An January 1946 Witnessed Fall: Krymka, Ukraine
The Chondrite That Keeps on Giving
|Stretch your imagination and pretend the surface of Krymka is the view outside your spaceship as you jump to hyperdrive while cruising the early solar system.|
Let’s be honest, usually when we talk about a meteorite being gorgeous, beautiful, amazing, stunning, or magnificent, the average person might not be able to tell it from one we describe as ugly, hideous, or gruesome. But in the case of Krymka, even the casual observer is impressed with the look to the point of using their own words like gorgeous, beautiful, amazing, stunning, and magnificent.
Krymka fell to earth as an LL3.1 chondrite on January 21, 1946, but as our meteorite classification scheme matured thanks to Grossman and Brearley (2005), today we refer to Krymka as an LL3.2.
Like any good Mensa brain teaser if I asked you to make a quick guess as to how many chondrules are in this picture, likely you would likely feel somewhere between disappointed and embarrassed with the answer.
The moment you start counting, the more the chondrules you see. If you use a magnifying glass it only gets worse (or better as I look at it).
A number of years ago, a slice of Krymka blipped my shopping radar and I jumped on the chance to add a slice to my collection. Arriving in my postbox was a absolutely gorgeous crusted complete slice with more chondrule density, definition, and diversity than I have ever owned in the form of a witnessed fall. I do have to qualify the statement as “owned” and not “seen” because I once spent some time with Semarkona in the meteorite lab at the Smithsonian. Semarkona is the world’s only LL3.00 and looks it!
Oddly, the fall of Krymka is reported to have been a shower of 25kg that was recovered soon after it arrived, and another 25kg was recovered at a later date. What’s odd about that you might ask? Well, nothing except the Catalogue of Meteorites reports only about 13kg is accounted for world wide. How could you misplace 39kg of meteorite this amazing.
The meteorite collecting vernacular contains many words that positively or negatively describe specimens. In the case of my slice of Krymka some of the positive words included complete slice, crust, LL3.x, witnessed fall, over half a century old, polished faces, high surface to weight ratio, collection documentation, and parallel cut surfaces.
This is what I consider the reverse face of my slice.
Weber, Semenenko, Stephan & Jessberger wrote in Meteoritics & Planetary Science 41, Nr 4, 571–580 (2006) an article titled:
TEM studies and the shock history of a “mysterite” inclusion from the Krymka LL chondrite
Krymka is characterized by the occurrence of a high modal abundance of xenolithic clasts (Semenenko and Girich 2001; Semenenko et al. 2001). These fine-grained foreign inclusions are dominated by carbonaceous clasts, which are of extraordinary scientific interest.
This very rare, fine-grained, dark material has so far been discovered only in two meteorites, Krymka (LL3.1) and Supuhee (H6). Laul et al. (1973) detected an enrichment of Ag, Tl, and Bi in these two ordinary chondrites. They concluded that this enrichment has its origin in an admixture of a phase rich in these elements in a late condensate introduced during a brecciation event. Since the petrographic carrier of the volatiles could not be specified, they named this material “mysterite.”
The mineralogical, chemical, and isotopic features, as well as the nature of the graphite and other minerals, were investigated to obtain information on their mineral associations with the aim of finding conclusive evidence concerning the origin of mysterite, a material that had already been associated with comets. The results of these combined investigations allow the following conclusions: the xenolith formation is a result of the accretion of heterogeneous components in a region depleted in chondrules. After this process, which was followed by lithification and a probable collisional fragmentation of a primary carbonaceous body, this xenolith and some others (Semenenko et al. 2005) were covered with extremely fine-grained silicate dust. Together with the main Krymka constituents, the xenoliths were accreted in the Krymka parent body.
The detailed TEM study of the Krymka carbonaceous xenolith K1 plainly indicates that a thermal and shock metamorphism must have taken place, either on a primary body of the xenolith or on the Krymka parent body itself.
Wikipedia provided the following explanation:
“Chondrules formed as molten or partially molten droplets in space before being accreted to their parent asteroids. Because chondrites represent the oldest solid material within our solar system and are believed to be the building blocks of the planetary system, it follows that an understanding of the formation of chondrules is important to understand the initial development of the planetary system.”
To me, when applying the above words to Krymka, my slice becomes a nursery of infant planets that, like baby dinosaurs preserved in the fossil record, never reached their potential growing to adult planets in our solar system.
Nittler, Alexander, Stadermann & Zinner observed in their article titled:
Presolar Al-, Ca-, And Ti-Rich Oxide Grains In The Krymka Meteorite.
Although a large number of presolar Al2O3 and MgAl2O4 grains have now been studied, only a handful of presolar hibonite (CaAl12O19) grains and a single presolar TiO2 grain have been previously reported. We report the identification and detailed isotopic characteristics of 46 presolar oxides from a new residue of the Krymka unequilibrated ordinary chondrite (LL3.1), including 15 Hibonites and 2 TiO2 grains.
The crust on Krymka, while as exciting and desirable as any other crust on a witnessed fall, but what I find truly amazing to see is the delicate boundary between the crust and the chondrules.
Look closely at how the chondrules brush up against the protective crust like a bag full of marbles.
As we begin a new year for the Accretion Desk, I would like to personally thank my readers. The emailed comments are fun to read. I know there is a small but growing number of collectors who specialize in historic meteorites, witnessed falls, or like me, prefer both. Thanks for reading!
Until next time…
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