Here's an example of a set of quantitative x-ray maps we did earlier this year of a hydrothermal quartz sample, showing trace level variation (though no detectable Ti) and the pixel level detection limits:
(https://smf.probesoftware.com/oldpics/i40.tinypic.com/mn2q7d.jpg)
Another example at the same conditions as above. First the quant weight percents:
(https://smf.probesoftware.com/oldpics/i44.tinypic.com/23m0j2p.jpg)
And here the quant detection limits:
(https://smf.probesoftware.com/oldpics/i44.tinypic.com/9ux7aa.jpg)
It is interesting to compare the above weight percent image in the first post, in which the color scale was adjusted manually, seen here again:
(https://smf.probesoftware.com/oldpics/i40.tinypic.com/mn2q7d.jpg)
With this image below, which are the same data but just displayed using the automatic log scaling with no adjustment. The only downside I can see to the log scaling is that you have to calculate the actual weight percents from the log values in one's head!
(https://smf.probesoftware.com/oldpics/i39.tinypic.com/do9w7t.jpg)
For more information on point analyses of trace elements in quartz, see this post:
http://smf.probesoftware.com/index.php?topic=29.msg387#msg387