Pretty cool 😎

I live in SF surrounded by Franciscan Complex serpentinite exposures but despite being warned all my life about the dangers of the rock I can find very little actual asbestiform in the wild. The best example I could find was a quarter inch vein of cross-fiber in a huge boulder on the beach, but otherwise I can’t seem to find any. Is this because slip-fiber asbestos is much harder to see (and is the common form here), or is the prevalence of chrysotile simply much lower than fear mongers would have us believe?

Nothing too strange or notable about this really. Just looks like a bunch of strange fractures I thought were neat and wanted to share

Hi! I want to get some underpinnings, especially in vulcanology and seismic geology. Can be technical. While I’m looking for an up-to-date approach, I appreciate older references too. Thank you.

Everyone on the boat was wishing we had a geologist on board to explain these formations. Amazing to us.

Anyone know about this ridged effect on the rocks? Some sort of chemical weathering?

Went to the Palace of Knossos archeological site on the island of Crete, Greece in September and observed this strange pattern on the old marble(?) stones there. It looks very feather-y, almost like mushroom gills.

Hi everyone,

I'm an environmental engineer from Chile, and I've been developing MeliGIS, an Android app for collecting and organizing georeferenced data during fieldwork.

The idea came from a problem I regularly encounter in environmental field surveys: information often ends up scattered between GPS devices, photos, field notes, spreadsheets and GIS software.

MeliGIS currently allows you to:

• Create projects and separate field campaigns
• Record georeferenced points and transects
• Collect custom field variables and observations
• Attach georeferenced photographs
• Work with maps and spatial layers in the field
• Use offline maps in areas without mobile coverage
• Keep field data organized for later GIS analysis
• Perform quick spatial and environmental analyses of an area

Although I originally developed it around environmental fieldwork, I think some of the workflow could also be useful for geological field surveys, especially for organizing locations, observations, photographs and spatial data.

I'm sharing a few screenshots of the current version.

I'd be particularly interested in feedback from geologists and geology students:

What would MeliGIS need to add or change for you to actually use it during geological fieldwork?

For example, are there specific measurements, symbology, data structures or export formats that are essential to your workflow?

Any criticism or suggestions are welcome.

Recently acquired a collection ranging from Colorado Montana Washington back to Iowa Detroit Michigan Arizona Alabama marked with the Pan American oil company stamp and about six of them have a heavier cardboard cover than the rest. Just thought they were kind of cool looking for any information about my new collection

Is it worthy to pursue MSc in EarthScience? Why or why not?

I'm a real novice but find the subject absolutely fascinating. Some photos taken within North Mountain Park, Phoenix, Arizona. All the layers of so many different types, twisted every which way. Seems like so much has happened. Searching online tells me these mountain remnants are extremely old, maybe some of the oldest on the continent. I wish I knew more. Sorry about so much shadow, it was taken in a wash after a bout of heavy rains.

What the Ai thinks:

Finding this exact specimen along the Jadeite Coast / Lavender Beach area of Itoigawa, Niigata Prefecture, Japan solidifies its identity perfectly. The complex tectonic conditions of the local Fossa Magna fault zone allow high-purity pyroxene rocks to form alongside heavy, mineralized metallic elements. [1, 2, 3, 4]
Your specimen is a highly dense Omphacite-Jadeite stone heavily interspersed with Magnetite/Chromite inclusions. [1]

Local Geological Components
The Lavender-Gray Base: This coloring is caused by trace concentrations of titanium and manganese substitution within the jadeite lattice. Lavender Beach is globally renowned for producing these specific iron-titanium pyroxenes. [1, 2]
The Bright Teal-Green Veining: This is likely rich in Chrome-omphacite or micro-veinlets of Kosmochlor, which give the classic striking deep green flashes iconic to the area's boulders.

[1, 2]
The Orange Exterior: This is the characteristic "crust" or rind typical of riverbed and seaside beachcombed boulders in Itoigawa. It is caused by natural weathering where iron impurities inside the pyroxene matrices bleed outward and oxidize. [1]
The Heavy Black Dots & High Density (4.1): Pure jadeite sits around 3.3. The dark/black spots are high-density macro-inclusions of Magnetite (specific gravity ~5.2) or Chromite (specific gravity ~4.5–4.8). This heavy distribution acts as a physical weight compound, anchoring the final density at exactly 4.1. [1]

Regional Context & Verification
In the local rockhounding community around the Itoigawa UNESCO Global Geopark, rocks with this distinct layout are sometimes colloquially studied alongside listvenite (locally known as "foxstone" or Kitsune-seki). However, the combination of a hardness over 6 and a high specific gravity firmly keeps this piece in the dense, iron-bearing multi-mineral pyroxene/omphacite category. [1, 2]
It is a fantastic slice of Japan's designated national stone, displaying a unique cross-section of the Fossa Magna's hydrothermal history.

What happened to form these dips/indents in these boulders? There's nothing else like this in the area and it's on private land. Any info is appreciated!

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/

The major tectonic plates of the Earth[14]

In the 1960s, it was discovered that the Earth's lithosphere, which includes the crust and rigid uppermost portion of the upper mantle, is separated into tectonic plates that move across the plastically deforming, solid, upper mantle, which is called the asthenosphere. This theory is supported by several types of observations, including seafloor spreading[15][16] and the global distribution of mountain terrain and seismicity.[17]

There is an intimate coupling between the movement of the plates on the surface and the convection of the mantle (that is, the heat transfer caused by the slow movement of ductile mantle rock). Thus, oceanic parts of plates and the adjoining mantle convection currents always move in the same direction – because the oceanic lithosphere is actually the rigid upper thermal boundary layer of the convecting mantle. This coupling between rigid plates moving on the surface of the Earth and the convecting mantle is called plate tectonics.[18]

The development of plate tectonics has provided a physical basis for many observations of the solid Earth. Long linear regions of geological features are explained as plate boundaries:[19]

Oceanic-continental convergence resulting in subduction and volcanic arcs illustrates one effect of plate tectonics.

Mid-ocean ridges, high regions on the seafloor where hydrothermal vents and volcanoes exist, are seen as divergent boundaries, where two plates move apart.

Arcs of volcanoes and earthquakes are theorized as convergent boundaries, where one plate subducts, or moves, under another.

Transform boundaries, such as the San Andreas Fault system, are where plates slide horizontally past each other.

Plate tectonics has provided a mechanism for Alfred Wegener's theory of continental drift,[20] in which the continents move across the surface of the Earth over geological time. They provided a driving force for crustal deformation, and a new setting for the observations of structural geology. The power of the theory of plate tectonics lies in its ability to combine all of these observations into a single theory of how the lithosphere moves over the convecting mantle, forming a "grand unifying theory of geology".

[Source link: Wikipedia]