#FoldFriday or is it #FridayFold ? Anyway , freshly bathed in this morning's early light, here's a lovely wee fold in kyanite-grade Moine schists above Loch Assapol in Mull. Fingertip at left for scale. #Geology #Mull #Metamorphic

Just in time for a slightly late #ThinSectionThursday! Here's some fabulous piemontite: a manganese epidote mineral that shows amazing pink-yellow-plum pleochroic colour change. The two images below show the same grains under plane polarized light, but rotated through 90 degrees . The clear mineral is quartz, and there are also some large flakes of very pale pink Mn-rich muscovite mica. This sample is from near Tongue, in Sutherland. #Geology #Metamorphic

#FridayFold An old picture of a limpet enjoying some beautiful folded greenschist-facies pelite in a rock pool near Thundergay, on the west coast of Arran. The pale bands are rich in fine-grained muscovite; the dark bands also have chlorite. The few rusty spots mark the position of pyrite crystals.

Out looking at metamorphic rocks on the south coast of Mull last week. We weren't expecting an ostrich! #Pareidolia #ThingsThatLookLikeOtherThings #Mull #Ostrich #Moine #Metamorphic

Fabulous spring weather in Mull just now. Here's a picture of the extreme south end of the Hebridean Craton: Lewisian rocks on on a wee island off Iona, which I visited for the first time this week Greenland and Canada in the distance #Geology #Lewisian #Metamorphic

#DogWalkingGeology Spud is admiring this lovely shingle-polished outcrop of Moine schist on the beach at Ardalanish, Mull. #Metamorphic #Mull

The GEOROC Database (Geochemistry of Rocks of the Oceans and Continents)
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https://georoc.eu/georoc/new-start.asp <-- shared link to GEOROC resource
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H/T Paul Cleverley glasses curly blonde hair
“The GEOROC Database (Geochemistry of Rocks of the Oceans and Continents) is a comprehensive collection of published analyses of igneous and metamorphic rocks and minerals. It contains major and trace element concentrations, radiogenic and nonradiogenic isotope ratios as well as analytical ages for whole rocks, glasses, minerals and inclusions. Metadata include geospatial and other sample information, analytical details and references….
Current content of GEOROC:
• 22,750 papers
• 685,660 samples
• 2,680,100 analyses
• 39,334,100 single data values…”
#opendata #geology #geoscience #GEOROC #database #global #igneous #metamorphic #rocks #minerals #geochemistry #results #analyses #published #metadata #spatial #GIS #mapping #papers #samples #datavalues

#DogWalkingGeology A #LifeGoal achieved Kyanite gneisses occur in the Mull Moine rocks, but I have *never* found a beach pebble of these rocks, despite searching intensely, until THIS MORNING. A very tasty cobble #Geology #Metamorphic #Mull

#ThinSectionThursday #MinCup24 It's kyanite for me! Rocks with kyanite are *always* good rocks Here's some nice bent and twinned kyanite crystals in a high-pressure granulite-facies gneiss from the Lewisian complex in South Harris. Field of view about 2mm across. More info in Alt text. #Geology #Kyanite #Lewisian #Metasediment #Metamorphic @MineralCup

#ThinSectionThursday Beautiful symplectite coronas around pink (black) garnets in this garnet-clinopyroxene-amphibole-plagioclase-scapolite gneiss from the Lewisian complex in South Harris. Field of view ca. 2mm wide. #Geology #Metamorphic #Microscopy #Texture

#ThinSectionThursday Raspberry pink-to-yellow plechroic piemontite, with pale pink muscovite mica, small, clear stand-out spessartine garnets, and blandly clear quartz, in this strange Moine metasediment from Strathconon in northern Scotland. Field of view about 2mm across. The second pic shows the same view between crossed polars, showing wonderfully bright birefringence colours. More info in Alt text of images. #Geology #Metamorphic #Manganese #Mineralogy #Moine

Very pleased with this boulder from a beach near Bunessan. The white quartz vein cuts gently across bedding and foliation in the grey metasediment, and both are cut by the later quartz-feldspar vein with pink margins. Lovely cross-cutting relationships reveal sequence of geological events #Geology #Mull #Moine #Stratigraphy #Metamorphic

Researchers Find Oldest Evidence Of Earth’s Magnetic Field
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https://www.forbes.com/sites/davidbressan/2024/04/29/researchers-find-oldest-evidence-of-earths-magnetic-field/?sh=3443e1c050fb <-- shared media article
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https://doi.org/10.1029/2023JB027706 <-- shared paper
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#geology #geomagnetism #paleomagnetism #earth #global #protection #magneticfield #cosmic #IsuaSupracrustalBelt #fieldwork #metamorphic #structuralgeology #greenland #tectonics #Eoarchean #mineralogy

#ThinSectionThursday A gloriously vivid eclogite-facies rock from the Eastern Glenelg gneisses. First image is between crossed polars, with large bright flakes of muscovite mica, with grey quartz +feldspar, plus a zoned yellow-to-purple crystal of epidote in the centre of the view. Second image is same, in plane polarized light. Field of view about 2mm wide. #Geology #Metamorphic #Microscopy

The lovely Scoor Pelitic Gneiss unit looking fabulous in the winter sunshine on the south coast of Mull yesterday. It's Neoproterozoic to Caledonian in age, but exactly how many metamorphic episodes it's experienced, and when, remains a bit mysterious. #Mull #Geology #Metamorphic #Moine

#DogWalkingGeology from yesterday.... Spud has found some garnet-tastic Moine metabasic tuffs(?) or maybe an intrusion. Each knobbly bit is a large garnet crystal, but alas they are never show external crystal faces, and are always stuffed with gazillions of quartz inclusions. Still, lovely to see! #Metamorphic #Garnet #Mull #Moine #Proterozoic

#DogWalkingGeology Some lichens hoping eventually to hide this lovely wee Z-foldded quartz vein in Moine meta-sandstone near Dun a' Gheird, in south Mull. #Geology #Metamorphic #Mull #Lichen #Mosstodon #lichensubscribe

#DogWalkingGeology from this morning: lots of pink garnets up to about 20mm across in this Moine garnet amphibolite (meta-basalt) from Ardalanish. These garnet crystals grew about 450 million years ago. The pale grey rock above is meta-sandstone, so didn't have the right chemistry to grow any garnet: it just stayed as quartz. #Geology #Mull #Metamorphic

Some nice beach boulders from during yesterday's wet and murky fieldwork in Iona with PhD student Kang. Two mylonized somethings (left and right) and a gneiss (centre) sitting on garnet-pyroxene meta-ironstone in the rain #Geology #Iona #Lewsian #Metamorphic #WhatAreTheseThings