Including Original "Paul H. Letters" Copyright © 1996-2017 Paul V. Heinrich - All rights reserved.

Thursday, 27 May 2004

what is the world standards for petrographical preparations (polarization microscopy)

what is the world standards for petrographical preparations (polarization microscopy)

Paul H bristolia at
Thu May 27 20:44:16 EDT 2004

E. L. Jones jonee at wrote:

>I am also interested in the use of "quartz"

>as index markers. This isn't in any of my

>reference books. Are they attached to the

>specimen and ground at the same time as the

>thin section?

No. The person grinding the thin section uses
the bifringence of whatever minerals are
present to judge the thickness of the thin
section. Quartz is used as an index marker
simply because, it is so common as to be
present in most sedimentary, igneous, and
metamorphic rocks. When it isn't present,
a person uses whatever mineral happens to
be in the thin section as an index.

Some web pages are:

Making Petrographic Thin Sections

Making Petrographic Thin Sections

Rock-Forming Minerals in Thin Section

Atlas of Rocks and Minerals Under the Microscope

Igneous rocks in thin section

Minerals in thin sections

>Another question I have. Is there a house

>that specializes in preparation? Kinda of

>like the $2 a carat faceting deals one can

>get in Thailand?

There are many places that specialize in making
thin sections. Typically, a person gets what
they pay for. A quick search using Google will
find a number petrographic labs that make thin
sections. If you are going to pay 5 to 50 dollars
a gram for a meteorite, paying 15.00 dollars for
a high quality thin section is the least of
your costs.

The people that use to make the thin sections for
my research (and search for more shocked quartz)
from samples in the Brushy Creek Carter is:

National Petrographic Service, Inc.
5933 Bellaire Blvd., Suite 108
Houston, TX 77081

Their price list is at:

Their price are average for what thin sections cost.


>Roman Davidov wrote:

>>Dear list members. Hello.

>>My question is: What is the world standards for

>>petrographical preparations. If I'm not mistaken

>>in English it sounds like "THIN SECTIONS".

Yes, as noted above, the term is "thin section".

>To be more concrete I mean: form and sizes of

>object glass (width,height,thickness);

The glass slide of the standard thin section is
27 x 46mm (1" x 1 7/8"). Larger slides are produced,
but size might vary according to the lab that
prepares them. For example, National Petrographic
has 38 x 75mm (1.5" x 3") and 50 x 75mm (2" x 3")
size glass slides for larger size thin sections.

>type of optical glue (we are using composition

>named "Canadian Balsam");

Hillquist A-B is used to glue slabs to slides.
However, Canadium Balsam is the standard for
attaching the coverslip. If you want to do any
microprobe, etxching, or similar work, i.e. for
identifying shocked quartz, the thin section needs
to be finished by polishing and the coverslip
left off.

>linear sizes of object (I'm sure that thickness

>is one to all of the world - 0.003 millimeters);

>form and sizes of cover glass.

The only requirement for the size of the object
is that it is a few mm smaller than the size of
the glass slide being used. The coverslip is
larger than the specimen and smaller than
the slide.

The coverslips come in sizes, thicknesses, and
optical character that are standardized for use
in making thin sections. A person needs to talk
with the people supplying the coverslips and
get the technical specifications of what they
are selling to see if they are suitable for
thin sections.

...text deleted...


Baton Rouge, LA

Monday, 24 May 2004

Meteor explodes above Montrose (Colorado)

Meteor explodes above Montrose (Colorado)

Paul H bristolia at
Mon May 24 09:07:38 EDT 2004

Meteor explodes above Montrose
Mike Robuck, Montrose Daily Press, CO - May 22, 2004

MONTROSE - When a meteor exploded Friday (21May) at 2:44 a.m.
over Montrose it was serendipity defined for Montrose
High School teacher Mike Nadiak and the All-Sky club
he oversees.

Re: NASA was on eBay

Re: NASA was on eBay

Mon May 24 09:03:52 EDT 2004

On Sun May 23 11:02:41 EDT 2004, Nicholas Gessler

>I heard that NASA was buying ferrite core memory.

>And I believe it to be true.

Below are some articles on that subject.

1. Shuttle program seeks computer parts on eBay
News Story by Brian Sullivan
MAY 13, 2002 (COMPUTERWORLD),10801,71140,00.html

2. For Old Parts, NASA Boldly Goes . . . on eBay
New York Times, May 12, 2002, By WILLIAM J. BROAD
NASA needs parts no one makes anymore.

3. Nasa trawls the web for spares
Nasa admits it trawls web auctions for obsolete
for use in shuttle launches.


Baton Rouge, lA

Friday, 21 May 2004

Moon Rock Stolen in Malta

Moon Rock Stolen in Malta

Fri May 21 15:35:36 EDT 2004

Reactions to the theft of the moon rock in Malta
By MaltaMedia News, May 21, 2004, 18:44 CET

"News: $5M Moon Rock Stolen From Malta Museum"
Fri, 21 May 2004, LinuXProX

Moon Rock Stolen from Malta Museum
The Scotsman

"A tiny moon rock believed to be worth about £3
million has been stolen from a Maltese museum,
30 years after US President Richard Nixon donated
it to the Mediterranean island nation."


Baton Rouge, LA

"Columbia Basin tektites"?

"Columbia Basin tektites"?

Fri May 21 14:49:47 EDT 2004

Marc D. Fries asked:

>I see that someone is offering "newly discovered

>Columbia basin tektites" on ebay right now.

>Has anyone heard of these? I haven't heard

>anything about them until now and my

>skepticism meter is pegged

Given that these alleged "tektites" look like
water-rolled pieces of basaltic scoria and the
Columbia Plateau is composed of basaltic volcanic
rocks, I would be extremely skeptical of these
so-called "tektites". I would certainly request a
written money back guarantee of their authenticity
and documented authentication in writing of their
identity before even considering their purchase.


Baton Rouge, LA

Wednesday, 12 May 2004

More About Permian-Triassic Boundary "GREAT DYING" Crater???

More About Permian-Triassic Boundary "GREAT DYING" Crater???

Wed May 12 17:38:45 EDT 2004

In the thread "[meteorite-list] FW: NASA ANNOUNCES
makinsomenoise wrote:

>Thanks for the sites, I've read her papers but it

>never seemed like she had enough conclusive evidence

>to prove her theory, never solid enough. I wonder

>if she found it."

Using Google, I found the text concerning the proposed

crater, although the original document is no longer
there, at:

In part, the text read:

"Bedout: A Possible End-Permian Impact Crater Offshore

Northwestern Australia

L. Becker1*, R. J. Poreda2, A. R. Basu2, K. Pope3, M.
Harrison4, C. Nicholson1, R. Iasky5

1Institute for Crustal Studies, Department of
Sciences, University of California, Santa Barbara
USA, 2Department of Earth and Environmental Sciences,
University of Rochester, Rochester, NY, USA, 4Geo Eco
Arc Research, Aquasco, MD 20608, 5Australian National
University, Canberra, Australia, 6 Geological Survey
Western Australia, Perth, Australia

* To whom correspondence should be addressed


The Bedout High located on the northwestern
margin of Australia has emerged as a prime candidate
for an
end Permian impact structure. Seismic imaging, gravity
and the identification of melt rocks and impact
from drill cores located on top of Bedout are
with the presence of a buried impact crater. The
breccias contain nearly pure silica glass (SiO2),
and shock-melted plagioclases and spherulitic glass.
distribution of glass and shocked minerals over
of meters of drill core implies that a melt sheet is
present. Available gravity and seismic data suggest
the Bedout High represents the central uplift of a
similar in size to Chicxulub. A single plagioclase
from the Lagrange-1 exploration well has an Ar/Ar age
250.7 1 4.3 million years. The location and age of
Bedout crater can account for reported occurrences of
impact debris in Permian-Triassic boundary sediments


" Geology of the Bedout Structure

The Bedout High is part of the Roebuck basin that
forms the
northwestern continental margin of Australia (Fig.
2.). Existing
studies of the structure include two regional seismic
conducted by the Australian Geological Survey (AGSO)
and the
Japan National Oil Company (JNOC) and two exploratory
drilled 9 km apart on the top and flank of the Bedout
Bedout -1 and Lagrange-1, that extend to depths of
3052 m
(9986 ft.) and 3273 m (10,738 ft.), respectively (Fig.
3, S-2).
Both wells drilled through ~3 km of marine and fluvial
consisting of carbonates with occasional interbeded
siltstones and
mudstones (Tertiary to Cretaceous) and sandstones
with claystones, siltstones and coal (Cretaceous to
Triassic) before
reaching a breccia. (Late Permian; Fig. S-2, 15). Two
of the 14
AGSO regional seismic lines cross over the Bedout
High (Fig. 2).
In addition, four wells penetrate Permian strata (two
are shown in
Fig. 2.) offshore that help to identify seismic
reflectors that define
the Bedout structure and stratigraphy. In both the
Lagrange-1 and
Bedout -1 cores and cuttings fluviatile and marine
(Middle to Late Triassic) sediments are deposited
directly on top
of the breccia (Late Permian; Fig. 4, S-2, S-3)."

Also, there is:




A map showing the location of the Bedout High can be
found at:


Baton Rouge, LA

Antarctica Meteorites Web Page

Antarctica Meteorites Web Page

Wed May 12 15:58:04 EDT 2004

There is a very nice web page about Antarctica
Meteorites on
Dr. Luann Becker's web site. It is "Antarctica
Meteorites -
Science Notes - 12/03/03" at:

There is a nice figure at:


Baton Rouge, LA

Monday, 10 May 2004

Re: Check this out, Martian NOT !!

Re: Check this out, Martian NOT !!

Mon May 10 21:32:15 EDT 2004

On May 10, 2004, Steven Drummond wrote:

>Hi, Check this out , Something this size weighing

>3 kilos, Must be from a neutron star . Certainly not

>a meteorite. I thought the list members would like to

>see this one .

>Good for a laugh anyway.

This is a nice example of botryoidal goethite or
hematite. :-)

Go look at 1. " Botryoidal hematite has the appearance
of grape clusters" in

2. "Hematite An excellent thumbnail floater
of botryoidal (almost oolitic in size)..." in
"Mineral Collection Images - My Mineral Collection,
Miscellaneous Systematic Oxides Page" at:

3. "Hematite, - botryoidal, Compton Martin" In
"minerals of England and Wales" at:


4. "Botryoidal Hematite" in "Various Crystals 1" at:


Baton Rouge, LA