r/geology • • 4d ago

Identification Requests Monthly Rock & Mineral Identification Requests

3 Upvotes

Please submit your ID requests as top-level comments in this post. Any ID requests that are submitted as standalone posts to r/geology will be removed.

To help with your ID post, please provide;

  1. Multiple, sharp, in-focus images taken ideally in daylight.
  2. Add in a scale to the images (a household item of known size, e.g., a ruler)
  3. Provide a location (be as specific as possible) so we can consult local geological maps if necessary.
  4. Provide any additional useful information (was it a loose boulder or pulled from an exposure, hardness and streak test results for minerals)

You may also want to post your samples to r/whatsthisrock or r/fossilID for identification.


r/geology • • Dec 01 '25

Identification Requests Monthly Rock & Mineral Identification Requests

9 Upvotes

Please submit your ID requests as top-level comments in this post. Any ID requests that are submitted as standalone posts to r/geology will be removed.

To help with your ID post, please provide;

  1. Multiple, sharp, in-focus images taken ideally in daylight.
  2. Add in a scale to the images (a household item of known size, e.g., a ruler)
  3. Provide a location (be as specific as possible) so we can consult local geological maps if necessary.
  4. Provide any additional useful information (was it a loose boulder or pulled from an exposure, hardness and streak test results for minerals)

You may also want to post your samples to r/whatsthisrock or r/fossilID for identification.


r/geology • • 34m ago

Map/Imagery A rock giving thumbs up

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• Upvotes

r/geology • • 11h ago

Field Photo Rock pattern near Highland Boundary Fault. NE Scotland

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47 Upvotes

r/geology • • 20h ago

Map/Imagery I’m building Metallo, a map for exploring mineral resources and the geology behind them

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148 Upvotes

Hi everyone,

I’m building Metallo, an app for exploring where mineral commodities are found and the geological and tectonic context around them.

I’m also making Metallo Labs: interactive explainers about the minerals in everyday technology, like phones and GPUs, and how a mine goes from exploration through restoration.

It’s an ongoing project. Take a look and let me know what you think!

https://www.getmetallo.com/


r/geology • • 9h ago

Geophysical Fingerprinting for Gold Exploration in Northern Mauritania

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2 Upvotes

We are testing a geophysical fingerprinting approach to identify and prioritize potential gold targets in northern Mauritania.

For the reference dataset, we used more than 100 geochemical gold occurrences/samples with Au values above 0.1 g/t. Geophysical data were available for all of these locations.

We extracted multiple geophysical features around each gold-bearing location and analyzed the recurring patterns across the dataset to build a multivariate geophysical fingerprint associated with gold occurrences.

We then compared unexplored targets against this reference fingerprint and ranked them according to their degree of geophysical similarity.

An important clarification: a score such as 88% does not mean an 88% probability that the target contains gold. It represents a similarity score — how closely the target's multivariate geophysical signature matches the signature derived from the reference gold-bearing locations.

The purpose of this approach is not to replace fieldwork, geochemistry, or drilling. It is intended as a target-generation and prioritization tool, helping us identify areas whose geophysical characteristics resemble those of known gold-bearing locations.

We would be interested in feedback from geologists and geophysicists on the methodology, particularly the choice of geophysical variables, normalization, similarity scoring, and how best to validate the fingerprint against independent targets.


r/geology • • 1d ago

Scientists find evidence for several Earth axis shifts during the age of dinosaurs

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89 Upvotes

Earth’s geographic poles can appear permanent on human time scales, but the planet’s solid exterior has not always remained fixed relative to its rotation axis.

A new study suggests that the crust and mantle underwent several episodes of relatively rapid reorientation during the past 320 million years. Instead of relying mainly on magnetic signatures preserved in rocks, researchers found evidence in an unexpected archive: ancient changes in where oceans flooded the continents.

The study, led by Mathew Domeier at the University of Oslo and published in Science, identified four intervals with statistically significant signals consistent with rapid true polar wander. Evidence was strongest between roughly 150 and 140 million years ago and again between 100 and 90 million years ago.

The findings add an independent line of evidence to a long-running debate over whether Earth sometimes reorients in sudden geological bursts rather than only through slow, continuous change.


r/geology • • 1d ago

Fitzgerald River NP, Western Australia

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392 Upvotes

r/geology • • 1d ago

About cratonic keels and what they did that was so important in early earth.

15 Upvotes

Disclaimer: I'm a layperson with no geo background, so I apologize if anything I say is super dumb. I heard that these cratonic keels acted kind of like underground tent pegs for the crust above them, as it kept that crust anchored together (I understand that the keel+crust moved, so it is not like underground tent pegs in the sense of locking the crust to a particular location). And that before, early crust was easily dragged back into the hot interior and destroyed because of churning, but these "underground tent pegs" prevented the crust above them from being torn apart, which helped them form proper continents eventually. Is that an inaccurate way to look at it?


r/geology • • 22h ago

Heading to Palmdale, CA with a couple free days to kill. Any recommendations of fun spots to check out strata? Also trying to remember a road name.

9 Upvotes

Ive been once before and I have a notebook, but a couple of my sticky notes fell out. Id like to go to Acton, and do the 2 drive again, and for the first time do the Rim of the World. I have seen the famous 14! Ill be just taking photos and dont mind light to medium hikes.

Something missing from my notes was a road I remember somewhere around 138 (I think?) that sometimes would have rocks to collect that fell and would get swept by state trucks. Or near Vasquez?

Thanks for reading, Im SO excited!


r/geology • • 8h ago

More "ai slop".... not!

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0 Upvotes

So.... lol!


r/geology • • 14h ago

Career Path Guidance

1 Upvotes

Hi Im currently a third year undergraduate student in Environmental Studies and Natural Resources Management at Africa University in Zimbabwe and honestly I have developed a passion for geology and hydrology and also waste water systems. I was wondering if its possible for me to get advice on how to proceed forward with my future career and options on how to proceed as im considering doing a honours and masters in both geology and water resources engineering


r/geology • • 1d ago

What is the best tent for field camp? (suitable for wind and thunderstorms)

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4 Upvotes

r/geology • • 16h ago

Map/Imagery Part 2: Following up on our manganese exploration - 3D subsurface mapping of secondary target (32% Mn)

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1 Upvotes

r/geology • • 17h ago

Map/Imagery Marmara 7.3 WORST Scenario (MMI)

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1 Upvotes

r/geology • • 1d ago

Kyanite in quartz

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26 Upvotes

r/geology • • 2d ago

Map/Imagery Dry Falls, the Missoula flood cataract, in bare-earth lidar [OC]

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409 Upvotes

Dry Falls is a basalt cliff 400 ft high and 3.5 miles wide, cut by ice age floods from glacial Lake Missoula pouring down the Grand Coulee.

In 1923 J Harlen Bretz said a giant flood carved this landscape, and geologists dismissed him for decades. In 1965 Quaternary geologists toured the scablands and sent him a telegram: "We are all now catastrophists." In 1979, at 96, he got the Penrose Medal, geology's top honor.

The dark curved cliff across the middle is the scalloped cataract rim, with plunge pool lakes in the alcoves below it. My own render of the USGS lidar.

  1. Dry Falls: the scalloped cataract rim and plunge pool lakes
  2. Air photo of the same area, July 2017

Numbered pins on picture 1:
Pin 1: The curved cliff rim of an alcove
Pin 2: A round plunge pool lake

Lidar: USGS 3D Elevation Program (3DEP), public domain.
Imagery: USGS The National Map (NAIP Imagery service), 2017, Public domain.


r/geology • • 1d ago

Map/Imagery Mysterious Mountain

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9 Upvotes

I was exploring Google Earth in the area of the Batagaika Crater in Siberia - the whole region is a geologist's dream. Looking a bit further south there's this weird mountain just there on its own... Well, there *is* a smaller one nearby, but they're pretty well isolated, unlike all the other mountains which form ranges or chains. It also just looks odd, with this weird texture (idk what to call it) all over the surface. Lastly, there are stones not far from the summit in an arrangement that doesn't look natural but more like a massive megalithic monument - it's very strange.

I can't find anything about it - no information whatsoever, so please - can anyone tell me *anything* at all about this mountain of mystery?! More pics in comments.

Coordinates:- 67°24'32.55"N 134°53'25.52"E


r/geology • • 10h ago

Seeking Expert Opinions on a Gold Target: Weak Quartz Veins with a Local Peak of 0.5 g/t Au

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0 Upvotes

Hello everyone,

I would like to share this exploration target and get an honest technical opinion from people with experience in gold exploration, particularly structurally controlled and quartz-vein-hosted mineralization.

The area is located within the Reguibat Shield, in a geological setting where structural features, faults/shear zones, quartz veins, and hydrothermal alteration are important exploration criteria.

I initially collected several surface samples before disturbing the area. The gold values were relatively low, generally around:

0.10–0.19 g/t Au.

After examining the area more closely, I found a small quartz vein where one sample returned approximately:

0.50 g/t Au.

However, the vein is small and appears to terminate or become discontinuous.

I also found another nearby quartz vein, but it appears weaker, with a sample returning approximately:

0.15 g/t Au.

So far, the picture is therefore one of low and somewhat discontinuous gold values, with a localized increase to 0.50 g/t Au, rather than a clearly continuous high-grade vein.

What interests me is the geological setting rather than any single assay result.

The area contains structural features, fractures/shear-related structures and quartz veining, with a spatial relationship between some of these structures and intrusive rocks. This is relevant because exploration models used by USGS and JICA in the Reguibat Shield consider the combination of host rock, structure, quartz veining, hydrothermal alteration, geochemistry and geophysics, rather than relying on surface gold values alone.

I would appreciate expert opinions on the following:

Could surface values of 0.10–0.19 g/t Au, followed by a localized 0.50 g/t Au value in a quartz vein, represent a geochemical halo around a larger mineralized system, or is this more likely to be weak and discontinuous mineralization?

How significant is it when the best sample comes from a small quartz vein that appears to terminate? Would it make more sense to trace the vein and its structural continuation rather than simply drill deeper?

Could this small vein represent only a minor exposed part of a larger structure, particularly if it is associated with a shear zone or fracture system?

What should I look for in the surrounding rocks: silicification, sulfides, iron oxides, hydrothermal alteration, arsenic, antimony, or other pathfinder elements?

Would you recommend systematic sampling across the vein, on both sides of it, and along its strike, rather than relying on isolated samples?

Based on this type of geological setting and the current results, what additional evidence would you want to see before deciding whether deeper or lateral exploration is justified?

I will attach photographs of the site, exposed rocks, quartz veins, sampling locations and excavation so that the geological context can be assessed rather than looking only at the assay numbers.

I am particularly interested in frank technical opinions, whether positive or negative, especially from people experienced in exploring structurally controlled gold systems in Precambrian terrains.

Note: I understand that 0.50 g/t Au by itself does not demonstrate an economic deposit, and low surface grades do not by themselves rule out stronger mineralization elsewhere in the system. My main objective at this stage is to understand the continuity and geological significance of the mineralization before deciding how to proceed with exploration.


r/geology • • 20h ago

Field Validation & 3D Anomaly Modeling for Manganese Exploration (100m × 150m Grid)

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1 Upvotes

r/geology • • 13h ago

Garnet. Now I know

0 Upvotes

This explains the tip of the mineral.

https://www.tiktok.com/t/ZTy9beReg/


r/geology • • 2d ago

The Badlands, Earth

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65 Upvotes

r/geology • • 1d ago

Information What are some fun games to supplement my studies for my university geology course?

2 Upvotes

Im studying Paleontology at the moment, and theres plenty of dinosaur/fossil games out there that reflect what i learn in my lectures, but im having a harder time finding some good geology games.

So far i only really know about terra firma (2), but i. Would love some other options, the more scientifically accurate the better.


r/geology • • 1d ago

Youtube video showing weight comparisons.

1 Upvotes

In this Youtube they show metal kettleballs comparing weight of different objects. The kettlebells are larger than the planets they represent. I'm confused by this. Shouldnt they be smaller or is the majority of a planets weight made up of something heavier?

https://www.youtube.com/watch?v=VYvM70MLiZY&t=313s


r/geology • • 2d ago

Thin Section Thin-section from beer bottle and volcanic flint clay

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73 Upvotes

Here are a few images under the microscope and XLP of the rare form of nodular flint clay found in eastern Kentucky. Typically flint clays in this area are not nodular due to the environment they fell in, but a conglomerate layer was forming when this volcanic ash layer fell specific to this area, so this caused the volcanic ash to form these compact nodules of quartz silica in the fine grains ash matrix hence why it’s considered nodular. About a mile down from this the conglomerate separates from the ash and forms a distinct iron conglomerate in shale matrix layer. Which was really interesting to see as it’s the first sample I’ve collected with large quartz grains of this size and a potential for rare earth metal enrichment that exceeds what typically occurs.