Sigmoidal structures (S-C structures) developed in deformed limestones within the Tellare fault. What's remarkable is the presence of white tensional veins (white) oblique to shear planes and parallel to the [theoretical] sigma 1. See first comment for a sense of scale. ⚒️ #geology

Welcome back to #fossilfriday! Here are the impressions of the Inoceramid clam Mytiloides mytiloides. This specimen comes from the Late Cretaceous (Cenomanian-Turonian) Greenhorn Formation (Colorado Group) in northwestern Nebraska.

Chloritoid crystals in a schist from the Massa Unit, Italy ⚒️ #geology

#FossilFriday Polished floor tile in the British Museum consisting of Carboniferous crinoidal limestone. The larger of the crinoid fragments are sections of stem segments (columnals) from the these so-called ‘sea-lilies’.

#FossilFriday pyritized ammonite from the Punta delle Rocchette Fm. Lower Jurassic.

#FridayFold folded Sinemurian limestones at Punta delle Rocchette, Southern Tuscany, Italy #geology #tectonics #structuralgeology

Upended strata pile-up in the Alps for #RockinTuesday. Parc National des Écrins (Yes, again! I had a fab time there last summer!), #France. Pointe des Estaris/Crête de Martinet (from the other side from yesterday...) #mountains #mountaineering #geology #landscape #scape #photography #EastCoastKin

Obicular #granite, #NewZealand. An uncommon type of granite when #magma crystallization rapidly occurs around seed crystals. #geology #rocks #photography #science

(Long) Before mobile phones: hand drawn PPL and XPL views of porphyritic dolerite from Ben Hiant, Ardnamurchan, Scotland. From my undergraduate mapping report. #ThinSectionThursday 🧪⚒️🌋

Incredible rock! A retrogressed eclogite in which amazing simplectites developed during amphibolite-facies metamorphism. Garnet is surrounded by coronas of plagioclase and hornblende. Omphacite is replaced by diopside + plagioclase simplectites. ❤️ ⚒️ #geology

Contact between fibrolite nodule (lower right) and biotite paragneiss

Asymmetric feldspar porphyroclast

Today I feel very stressed, but not as much as this ultramylonite from Mt. Grighini, Sardinia FOV 3 mm. CPL light #geology #ThinSectionThursday

Folded migmatites from Crevola, Val Sesia (Italy)

Jaume Verges explaining thrust-related synsedimentary folds in the Pyrenees. July 2024 - DRT meeting #geology #pyrenees

Thin Section Thursday! Ophitic texture of plagioclase laths encased in clinopyroxene in a gabbro from the Glen Mtns. Layered Complex in southwestern Oklahoma. Contributed by Robert Puckett. You can contribute too! Send images to akoziol1 at udayton dot edu. #thinsectionthursday

Pyrope and minor kyanite in matrix of phengite and palisade-textured quartz from the Dora Maira massif, N. Italy. Section is slightly above standard thickness. #thinsectionthursday

I've seen fossils in some remarkable places, but this takes the prize: the benthic foram Nummulites in the base of the Great Pyramid of Giza. These massive blocks were quarried from the Eocene Mokkatam Formation when a relictual population of woolly mammoths still lived on Wrangel Island.

This is cool. This rock WAS an eclogite and now it is just amphibole and chlorite aggregates, but the opaque minerals still mimic the shape and the internal foliation of grains that do not exist anymore. 4th photo is all that's left of the original assemblage: some omphacite relics inside amphibole

Chopsticks

Sometimes even the most 'static' rocks show evidence of deformation. This prismatic amphibole crystal is slightly bent and crosscut by a series of cracks that appear related to the bending ⚒️ #geology #amphibole #structuralgeology

X marks the spot

A bridge on a river or an amphibole crystals stabbing another. You decide

Amphibole 'star destroyer' sailing in outer space (made of chlorite) ⚒️ #geology

Poor garnet replaced by epidote, albite, and pargasitic amphibole

The canyon, a fracture filled of amphibole in a crack within a large pyroxene crystal

Contact between garnet and clinopyroxene in retrogressed eclogite. Lots of pargasitic amphibole around

Inside a very large pyroxene (half the thin section) in retrogressed eclogite-facies metagabbro from Voltri, Italy ⚒️ #geology

Preserved liquefaction-related structures (convoluted beds) in metasandsone in the low-grade metamorphic rocks of the Farma River, Siena, Italy

Crenulated veins in Permian rocks from the Farma river valley

Crab spider from Southern Tuscany

"Anagenite", an old term for the quartz-rich metaconglomerates of the Verrucano from Tuscany. The Middle Triassic in Southern Europe was dominated by braided rivers in an arid environment and these deposits is all that's left of them

Well, it's friday somewhere Folded layers of turbidites from the Farma River valley. What's nice about this outcrop is that the metasandstone layers still contain nice sinsedimentary folds folded by tectonic folds. My secret dream is to bring here students just to drive them crazy

My final #FridayFold from December's visit to Mosaic Canyon in Death Valley NP in California. This one is pretty crazy, with at least two hinges. See if you can make any sense of it. ⚒️

The fortress of San Silvestro, near Campiglia Marittima, a medieval mining town. People lived in this harsh place to mine copper and silver from Ag-bearing galena, but eventually the place was abandoned due to the scarcity of water, which made impossible to use more advanced forms of mining.

Dikes of 'mortadella' breccias (cit. @robrizzo.bsky.social ) Origin: unknown #geology

The Island of Montecristo, perhaps the wildest place you can find in Italy. It is completely uninhabited and far from the civilized world (70 km from the coast). There are only two guards stationed here during summer. Getting there is logistically tough and expensive.

Eclogite

I have a feeling that there are quite a few garnets in this rock

City of ̶a̶n̶g̶e̶l̶s̶ amphiboles

Folded serpentinite in the upside down

Waves of antigorite in a stormy world ⚒️ #geology #serpentine

"I once was cordierite" surrounded by quartz

Quartz veins, crosscutting a network of talc veins in carbonated serpentinite from Cavo, Elba ⚒️ #geology

Welcome back to #TrilobiteTuesday Here is Bumastus ioxus from the Lower Silurian Rochester Shale (Clinton Group) from Middleport, New York State.

Embayed quartz in a subvolcanic porphyry from Elba #geology

Ultramylonite, oil on canvas #geology

Swim freely, my little quartz fishes Ultramylonite Grighini Mts, Sardinia

The metamorphic assemblage olivine (high birefringence grains) + anthophyllite (grey prismatic xx), plus some tremolite to accommodate extra Ca. A contact metamorphosed serpentinite. Monte Capanne Pluton aureole ⚒️ #geology

A rocket in space according to normal people A tourmaline grain surrounded by deformed quartz and feldspar according to geologists ⚒️ #geology #thinsection