[meteorite-list] Re: Package arrival re: Ebay Item #2175659927

From: Robert Verish <bolidechaser_at_meteoritecentral.com>
Date: Thu Apr 22 10:25:46 2004
Message-ID: <20030529172145.37981.qmail_at_web80510.mail.yahoo.com>

Hello Russ and List,

My best guess is that this is an accumulation of
naturally-occurring radioactive minerals or salts that
are called by geologists as a "roll-front" ore body,
the result of oxidixing groundwater percolating
through and past the rusting mass of the iron
meteorite. Typically, a fossilized log is the locus
for this accumulation. I've never heard of an iron
meteorite doing this, but (still with questions about
the proper pH for this to occur) I don't see why it
couldn't concentrate uranium oxides or salts.

Here is a web page/.pdf document that describes how
and where (there's a map) this occurs:

<http://www.epa.gov/epaoswer/other/mining/techdocs/uranium.pdf>

The following is from page 8 of the above document:

*******************
1.3.2.1 Stratabound
Stratabound is a term used to describe ore deposits
that are contained within a single layer of
sedimentary
rock. In the United States, stratabound uranium ores
are found in three major geographic areas: the Wyoming
Basin, south Texas, and the Colorado Plateau. Grades
of ore mined from these deposits range from 0.15 to
0.30 percent U O . 3 8
The ore is found in bodies ranging in size from two
tons to more than 10 million tons. Several of these
bodies may make up one uranium deposit (Tatsch, 1976).
The current theory on the genesis of stratabound
uranium orebodies proposes that they formed through
the
transport of uranium (and associated elements) by
oxidizing groundwater. Groundwater flowed through
uranium-containing rocks or sediments, leaching
uranium from the rock through the oxidation of U to U
. 4+ 6+
The U ion is soluble in groundwater as one of many
different uranyl complex ions. These uranium ions 6+
remained in solution until they encountered and moved
through a reducing environment. There the uranyl
ions were reduced and a uranous mineral, such as
uraninite, was precipitated.
The uranium deposits of the Wyoming Basin and south
Texas are known as "roll-front" deposits, a uranium
ore-body deposited at the interface of oxidizing and
reducing groundwaters. These deposits are found in
permeable sandstone beds that are generally
interbedded with silty claystones or shales. Tongues
of
oxidizing groundwater containing uranium (vanadium,
molybdenum, selenium, and sulfur may also be
present) in solution flowed through the sandstone beds
until reducing groundwater was reached. Precipitation
of the uraninite and accessory minerals occurred at
the interface of the oxidized fluids and the reducing
environment. A zonation of mineralization is typically
noted in these deposits; pyrite and calcite are found
at
the leading edge of the interface, pyrite and
uraninite in the ore-zone and siderite (FeCO ),
goethite (FeO OH) 3
and hematite (Fe O ) on the trailing edge. The
deposits display a crescent shape in plan view,
resulting from 2 3
the configuration of the interface between the tongues
of oxidizing groundwater and reducing groundwater.
As the interface of the oxidizing and reducing
environments migrated, the uranous minerals were
deposited
over a laterally extended area. The roll-front ore
bodies may only be a few meters in height, but may
extend
over a hundred meters in length. These deposits are
particularly well suited for in situ solution mining
techniques (see Beneficiation section) due to the high
permeability of the host sandstones and their
generally
shallow depths (Guilbert and Park, 1985; Texas
Department of Water Resources, 1984).
The Salt Wash uranium-vanadium deposits of the
Colorado Plateau (includes the Uravan Mineral Belt in
Colorado and Utah) were formed when uranium- and
vanadium-enriched groundwater flowed through zones
of high permeability containing solids (organic
matter), gases (hydrogen sulfide), or liquids capable
of reducing the uranyl ion. The uranium and vanadium
minerals were deposited in the areas where these
substances created reducing environments. The deposits
are generally tabular shaped and are found in
sandstones, limestones, siltstones and conglomerates
scattered throughout western Colorado, eastern Utah,
northeastern Arizona and northwestern New Mexico.
Grades of these deposits range from 0.16 percent to
0.25 percent U O . Significant vanadium is also
associated with these deposits, which grades about one
3 8
percent V O . Other metals associated with these
deposits are copper, silver, selenium, molybdenum, 2 5
chromium, lead, zinc, arsenic, cobalt and nickel.
Although the primary ore minerals associated with
these
deposits are the reduced minerals pitchblende and
coffinite, the brightly colored weathering products of
these
two minerals are also present, the oxidized uranium
and vanadium minerals tyuyamunite, carnotite, and
montroseite (Guilbert and Park, 1985).
The humate uranium deposits of the Colorado Plateau
(located in northwestern New Mexico and known as
the Grants Mineral Belt) have provided over 50 percent
of the total U.S. uranium production. These deposits
occur in sandstones, arkoses and siltstones of the
Morrison Formation. The uranium is found associated
with tabular layers of organic matter (humates)
averaging 0.5 to two meters thick and up to hundreds
of meters across. The uranium ore contains the
minerals uraninite and coffinite and an
organo-uraniferous mineraloid.
These compounds coat sand grains, and fill pore spaces
and fractures. Locally, some younger oxidizing "roll
fronts" have advanced through the uraniferous humate
deposits and redistributed the uranium into the
characteristic roll-front deposit (Guilbert and
Parker, 1985).
********************

This is my best guess at what is occurring here at the
Canyon Diablo area.

With best regards,
Bob V.

--- LabNEMS <staff_at_meteorlab.com> wrote:
> Hello Bob:
>
> The data is posted at
> http://www.meteorlab.com/File2003-34/file2003-34.htm
>
> Please review as time allows for you.
>
> I know that you have a huge amount of field
> experience.
> Do you have any experience with radioactive salts or
> the natural
> occurrence of radioactive minerals. This is all
> pertaining to
> the anomaly in Specimen B as described in the above
> address.
>
> Thanks very much.
>
> Russ Kempton.
>



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Received on Thu 29 May 2003 01:21:45 PM PDT