>From: <name withheld to protect the sender>
>Subject: Re: Geochemistry
>
>Dave - one common method is to use electron microprobe analysis to provide
>trace element finger prints of various minerals in each deposit, then match
>samples to origination deposit using the fingerprint. Quartz may or may
>not be the best mineral to use.... depends on the deposits. This is a very
>low cost method of tracing - a grad student or summer student type project.
>It does depend on your being lucky and finding distinct finger prints
>between the two original deposits... and if 3 or 4 sources are possible, it
>obviously gets more complicated.
>
>
>>Is it possible to determine whether a quartz (or other persistent) crystal
>>came from Formation A, 1000 miles away, or Formation B nearby? If one
>>ignores the sedimentology issues such as roundness, size, sorting, and
>>association, what seems to be left is instrumental methods. Are there
>>isotopic fingerprints for quartz in various formations (e.g. Wasatch, Uintah
>>Mountain Quartzite, Toroweap, etc.) that may be contributors to ancestral
>>Grand Canyon alluvium c. 5000 ybp?
>>
>>The issue is: are these unconsolidated sediments lacustrine or river? The
>>sediments may or may not display any geomorphological or sedimentological
>>evidence of their origin.
>>
>>The research possibilities are: Develop a set of historic high water marks
>>in Grand Canyon. This would show the extent of ponding from lava dams and
>>would show the highest of ancestral Colorado River Flows.
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