Le rover Curiosity a brisé une roche en roulant dessus, dévoilant des cristaux clairs et laiteux. La zone étant riche en sulfates, il est très probable que ce soit des cristaux de gypse, parmi les plus beaux que je vois depuis le début de la mission ! 1/3
Plate Tectonics Has a Surprise Silver Lining - Without this restless geologic process, which triggers destructive earthquakes, Earth would not be habitable, by Robin George Andrews May 29, 2024
"...on geologic timescales, plate tectonics ensures that Earth won’t grow so catastrophically hot that its surface becomes unlivable. Without plate tectonics, Earth would turn into Venus. And no planet aspires to be more like Venus.
...And, had it not been for—among other things—our world’s endlessly shifting tectonic plates, Earth could have shared the same grim fate as Venus.
Yes, those tectonic plates buckle and stretch, slip and slide, creating faults that jolt and snap, which generate earthquakes—sometimes devastatingly so. But these tremors are the vital sign of a planet with a beating geologic heart, an orb with a transmogrifying face..."
[I immediately thought of Calvin and Hobbes here, lol.]
Happy #FossilFriday, check out this Allosaurus fossil with amethyst growing at its center! It's likely water rich with silica and a touch of iron leeched into the bone during the fossilization process, allowing the growth of crystals over time. (1/2) #paleontology#geology#dinosaur#allosaurus#science
@mrundkvist
now I'm trying to figure out where I learned the factoid that the Silurian had been previously called the Gotlandian by a few geologists (not majority), before Murchison got his way.
@k_kuhlman Nevertheless those little blue cubes are quite rare. Literally found in only two places in the world - it's a copper/silver/lead mineral. I've seen cubes twice this size sell for $1000 or more apiece.
View from the south to the Vercors plateau, Drôme, France. In the middle ground you can see the curved 'barre tithonique' (solid limestone of Upper Jurassic age). Behind that is the Lower Cretaceous limestone of the Glandasse (2041 m), which forms the edge of the Vercors plateau. #geology#fridayfold#foldfriday#france#alps
@studiohaverstraat Also seen : "la dent de Die" below which Romans used to carry large carved blocks from Plaine de la Queyrie down to Die during the 2nd and 3d Centuries. And in the background, the "Grand Veymont", 2341m. Turn around and you will see the Saou perched syncline, one of the highest ! #MyOfficeViewIsBeautiful#Mountains#Drome#Vercors
A 1 micrometer diameter rock would be perfect for your nutritional needs. With our "micron" service we'll send you the rocks you need for only $ 10.00 (US) per week. Or you can get a yearly supply for only $500.00 - a $20 discount!
So, long #geology story long, I was driving the Modesto-Oakland leg of my weekend journey on Friday, and I accidentally went up Corral Hollow Rd instead of Patterson Pass. It was an interesting explore, although ultimately it dead-ended and I had to turn around. There’s a state park in there called Carnegie (really a rec vehicle place), so I checked out the butterfly situation. I crossed a wash several times, and I saw a lot of this material. At first I assumed it was old road tar, but it was weathering funny. I picked up a piece and discovered it was quite heavy, so I snagged a chunk and brought it home to clean. Seems to have a lot of feldspar - probably calcic. And mostly fine-grained mafics.
My guess is that I stumbled upon some un-serpentinized ultra-basic material from the Franciscan. I’ve heard it’s around, but in all my years of living in Northern #california I’ve never seen any in the field.
Anybody else know?
Now that the specimen is clean and dry, my loupe shows growth or reaction rings on the edges of the feldspars, and apparently some small garnets. So I'm going with Gabbro or possibly Eclogite.
The crystallization of large replenished magma bodies is amazingly complex. The photos of layered rocks from the Bushveld Complex in this new #OpenAccess paper are mind-bogglingly wonderful 🤩 🤯 🤓 . The wider applicability of their conclusions might be disputed by some, but good stuff though! https://doi.org/10.1016/j.lithos.2024.107621#Geology#Igneous#LayeredIntrusions
#Eruption#Volcanos#Geology
Per the Guardian, the erupting volcano,
"Ibu is one of Indonesia’s most active volcanoes, erupting more than 21,000 times last year. "
Doesn't that translate to it erupted all year long? How are we defining an eruption if we can count multiple eruptions a day?
#OnThisDay, May 18, 1980, Mount St. Helens erupted in Washington state. It has often been declared the most disastrous volcanic eruption in U.S. history (depicted in St. Helens, 1981)
Happy birthday to Danish #seismologist Inge Lehmann (1888 – 1993) who demonstrated that the Earth's core is not a single molten sphere, but contained an inner solid core, in ‘36. She was a pioneer #womanInScience, a brilliant seismologist & lived to be 105.
As she first postulated, the #earth has roughly 3 equal concentric sections: mantle, liquid outer core & solid inner core. 🧵1/n
Opals form in cavities within rocks. If a cavity has formed because a shell was buried in sand or clay that later became rock, and conditions are right for opal formation, then it forms a fossil replica of the original object.
From a 1929 book on Child's Geography:
"But the World still kept on cooling and cooling, and as it cooled it shrank and shriveled and wrinkled and crinkled and puckered like the outside of a prune. You know a prune was once smooth and round when it was a plum. These little wrinkles and crinkles rose up out of the ocean and were the continents and mountains, so you see how big the wrinkles and crinkles really are."
