always double check!
Jan. 15th, 2009 09:22 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
kareinaYesterday I hoped to finish chapter five today. Then I remembered that I was scheduled to use the microprobe today. So instead of working on Chapter five this morning I looked over my photos from the monazite sessions on the microprobe for sample RC0704 to see which ones were in the cores of garnet, which in the rims, and which weren't in garnet at all. The reason for this is that this sample has some monazite which is very low in yttrium, and some which is rather high in Yttrium. Since garnet is also able to incorporate yttrium in its crystal structure, and since it tends to be *much* larger than monazite, a general rule of thumb is that low-Y monazite grew at the same time as garnet, whcih hogged most of the Y available then, while high Y-monazite grew either at a time when there was no garnet growing yet, or garnet was breaking down, making the Y available for the monazite. Since there seems to be a pattern as to which type of monazite is located in the garnet cores, and which in the rim, I deemed it important enough to analyze some of the garnet around the monazite, to see if A) I am correct about which part is core and which rim (the composition is *very* different from one to the other!) and B) if there is enough Y in these garnets to measure, and see if the amount of Y in the garnets changes near the monazite grains. To do this I needed to select the garnets to analyse.
I managed to make my selections in plenty of time and went in to uni, where I set an all-time record for how quickly I was able to set up the microprobe to do the analyses. This is only because I am analysing *far* fewer spots this time--my funding is running low, so I had to keep it to the bare minimum.
I had thought to head to the SCA special occasion fencing night taught by a visitor from the mainland that is happening tonight after my microprobe session, since normally, after spending a couple of hours staring at three different monitors getting the spots to be analysed selected I am too tired to work. But I got home from uni with plenty of energy to work, so I stayed home and![[livejournal.com profile]](https://www.dreamwidth.org/img/external/lj-userinfo.gif)
clovis_t went without me. I managed to accomplish a far bit of stuff, but, most importantly, I have reminded myself
I collected most of my samples for my PhD project in March of 2006, consequently their field numbers start 06___. Those samples all came from the northern fault block of the Collingwood River Metamorphic Complex. In November of 2007 my advisor and I did one additional trip, to the southern fault block of the Collingwood River, in search of the long-lost Tasmanian whiteschist. We found it, and collected a number of other samples from the area as well. Whilst we were out, we also stopped by the northern block and picked up another couple of oriented samples, just for good measure.
In October of 2008 we decided that there was just enough funding left to do some detrital zircon dating for two samples from the Collingwood River. I was told to select "sandy" samples as being most likely to contain zircons. So I picked out half a dozen from both the northern and southern blocks of the Collingwood River which were sandier than the others, though not necessarily sandy enough, and brought them along to my lesson on rock crushing. My teacher du jour narrowed it down to three likely candidates, two with 06___ numbers, and one with a 07___ number. So we, thinking that there might be value in having one from each fault block, chose one of each and we commenced crushing.
Since then I've been thinking in terms of having crushed one from each fault block, so was not too surprised when their detrital zircon patterns were somewhat different from one another. Today, at long last, I decided to make the figure showing the location these two samples were collected from. Yup, you guessed it. They are both from the north block! They were collected from locations not more than 250 meters apart along the highway.
However, since the other 07___ samples were all rejected as not being sandy enough to bother, I can't really complain that I don't have one from each block. There is just that lingering embarrassment that one gets when one realizes that the assumption under which one has been operating doesn’t actually apply. The best cure for that? Admit the mistake publicly—then it won’t ever be repeated!
I managed to make my selections in plenty of time and went in to uni, where I set an all-time record for how quickly I was able to set up the microprobe to do the analyses. This is only because I am analysing *far* fewer spots this time--my funding is running low, so I had to keep it to the bare minimum.
I had thought to head to the SCA special occasion fencing night taught by a visitor from the mainland that is happening tonight after my microprobe session, since normally, after spending a couple of hours staring at three different monitors getting the spots to be analysed selected I am too tired to work. But I got home from uni with plenty of energy to work, so I stayed home and
clovis_t went without me. I managed to accomplish a far bit of stuff, but, most importantly, I have reminded myself I collected most of my samples for my PhD project in March of 2006, consequently their field numbers start 06___. Those samples all came from the northern fault block of the Collingwood River Metamorphic Complex. In November of 2007 my advisor and I did one additional trip, to the southern fault block of the Collingwood River, in search of the long-lost Tasmanian whiteschist. We found it, and collected a number of other samples from the area as well. Whilst we were out, we also stopped by the northern block and picked up another couple of oriented samples, just for good measure.
In October of 2008 we decided that there was just enough funding left to do some detrital zircon dating for two samples from the Collingwood River. I was told to select "sandy" samples as being most likely to contain zircons. So I picked out half a dozen from both the northern and southern blocks of the Collingwood River which were sandier than the others, though not necessarily sandy enough, and brought them along to my lesson on rock crushing. My teacher du jour narrowed it down to three likely candidates, two with 06___ numbers, and one with a 07___ number. So we, thinking that there might be value in having one from each fault block, chose one of each and we commenced crushing.
Since then I've been thinking in terms of having crushed one from each fault block, so was not too surprised when their detrital zircon patterns were somewhat different from one another. Today, at long last, I decided to make the figure showing the location these two samples were collected from. Yup, you guessed it. They are both from the north block! They were collected from locations not more than 250 meters apart along the highway.
However, since the other 07___ samples were all rejected as not being sandy enough to bother, I can't really complain that I don't have one from each block. There is just that lingering embarrassment that one gets when one realizes that the assumption under which one has been operating doesn’t actually apply. The best cure for that? Admit the mistake publicly—then it won’t ever be repeated!
