#geoscience

[monarchbutt]

whenever i can't picture dinosaurs existing i just humble myself by looking at birds alive today. what the actual fuck is that thing

[mindblowingscience]

Hadean zircons reveal crust recycling and continent formation more than 4 billion years ago

Parts of ancient Earth may have formed continents and recycled crust through subduction far earlier than previously thought. New research le

Parts of ancient Earth may have formed continents and recycled crust through subduction far earlier than previously thought. New research led by scientists at the University of Wisconsin–Madison has uncovered chemical signatures in zircons, the planet's oldest minerals, that are consistent with subduction and extensive continental crust during the Hadean Eon, more than 4 billion years ago. The findings challenge models that have long considered Earth's earliest times as dominated by a rigid, unmoving "stagnant lid" and no continental crust, with potential implications for the timing of the origin of life on the planet.

Continue Reading.

[geoledgy]

I designed and made button pins for my coworkers based on their program area as a parting gift...very fun to make I love buttons

Please do not use, repost, nor replicate these designs.

[aro-geo-turtle]

What people think studying geology is like: Here, memorize these 100 cool rocks and where to find them and also here's how plate tectonics works.

What studying geology is actually like: All rocks are actually one of these 10 rocks except when they're not, but those are like super rare so don't worry about it. The Earth's mantle isn't really made of magma and its also green actually. Rotate this cube in your mind seven different ways. Remember not to lose your protractor. We combined a compass and a level into one horrible machine, now go chuck it at a hillside in the rain in seven different ways. Do you remember anything from high school trigonometry? Cause you'd better. Move this object into the theoretical construct where space isn't real and all angles are doubled for some reason. Time to play in the sandbox! You think you know how the concept of temperature works? Haha fuck you. Now rewrite how your brain thinks about 3D space.

[void-of-unparalleled-chaos]

Being in geoscience is funny because all of our perceptions of time are completely skewed. No other field would you have someone tell you that 1,000,000 years isn't very long ago. Anything under 5,000,000 is chump change (and I am being stingy).

[letstalkrocks]

Today's Specimen: Ametrine

Ametrine is a variety of quartz with areas of natural purple and yellow/orange colouration. It's name comes from the colours it produces, resembling both amethyst and citrine. Ametrine deposits can be found in Bolivia, Brazil, and India, with the majority coming from a single mine in Bolivia. It is ranked at about a 7.0 on the Mohs hardness scale. Alternate names for ametrine include: Bolivianite, Golden Amethyst, and Trystine.

Stay tuned for another rock talk!

[thejustinestuff]

Happy World Geologists' Day! 🌏 ⚒️

[metamorphosedsapphic]

year 2, semester 4, metamorphic petrology field trip

it's a good thing I love walking. Otherwise I'd hate this more than anything.

36°C heat, with only the sun and ourselves to keep us company, we started walking up a slope toward the large marble quarry that Penteli is known for. Same marble that built the great monuments of ancient Athens, of course. On the way up we stop to look at a good outcrop of (ortho)gneiss from a metamorphosed granite, a sample of which is here on the left, rich in mica and thinly banded and sparklier than the night sky, metamorphic petrology has so cooked us that we all saw it's green and schistose and called it greenschist, lol.

Greenschist we did find further up the path, though it's mixed with marble, and we got told the (newfound) bit of geology wisdom that, actually, that term is pretty much useless due to the sheer amount of protoliths that can spawn it rendering the term kind of too vague. So this is actually a basaltic intrusion, metamorphosed to the greenschist phase (thus a "metabasalt"), turned schistose due to stresses, and bundled together with some nice white marbles, that metamorphosed alongside them.

The views in and from that quarry are beautiful, if only Mt. Penteli wasn't literally the most fertile ground for fires it'd be greener.

The metabasalt intrusions ultimately ruin the market value of the marble, so the quarry was abandoned. A student doing her dissertation, however, told us about its metamorphosis. The highest temperature reached was 350°C at 6-8 kbars, very close to the blueschist fascies and so in one sample they even found blueschist minerals like glaucophane. Greece is today where the ancient Tethys ocean once laid, and many terranes were subducted into forming the landmass of today.

We then went on a 5km hike up Mt. Penteli on a quest to see the general geology of the area. Essentially (and reductively,) the mountain is like a large anticline fold or an upside down U, with orthogneiss as the lowermost layer and strata of marbles and metapelite schist above. Of course, it's more complicated. Faults and folds have made the anticline nigh unrecognisable, the metapelites vary wildly in schistosity and they often mix with the marbles to form the sparkliest rock you'll ever see, a metamorphosed marl, and the basalt intrusions from earlier show up either schistose or massive or granular, along with dikes of quartz and calcite, and interspersed are pockets of more gneiss.

The climb to the (almost) top was beautiful, although doing it by foot at this weather sucked. The sun blazed unwaveringly and the view was stunning.