Two generations of precipitates of ilmenite and apatite in garnet. PPol, fov=1cm, entirely within one growth sector of a single garnet crystal. Normal to the growth face lies in the plane of the section. First generation (coarse) follows included fabric NW-SE, second generation (streaks) are submicron crystals decorating unannealed growth dislocations. Note depletion haloes.

#thinsectionthursday Precipitates of ilmenite and apatite in garnet. PPol, fov=1cm, within one growth sector of a single garnet crystal. First generation (coarse) follows included fabric NW-SE, second generation sub micron crystals decorate unannealed growth dislocations. Note depletion haloes.

Thin Section Thursday! Coronitic and symplectite texture in a cpx-ilm-grt amphibolite from Precambrian basement of Southern Brasilia Orogen, city of Campinas - SP - Brazil. Shown in plane and cross-polarized light. Contributed by Helena Paiva.
#thinsectionthursday

A backscattered-electron image of mostly hornblende, centered on a bright illmenite grain surrounded by titanite.

Titanite encircling illmenite in an amphibolite-facies metabasalt.

#ThinSectionThursday #Metamorphic #Titanite

Cross polarised light view of pegmatitic dolerite. Field of view is mainly large clinopyroxene prisms showing strong cleavage and second order interference colours. Two olivine crystals on right show fracture while a band of plagioclase laths run down the centre showing simple and polysynthetic twinning.

Pegmatitic dolerite from Fair Head, County Antrim in XPL for #ThinSectionThursday. Same location as two weeks ago but much coarser grain size. Stunning clinopyroxene showing birefringence progressions at edges and cracks, plus fractured olivine and twinned plagioclase. 🧪⚒️🌋

Thin Section Thursday! Rapid growth of olivine in a basalt experiment. Features skeletal branching (thicker, higher birefringence) and progressive infilling (lower birefringence domains). Crystal is about 1mm in size. XPL Contributed by Thomas Shea, Univ. of Hawai’i
#thinsectionthursday

Thin Section Thursday! Mica and Quartz in gneiss, XPL, gypsum plate inserted. Contributed by Bernhard Seubert.
You can contribute too! Send image(s) and short explanation to akoziol1 at udayton dot edu. #thinsectionthursday

Have had a quick look and could not see any with ocelli but a marvellous variety of relationships between olivine, plagioclase, and clinopyroxene. Might have to post the "pegmatite" one for next week's #ThinSectionThursday!

A plane polarized light image of mostly feldspar that has unmixed in the solid state to bands of sodic and potassic rich zones.

A cross polarized light image of mostly feldspar that has unmixed in the solid state to bands of sodic and potassic rich zones.

Perthite, in a fayalite-hastingsite hypersolvus granite, Cauro-Bastelica Complex, Tolla dam, Corsica

The minerals crystallized from melt at high temperature and water-poor conditions.

#ThinSectionThursday #Minerals #Corsica #Granite

Thin Section Thursday!
Fe-poor zoned sphalerite crystal in thin section (PPL) - ID verified by microprobe analysis. Photo by Ingrid Kjarsgaard (c)
You can contribute too! Send image(s) and short caption to akoziol1 (at) udayton dot edu. #thinsectionthursday

An photomicroscopic image of rock (syenite). Taken in cross-polarised light, small crystals of dalyite show bright interference colours. Surrounding alkali feldspars appear first order grey.

Little (< 0.3 mm) intercumulus crystals of dalyite (bright interference colours) surrounded by alkali feldspar in a peralkaline syenite.

#thinsectionthursday #geology #science #minerals #rocks #microscope #microscopy

Photomicrograph of olivine dolerite. Isolated, euhedral to subhedral olivine phenocrysts (showing second and third order interference colours) are surrounded by a groundmass made up of opaque iron oxides and an ophitic intergrowth of small, euhedral plagioclase laths surrounded by large clinopyroxene crystals.

Spectacular olivine dolerite from Fair Head, County Antrim in XPL for #ThinSectionThursday. Olivine shows particularly vibrant interference colours while the ophitic intergrowth of twinned plagioclase and clinopyroxene is a textbook quality example. 🧪⚒️🌋

T.S. Thursday:
2.8 Ga Granodiorite from the Beartooth Mtns, MT in crossed polars and cathodoluminescence. In CL the red zone between microcline and plagioclase is a fine-grained myrmekite (plagioclase and quartz intergrowths). Contributed by Darrell Henry.
#thinsectionthursday

Thin Section Thursday!
Blue Osumilite in an ~9 Ma rhyolite lava from Jackson Hole, Wyoming. Plane polarized light. Mineral confirmation by Raman spectroscopy.Contributed by Matt Brueseke. Send image(s) and short caption to akoziol1 (at) udayton dot edu. #thinsectionthursday

A colorful image showing black garnets, olivine, orthopyroxene and clinopyroxene.

A cross-polars image of a garnet lherzolite xenolith from the Cretaceous Nikos kimberlite on Somerset Island, arctic Canada. 2mm scale bar in the lower right corner.

#ThinSectionThursday #Kimberlite #Xenolith #Mantle

Thin Section Thursday! Feldspar and quartz Cross polarized light. Contributed by Bernhard Seubert.
You can contribute too! Send image(s) and short explanation to akoziol1 at udayton dot edu. #thinsectionthursday

piemontite

piemontite

piemontite

piemontite

#ThinSectionThursday Fun with the piemontite schist!
4th picture shows the change in color of the same (pink) piemontite grain after rotating the stage.

FOV 3 mm
⚒️ #geology #minerals

A cut fact of a basaltic pillow with the quenched pillow rind on the left (swiss army knife for scale).

A transmitted light photo of a thin section spanning the pillow rind on the left to the pillow interior. Gas bubbles show as round white patches within the pillow interior. Horizontal field of view 3.5 cm

Hand sample and thin section of a pillow rind and interior from Palaeogene lavas of eastern Baffin island. The solidifying melt continued to exsolve gas bubbles, trapped in the pillow interior by the rind.

#ThinsectionThursday #BaffinIsland #Basalt #Geology

Microscope image of Ailsa Craig Common Green microgranite thin section. Mostly quartz and cloudy feldspar with patches and clots of very dark green and brown minerals infilling gaps.

A tiny replica curling stone sitting on top of a sample of the same green spotty rock. They are sitting on a desk under a computer monitor next to other minerals.

Olympic curling has to be the sporting highlight of the Scottish geological calendar. 🥌 All the stones come from Ailsa Craig in the Firth of Clyde. The distinctive black spots are (mostly) the very weird and rare amphibole arfvedsonite. #ThinSectionThursday

Thin Section Thursday!
Incipient crystallization of plagioclase during continuous decompression in an experimental charge. Backscatter Electron Image. Contributed by Thomas Shea, Univ. of Hawai’i
Send image(s) and short caption to akoziol1 (at) udayton dot edu. #thinsectionthursday

Overlapping circles showing plane- and cross-polarised light view of porphyritic dolerite from Ben Hiant, Ardnamurchan, Scotland. Large, euherdal olivine and plagioclase, with infilling clinopyroxene, oxides, and glassy bearing smaller, euhedral plagioclase.

(Long) Before mobile phones: hand drawn PPL and XPL views of porphyritic dolerite from Ben Hiant, Ardnamurchan, Scotland. From my undergraduate mapping report. #ThinSectionThursday 🧪⚒️🌋

ultramylonite

Today I feel very stressed, but not as much as this ultramylonite from Mt. Grighini, Sardinia

FOV 3 mm. CPL light
#geology #ThinSectionThursday

Piemontite in phengite-carbonate schist, Lago di Cignana, N. Italy.

Piemontite in phengite-carbonate schist, Lago di Cignana, N. Italy.
#thinsectionthursday

Dolomite, Meramecian, Visean, Mississippian. South of Joplin, Missouri.

Or, we could discuss dolomite!

Here from Meramecian (Visean; Mississippian) strata south of Joplin, Missouri.

#thinsectionthursday

Fractured glassy breccia meets bubbly microcrystalline basalt in a hyaloclastite from Iceland (or is it Greenland, I can never remember...).

#thinsectionthursday #geology #science #minerals #rocks #microscope #microscopy

Thin Section Thursday!
Julian schist: Mica schist in XPL from the Julian Schist at Julian, California USA. Contributed by Paolo Sanchez.
You can contribute too! Send image(s) and short caption to akoziol1 (at) udayton dot edu. #thinsectionthursday

Pyrope and minor kyanite in matrix of phengite and palisade-textured quartz from Dora Maira. Section is slightly above standard thickness.

Pyrope and minor kyanite in matrix of phengite and palisade-textured quartz from the Dora Maira massif, N. Italy. Section is slightly above standard thickness.
#thinsectionthursday

You're not following MSA??? ⚒️ #ThinSectionThursday
Clearly a dinosaur footprint there... ;-)

Thin Section Thursday!
Zircon in quartzite, possibly making a rude gesture? Ogallala Formation, 10X, crossed polars. Contributed by Maddie Wright. You can contribute too! Send images and a short caption to akoziol1 at udayton dot edu. #thinsectionthursday

#thinsectionthursday

An image of a rock thin section viewed under the microscope in cross polarised light. The sample is dominated by large olivine and clinopyroxene crystals which are exhibiting bright second order interference colours. They are set in a much finer groundmass which contains abundant plagioclase crystals, recognisable through their first order grey interference colours and long, thin crystal shapes. Large vesicles are scattered through the sample, appearing rounded and black.

Olivine and clinopyroxene phenocrysts in a plagioclase-rich groundmass - Vesicular basalt lava flow, Azores

#thinsectionthursday #geology #science #minerals #rocks #microscope #microscopy