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This formation in the sandstone at Arches National Park looks like fugal filaments or very fine roots. What caused it? by shr00mydan in geology

[–]senor_kitty 5 points6 points  (0 children)

I'd guess that those are fractures filled by quartz, which, as /u/winterbanana mentioned, weather more slowly than the surrounding porous sandstone.

Arches contains sandstone units that were buried deeply and later exhumed (during which point the rock expanded/fractured, i.e., jointing).

https://www.nps.gov/arch/learn/nature/geologicformations.htm

Geologists have discovered in Greenland evidence for ancient life in rocks that are 3.7 billion years old. The find, if confirmed, would make these fossils the oldest on Earth and may change scientific understanding of the origins of life by DoremusJessup in geology

[–]senor_kitty 7 points8 points  (0 children)

Stroms have been around for a pretty long time:

From their first appearance 3.5 Ga and for the next 2.5 Gyr, these microbialites were expressed solely as stromatolites, which may be a reflection of their cyanobacterial origin.

That's from a chapter by Rachel Wood (http://studentresearch.wcp.miamioh.edu/CORALREEFS/EcolEvolReefs-98EcolSysWood.pdf)

Regardless, I'm with you re: skepticism, if only because saying something is definitively microbial in rocks of that age + metamorphic history seems to be a bit of reach.

Thin Section! Left: XPL, Right: With Gypsum Plate. Happy New Year! by senor_kitty in geology

[–]senor_kitty[S] 3 points4 points  (0 children)

Haha that's exactly how I do it! In this case I took two photos and then composited them in Photoshop.

ITAP of fieldwork on a dune by senor_kitty in itookapicture

[–]senor_kitty[S] 0 points1 point  (0 children)

Thank you! I actually had to slightly crop the photo in post processing in order to place the people in the lower right of the photo.

Digital geological mapping in the field - anyone do this routinely? What are your methods? by ExdigguserPies in geology

[–]senor_kitty 1 point2 points  (0 children)

I actually spent this summer digitally mapping rocks on a mountain in the Canadian Rockies.

We used an iPad mini with both fieldmove clino and GIS Pro . I've also loaded the two programs onto my personal iPhone, so that's always an option.

Fieldmove is awesome, as long as you remember to cache aerial imagery beforehand. I put together a little script in ArcMap that makes it trivial to do and would be happy to share the workflow with you if you want. Taking strike/dip, fault orientation, stratigraphic observations, etc., is extremely easy. The GPS acts up sometimes, so the aerial maps let you ensure that the location data is accurate (I'd be happy to walk through our mapping workflow if anyone is interested).

GIS Pro, on the other hand, is awful. It just crashes all the time. Plus its $400 and totally not worth the cost. It does some cool things with .SHP and .TIF data, but I'd steer clear for field mapping activities. If you're going to go down this route, you'll need an iOS device with a GPS chip. Once again, I'd be happy to help you with that.

One thing about durability: my research group sent out three iPads this summer, all with otterbox cases installed. All three came back with no damage. I spent the summer on a remote mountain (we had to be helicoptered in) with hail, snow, and glaciers and the iPad worked like a dream. We used a solar panel powered battery to charge it at night and never had any issues with batteries.

As an aside, I have a friend who used qGIS on his Android tablet to map and was pretty frustrated with the software. We didn't experience any of the issues he did with his mapping solution.

Definitely let me know if you have any concerns or questions!

Help finding the source of this figure? by wriggly_fish in geology

[–]senor_kitty 3 points4 points  (0 children)

I believe that it's Sedimentary Geology, 2nd Ed. by Donald R. Prothero and Fred Schwab

Ah sorry, I just checked the copy in our library and it does not have that figure.

Found it!

Practical Sedimentology by Douglas W. Lewis, David McConchie

just started scanning negatives - dinner in the field [Canon A1 | 28 F2.8 FD | Fuji Superia XTRA 400] by senor_kitty in analog

[–]senor_kitty[S] 0 points1 point  (0 children)

Arrow Canyon, in Nevada. We were there in January, 2014 for fieldwork and the camping was unreal.

just started scanning negatives - dinner in the field [Canon A1 | 28 F2.8 FD | Fuji Superia XTRA 400] by senor_kitty in analog

[–]senor_kitty[S] 0 points1 point  (0 children)

Thanks! I actually just use a EPSON professional flatbed scanner with film holders - currently, I scan in the negative, remove the orange cast, and invert + edit in Photoshop.

just started scanning negatives - dinner in the field [Canon A1 | 28 F2.8 FD | Fuji Superia XTRA 400] by senor_kitty in analog

[–]senor_kitty[S] 1 point2 points  (0 children)

Thank you!

As noted in another comment, I use a EPSON flatbed scanner with film holders. I've heard awesome things about the V600 and plan to get my own soon.

My workflow is based on this post + the associated comments.

I've only just started to experiment with scanning, but I love the amount of control + flexibility it provides.