Geology

Geologists have long known that around 155 million years ago, a 5,000 km long piece of continent broke off western Australia and drifted away. They can see that by the 'void' it left behind: a basin hidden deep below the ocean known as the Argo Abyssal Plain. The underwater feature also lends its name to the newly formed continent: Argoland. The structure of the seafloor shows that this continent must have drifted off to the northwest, and must have ended up where the islands of Southeast Asia are located today.

How diamonds form still isn't entirely understood, but laboratory experiments show that the gemstones crystallize only under extreme pressures. Most naturally occurring stones have been traced to the upper mantle, at depths between 93 and 186 miles (150 to 300 km), where pressures can reach beyond 20,000 atmospheres.

For a long time, this put diamonds in competition with a gem called peridot for the title of deepest-occurring gemstone. Peridot is the gem form of a mineral called olivine that makes up more than half of the upper mantle, which extends from the base of the crust down to 255 miles (410 km). But in 2016, scientists described a collection of superdeep diamonds sourced from around 410 miles (660 km), and another batch in 2021 was determined to come from a depth of 466 miles (750 km).

cross-posted from: https://mander.xyz/post/2703469

cross-posted from: https://mander.xyz/post/2703465

cross-posted from: https://mander.xyz/post/2702615

One stop shop for for all of your pedology needs and dank soil compass memes.

[email protected] /c/[email protected]

"The Atlantic is expanding at about 10 ppm (points per month)."

cross-posted from: https://lemmy.ca/post/1673900

Non-Paywall Article

Impact melt breccia (grey) and upthrust rocks (brown). The breccia is interesting because the melt was a carbonate. So it's sort of like a carbonatite lava.

Does Arizona and Australia share the same rock formation layers? I was watching a TV show and a lot of the Australian landscaped looked very red and similar to Sedona Arizona. Do they share the same layers?

Fallout layer due to first nuclear test as horizon marker, among others

Thompson was one of the first women to achieve distinction in the study of geology

I have been working on cataloging, organizing, and photographing the micromount collection that was made for my grandfather by Don Cooke. This is a nice little (well every specimen in this collection is little) Brochantite from Eureka, Utah. The main crystal is about 2mm long. More images of the specimen can be found here: https://imgur.com/a/QGUqBfM

I will try and share some more images of the collection in the next few days.

Enough rock fell off a Himalayan peak to bury Paris to the height of the Eiffel Tower

https://archive.is/oO0dC

As requested by @[email protected] -- post pictures of rocks. We will try to identify them.

Note that copy/pasting pictures works in the comment field, assuming you're on the website. How it works in the multitude of apps -- dunno ;)

Hi there,

Thanks for setting this up. Can you create a minerals and rocks identification thread that's pinned? I'll do my best to identify (10+ years in Archean mineral exploration and other areas)

A freshman-level introduction to Physical Geology. All learners are welcome!

20 lectures at the time of posting the playlist.

Hi folks. All 90 of you. Two weeks in and we're at 90. It's a far cry from the 173k on r/geology.

tl;dr: is it okay so far?

So far it's been mostly me, just trying to populate the community on a somewhat regular basis to keep the snowball rolling. And I just wanted to ask, is it okay that I'm doing pretty much exactly this? I know that the 90:10 rule applies here, maybe even more so until network effects take over. But I worry that I'm shouting into the void. Is there anybody out there? Just nod if you can hear me.

Assuming it's okay to keep shouting into the void as though this community is my personal blog, for the time being, is there anything you'd like to see? Exactly one of the posts gained any traction (the equivalent of hitting the Reddit front-page), but that doesn't necessarily reflect on what you, all 90 subscribers, want to see here while you're doomscrolling.

So I'm begging you, try licking this clear rock here. It's probably not salt, because it isn't cubic. And all the undergrads have been dropping HCl on it to see if it effervesces, so it's probably sour now from all that acid. Maybe it's a sugar crystal I grew in my coffee cup, suspended on a string and I'm hoodwinking you all. Meow.

Are there geology MOOCs anywhere? Every time I go looking I find at most like three but one's in Chinese (which I don't know nearly well enough to take a course in), one's some advanced thing, and the other... I don't even remember.

Anyway, is there anywhere I could possibly peek into a course like... Rocks an' Whatnot 101 maybe? Dirt Stuff for People with Clean Hands, maybe? :'D I can't promise I won't end up disinterested or get bored or distracted and quit, but I want such courses to be a thing anyway.

I keep this one on hand for discussions with people who say "but the climate has always varied". Rate of change is a thing.