The Piqiang Fault is a northwest trending strike-slip fault that laterally partitions the Keping Shan Thrust Belt in the NW Tarim Basin, China. The reddish, greenish and brownish bands are continental Devonian sandstones, Silurian deeper marine sediments and Cambro-Ordovician limestones, respectively.

I'd like to show you the polished surface of a molybdenite ore sample from the Sorsk deposit quarry (Kuznetsk Alatau, Siberia). This sample was collected back in 1960 by the founder of our department, Yu.V. Smirnov. The genesis of the deposit is classified as a high-temperature hydrothermal type (450-500 °C).

For the longest time, this amazing sample lay on a shelf, gathering a thick layer of dust and attracting absolutely no attention, until I found it. And yet, it is truly beautiful. After sawing and polishing, the intense processes of the granite's hydrothermal alteration became visible, expressed by the formation of nests and veins of quartz with oriented aggregates of radial-fibrous molybdenite.

This specimen has it all: well-formed, idiomorphic needle-like molybdenite crystals up to 5 cm in size, semi-transparent quartz with milky-white filamentous cracks, and relics of the original granite itself.

Found in Serifos (Greece) which is know for the ancient iron mines (3000 BC). You can see abandoned mines in almost every mountain or hill.

Any idea of the first crystal might be? Can't be scratched with a steel knife so grey quartz (?) Also the grey mineral is easily scratched with fingernails. The black spots I'm sure it's magnetite.

Last photo of all the stuff i carry back home. Some iron oxide stains, two possible white clays and some iron ore lumps.

Every time I visit a place I end up carrying at least 3 kg of rocks hahaha.

So I am trying to create a secret island country or a hidden country within a continent no biger than Cuba. Now here is the thing, I want it to transition from basically the desert mountains of Afghanistan , to perpetually green meadows and fertile agriculture fields fed by a navigable river birthed by springs, and ending up into a Louisiana Bayou like coast.

Would that be possible on Earth? Do you have any examples of a region? How far from the Equator would it be? Would it need to be larger?

I was cleaning my room and decided to organize my rock coleccion after almost 5 year. In couples of day I'll get my geology degree and this rocks feels so personal to me rn.

Anyways, here some of my favorites

The first img is a mica-esquito with granate.

Working on a tool that automates the tedious statistical validation part of geophysical analysis. Currently seeing geophysicists spend 2-3 days manually processing contingency tables from neural network classifications.

**The Problem:** You have contingency tables showing neuron-to-lithofacies assignments (Excel format), but then spend days manually:

- Creating confusion matrices

- Running chi-square tests

- Calculating Cramer's V and effect sizes

- Validating statistical assumptions

- Generating professional reports

**The Solution:** Software that takes your contingency table Excel files and automatically:

- Generates traditional confusion matrices

- Runs complete statistical test suites (chi-square, Cramer's V, etc.)

- Provides quality grades (A-F) for reliability assessment

- Creates publication-ready visualizations

- Batch processes multiple datasets for comparison

**Question:** If this reduced your statistical analysis from days to 15 minutes, would you/your company use it?

**For those doing lithofacies classification:** What's your biggest pain point with contingency table analysis? Do you currently do this manually in Excel, or have you found better tools?

I'll analyze your SOM data for free to demonstrate the tool.

Send me:

- Your contingency tables Excel file (anonymized/public data preferred)

- 2-3 questions about your current analysis workflow

I'll return:

- Complete statistical analysis

- Professional visualizations

- 15-minute screen sharing walkthrough

First 10 responses only. Just want to validate this solves real problems.

In China, specifically in the Guangxi region, sinkholes called "tiankengs" have been discovered, containing ancient forests. These sinkholes, formed by the dissolution of limestone rocks by underground rivers, are unique geological formations and natural laboratories for studying the evolution of ecosystems in isolation. One of these "underground forests" was discovered in 2022 near Ping'e Village in Lei County, its depth was 192 meters (630 ft) and its width was 306 meters (about 1000 ft). Ancient trees, some up to 40 meters high (roughly 130 ft), grow inside the sinkholes, as well as dense undergrowth.

Excited to report that the Rockd app now has stratigraphic columns (and some fixes that make exploring the map quite a bit nicer)! https://bsky.app/profile/rockd.org/post/3lxaycwjw2s24

The AAPG Foundation supported this new feature, in part because it's nearly the 40th anniversary of the COSUNA stratigraphic charts for North America, and Macrostrat (the source of Rockd's data) owes a lot to that effort. Lots of new changes to Macrostrat will deepen this area in the future with new column datasets.

You can access the columns from the info popup when you click a map location (or from the "Stratigraphic name" area on the Dashboard.

I'm excited to to see what this community thinks!

This appears to be a volcanic dike intrusion just above the small cave.
Is it just happenstance that the cave is located here or is there a direct correlation to the dike and the presence of the cave? I can imagine differential weathering of the dike material would cause this.

North Central Washington State, Okanogan County

This is the effusive lava flow from Mt Etna from Friday evening (22/08/25). This is from a fissure that opened on 20th August on the flank of the South Eastern Crater(s). We flew over last evening (Saturday) and saw an increase in activity with tephra being erupted out of the crater and a significantly larger flow to a lot lower levels. Interesting to see fast moving lava flows like this on Etna.

I am an entomologist at a non-profit organization. One of our projects involves sampling subterranean arthropods. We would like to put traps as far underground as possible (10s to 100s to 1000+ feet). The traps are narrow pieces of PVC pipe which should fit easily down holes left from core sampling. This has been done successfully in the past in holes from core samples. So far, we have not had much luck finding good leads for organizations that might be willing to let us place traps in previously drilled core holes, but we are still working on that.

However I did speak to someone who previously did core sampling with the Army COE, who suggested that there were some samples done many years ago. and that the holes would still be open and we should considered using them. I assume that after so long that the holes would become filled in with debris or overgrown with plant roots. Has anyone ever revisited a core hole years later? Would this be at all possible?

Also on a side note if a scientist reached out to you and asked if after you were done drilling a sample that they would like to put a trap down the hole is that something you'd ever consider allowing?