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#platetectonics

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Public
Magpieblog

In less than 10 million years, California could be an island offhore of North America, and the new coastline might be in Nevada. Geologists are studying an extensive series of earthquake faults in western Nevada to determine whether parts of western North America might be starting to wander off.

#PlateTectonics #earthquakes #NorthAmerica #seismology #geophysics

unr.edu/nevada-today/nevada-st

University of Nevada, RenoFinding faultsBy Mike Wolterbeek
Public
Bill Minarik

Quebec has industrial quantities of kyanite -although I don't think any are being mined today. They're in the Grenville, the roots of the Himalayan-scale mountains formed over a billion years ago. The screenshot below is from MinDat: mindat.org/locentries.php?p=14

The Ministère has an awkwardly translated page "Mineral Substances in Quebec" that includes Kyanite in its list of wealth:
gq.mines.gouv.qc.ca/portail-su

A screenshot of the MinDat page on Kyanite in Quebec. The blue 'hammer and pick' icon denotes the Narco deposit NE of North Bay. Above are images of kyanite from the Narco deposit, Temiscamingue, Quebec
#MinCup24#Kyanite#Quebec
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💧🌏 Greg Cocks

Earth May Have Had A Ring System 466 Million Years Ago
--
phys.org/news/2024-09-earth-mi <-- shared technical article
--
doi.org/10.1016/j.epsl.2024.11 <-- shared paper
--
“HIGHLIGHTS:
• Earth may have had a ring during the middle Ordovician, from ca. 466 Ma.
• Breakup of an asteroid passing within Earth's Roche limit likely formed the ring.
• Among several features preserved is a near-equatorial band of impact craters.
• Shading of Earth by the ring may have triggered a global icehouse period…”
--
#GIS #spatial #mapping #model #modeling #geology #structuralgeology #planetarygeology #rings #climatechange #paleoclimate #Ordovician #asteroid #rochelimit #craters #impactcrater #crater #icehouse #meteorite #platetectonics #HirnantianIcehouse

graphic - close up of rocks / asteroids making up the rings around Saturn
maps - Areas of continental crust distal to the equator during the Ordovician. Areas older than Ordovician are indicated in salmon colour, Ordovician rocks are dark blue, and younger are in grey. Light blue indicates lakes in Africa. The labelled point (L) in Africa is the Luizi impact structure, which has a very poorly defined age that could plausibly be Ordovician, constrained to be between 0 and 573 Ma
map - Positions of the Ordovician impact craters on the reconstructed plate positions of the MER21 model, showing the movement of continents and trace of impact sites from 467 to 450 Ma. AMZ, Amazonia; ANT, Antarctica; AS, Arabian Shield; AUS, Australia; AZ, Azania; BAL, Baltica; IND, India; LAU, Laurentia; NC, North China; SA, Southern Africa; SAH, Saharah; SC, South China; SEA, South-eastern South America; SIB, Siberia; SSA, Southern South America; T, Tarim; WAF, West Africa.
maps - Areas of continental crust proximal to the equator during the Ordovician. Areas older than Ordovician are indicated in salmon colour, Ordovician rocks are dark blue, and younger are grey. Light blue indicates lakes in Europe and Russia. The labelled pink points are the recognised Ordovician impact spike craters: in Australia, Lawn Hill (LH); in North America, Tunnunik (T), Pilot (P), Lac Couture (LC), East Clearwater Lake (ECw), La Moinerie (LM), Charlevoix (Ch), Brent (B), Slate Islands (SI), Rock Elm (RE), Decorah (D), Calvin (Ca), Glasford (G), Ames (A); in Europe, Lochne (Lo), Malingen (M), Granby (G), Tvaren (T), Hummeln (H), Ilyinets (Iy) and Kardla (Ka) (the latter two are situated on the western edge of the map for Russia). The labelled black points are impact structures with very poorly defined ages that could plausibly be Ordovician in age (Parisi et al., 2024; Schmieder and Kring, 2020), but have not been included in [their] considerations: Goyder (Gy), Glikson (Gl), Matt Wilson (M), Woodleigh (W), Liverpool (L), Glover Bluff (GB), Crooked Creek (CC), Santa Fe (SF), Holleford (H), Île Rouleau (IR), Presqu’île (P), Lumparn (L), Saarijärvi (Sj), Summanen (Sm), Kamenetsk (K), Ramgarh (R).
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Bill Minarik

Why study and synthesize #Ringwoodite? Experiments (below, a diamond anvil pressure device that's transparent to visible light; Schmandt et al, 2014) and natural samples from the Earth's mantle (see ksircombe's posts: aus.social/@ksircombe/11312421) suggest that there's an ocean or two worth of water stored in Earth's Ringwoodite. It's likely kept the planet habitable for the last 4.5 billion years.

Plus Ringwoodite is more Blue than #Kyanite !
#MinCup24 #Mantle #PlateTectonics #BlueMinerals

A single crystal of bright blue Ringwoodite containing 1 wt% water in its structure. It's contained in a diamond anvil pressure cell at 30 GPa pressure. Laser heating spots are also apparent. From Schmandt et al. (2014)
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💧🌏 Greg Cocks

Geologists Stunned On Discovering A Part Of The Earth That Disappeared 20 Million Years Ago
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good.is/geologists-stunned-at- <-- shared technical article
--
doi.org/10.1016/j.gr.2023.09.0 <-- shared paper
--
youtu.be/VyEUWySaFPc?si=rzUiIh <-- reconstruction animation
--
#GIS #spatial #mapping #remotesensing #geomagnetism #argoland #kinematicreconstruction #platetectonics #GPlates #junctionregion #PhilippineSeaPlate #Borneo #NewZealand #Japan #Zealandia #Philippines #NewGuinea #junction #subduction #plates #geology #structuralgeology #pontus #pontusplate #paeleogeography #geologichistory #Zealandia #seismology #spatialanalysis #spatiotemporal #tomography #model #modeling

maps - paleogeography over time
maps - the Pangea-Tethys and Panthalassa plate tectonic realms separated by the Juction Region
map - tectonics of the Philippine Sea Plate, highlighting the different microplates that formed as a result of oceanic spreading at different spreading centers
map - reconstructed region
Public
Chris Rowan

This is a nice write-up of how plate tectonics may have got going on Earth: a progressive development over a couple of billion years, from no plate boundaries, to localised and intermittent ones, to a full planetary system, makes a lot of sense. It would also explain why different lines of evidence produce such different start dates: it's a convolution of a fragmentary and intermittent process and a fragmentary and intermittent geological record.
#geology #PlateTectonics

nature.com/articles/d41586-024

www.nature.comGeology’s biggest mystery: when did plate tectonics start to reshape Earth?Researchers have spent decades hunting for clues about the origins of the process that moves the continents around. Its deep history is finally starting to come into focus.
Continued thread
Public
Ele Willoughby, PhD

The early ideas about plate tectonics were still quite controversial & unpopular. Heezen dismissed this as "girl talk" - though really a vital piece of #PlateTectonics puzzle.⁠
⁠
Tharp believed rift was real though she hadn't convinced Heezen. In 1952, they began working on physiographic maps, which really gave a sense of the geology, & were not US Navy classified, so they could publish. A 2nd project involved plotting earthquakes, & Heezen insisted they work at same scale. 🧵3/n

Public
Magpieblog

No, this big swarn of earthquakes happening under the Pacific Ocean west of Canada's Vancouver Island isn't a sign that a big subduction quake is imminent. But the tremors do mean that scientists are about to get a good look at how new crust forms as the sea floor spreads on a mid-ocean ridge.

#geology #geophysics #PlateTectonics #SeafloorSpreading #MidoceanRidges #PacificOcean #volcanism

livescience.com/planet-earth/e

Live Science · 2,000 earthquakes in 1 day off Canada coast suggest the ocean floor is ripping apart, scientists sayBy Stephanie Pappas
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