Khohar, India: One of a Pair of L3 Twins
|This slice of Khohar recently entered my collection. Khohar is an L3.6 S2 chondrite that fell in 1910, the same year as another of the very few L3 chondrites whose fall was witnessed.|
Here is a secret code:
Now if this list of falls were much larger than 10, the pattern would be subtle or non-existent, but with only 10 specimens to work with, and fall dates spanning almost a century and a half, the fall dates seem hardly random. The actual time from first to most recent witnessed L3 fall is 148 years with the earliest fall of an L3 chondrite, named Mezo-Madaras, in 1852 and the latest L3 fall in 2000 named Itawa Bhopji.
divides 150 (years) by 10 (the number of L3 falls), then randomness
should dictate a 15-year span between witnessed L3 falls --and this
did seem to occur between three pairs of specimens. What is harder
to ignore is that the pairs of same-year falls given such a small
pool of specimens. The pairs, Khohar and Hedjaz in 1910, and Bovedy
and Andreevka in 1969 seem too much for coincidence alone even
though I subscribe to the tenet of parsimony in science meaning the
simplest answer is the right answer.
However, instead of belaboring an unrelated series of intangible points, I would like to present some pictures of a rarely seen L3 chondrite named Khohar. Two other L3 falls I have in my collection were featured in previous Accretion Desk articles with Bovedy in August 2005, and Dubrovnik in October 2005. Pictures from those two falls have also been included here.
|Looking like a big nose with one black eye and one white, this close-up in Khohar shows the dramatic difference between perfect chondrules that push a type 3.x number lower, and the irregular shaped inclusions that raised the number.|
The presence of metal particles having nonchondritic chemical composition with particles of nearly pure metallic iron, as well as their association with graphite having interstellar isotopic signatures in Khohar was unexpected.
The comparison of the compositions of the metal particles with experimental data for the Fe-Ni-Co system at equilibrium showed that the particles are out of equilibrium. This suggests that metal particles and graphite from different sources were probably mixed and compacted to form this spherical object in Khohar.
The mechanism, location, and period of mixing are unknown. Such clasts with no chondritic features are good candidates for an in situ search for extrasolar material in meteorites.
Khohar fell at 1:00 in the afternoon on
September 19, 1910. It is reported that:
"After detonations, a stone fell at Khohar. Twenty-two pieces, weighing from 4.8kg to 15g were collected."
From this rather weak amount of information, I suspect that a single stone fell, broke, and was further assisted in its dismemberment by locals--a practice all too common in meteorite history.
Dubrovnik is a polymict breccia classified as an L3-6 chondrite. Its arrival on earth was reported as:
"After a noise like a thunderclap, a single stone was observed to hit a tree before embedding itself several feet into the ground."
The stone fell on February 20, 1951 at 1400 hours, and a mass of 1.9kg was later recovered from the field by Nico Cvjetkovic, Tomislav Cvjetkovic and George Antunovic.
I guess that since it hit a tree, this should be listed as a hammer stone, but it is absent from the IMCA Meteorite Hits page.
Bovedy fell in 1969, the same
year as another L3 chondrite.
The description states:
"A fireball was observed over the British isles moving from southeast to northwest. Three days later, a specimen, in two pieces totalling 513g, was found at Sprucefield, after it had fallen through an asbestos roof. A second stone fell on a farm at Bovedy, about 60 miles northwest of Sprucefield, and weighed 4.95kg."
This hammer stone is listed on the IMCA Meteorite Hits page.
As 2006 reaches its tipping point, it is nice to know that some of the seeds I planted in Tucson back in February can finally be harvested. Khohar was just one of a handful of seeds I sowed while walking the hallways and chatting with like-minds.
While the events and acquisitions of Tucson are worth their weight in anorthositic regolith breccia, the face-to-face contact with dealers and collectors, and the inside scoop on rare specimens, and the hints of what might be available in the future are all indispensable collecting tools for anyone serious about meteorites.
And no doubt if you have read this far, you are one of the serious ones.