[meteorite-list] Meteorite Concentration was Franconia AREA
From: MEM <mstreman53_at_meteoritecentral.com>
Date: Wed, 1 May 2013 09:29:14 -0700 (PDT)
>How many meteorites can dance on the head of a pin?? Depends on where the pin on the mapboard.
>Glaciers are a non issue and had they been, all the "fields" would lie in and around a terminal moraine-- not a strewn field.? Hopefully, someone, sometime will repost the special geological situations found in Antarctica which favor meteorite concentration on "ice sheet" glaciers. vs alpine glaciers vs no glaciers (below).
>Cogitating the Mohave meteorite ground loading:
>Meteorite "falling" should be uniform for the entire planet surface, statistically.? It is ground/soil type, obscuration by clutter, surface movement and weathering that dictates how much of that fallen material lies in our own back yards which we are able to recover.
>Look at the more accurate fall rates we are getting via Doppler Radar
>analysis --one every 2 months nation wide?? Assume there is a fall in Arizona
>every 3 years --a low value for argument sake.? Divide that by 30-40-50+k
>years and one should be asking why so few, not why so many. Do a land area percentage to get Mohave County's share and get a population figure for meteorites on the ground there.? There should be several non- paired L6 fields overlapping.? Agreed that terrestrial dating is the most accurate, however it may not be practical to date them all. Dating some might better describe the true mapping of different unobserved falls.
>Mohave County is a desert-- replete with desert pavement, scant vegetation, and a lack of substantial precipitation-- for dozens of thousands of years.? It is simply a place where there wasn't a lot of surface movement so what falls, lays.? Desert pavement tends to prevent smaller stones from burring deeply.? They last longer as recognizable meteorites and are easier to find.? (use your lottery winnings to build droids and drones, Mike)
>Couple this understanding with fall statistics and there are going to be a lot of L6s, not so many H4s and an occasional Martian.? Ergo we should expect a mix of finds that looks like the global collection of falls/finds. Given we tend to focus on OCs as they are easier to identify and collect, working backwards one can get an idea of how many rare ones are still out there for when we have cheap mini mineral-detection drones with xray chips to sample them with. Circa 2020? Hunting meteorites from your sofa--wait and see.
So there is no mystery as to why Mohave County yields so many meteorites.? At least some collectors had the dedication to log their finds so we might forecast the population of individual stones yet on the ground. Whether we revise our nomenclature to go back and create a consolidated category of OCs to satisy our OC (obsessive compulsive) needs for pin dancing, it isn't a process I would argue for or against unless it was going to yield scientific information meriting the coast. (But it would be a pop-corn even on the met-list).
Since it may come up, so far as I know the Mohave is not much like
the Roosevelt County NM finds which lie on a somewhat scoured desert pavement: breached surface which apparently can bring more deeply buried specimens to the surface.? This would be the closest allegory to the way meteorites are found in Antarctica, only the "feed stock"of soil is not being moved along to the surface the way Antarctic ice is forced to the surface by underlying ridges--whose ice is scoured away to reveal its load of rock and meteorites.
>----- Original Message -----
>> From: Michael Mulgrew <mikestang at gmail.com>
>> To: Meteorite List <meteorite-list at meteoritecentral.com>
>> Sent: Tuesday, April 30, 2013 12:47 AM
Subject: Re: [meteorite-list] Franconia AREA (was, Re: ...terminology...)
>> And even if there was, I think the chances of a glacier arranging who
>> knows how many separate meteorite falls into a typical strewn field
>> ellipse distribution may be even less than the chances of so many
>> falls concentrated in one area along the same trend line.? After I win
>> the lottery I'll fund the effort to figure it out, because I think my
>> chances at the lotto are better than multiple falls happening in the
>> exact same strewn field ellipse over the millennia.
>> Michael in so. Cal.
Received on Wed 01 May 2013 12:29:14 PM PDT