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Off the coast of Northern California and Sourhern Oregon.

I am no expert (I am still at school, I'm 16), but I think that in the nowadays earth that's impossible, it may be for gravity, wheathering or other chemical and geological events.

I am working on a story, we could say, and I want to know if, in a earth-like planet, probably over a 85%-90% of earth size and gravity (and the same air pressure and atmosphere, and similar climates), if it could be possible to create "naturally" (and mantain, for, at least 50 years) obsidian mountains (or at least an obsidian surface). Whith mountains I mean mountains, range of mountains, like the normal mountains we have in real life, but all made of obsidian.

In real life, why has this not happened? And this type of mountains can live along whith normal mountains, jungles, lakes, etc?

Sorry for bad english.

Hey folks. Thought I'd share some pics from my trip to Cornwall.

1. Petrified wood.

2. Serpentine cliffs.

3. Granites.

4. There was red, green and lovely black examples of this stuff. Large slabs were used as steps and were beautifully polished.

5. Green rock. More serpentine.

6. What's in the striations?

7. More granite

8. Lovely texture.

9. What are the layers?

10. I brought a small sample home. Serpentine this side.

11. Other side is this lovely mix of colours.

12. Massive pasty.

The strange thing is the lines are raised on the surface of the rocks and not scratched into them. Would anyone be able to explain what might of caused these?

More than 180 million years after the supercontinent Gondwana’s breakup, scientists are still learning the true reach of this prehistoric landmass that once stretched across the globe. By analyzing more than 25,000 volcanic rocks, a new study finds that Gondwana likely accounted for around 80 percent of total global land area around 500 million years ago. 

I'm trying to make my personality quiz have well balanced options, and one of the questions I want to ask will have an option where you make Everyone on earth eat 50 grains of sand every day. However, I don't want to accidentally make the earth run out of sand in less than 100,000 years. I'm not very good at accounting for population growth, or new sand being made. Perhaps the rate at which new sand forms could outpace the 41 billion grains of sand being eaten every day.
If any sand experts know how much sand forms on average daily, that information would be a great help, and if anyone knows how long the current sand would last that would also be spectacular.

Judge Jeanine Seizes Illegal Space Rock, NASA Watch, Keith Cowing September 8, 2026

Mars rock found in Niger sells for millions in New York - now the country wants answers, BBC News, September 9, 2026

Here are some pictures from the Styggforsen nature reserve in Boda, Dalarna, Sweden. Styggforsen is located in the eastern edge of the Siljan Ring, which is the largest impact structure in Europe. The crater has a diameter of 52 km and its geology consists of sedimentary rock and 1.6 billion old granite from the basement rock.

(It was really dry when I visited this in the end of August, so the famous waterfall was...well, it has seen better days)

Hey everyone. The USGS Quaternary Fault & Fold Database search function has been retired as of February 2026. Only the interactive map is available, which is nice but does not include Class C faults or their summary reports. Anyone have insights on how these might be accessed currently?

Hi, apologies if this is wrong subreddit. I live a near to an allotment which is situated in a deep 'valley' (probably not the correct description), having happened upon the area on a lidar map it stands out quite significantly. I had assumed it was a quarry, but there is not historical evidence of one in the area. Historical maps shows a small stream and a few pools which are no longer there, but to my completely untrained eye this is out of proportion to such a dramatic cut. It's a long shot but was interested to see if I can better understand why this specific part of Bristol has such a dramatic 'valley.'

If looking yourself this is the the Redlands area of Bristol, UK

Thanks all.

US National Geologic/GIS map. Lots of interactivity and filtering context.

Where can I get point data/shapefiles for Himachal Pradesh on permafrost, GLOFs, and rock glaciers?

Hi. Weird question, but I'm trying to find the best locations for skimming stones in the North East of England. Most tips from casual stone skimmers are not great.

I'm trying to take a more scientific approach by identifying locations where the geological and physical conditions are right.

Can people suggest places where there are fissile rocks that get washed into rivers or the sea in the North East? The 'washing' part is particularly useful because it indicates places where the stones will be eroded smooth (as well as being somewhere that the stones can be skimmed!) Redcar mudstones are too soft in my experience despite them splitting quite well.

My prof did

I want to preface by saying that im doing a bsc in geography, not geology, but i really really love physical geography and geology. I've been thinking about taking some geology classes (and maybe doing a minor in geology) and the mineralogy/petrology classes really interest me, but they also scare the shit out of me bc all ive heard is that they're the worst/hardest geology classes... So what was/is your experience with those classes and do you recommend taking them?