Solar Anamnesis
4/5/2017 8:15:36 AM |
The image has been scaled down to 15% of its original size in order to be view-able by most people in their internet browser. |
MexicoDoug
4/4/2017 3:06:12 PM |
I looked at the whole section area to count how many "good" chondrules are discernible, which is a solid high olivine bar, so an underestimate. First I estimated it as 3.716 square cm. Then I selected a 5.0 mm x 5.0 mm patch (0.25 sq. cm), for fun, the one exactly centered on my "typical chondrule size" in the link. I counted 32 chondrules. That extrapolates to 39.6 dozen (475) chondrules in this thin section ---on the low end of the estimate!!! Check it out: i.imgur.com/bYmNBHg.jpg |
MexicoDoug
4/4/2017 2:41:54 PM |
Oops! I forgot the Pi/2 factor (Sorry!), so I should have said 8.9 micron resolution on the high res image and 15.9 micron on the MPOD displayed image. (And the link I made is 0.62 mm x 0.63 mm not 1x1). John, I just counted chondrules for your comment. Let me tell you this is hard & tedious! I kept it to fairly well defined chondrules, so there are plenty more. Now I understand why authors erroneously bias to larger chondrules in literature, it's the pic resolution and eyesight! Solar was VERY modest with his Sagan impression of "dozens and dozens" LOL! More above: |
MexicoDoug
4/4/2017 1:26:34 PM |
...and that 25 micron resolution was for the MPOD gallery image, not the full resolution image in the link given. There, resolution is 14 microns and I just checked. This is the granularish PO chondrule I called typical in an approx 1 mm x 1 mm field from the image: imgur.com/WqTEOq1 |
MexicoDoug
4/4/2017 6:49:08 AM |
Lucky pick on the chondrule, thanks again Solar A for taking a second look at this beautifully composed stacked image, it is so ... sharp, resolution is around 25 microns! John, the chondrules are there I think what is going on is the image has so much data that it is confusing to process, like looking into a dense forest when from afar the larger trees are dominant, up close so much more becomes visible, so many small trees and bushes come out of the shadows. I had to convince myself of that by looking at small sections at a time. You can get a percent of the volume occupied by chondrules quite well at this resolution and large field. |
Solar Anamnesis
4/3/2017 6:35:16 PM |
@MexicoDoug Wow! You did a great estimation! I estimate the width to be 25.86mm and the height at 20.33mm |
Solar Anamnesis
4/3/2017 6:32:08 PM |
@MexicoDoug The dark brown and black chondrule, nearly perfectly circular at the very top, slightly right of center is 1.19mm |
John Divelbiss
4/3/2017 6:10:56 PM |
my first sentence was meant to imply the chondrules are usually easy to see, but this section is a different. |
John Divelbiss
4/3/2017 6:09:18 PM |
Usually a Saratov thin section would show many nice perfectly round chondrules that are hard to see. This section does not have a lot of the notable round chondrules. Maybe it is the scale as Doug suggests in trying to discern this photo. I am curious too about what I'm seeing. Maybe Saratov has another lithology that is a little different? |
Solar Anamnesis
4/3/2017 12:32:32 PM |
@MexicoDoug I can provide you the image with a 1 millimeter scale with subdivisions. Just let me know and I can try to get it to you. On my site under "About" is my contact info. |
MexicoDoug
4/3/2017 11:36:09 AM |
Nice work Solar! No scale here, so that made a nice project: Assuming the chondrules are typically ~1 mm, eyeballing the field of view is ballpark 20 mm x 26 mm. To arrive at this I chose the chondrule centered at (290, 694) taking the origin as the lower left, as the typical size in the field and found it 40 pixels in diameter. I multiplied it by pi/2 to adjust for the average cross section considering the slices are at random chords, not through actual great diameters. Based on that, the 1617x1271 image would be 25.7 mm x 20.2 mm. Of course it all depends on my selection of the typical chondrule and Saratov's mean chondrule diameters, and I haven't thought hard enough whether this is the right way to do it but it reminded me of a problem in high school called Buffon's Needle. Would love to know the actual field measurements, thanks! |
Jansen Lyons
4/3/2017 10:17:05 AM |
Very interesting TS! Thanks the share, Saratov is a nice meteorite for sure.
God bless! |
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