to birefringence under the crossed polar lenses of the microscope. (See: a particularly stunning example of these sorts of colours.)
(8) Set the glass plate into the oven to dry for half an hour
(9) Carefully, with a very, very clean brush, put the remaining sand (about 1/4 teaspoon worth) onto a sheet of paper. Set another sheet of paper around the outside of a magnet, and pass it over the sand at a distance of ~1.5 cm to draw off anything which is strongly magnetic
(10) Remove the paper from the magnet, set aside the grains thus collected, and put clean paper on the magnet. This time pass it over the sand just above the grains, to draw off the moderately magnetic stuff.
(11) Remove the paper from the magnet, set aside the grains thus collected, and put clean paper on the magnet. This time actually touch the sand with it, to draw off everything that is weakly magnetic. This leaves you with a *very* tiny pile of very tiny grains of zircon and anything else in your sample which is small enough, heavy enough, and non-magnetic enough to have survived the cleaning ritual.
(12) Prepare the zircon mount by cleaning two glass plates. Put a sheet of special double-sided tape onto one of them, remove the cover-paper, then set the ring-mould on that and trace a circle onto the tape, and add lines bisecting the circle at right angles to one another to mark the center of the circle.
Now the truly difficult part begins:
(13) Carefully sprinkle a small amount of the zircon containing sand onto the plain glass plate and look at it under the microscope set up with crossed polars so that they zircons can be distinguished from the non-zircons. The non-zircons in this sand are either dark or white in crossed polarized light, not brightly coloured like in the link above.
(14) using a clean, specially prepared paint brush, which has most of its bristles cut off to tiny nubs, and one single hair which sticks out from the rest by 3 or 4 mm, carefully pick up one zircon at a time from the clean glass plate and transfer it to the center region of the tape-covered glass plate.
That *sounds* ever so much easier than it is! First of all, the microscope with which we are looking at the zircons on the clean glass plate is a standard one, which means what you see through the scope is both upside down and backwards. It is also needful to use the 20-times magnification lens to be able to see the zircons, since they are so tiny. This makes it difficult to even get that single hair into the field of view in the first place, and it is ever so much harder to actually move it the direction it needs to go to touch the zircon grain once you've found it. In addition, the thing which makes the part about "pick up" the crystal possible is either static electricity (rub the brush against your hair for a bit) or saliva (lick the brush)--either of which is a limited-time-only phenomena--if you take too long getting that hair into place, the grain isn't going to stick to it!
I soon found out that since I am not practiced at this skill I had a choice. I could *either* touch the zircon at which I was aiming, *or* I could pick up one (or often, many) random grain(s) with the hair. I could not manage both at once! So I contented myself with aiming at specific zircons, picking up grains of *something*, and transferring them over to the tape-covered glass plate, and trying again.
Anyone else out there in the geoblog sphere have any experience with this? Would such a thing be easier?