mastodontech.de ist einer von vielen unabhängigen Mastodon-Servern, mit dem du dich im Fediverse beteiligen kannst.
Offen für alle (über 16) und bereitgestellt von Markus'Blog

Serverstatistik:

1,4 Tsd.
aktive Profile

#ThinSectionThursday

0 Beiträge0 Beteiligte0 Beiträge heute
John Faithfull 🌍🇪🇺🏴󠁧󠁢󠁳󠁣󠁴󠁿🧡✊🏻✊🏿<p><a href="https://mastodon.scot/tags/ThinSectionThursday" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ThinSectionThursday</span></a> Here's a lovely porphyritic camptonite (probably Permian) from North Hoxa, Orkney, seen in plane-polarized light. The large brown crystal is kaersutitic amphibole, the smaller clear crystal near the bottom of the photo is olivine, &amp; the large greyish crystal on the right is clinopyroxene (with a hole in it!). These phenocrysts sit in a finer-grained groundmass of amphibole, clinopyroxene, magnetite &amp; analcime. The field of view is about 2mm wide. <a href="https://mastodon.scot/tags/Geology" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Geology</span></a> <a href="https://mastodon.scot/tags/Microscopy" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Microscopy</span></a> <a href="https://mastodon.scot/tags/Orkney" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Orkney</span></a></p>
John Faithfull 🌍🇪🇺🏴󠁧󠁢󠁳󠁣󠁴󠁿🧡✊🏻✊🏿<p>Just in time for a slightly late <a href="https://mastodon.scot/tags/ThinSectionThursday" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ThinSectionThursday</span></a>! 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. <a href="https://mastodon.scot/tags/Geology" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Geology</span></a> <a href="https://mastodon.scot/tags/Metamorphic" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Metamorphic</span></a></p>
John Faithfull 🌍🇪🇺🏴󠁧󠁢󠁳󠁣󠁴󠁿🧡✊🏻✊🏿<p><a href="https://mastodon.scot/tags/ThinSectionThursday" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ThinSectionThursday</span></a> A lovely norite from the Huntly intrusion in NE Scotland, with elongate pale brown orthopyroxene crystals, deep brown (coloured) biotite, and a little black ilmenite, in clear (striped) plagioclase. Field of view 2mm wide. Section made at his home by the legendary amateur petrographer, Alex Herriot of East Kilbride, now in the Hunterian museum. <a href="https://mastodon.scot/tags/Geology" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Geology</span></a></p>
John Faithfull 🌍🇪🇺🏴󠁧󠁢󠁳󠁣󠁴󠁿🧡✊🏻✊🏿<p>The <a href="https://mastodon.scot/tags/ThinSectionThursday" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ThinSectionThursday</span></a> tradition has been very quiet of late. I'm going to try to get back to tooting something every week... 🤞 🤓 </p><p>This looks like a shitstorm of stuff flying over the battlements of some dark fortress. </p><p>The "stuff" = mullite crystals. The white sky = plagioclase, the battlements = dendritic plagioclase crystallites, &amp; darkness = glass. FOV ~2mm wide. Plane polarized light illumination.</p><p>The rock is an aluminous xenolith from the Rubh a' Chromain sill, Mull. <a href="https://mastodon.scot/tags/Geology" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Geology</span></a> <a href="https://mastodon.scot/tags/Mull" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Mull</span></a></p>
Sean Mulcahy<p>Andalusite from metasediment intruded by the Kitsumkalum pluton east of the Coast Mountains batholith in British Columbia <a href="https://mastodon.social/tags/ThinSectionThursday" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ThinSectionThursday</span></a> <a href="https://mastodon.social/tags/Geology" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Geology</span></a></p>
Bill Minarik<p>A thick section in both transmitted light (crossed polarizers) &amp; reflected light. It shows the results of an experiment at mantle conditions to equilibrate the microstructure of olivine grains (colorful) and iron-nickel-sulfur melt (bronze colored, unmixed on solidification). The sulfide melt largely forms pockets at grain corners, and does not interconnect along grain edges. This melt can not easily separate from the silicate.<br><a href="https://fosstodon.org/tags/ThinSectionThursday" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ThinSectionThursday</span></a> <a href="https://fosstodon.org/tags/Mantle" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Mantle</span></a> <a href="https://fosstodon.org/tags/ExperimentalPetrology" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ExperimentalPetrology</span></a> <a href="https://fosstodon.org/tags/CoreFormation" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>CoreFormation</span></a></p>
Bill Minarik<p>A cross-polarized image of a chondrule from the Allende (CV3) meteorite. The thin blades are crystals formed from the melt at very high cooling rates. HOV ~ 0.7 mm</p><p><a href="https://fosstodon.org/tags/ThinSectionThursday" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ThinSectionThursday</span></a> <a href="https://fosstodon.org/tags/Meteorite" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Meteorite</span></a> <a href="https://fosstodon.org/tags/Chondrule" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Chondrule</span></a> <a href="https://fosstodon.org/tags/Allende" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Allende</span></a></p>
John Faithfull 🌍🇪🇺🏴󠁧󠁢󠁳󠁣󠁴󠁿🧡✊🏻✊🏿<p><a href="https://mastodon.scot/tags/ThinSectionThursday" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ThinSectionThursday</span></a> <a href="https://mastodon.scot/tags/MinCup24" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>MinCup24</span></a> 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. <a href="https://mastodon.scot/tags/Geology" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Geology</span></a> <a href="https://mastodon.scot/tags/Kyanite" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Kyanite</span></a> <a href="https://mastodon.scot/tags/Lewisian" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Lewisian</span></a> <a href="https://mastodon.scot/tags/Metasediment" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Metasediment</span></a> <a href="https://mastodon.scot/tags/Metamorphic" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Metamorphic</span></a> <span class="h-card" translate="no"><a href="https://mastodon.social/@MineralCup" class="u-url mention" rel="nofollow noopener" target="_blank">@<span>MineralCup</span></a></span></p>
John Faithfull 🌍🇪🇺🏴󠁧󠁢󠁳󠁣󠁴󠁿🧡✊🏻✊🏿<p><a href="https://mastodon.scot/tags/ThinSectionThursday" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ThinSectionThursday</span></a> Here's an early thin section (date about 1870?) of troctolite from the Rum Layered Intrusion, from the collection of Matthew Forster Heddle, now in the Hunterian museum, Glasgow. I love the oval cover slip! The plagioclase feldspar shows brilliant colour stripes, rather than the expected black and white, due to being much thicker than the modern standard 30 microns. See image Alt-text for more info... <a href="https://mastodon.scot/tags/Geology" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Geology</span></a> Mineralogy <a href="https://mastodon.scot/tags/Microscopy" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Microscopy</span></a></p>
John Faithfull 🌍🇪🇺🏴󠁧󠁢󠁳󠁣󠁴󠁿🧡✊🏻✊🏿<p><a href="https://mastodon.scot/tags/ThinSectionThursday" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ThinSectionThursday</span></a> No fancy minerals in today's rock, but it does feature clear skeletal plagioclase crystals looking like a wee propeller &amp; a wee hand pointing upwards (or giving the finger?? 😁 ) The rest of the rock is brown glass, with finely dendritic-skeletal magnetite and clinopyroxene. From Scobull, on the Isle of Mull. Field of view 2mm wide. <a href="https://mastodon.scot/tags/Geology" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Geology</span></a> <a href="https://mastodon.scot/tags/Microscopy" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Microscopy</span></a> <a href="https://mastodon.scot/tags/quenching" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>quenching</span></a> <a href="https://mastodon.scot/tags/Supersaturation" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Supersaturation</span></a> <a href="https://mastodon.scot/tags/Mull" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Mull</span></a></p>
John Faithfull 🌍🇪🇺🏴󠁧󠁢󠁳󠁣󠁴󠁿🧡✊🏻✊🏿<p><a href="https://mastodon.scot/tags/ThinSectionThursday" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ThinSectionThursday</span></a> 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. <a href="https://mastodon.scot/tags/Geology" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Geology</span></a> <a href="https://mastodon.scot/tags/Metamorphic" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Metamorphic</span></a> <a href="https://mastodon.scot/tags/Microscopy" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Microscopy</span></a> <a href="https://mastodon.scot/tags/Texture" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Texture</span></a></p>
John Faithfull 🌍🇪🇺🏴󠁧󠁢󠁳󠁣󠁴󠁿🧡✊🏻✊🏿<p><a href="https://mastodon.scot/tags/ThinSectionThursday" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ThinSectionThursday</span></a> a weird but beautiful corundum-muscovite -biotite-feldspar gneiss from Egan Chutes, Bancroft, Ontario viewed between crossed polars (bright colours), and in plane polarized light (mostly colourless). Field of view 2mm across. Thin section made by the late Sinclair Ross of Elgin, whose magnificent collection is now in the Hunterian museum. See Alt text for more info <a href="https://mastodon.scot/tags/Geology" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Geology</span></a> <a href="https://mastodon.scot/tags/Mineralogy" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Mineralogy</span></a> <a href="https://mastodon.scot/tags/Microscopy" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Microscopy</span></a></p>
John Faithfull 🌍🇪🇺🏴󠁧󠁢󠁳󠁣󠁴󠁿🧡✊🏻✊🏿<p>A day late for this weeks <a href="https://mastodon.scot/tags/ThinSectionThursday" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ThinSectionThursday</span></a>, here's some more epidote, this time from highly altered basalt lavas high on Ben More in Mull, viewed under a polarizing microscope. The bright (pale greenish) crystals of epidote are intergrown with grey (clear) fibrous zeolite mineral. Field of view about 2mm wide. See Alt text for more info. <a href="https://mastodon.scot/tags/Geology" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Geology</span></a> <a href="https://mastodon.scot/tags/Microscopy" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Microscopy</span></a> <a href="https://mastodon.scot/tags/Mull" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Mull</span></a> <a href="https://mastodon.scot/tags/Petrography" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Petrography</span></a> <a href="https://mastodon.scot/tags/Mineralogy" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Mineralogy</span></a></p>
Bill Minarik<p>Plain light thin section (~ 4 cm wide)<br>Pale pink garnets (inclusion-rich cores and inclusion-free rims) surrounded by mostly biotite.</p><p>From the Nuvvuagittuq formation near <a href="https://fosstodon.org/tags/Inukjuak" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Inukjuak</span></a> Canada.</p><p>Coupled Sm-Nd isotopes suggest that the original rock (the protolith) may be as old as 4.3 billion years. This sample has been pervasively metamorphosed at least four times since then.</p><p><a href="https://fosstodon.org/tags/ThinSectionThursday" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ThinSectionThursday</span></a> <a href="https://fosstodon.org/tags/Archean" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Archean</span></a> <a href="https://fosstodon.org/tags/Quebec" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Quebec</span></a></p>
John Faithfull 🌍🇪🇺🏴󠁧󠁢󠁳󠁣󠁴󠁿🧡✊🏻✊🏿<p><a href="https://mastodon.scot/tags/ThinSectionThursday" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ThinSectionThursday</span></a> A beautifully zoned epidote crystal with an older brown allanite core in Lewisian gneiss from the summit of Dun I, the highest point on Iona. From the <a href="https://mastodon.scot/tags/Hunterian" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Hunterian</span></a> collections in Glasgow. Field of view about 0.5mm across. See Alt text for more... <a href="https://mastodon.scot/tags/Geology" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Geology</span></a> <a href="https://mastodon.scot/tags/Iona" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Iona</span></a> <a href="https://mastodon.scot/tags/Mull" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Mull</span></a> <a href="https://mastodon.scot/tags/Lewisian" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Lewisian</span></a> <a href="https://mastodon.scot/tags/Microscopy" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Microscopy</span></a> <a href="https://mastodon.scot/tags/Mineralogy" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Mineralogy</span></a></p>
John Faithfull 🌍🇪🇺🏴󠁧󠁢󠁳󠁣󠁴󠁿🧡✊🏻✊🏿<p><a href="https://mastodon.scot/tags/ThinSectionThursday" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ThinSectionThursday</span></a> 🤩 🤓 A C19th thin section of Scottish agate, using different polarized light techniques, from the Heddle collection in the Hunterian museum. Agate is basically quartz, but has a distinctive micro/nano-structure of tiny elongate, often twisted fibres at right angles to the bands. This section is a bit thicker than modern standard of 30 microns so colours are a bit more intense. FOV ca. 2mm wide. See Alt text for more. <a href="https://mastodon.scot/tags/Geology" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Geology</span></a> <a href="https://mastodon.scot/tags/Microscopy" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Microscopy</span></a> <a href="https://mastodon.scot/tags/Agate" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Agate</span></a> <a href="https://mastodon.scot/tags/Mineralogy" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Mineralogy</span></a></p>
John Faithfull 🌍🇪🇺🏴󠁧󠁢󠁳󠁣󠁴󠁿🧡✊🏻✊🏿<p><a href="https://mastodon.scot/tags/ThinSectionThursday" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ThinSectionThursday</span></a> 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. <a href="https://mastodon.scot/tags/Geology" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Geology</span></a> <a href="https://mastodon.scot/tags/Metamorphic" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Metamorphic</span></a> <a href="https://mastodon.scot/tags/Manganese" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Manganese</span></a> <a href="https://mastodon.scot/tags/Mineralogy" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Mineralogy</span></a> <a href="https://mastodon.scot/tags/Moine" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Moine</span></a></p>
John Faithfull 🌍🇪🇺🏴󠁧󠁢󠁳󠁣󠁴󠁿🧡✊🏻✊🏿<p><a href="https://mastodon.scot/tags/ThinSectionThursday" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ThinSectionThursday</span></a> Beautiful and unusual curved feathery crystals of clinopyroxene, plus straighter, blockier orthopyroxene crystals, in this glassy boninite lava from Trimiklini, Cyprus. These crystals grew extremely quickly during rapid cooling. More info in Alt text. <a href="https://mastodon.scot/tags/Geology" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Geology</span></a> <a href="https://mastodon.scot/tags/Microscopy" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Microscopy</span></a> <a href="https://mastodon.scot/tags/Supercooling" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Supercooling</span></a> <a href="https://mastodon.scot/tags/HunterianMuseum" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>HunterianMuseum</span></a></p>
John Faithfull 🌍🇪🇺🏴󠁧󠁢󠁳󠁣󠁴󠁿🧡✊🏻✊🏿<p><a href="https://mastodon.scot/tags/ThinSectionThursday" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ThinSectionThursday</span></a> Three ways of looking at a favourite rock with a polarizing microscope. The view is ca. 2mm wide. Swarms of wee blobby crystals of cordierite, embedded in big plagioclase plates, with a single big mullite crystal in the middle of the bottom edge. From Tiroran, on Mull, and now in the Hunterian collections in Glasgow. See Alt text for more. <a href="https://mastodon.scot/tags/Geology" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Geology</span></a> <a href="https://mastodon.scot/tags/Microscopy" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Microscopy</span></a> <a href="https://mastodon.scot/tags/Mull" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Mull</span></a></p>
John Faithfull 🌍🇪🇺🏴󠁧󠁢󠁳󠁣󠁴󠁿🧡✊🏻✊🏿<p><a href="https://mastodon.scot/tags/ThinSectionThursday" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ThinSectionThursday</span></a> A complex bit of Earth's mantle brought to the surface by a kimberlite (strictly, an orangeite) from Finsch mine, South Africa. The stand-out clear (black) grain is pyrope garnet. Most of the clear (bright coloured) grains are olivine. The pale brown (rainbow) rim around the pyrope is phlogopite mica, formed by a process called metasomatism. These rocks contain diamonds, but none visible here! See ALT text for more info... <a href="https://mastodon.scot/tags/Geology" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Geology</span></a> <a href="https://mastodon.scot/tags/Mantle" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Mantle</span></a> <a href="https://mastodon.scot/tags/Xenolith" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Xenolith</span></a> <a href="https://mastodon.scot/tags/Diamond" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Diamond</span></a> <a href="https://mastodon.scot/tags/Microscopy" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Microscopy</span></a></p>