Keyboard Shortcuts
Likes
Search
Re: XRF - comparing Dud's with my Si-PIN
¿ªÔÆÌåÓý
Hey Dud, it is due to the ionic radius and crystal structure that this occurs. Monazite is monoclinic and incorporates the LHEE, xenotime is tetragonal and incorporates the HREE; both are phosphates. Zircon is a silicate and does not incorporate HREE
as much. There are at least two generations of zircon at Petaca, and the first is poorer in REE. Pegmatites crystallize very quickly, with late stage fluids corroding the first crystallized minerals. Real common in these systems.?
Steve
From: [email protected] <[email protected]> on behalf of Dude <dfemer@...>
Sent: Saturday, January 18, 2020 10:09 PM To: [email protected] <[email protected]> Subject: Re: [XRF] XRF - comparing Dud's with my Si-PIN ?
Steve, Zircon HREE¡¯s are interesting. Why do the heavies kick up in the xenotime. ?Are there other zircons in the area that still hold the HREE without any exsolution and at what concentration? ?How many episodes of mineralization have these materials been through or is it all one unaltered emplacement? Dud
From: [email protected] [mailto:[email protected]]
On Behalf Of WILLIAM S Dubyk ? Here are a couple of examples of how messy these minerals can be. The zircon from the Coats is a variety called cyrtolite. If you look at the photos at the bottom of the sheet you can see how xenotime is shot through the zircon; these minerals are chemically different but structurally the same. As the zircon crystallized, the xenotime exsolved. Next example is a very strange powdery looking thorite. The normally dark glassy thorite has been replaced by xenotime at a late stage, hence an odd altered white thorite that is about 15% REE. Note how high Dy is in these analyses. Beam sizes varied from 3 to 20 microns. Late stage xenotime alteration of minerals is very common in the district, and these types of alteration and exsolution examples are common in many rare mineral districts. ? Steve ?
From: [email protected] <[email protected]> on behalf of Dude <dfemer@...> ? Geo, I would venture to say precise quantitative analysis is beyond the reach of the professionals as well. For a simple matrix it works fine but for a complicated matrix like rocks and junk it doesn¡¯t and varies wildly.? A ?SEM Micro probe properly calibrated is great, but a wide beam on a target leaves a lot to be desired as you¡¯ll get a mix of interferences. Then there¡¯s the software, some good, some bad and none doing everything well and all are complicated to set up. ?Believe nothing, verify everything and use it as an anomaly finder, then send it out for a real ICP/MS analysis. Soils is FP the other is a element cal. ?Soils has 3 beams with filters at 50, 40 and 10 Kv Mining uses 50 and 10 Kv beams. The new software is called Geochem and you don¡¯t need to switch between the modes. It¡¯s expensive though.? I mostly use soils mode as I¡¯m looking for ppm anomalies. ? A direct inter-comparison is not going to work very well unlike gamma spec where the target is the source. In the XRF world we provide the source which is going to be very different between everyone¡¯s setup, beam size, ?intensity and to a lesser extent detector characteristics. ? I¡¯m still looking for a CdTe rig . I have a 60kV microfocus system I¡¯d like to get running with it. I can use the LE ?HPGe detectors but a CdTe will have better resolution and no LN2 issues Dud ?
From: [email protected] [mailto:[email protected]]
On Behalf Of GEOelectronics@... ? "Based on the reported percentages the assay you are looking at was done using the Soils mode which is used when looking at PPM level concentrations. The Soils mode will well over report percent level concentrations? For samples with percent grade material they would be shot with the Mining Plus mode." ? I agree that precise quantitative analysis is beyond the reach of our amateur efforts at the moment. My first question is what is the difference between SOILS mode and Mining Mode? Or perhaps I should ask WHERE is the difference? Is it a scanning technique or is it all in software? ? The price of FP software has declined by about 50% already, but that took some years to happen. Meantime I think we can all agree that direct comparison to a known assayed mineral is a legitimate goal, as long as the sensors are the same type? ? That's how I do uranium ore %, Cs-137 in soil,? and radium sample estimate , by direct comparison with calibrated samples. ? On another thread, has anyone else anywhere else reported getting one of these DP-5 processors up and running? It seems that maybe 20 or so of them have actually been sold, maybe a few more. ? Geo ?
----- Original Message ----- ? So qualitatively the results from both XRFs seem to be similar.? I will be looking at other specimens that you analyzed as well to see if they jive with my setup. ?
So what about the ? Charles ? On Sat, Jan 18, 2020 at 10:27 AM Dude <dfemer@...> wrote:
? ? ?
|