HDTenEightyP/NetNews huggingface dataset:
From: ricky@winvmd.vnet.ibm.com (Rick Turner)
Subject: Re: Tsavorite as a Gemstone
Date: Tue, 10 Nov 92 08:39:57 GMT
Organization: IBM UK Scientific Centre
Followup-To: sci.geo.geology

true tsavorite is a bright green color, due to the presence of vanadium
and if I recall correctly, titanium. Be careful who you buy from as genuine
tsavorite is very expensive - the last time I looked prices were up in the 
thousands of dollars per carat bracket. If you are offered a stone over 2 carats
or at a 'bargain' price then it almost certainly isnt true tsavorite. Unlike
most gemstones, tsavorites color is usually diagnostic - it's a peculiar bright
emerald green. Once seen, never forgotten!

Most of the genuine material came out of a mine on the edge of the Tsavo
National Park (hence the name) in Tanzania about 20 years ago. Production was
limited to say the least, and most of the material was badly flawed. As a
result almost all the stones cut from it were under two carats. I have a couple
of dozen stones that I got in Kenya in the late seventies. They're all about
a carat and typical of most of the material.

Somewhere I have more information both on the stone and on the mine that it came
from; if you are interested let me know and I'll try and dig something out.

Rick 
Newsgroups: sci.geo.geology
From: rwmurphr@wildcat.ecn.uoknor.edu (Robert W Murphree)
Subject: Impact processes Reference
Summary: Looking for good paper discussing shockwave
Date: Thu, 12 Nov 1992 04:24:20 GMT
Organization: Engineering Computer Network, University of Oklahoma, Norman, OK, USA
Keywords: impact, crater, shock wave, planets

I've been trying to get a somewhat more detailed understanding of
high velocity impact cratering as a process. I think what I'd like
to read is a detailed description of how the shock-wave propagates
out from the projectile and the decompression wave propagates back
and how that leads to the excavation process.  Hopefully with
lots of pictures, one or two equations, and maybe a reference to 
some animation and/or animated diagrams I could watch.

The best textbook so far is "The solar system" by john wood.  But
I know there are many others.  How about references to particular
papers.

A non-geologist, thanks in advance.

Robert W. Murphree

Newsgroups: sci.geo.geology
From: zrwv05@hou.amoco.com (Rod VanKoughnet)
Subject: Re: Petosky or Petoskie (Michigan?) fossil cora
Reply-To: zrwv05@hou.amoco.com
Organization: Amoco
Date: Wed, 11 Nov 1992 13:33:34 GMT


I was looking for my my Petoski stones just last week...found 'em in my fish aquarium.
My friends in grade school used to find them in a lake, or lakes in Michigan.  I think Devil's lake is one of the locations.  There is also a town in Michigan, which these fossils are named after.  That would probably be a good place to start looking.

Rod

Xref: sparky sci.geo.geology:2368 alt.sci.planetary:318
From: willmann@seismo.CSS.GOV (Raymond Willemann)
Newsgroups: sci.geo.geology,alt.sci.planetary
Subject: Re: role of meteoroids in continental rifting
Date: 13 Nov 92 17:27:21 GMT
Followup-To: sci.geo.geology
Organization: Center for Seismic Studies, Arlington, VA


In article <1992Nov12.172311.5362@slustl.slu.edu>, guy@slustl.slu.edu (Guy Smith) writes:
|> In article <1992Nov11.153514.15715@mailer.cc.fsu.edu> cain@geomag.gly.fsu.edu (Joe Cain) writes:
|> >	This leads me to another question for the net. I have read
|> >that the interior of the Earth has cooled some 100 degrees (C or K)
|> >per gigayear over the eons. Does anyone know if this figure means that
|> >the isotherms have been moving down uniformly, or whether the
|> >implication is that only given layers have so cooled? If the
|> >temperatures have changes over the past it might have implications on
|> >the geochemistry of ancient rocks in ascertaining their origin. 
|> 
|> The temperature *gradient* shouldn't change much, below the boundary
|> layer, as convective systems tend to stay close to adiabatic. A higher
|> heat flux could simply be accommodated by an increase in convection
|> rate or perhaps changes in convective geometry. This doesn't rule out
|> a uniform cooling of the earth but I can't see that it is required
|> either.

Perhaps the original reference was to a "parameterized convection" study.
In this kind of study, the Nusselt number is assumed to be proportional
to some fractional power of the Rayleigh number.  Along with various
other assumptions (viscosity dependence on temperature, rate of heating
from within and below) this gives you an ordinary differential equation
for temperature (at the center of the convection cell) as a function of
time.  The equation has been solved with a variety of different
assumptions many times since Sharpe and Peltier's 1978 paper.  The
fundamental conclusions seem to be remarkably robust:
   1) From any initial temperature, the steady-state temperature
	is reached quickly (within a few 100 million years).
   2) The earth's mantle is cooling, so that the temperature will
	remain at it's steady-state value for the current rate of
	radiogenic heating (which decreases with time, of course).
   3) The heat loss required for the temperature decrease is a significant
	fraction of the total heat flux from the earth (10% ?).
From: 00bndaniels@leo.bsuvc.bsu.edu
Newsgroups: sci.geo.geology
Subject: Re: can 1811 happen again ???
Date: 12 Nov 92 18:20:47 GMT
Organization: Ball State University, Muncie, In - Univ. Computing Svc's

In article <1992Nov9.183113.16783@hou.amoco.com>, zawr02@hou.amoco.com (Andrew W. Robinson) writes:
> In article 1d3o4uINN86j@gap.caltech.edu, hough@seismo.gps.caltech.edu (Susan Hough) writes:
>>In article <1992Oct30.193732.27276@constellation.ecn.uoknor.edu> jahern@geohub.gcn.uoknor.edu writes:
>>>In article <1992Oct29.134821.11189@bsu-ucs> 00bndaniels@leo.bsuvc.bsu.edu writes:
>>>>I have a question about an article stating that there is less 
>>>>than a 6% chance of an earhtquake occuring on the New Madrid
>>>>Fault, by the year 2000.  I know the fault hasn't moved in 
>>>>over 155 years, and am curious to know if itmay move again 
>>>>by the year 2000.  I am concerned because I live in Indiana 
>>>
> Paleoseismicity studies conducted back in the early and mid 1980's suggested a
> recurrence interval for the big New Madrid quakes of about 600 years.  The next
> big one would be expected in about 300-500 years.
> 
> At a meeting on the seismic hazards in the eastern US help in 1984, Dr Otto Nuttli
> made a "back-of-the-envelop" calculation for the worst case New Madrid
> earthquake today.  Using broad assumptions about the fault and the stress buildup,
> he arrived at a magnitude of about 5.6.
> 
> Based on these lines of reason, 6% is probably a reasonable estimate of the chance
> of a major earthquake in the New Madrid area before the year 2000 (look at it as
> a 94% or better chance that one will not happen).  But as Susan points out, we know
> less about the Wabash seismic zone which is closer to Indiana...(sorry, couldn't resist
> interjecting a little drama :-).
> ---
> 
> Andrew Robinson
> --------------------------------------------------------------
> Amoco Production Company
> Robinson_Andrew_W/ets_ess@hou.amoco.com	
> --------------------------------------------------------------
> Opinions expressed are solely my own.
	What is the "Wabash seismic zone" you are reffering to??
Barron Daniels
Newsgroups: sci.geo.geology
From: oral@E34-530-1.MIT.EDU (gamiteer)
Subject:  IP address :cddis@gsfc.nasa.gov
Organization: Massachvsetts Institvte of Technology,    Cambridge, Massachvsetts
Date: Fri, 13 Nov 1992 02:43:40 GMT



what is the IP address for cddis@gsfc.nasa.gov

MIT nameresolvers cannot get it.

cheers
burch
From: mjohnson@cco.caltech.edu (Mary L. Johnson)
Newsgroups: sci.geo.geology
Subject: Re: Petosky or Petoskie (Michigan?) fossil coral (Q)
Date: 11 Nov 1992 17:36:50 GMT
Organization: California Institute of Technology, Pasadena
Distribution: usa
NNTP-Posting-Host: alumni.caltech.edu
Summary: Petoskey Stones...

In article <hank.721427050@well.sf.ca.us> hank@well.sf.ca.us (Hank Roberts) writes:
>
>Something I once saw and admired: a bit of nicely polished fossilized
>coral, which I was told comes from one location; my best recollection
>of the name is in the header.  Anyone know of this material?

This is Devonian (?) fossil coral from the NW corner of Lower Michigan.
Such things are called "Petoskey Stones" and are found on the
beaches of Petoskey (Petoskey Stone Beach State Park), Charlevoix, etc.
(I lived in Charlevoix during first - third grades in gradeschool;
collected dionella and other critters in the gradeschool playground -
long time ago ...)

Hardness is basically that of calcite marble (3), so forget using them as
gemstones, but the material does take a nice polish.  Stones are gray
masses of white spoked "daisy patterns", some with dark centers;
in grade school we thought the ones without dark centers weren't ripe
yet.  Give 'em another 200 million years, I guess...

--Dr. Mary L. Johnson
mjohnson@alumni.cco.caltech.edu



Newsgroups: sci.geo.geology
From: hank@well.sf.ca.us (Hank Roberts)
Subject: Petosky or Petoskie (Michigan?) fossil coral (Q)
Summary: wanted, info/source
Organization: Whole Earth 'Lectronic Link
Distribution: usa
Date: Tue, 10 Nov 1992 20:24:10 GMT


Something I once saw and admired: a bit of nicely polished fossilized
coral, which I was told comes from one location; my best recollection
of the name is in the header.  Anyone know of this material?
From: zawr02@hou.amoco.com (Andrew W. Robinson)
Newsgroups: sci.geo.geology
Subject: Re: can 1811 happen again ???
Date: 9 Nov 92 18:31:13 GMT
Reply-To: zawr02@hou.amoco.com
Organization: Amoco

In article 1d3o4uINN86j@gap.caltech.edu, hough@seismo.gps.caltech.edu (Susan Hough) writes:
>In article <1992Oct30.193732.27276@constellation.ecn.uoknor.edu> jahern@geohub.gcn.uoknor.edu writes:
>>In article <1992Oct29.134821.11189@bsu-ucs> 00bndaniels@leo.bsuvc.bsu.edu writes:
>>>I have a question about an article stating that there is less 
>>>than a 6% chance of an earhtquake occuring on the New Madrid
>>>Fault, by the year 2000.  I know the fault hasn't moved in 
>>>over 155 years, and am curious to know if itmay move again 
>>>by the year 2000.  I am concerned because I live in Indiana 
>>
Paleoseismicity studies conducted back in the early and mid 1980's suggested a
recurrence interval for the big New Madrid quakes of about 600 years.  The next
big one would be expected in about 300-500 years.

At a meeting on the seismic hazards in the eastern US help in 1984, Dr Otto Nuttli
made a "back-of-the-envelop" calculation for the worst case New Madrid
earthquake today.  Using broad assumptions about the fault and the stress buildup,
he arrived at a magnitude of about 5.6.

Based on these lines of reason, 6% is probably a reasonable estimate of the chance
of a major earthquake in the New Madrid area before the year 2000 (look at it as
a 94% or better chance that one will not happen).  But as Susan points out, we know
less about the Wabash seismic zone which is closer to Indiana...(sorry, couldn't resist
interjecting a little drama :-).
---

Andrew Robinson
--------------------------------------------------------------
Amoco Production Company
Robinson_Andrew_W/ets_ess@hou.amoco.com	
--------------------------------------------------------------
Opinions expressed are solely my own.
Newsgroups: sci.geo.geology
From: rlw@atlanta.dg.com (Richard Wright)
Subject: Diamonds are common?  
Date: Fri, 6 Nov 92 20:36:06 GMT
Organization: Data General Corp. ASSD, Atlanta, GA

I need help with an ongoing net argument. My opponent recently referred
diamond as 'a common mineral'. He obliquely referred to the DeBeers
cartel's ability to manipulate prices and maintain high prices for
diamonds in spite of increased production. While I agree that diamonds
are not as rare as their price would lead one to believe, I do not think
they can be classified as 'common'. I need some expert help. 

If anyone has hard facts as to:
	* the rarity of diamonds
	* standard definitions/classifications of minerals with regard
	  to their availability/commonality/rarity
	* recent production totals for: 
		- So. Africa
		- India
		- So. America
		- USSR/Russia/Siberia
		- Australia
		- USA
		- Any other non-trivial producers of diamonds
	* Any generally accepted reference work that confirms that 
	  diamonds are rare (or at least non-common)

PLEASE PLEASE PLEASE send those facts/references to me (email would be 
best, but I will monitor this group for a while in case someone has
something to contribute and can't email for some reason. 

I am under a slight time constraint before my rebuttal would be 'dated', 
so immediate replies are best. Thanks again. 

				Richard
   
*-----------------------------------------------------------------------*
* "Listen, three eyes," he said, "don't you try to outweird me, I get   *
*  stranger things than you free with my breakfast cereal."             *
*-----------------------------------------------------------------------*
* Richard L. Wright, Jr             * Disclaimer:                       *
* Data General Corporation          *  The views expressed here are the *
* System Evaluation and Performance *  One True Way to Enlightenment.   *
*   Analysis Center (SEPAC)         *  Everyone shares my views, they   *
* Norcross, Georgia, USA  30092     *  just don't realize it yet.       *
* (404) 448-6072                    *      Riiiiiight.                  *
*-----------------------------------------------------------------------*
From: shaw@s119.es.llnl.gov (Henry Shaw 510 423-4645)
Newsgroups: sci.geo.geology
Subject: Re: taafite (is it a known gem name?)
Date: 11 Nov 92 01:10:51 GMT
Organization: Earth_Sciences_Dept.,_LLNL

In article <1dosq2INNfoh@seven-up.East.Sun.COM>, gsteckel@vergil.Eng.Sun.COM (Geoff Steckel - Sun BOS Hardware CONTRACTOR) writes:
|> The science fiction writer Roger Zelazny wrote a short story
|> 'Time Regarded as a Helix of Semi-Precious Stones', which listed
|> among commonly known names 'taafite'.  I have been unable to find
|> this in common handbooks of gems & minerals, encyclopedias, etc.
|> Does anyone know this name or have a suggestion on where to find
|> it, if it is not a creation of the author?


Taaffieite (note difference in spelling) is a beautiful, rare, violet mineral that is 
sometimes cut into gemstones.  I happen to have one facteted stone that I bought while 
in Sri Lanka a number of years ago.

It's formula is Mg3BeAl8O16, Sri Lanka is the type locality for the mineral.
See American Mineralogist (1952), v37, p360; (1984) v69, p215.

-- 
Henry Shaw, Earth Sciences Dept., LLNL |    All opinions are my own.
Internet: shaw4@llnl.gov               |  
CIS: 76347,2523                        |
Fidonet: Henry Shaw at 1:161/55        |
From: shaw@s119.es.llnl.gov (Henry Shaw 510 423-4645)
Newsgroups: sci.geo.geology
Subject: Re: Tsavorite as a Gemstone
Date: 10 Nov 92 01:20:52 GMT
Organization: Earth_Sciences_Dept.,_LLNL

In article <1992Nov8.052704.1380@news2.cis.umn.edu>, naeve@psych.umn.edu (Susan Naeve) writes:
|> 
|> 	I am interested in whether tsavorite (a type of green garnet from the Tsavo  
|> National Park in Kenya) is suitable to be set in a ring to be worn everyday.  I  
|> would like to know about its hardness and durability - by this I mean its  
|> resistance to abrasion and fracture.  I am also interested in any information  
|> about current market value and general availability of cut tsavorite stones.  I  
|> have dug around in a few standard gemology textbooks, but have found little  
|> information about tsavorite specifically - only garnets in general.  I love the  
|> look of one I have seen, but want to know if this would be a durable as well as  
|> enjoyable purchase.  Any guidance would be very much appreciated - I am not a  
|> geologist or gemologist, and apologize in advance if this is misplaced in this  
|> group.   THANKS!   -S. Naeve   (naeve@turtle.psych.umn.edu)

Tsavorite is the name gem dealers have given to garnets in the 
uvavorite-grossular solid solution:  Ca3(Al2,Cr2)Si3O12.

Garnets have a hardness of between 6.5-7.5 and are thus comparable to 
quartz (amethyst, rose quartz, agate, jasper, etc.).  Although not 
as resistant to scratching as other gems, it should be a perfectly 
acceptable ring stone.  Garnets have no good cleavage, so they are 
relatively "tough", and will not fracture as readily as many other 
stones that, though they might be harder, do have good cleavage 
diamond, for instance).

In short, enjoy your ring.  

-- 
Henry Shaw, Earth Sciences Dept., LLNL |    All opinions are my own.
Internet: shaw4@llnl.gov               |  
CIS: 76347,2523                        |
Fidonet: Henry Shaw at 1:161/55        |
Newsgroups: sci.geo.geology,comp.databases,comp.sys.ibm.pc.misc,comp.sys.mac.misc
From: stgprao@st.unocal.COM (Richard Ottolini)
Subject: Re: role of meteoroids in continental rifting
Organization: Unocal Corporation
Date: Tue, 10 Nov 1992 18:13:23 GMT

Try some physics.
By my calculations, a meteor hitting the earth at 7 km per sec is moving 20E9
faster than a tectonic plate.  Say if there is a 50% conservation of momentum
(the other 50% of energy converted into heat), then the meteor can move a body
a billion times heavier than itself, or approximately 2000 times larger in
radius.  Is that large enough?
This argument assumes force is evenly transmitted through a plate.  I doubt
whether that is possble given the low strength of rock.
Xref: sparky sci.geo.geology:2311 ca.earthquakes:1305
From: mtr@geovax.ed.ac.uk
Newsgroups: sci.geo.geology
Subject: help-fault plane solutions
Date: 10 Nov 92 20:13:02 GMT
Organization: University of Edinburgh, Geography Department.

exit
exit
write
From: frost@qut.edu.au
Newsgroups: sci.geo.geology
Subject: re clay minerals society address
Date: 12 Nov 92 12:27:11 EST
Organization: Queensland University of Technology

Re: address of clay minerals society

Can any one help me with the address, phone numbers fax nos 
and email of the clay minerals society?
Also I need to find similar info for the clay minerals 
repository at the university of missourri.

many thanks
Ray Frost
school of chemistry
QUT, Brisbane Australia
ph 07 864 2407
fax 07 864 1804
frost@qut.edu.au
From: jcp@logjam.trg.saic.com (John C. Peterson)
Newsgroups: sci.geo.meteorology
Subject: Re: Thick Air
Date: 10 Nov 92 18:55:44 GMT
Organization: Technology Research Group, SAIC

In article <1992Nov9.004543.21248@cid.aes.doe.CA> afsfpel@cid.aes.doe.CA (Yves Pelletier) writes:
>In article <1992Nov6.183015.24342@kakwa.ucs.ualberta.ca>,
>sherwood@space.ualberta.ca (Sherwood Botsford) writes:
>|> <MRS9@psuvm.psu.edu> writes
>|> > This is a question from a layman.  It seems that when I bicycle
>|> > in the winter time, the air feels thicker and more dense.
>|> > Is this a phantom feeling on my part--or is there some basis
>|> > for my feeling?  How is this related to barometric pressure?
>|> 
>|> It is thicker, (More dense.  See other posts) but I don't think that is  
>|> what you are perceiving.
>|> 
>|> There are several physiological events that you may be interpreting as  
>|> thick air:
>|>  [...edited...]
>
>My two cents...
>
>Aircraft aerodynamic performance improves very noticeably in cold air. 
>This suggests to me that, beyond the physiological effects that you mention,
>the aerodynamics of a cyclist in cold air may well undergo a large enough
>change to be noticeable as well.
>

   Yes indeed. More specifically, aircraft performance is dependent on
air density. Of course, density is a function of temp and pressure, and is
easily estimated (humidity is a factor too, as was pointed out), using the
ideal gas law PV=nRT. Just group (n/V), to get something proportional to
density.

   Although parasitic and lift induced drag is higher in denser air, the
lift generated by the wing is also higher. Second, the engine generates
more power in denser air. Pilots use a system they call "density altitude"
to quantify this. For given conditions of pressure/temp., the density is
equated to an altitude in a "standard atmosphere". At that altitude in the
std. atmosphere, the density is the same as the given situation. Any good
pilot computes density altitude, and checks the aircraft performance tables
as part of pre-flight. Just as an example, flying in Minnesota during the
winter months, density altitudes of MINUS 5000 feet are not at all uncommon.

Just my $0.02

-- 
John C. Peterson  KD6EKQ        | (+1) 619-546-6539 | Disclaimer: The opinions
Science Application Intl. Corp. |  jcp@trg.saic.com | expressed are mine alone,
10260 Campus Point Dr. MS-C6    |                   | and do not reflect those
San Diego, CA 92121             |                   | of SAIC.
From: martineau@macmartineau.ccr.hydro.qc.ca (Alain Martineau)
Newsgroups: sci.geo.meteorology
Subject: Re: Lightning strike frequency
Date: 5 Nov 92 12:40:08 GMT
Followup-To: sci.geo.meteorology
Distribution: usa
Organization: Hydro Quebec

In article <26OCT199212514630@csa3.lbl.gov>, jtchew@csa3.lbl.gov (Ad
absurdum per aspera) wrote:
> 
> >I've read that lightning strikes the ground an average of 40 million times 
> >in the US each year.  Does anyone know where I could get a more detailed 
> >breakdown of this statistic - by state, month, or for an individual year?
> 
> Richard E. Orville of the State University of New York at Albany
> should be able to tell you more.  This sort of thing seems to
> get published mostly in the Bulletin of the American Meteorological
> Society, but it's also worth your while to search the Journal of 
> Geophysical Research and Monthly Weather Review.
> 
> Just as a sanity check on the numbers, Orville reports that the
> East Coast lightning direction-finder network has seen rates as 
> high as 50 836 flashes in 24 hours over about 250 000 km^2 (Orville,
> "Lightning Phenomenology," in _The Earth's Electrical Environment_,
> Washington: National Academy Press, 1986).  He and others have 
> continued this research and expanded the network, so you'll probably 
> want to look up something more recent before citing specific figures.
> 
> You might also be able to get something useful out of the Electric
> Power Research Institute in Palo Alto, CA, as power utilities are
> quite interested in cloud-to-ground lightning for obvious reasons.
> 
> Good luck,
> --Joe
> "Just another personal opinion from the People's Republic of Berkeley"

I work for a power utility and we have a lightning detection system. I
don't
know the statistics but I just wanted to jump on this thread to ask the net

if anybody knew of a public program that could put lighning strikes on a
map,
running on MS-Windows or X windows. We want to be able to zoom, pan, edit
the
map, and change put different colors for different intensities and age of
lightning strikes. The input we get is latitude, longitude, intensity and
time of day.


Alain Martineau
Hydro Quebec
martineau@macmartineau.ccr.hydro.qc.ca
Newsgroups: sci.geo.meteorology,sci.geo.fluids
From: stvjas@meteor.wisc.edu (Stephen Jascourt)
Subject: Re: Small-scale fluid dynamics
Organization: University of Wisconsin, Meteorology and Space Science
Distribution: na
Date: Sun, 8 Nov 92 09:30:45 GMT

In article <1992Nov8.042136.25456@constellation.ecn.uoknor.edu> jlevit@alliant.backbone.uoknor.edu (Jason John Levit) writes:
>Hi all.  I'm looking for a good book (or books) that deal with the
>mechanics and dynamics of small-scale fluids and small-scale fluid
>flows.  Does anyone out there in net-land have a suggestion?  Thanks!
>
>Jason J. Levit
>
>
>
>-- 
>Jason John Levit                    Undergraduate Research,
>     N9MLA               Center for Analysis and Prediction of Storms
>University of Oklahoma        jlevit@alliant.backbone.uoknor.edu
>Meteorology Major                jlevit@geoblue.gcn.uoknor.edu

For an atmospheric scientist and a mechanical engineer, small scales with
respect to fluid motions can mean very different things. You might want to
be more specific about what you are looking for. A very comprehensive
fluid dynamics book is by Yih, I think it's just called Fluid Dynamics.
You may also want to look in some boundary layer meteorology books.

Stephen Jascourt   stvjas@meteor.wisc.edu
Newsgroups: sci.geo.meteorology