[meteorite-list] World record 1, 250g tektite from Philippines??

From: Aubrey Whymark <tinbider_at_meteoritecentral.com>
Date: Wed, 16 Feb 2011 03:52:19 +0000 (GMT)
Message-ID: <99531.74359.qm_at_web28516.mail.ukl.yahoo.com>

Forgot to mention

What is the biggest feasible tektite?

Well, 1 kilos should not exist as at that size the inequal cooling of the glass should fragment the specimen. We do see this in the Philippines - fragments of true monsters! Always fragments of very large spheres probably a couple of kilos in size or more! So, the largest possible tektite - Well we have around 1,070g, possibly slightly more. The largest will likely be a dumbbell - a double 1,070g sphere. So a dumbbell weighing 2 kilos or slightly more is a possibility. This will occur in the Philippines - chances of one being found is close to zero. You can count the 1 kilos on a hand and most Philippinites are spherical. Dumbbells are relatively rare. So maybe after we have found 100 or 1,000 1 kilo spheres perhaps we'll chance upon a monster dumbbell!

Aubrey
www.tektites.co.uk


--- On Wed, 16/2/11, Aubrey Whymark <tinbider at yahoo.co.uk> wrote:

> From: Aubrey Whymark <tinbider at yahoo.co.uk>
> Subject: Re: [meteorite-list] World record 1, 250g tektite from Philippines??
> To: "meteorite list" <meteorite-list at meteoritecentral.com>
> Date: Wednesday, 16 February, 2011, 3:42
> Hi
>
> This size tektite is perfectly feasible from China, but it
> would have been a Muong Nong-type tektite, which I consider
> to be someway between tektites and impactites. It would not
> have been a true splashform.
>
> If we take only true splashforms, ignore the incompletely
> melted and homogenised layered Muong Nong-types, then the
> largest tektites occur some 1,750 km from the impact site.
> This is true of the Australasian impact and the Chesapeake
> impact.
>
> Why do the biggest tektites not occur closest to the
> impact?
> Well, the reasons are complex, but basically as you move
> closer to the impact site the energy levels decrease as the
> energy of impact is spread over a wider area. The melt sheet
> is not ejected into 'space' before being disrupted. So
> proximal tektites form at lower atmospheric levels - they
> interact with the atmosphere and cascade into smaller forms.
> The large blocks of semi-melted material comprising Muong
> Nong tektites form at even lower energy levels -
> insufficient to even fully melt them.
>
> Back to the medial distance Philippinites. The melt sheet
> just about reached space before being disrupted into tektite
> bodies. (Rare Philippinites show some plastic deformation
> during their exit). The viscosity was low (as Philippinites
> are mainly spherical), but not as low as Australites (which
> encourages further break-up). A large sphere remains as a
> sphere and will not interact with the atmosphere to form a
> disc that cascades into smaller spheres.
>
> Move from the Philippines to Australia and tektites become
> progressively smaller as expected. The temperature of the
> melt was higher and the viscosity even lower. Also distal
> tektites were ejected at a lower angle and although no
> plastic distortion is recorded (perhaps due to them being
> exceedingly hot and the low viscosity), some atmospheric
> interaction, due to the lower ejection angle may have
> resulted in an early cascading effect.
>
> So 1,750 km or thereabouts from the impact site is perfect
> for ejection angle, viscosity and exiting the atmosphere.
> Perhaps this is the magic 30 degrees whereas Australites
> were maybe ejected at c. 15-20 degrees??
>
> Aubrey
> www.tektites.co.uk
>
>
>
> --- On Tue, 15/2/11, Yinan Wang <veomega at gmail.com>
> wrote:
>
> > From: Yinan Wang <veomega at gmail.com>
> > Subject: Re: [meteorite-list] World record 1, 250g
> tektite from Philippines??
> > To: "meteorite list" <meteorite-list at meteoritecentral.com>
> > Date: Tuesday, 15 February, 2011, 17:05
> > Here's a big fish story for you all;
> >
> > About ten years ago I was visiting a mineral shop
> inside a
> > park in
> > china and they had a football (American football)
> shaped
> > tektite
> > slightly larger than a football. I was quite sure it
> was a
> > tektite and
> > not slag nor obsidian. Must've massed about 8-12
> kilos. It
> > was priced
> > at the equivalent of $700 USD, but back then I didn't
> > appreciate
> > meteorites and tektites and thus I ignored it. Only
> > recently did I
> > realize the importance of it, oh well.
> >
> > -Yinan
> >
> > On Tue, Feb 15, 2011 at 7:28 AM, Aubrey Whymark <tinbider at yahoo.co.uk>
> > wrote:
> > > Hi
> > >
> > > Still seeking the new owner of a possible world
> record
> > breaking tektite which came to light on 07 February
> 2011 in
> > Paracale, Philippines. Very keen to know the true
> weight as
> > the weight given by dealers here can be highly
> misleading.
> > Certainly in the 900g to 1,250g range though and the
> weight
> > estimate could well be realistic. You can let me know
> > anonymously if you like - off-list. For the record
> the
> > heaviest Philippinite is 1,070.54g and the heaviest of
> all
> > tektites (excluding Muong Nong-type layered
> impactites) is
> > either 1,070.54g (as above) or possibly a 1,200g
> Indochinite
> > (shape is right, but might be a rolled/water worn
> Muong
> > Nong-type).
> > >
> > > Also, I will be giving a presentation on tektites
> at
> > Rizal Technological University on Boni Avenue in
> > Mandaluyong, Manila, Philippines. It will be in the
> new
> > building - Astronomy Centre at 9am (yes, very early)
> on
> > Saturday 19th February. All welcome I am told.
> > >
> > > Regards, Aubrey Whymark
> > > www.tektites.co.uk
> > >
> > >
> > >
> > >
> > >
> > >
> > >
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Received on Tue 15 Feb 2011 10:52:19 PM PST