r/geology

Ask anything to do with caves or speleology in general, I’ll answer as best I can and point to more resources too, any questions about karst works too but I may not know.

Photos: 1) soda straw. 2) cave bacon. 3) small fault. 4) odd colouration. 5) fluorescent calcite. 6) acicular aragonite. 7) parasitic fold. 8) more bacon. 9) shell. 10) cave salamander. 11) cave rafts. 12) rings in a broken stalagmite. 13-14) acicular aragonite and anthodites. 15) dissolution in action. 16) big fault. 17) cave shield.

Last week I was on vacation in southern Spain, and was able to visit some awesome beaches. While the family was sunbathing and swimming, I made sure to check out the surrounding rocks.

I was impressed with the folds in the cliffs at this beach between Torrox and Nerja.

From what I could find out, they are part of the Torrox Unit within the Upper Alpujarride Complex in the Betic Cordillera.

The unit mainly consists of different gneisses, with overlying metasandstones and dark mica schists rich in graphite, which I assume these cliffs are made of?

Apparently there is a complex metamorphic history, which occurred from the Variscan to the Alpine Orogeny.

I found this paper ( www.ugr.es/\~grupo179/pdf/Sanchez Naval 2017.pdf )discussing the metamorphism of the Complex, but honestly some stuff went over my layman's head.

If someone knows more about these cliffs and the surrounding geology, I'd be thrilled to learn.

The last two pics are of a sample rock I found at the beach.

Columnar basalt of the Columbia River Group exposed via erosion at Latourell Falls

I got to visit this incredible site with my sea kayak twice over the last two weeks. I wish I’d taken closer photos from the water, but on the first visit I was making time to a distant destination, and on the second pass a week later the water was too rough to get close to the really big and twisted piles of columns. Still, I was able to find enough shelter in Woodbine Harbour to get out and walk around on them!

Travelling through Nova Scotia and stopped to take some photos of the incredible scenery. Taken in Blue Rocks, Nova Scotia.

Hello, I’ve passed this part of Unalaska island a lot and always wondered what was up with the semicircular shape starting halfway up this cliff face. I thought yall might have an idea. We see so much nutso geological stuff on the coast of Alaska, if it’s interesting to the sub I’ll keep sharing. Thanks for your consideration.

I found it at a creek in Dallas, Texas. It slightly lets light in, resembles quartz, but I thought it was petrified wood when I first pulled it out. It wasn’t in the water, but buried in a bunch of dry rocks. My fingernail doesn’t leave a scratch on it, and other rocks don’t either. It doesn’t feel easily breakable but I also don’t want to break it lol. Thanks!

Here are some of my favourite minerals, most names should be displayed if you want to research how each one is formed. If you’re ever in Prague I’d 100% recommend you to check out the museum not only for their mineral hall but very well developed exhibitions!

Nález Česká republika

Queen’s College, University of Dublin. Geology bldg announcements board. Sign up! 😎

I an betting the rock split then a tree did is way between it.

I have been doing some exploration at this underground burning coal seam. Water seems to penetrate through the ground and steams come back up. This is not very obvious in this clip but nearby its much more obvious. My friend is here with a lighter sparking a vent and these puffs of steam come up.

What might be happening here?

Guys I’m in the biology game but love me some rocks. Here are a few of the great things I saw at the Harvard Museum of Natural History. These pics won’t do the collection justice.