[meteorite-list] Article : 21st Century Meteorite Falls, Part Two

From: finbarr connolly <finconnolly71_at_meteoritecentral.com>
Date: Thu, 20 Oct 2016 22:02:54 +0100
Message-ID: <CACRq3w__1Nfh3ODhz8Ay1TMnR1H8CJTPBB=LgULB2OaZ5hyPvA_at_mail.gmail.com>

I find the relatively static number of falls very surprising, considering
the proliferation of cameras compared to earlier times. Still waiting for
our first British Isles fall of the 21st century!

Finbarr.

On Thu, Oct 20, 2016 at 9:46 PM, Carl Agee via Meteorite-list <
meteorite-list at meteoritecentral.com> wrote:

> Always an interesting topic!
>
> A couple of things come to mind:
>
> Morocco has 8 falls in the 21st century, which you suggest has to do
> with the meteorite-savvy population and desert terrain. California has
> a very similar area and population density -- also a west facing coast
> line, a fair amount of desert, and a mountain range. How many 21st
> century falls in CA?
>
> We are over-due for a lunar falls! There are now 265 classified lunars
> -- all of them finds. Compare that with 5 martian falls and 177
> classified finds, or for example mesosiderites with 6 falls and 261
> classified finds. Aubrites have 9 falls and 63 finds.
>
> Brachinites have no falls (40 finds), any others?
>
> Carl
>
>
> *************************************
> Carl B. Agee
> Director and Curator, Institute of Meteoritics
> Professor, Earth and Planetary Sciences
> MSC03 2050
> University of New Mexico
> Albuquerque NM 87131-1126
>
> Tel: (505) 750-7172
> Fax: (505) 277-3577
> Email: agee at unm.edu
> http://meteorite.unm.edu/people/carl_agee/
> http://compres.us/about-us/compres-president
>
>
>
> On Thu, Oct 20, 2016 at 1:57 PM, Galactic Stone & Ironworks via
> Meteorite-list <meteorite-list at meteoritecentral.com> wrote:
> > "...In the first 10 years of the 21st Century, we have seen 58 new
> > meteorite falls (as of this writing). As we close out the first decade
> > of this new century, let us examine some of the facts and numbers
> > surrounding these recent falls. For the purposes of this article, we
> > will only examine those falls which have been officially recognized by
> > the Meteoritical Society. There have been a few documented falls that
> > have not been approved yet (Zunhua and Cartersville), so these falls
> > will not be included in this analysis..."
> >
> > I wrote the above introductory paragraph nearly 6 years ago (early
> > 2010) when I did my first analysis of recent meteorite fall
> > statistics. More than 5 years later, we have had 40 more
> > officially-recognized falls. In that same span of time, we have also
> > had Breja, Addison, Oslo, Mahbse Aarraid, and the recent White
> > Mountains fall that are well documented falls that have not been
> > approved or published in the Met Bull. A quick look at the overall
> > numbers shows a very slight increase in the number of approved falls
> > in the last 6 years compared to the previous 9.5 years. This is likely
> > due, in part, to increased awareness of meteorites and increased
> > recovery rates.
> >
> > Also, it seems that NonCom has been moving a bit faster to approve new
> > falls and publish them in the Met Bull. Taking all of these recent
> > falls into account, we have now had 98 official falls since the year
> > 2000. If one chooses to include the recent unofficial falls which will
> > likely be approved in the near future, then we have had over 100
> > meteorite falls in the 21st century.
> >
> > So, in the first 16 years (2000-2016) of this century, we have
> > averaged just over 6 approved falls per year. This represents an
> > uptick in the average number of approved falls compared to the
> > previous period of 2000-2010 where the average was 5. This is not so
> > clear cut though, because a couple of older falls were approved in the
> > years since, including Zunhua (as it was known in 2010), which was
> > approved in late 2015 as Xinglongquan. For tidy conversational
> > purposes, it's safe to say that we expect about 5 to 6 new approved
> > falls each year. A number of 5 per year being more conservative and
> > closer to 6 if you take into account that some falls are not recovered
> > or approved until a year or more after the date of their fall.
> >
> > Now let's take a look at the numbers and have some fun with them :
> > Which petrologic type do you think was the most common type recovered
> > during the first 16 years of this century?
> >
> > Well, it's safe to say that it is an ordinary chondrite. No surprises
> there.
> >
> > More specifically, we have a tie between L6 and H5 chondrites at 23 each.
> >
> > Anyone want to guess what the third most common type is?
> > The third most common is the L5 chondrite with 10 approvals.
> > Well, surely the fourth most common is probably an H chondrite, right?
> Wrong.
> >
> > The fourth most common type is the eucrites with 7.
> >
> > Wait, that seems like too many Vestans! How can eucrite be in the top
> > 4 common types? The answer is simple, it's because we are playing
> > semantics with petrologic grades here.
> >
> > There have been 23 L6 chondrites, 23 H5 chondrites, 10 L5 chondrites,
> > and 7 eucrites. But, there are many subtypes of H and L chondrites
> > that are approved by NonCom, compared to the much smaller clan of
> > eucrites. In total, there were 42 L chondrites and 40 H chondrites of
> > various petrologic grades (L3, L4, L5, L6, etc) compared to just 7
> > eucrites. Throw in the 10 LL chondrites that were approved and the
> > numbers become more lopsided in favor of ordinary chondrites over
> > eucrites - 92 to 7.
> >
> > After the ordinary chondrites and eucrites, the most numerous of
> > meteorites recovered from 2000 to 2016 were carbonaceous chondrites
> > followed by a sprinkling of achondrites of different types.
> >
> > Worthy of note, thus far there has only been one iron fall (Kavarpura,
> > 2006) and no pallasite falls.
> >
> > There have been 39 hammer falls to date since Jan 01, 2000 - that is
> > roughly 40% of known falls.
> >
> > Number of official falls by country :
> >
> > USA : 17
> > India : 12
> > Morocco : 8
> > China : 5
> > Mauritania : 4
> > Australia : 3
> > Brazil : 3
> > Canada : 3
> > Germany : 3
> > Nigeria : 3
> > Turkey : 3
> > Argentina : 2
> > Burkina Faso : 2
> > Czech Republic : 2
> > Denmark : 2
> > France : 2
> > Iran : 2
> > Kenya : 2
> > Russia : 2
> > Spain : 2
> > Sudan : 2
> > Algeria : 1
> > Cambodia : 1
> > Colombia : 1
> > Croatia : 1
> > Ecuador : 1
> > Italy : 1
> > Japan : 1
> > Lesotho : 1
> > Libya : 1
> > Madagascar : 1
> > Mali : 1
> > Mexico : 1
> > Norway : 1
> > Pakistan : 1
> > Peru : 1
> > Poland : 1
> > Romania : 1
> > Slovakia : 1
> > Slovenia : 1
> > South Korea : 1
> > Tunisia : 1
> > Uganda : 1
> > Uzbekistan : 1
> > Western Sahara : 1
> > Yemen : 1
> > Zimbabwe : 1
> >
> > A few things we can surmise from these country numbers. Obviously the
> > USA had the most falls. This is largely due to the number of cameras
> > and observers watching the skies, combined with a robust system of
> > quickly tracking down falls to recover them. India is somewhat
> > surprising with the second-most number of falls, and this is due in
> > part to how densely-populated that nation is. Morocco, despite it's
> > small geographic size, was in third place. Morocco's performance can
> > be attributed to the meteorite-savvy nature of the local population.
> >
> > China is in fourth place, which is very surprising when considering
> > how big China is in geography and population. Another surprise is
> > Russia, which had only two known falls. I think China and Russia's
> > lack of recoveries is due in part to the difficult nature of the
> > terrain in those countries (compared to a nation like Morocco that has
> > a lot of desert), and the undeveloped nature of their meteorite
> > recovery programs.
> >
> > Although the USA has no government-sponsored program to recover
> > meteorites in America, there is a thriving culture of participation by
> > private hunters, which explains the relatively high recovery rate.
> > This stands in stark contrast to Australia which has a quasi-official
> > program to recover meteorites, but only has three recoveries to show
> > for it. Another big country with a small number of recovered falls is
> > Canada, and once again, I think difficult terrain is responsible for
> > some of that, and the rest can probably be explained by how
> > sparsely-populated some areas are.
> >
> > Number of official falls by petrologic type :
> >
> > C2-ung : 1
> > CM : 1
> > CM2 : 1
> > CO3.6 : 1
> > CV3 : 1
> > EL6 : 1
> > LL3.2 : 1
> > LL5 : 3
> > LL6 : 6
> > L3 : 1
> > L4 : 4
> > L5 : 11
> > L5-6 : 1
> > L5/6 : 2
> > L6 : 23
> > H/L3 : 1
> > H/L4 : 1
> > H3-5 : 2
> > H3.8 : 1
> > H4 : 3
> > H4-5 : 2
> > H4/5 : 2
> > H5 : 23
> > H5/6 : 2
> > H6 : 4
> > Eucrite : 7
> > Howardite : 1
> > Martian : 1
> > Ureilite : 1
> > Iron IIE-an : 1
> >
> > That?s it for this installment. I?ll see you again in several years.
> > In the meantime, good luck and happy hunting! :)
> >
> > 21st Century Meteorite Falls (Part One) :
> > http://www.galactic-stone.com/pages/20falls
> >
> > Recent Meteorite Falls (updated tally page) :
> > http://www.galactic-stone.com/pages/falls
> >
> > Witnessed Falls available for purchase :
> > http://www.galactic-stone.com/pages/fallcatalog
> >
> > This article is ? Galactic Stone & Ironworks Meteorites, 2016.
> > ______________________________________________
> >
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Received on Thu 20 Oct 2016 05:02:54 PM PDT