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John Kashuba

John is a natural history enthusiast living in Oregon.

Two IMR Inclusions in NWA 869

Two IMR Inclusions in NWA 869

About 1% of the volume of NWA 869 L3-6 is impact melt rock (IMR) according to Metzler et al. Their study tells us a lot about these highly variable fine grained inclusions we find in cut stones. Some IMR clasts include mineral and rock clasts, some do not. The crystallized fallback material is depleted in […]

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Crystalline Lunar Spherules

Crystalline Lunar Spherules

It’s a harsh place, the surface of the moon. NWA 8010 is a lunar regolith breccia meteorite that bears witness to this. Melt veins are formed by large impacts. The veins in NWA 8010 did not cool instantly into glass. They had time to nucleate along wall rock and crystallize into feathery tufts of very […]

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Zoned Grains in Moss CO3.6

Zoned Grains in Moss CO3.6

The outer portion of some olivine grains in the Moss meteorites have levels of iron elevated above those in the center of the grains. This difference can be seen in some grains that have been thin sectioned. These photos are all of one rather small sample. All photos are in cross-polarized transmitted light.

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Symplectites in NWA 5784 diogenite

Symplectites in NWA 5784 diogenite

The wavy black forms signal a symplectitic texture. Symplectites appear in metals, minerals and other materials. They are intergrowths of two or more constituents and appear in a variety of configurations. They may be considered a disequilibrium textural feature. The different phases may form from: a single phase that becomes unstable from a pressure or […]

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ASU Higher Magnification

ASU Higher Magnification

This is a selection of photos of various thin sections in the horde released by Arizona State University earlier this year.  Most are at a higher magnification than those I usually place here.

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Selma H4

Selma H4

The Selma meteorite was found near that Alabama city in 1906. At 310 pounds it was then the largest meteorite found in the United States. It was purchased by the American Museum of Natural History (New York). The thin section pictured here was deaccessioned by Arizona State University in early 2014 and is now in a […]

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Romero H4

Romero H4

Earlier this year Arizona State University released about a hundred surplus thin sections. This was through a trade with meteorite dealer Anne Black. I bought a few of these slides from her. I chose the only Romero H4 she had because it had an inclusion. The write up in the Meteoritical Bulletin Database gives only […]

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Layered Chondrules in Allende CV3

Layered Chondrules in Allende CV3

These photos were taken of four thin sections that were deaccessioned by a US university. They appear to have been made by different people and at different times. On one, the cover slip cement has turned yellow. Some have labeling engraved on the slide behind the sample. Some of this can be attributed to the […]

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Overgrowths

Overgrowths

These chondrules show the effects of multiple heating events coupled with accretion. They are chondrules and mineral grains that have gathered nebular dust, been heated and ended up with porphyritic olivine and pyroxene jackets.

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Dhofar 008 L3.3

Dhofar 008 L3.3

In thin section under the microscope it is easy to see that the components of Dhofar 008 L3.3 underwent several episodes of processing before their final assembly and delivery to earth. We see it in layered features and in the presence of enveloping compound chondrules. Enveloping compound chondrules have one or more chondrules completely enclosed […]

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Ibitira

Ibitira

Ibitira is the exception that nags us when we introduce people to the appearance of meteorites versus meteor wrongs. We like to say that if it has bubbles it isn’t the real thing, thus dismissing slag, lava and their cousins. But Ibitira and a few other exceptional meteorites do have vesicles. Ibitira is exceptional also […]

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Allende Special

Allende Special

The Allende CV3 meteorite contains many components. Here are some less common chondrules, a collection from three Allende thin sections. Except for the last two, the views are 3.1 mm wide. The others are 0.9 mm and 1.1 mm wide details. All are in cross-polarized light. The first chondrule is also shown in Richard Norton’s […]

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DaG 978 C3-ung

DaG 978 C3-ung

Dar al Gani 978 resembles CR chondrites in that it has relatively large chondrules which contain blebs of metal. Certain elemental abundances resemble those of CM–CO chondrites and others are similar to the CV–CM–CO range. O-isotope data are similar to CO and CV chondrites. DaG 978 is a type-3 ungrouped carbonaceous chondrite.

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NWA 4540 CO3.5

NWA 4540 CO3.5

CO3s, carbonaceous chondrites of the Ornans type, contain the smallest chondrules of any of the major chondrite types. Still, chondrule sizes vary among CO3s. And within this CO3 there is a variety of chondrule sizes and a great variety of chondrule types and other matter. It is good to be observant when scanning a thin […]

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Tissint Martian Meteorite

Tissint Martian Meteorite

Tissint is the fifth witnessed Martian meteorite fall.  It is a Shergottite.  Many pieces totaling over 7 kg fell east of Tata, Morocco about 2 AM, July 18, 2011.  The stones have a shiny black fusion crust which is glossier over olivine macrocrysts.  Olivine macrocrysts and microphenocrysts are held in a finer groundmass of pyroxene, […]

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