This page shows the latest additions to the Photo Gallery.
Mud Stone Showing Calcite Filled Fractures
Mud stone from along the San Andreas fault zone showing calcite filled fractures. Magnification 10X. Photo provided by Felix Desperrier, Sonoma State University, CA.
Cathodoluminescence and Rare Earth Minerals Exploration
These CL photos are from the special issue of Elements, dedicated to Rare Earth Elements. Volume 8, No. 5, October 2012.
Cathodoluminescence is a very important tool in the study of rare earth minerals. Dr. Anthony N. Mariano has pioneered its use for many years and especially when coupled with spectral measurements of the CL emission. Elsewhere on this web site photo gallery is an example of the spectra of CL emissions from a rare earth-doped synthetic calcium fluorite.
The first example is a CL image of xenotime and associated minerals in peralkaline granite.
Here is a labeled version below. Click on the photo to see a larger version.
This first example is from the paper by:
Chakhmouradian, A. R. and Zaitsev, A. N., Rare Earth Mineralization in Igneous Rocks: Sources and Processes. pp 347-353. Figure 5C.
Second example is from Mariano, A. N. and Mariano, A., Jr. , Rare Earth Mining and Exploration in North America, pp. 369-376. Figure 3C.
This is a Cathodoluminescence micrograph of Sm3+ - activated apatite (light pink) in a dolomite carbonatite matrix (field of view = 2.5 mm).
All three photographs were taken by Dr. Anthony N. Mariano.
Dolomites, Early Ordovician
Dolomites from the Arbuckle Group from the deep subsurface in Kansas
- Formation: Early Ordovician Arbuckle Group at depth > 4,000 feet.
- Scale: The long dimension of the image is 5 cm.
- Photo attribution: Brad King and Wayne Dickerson of the University of Kansas at the Kansas Geological Survey's Digital Cathodoluminescence Imaging Laboratory.
- Blue specks: These are small air bubbles that were trapped in a blue-dyed impregnating epoxy resin. The bubbles are now partly filled with aluminum oxide polishing paste — white in reflected light, but with blue CL luminescence.
(Photo set and description provided by Dr. Greg Ludvigson)
More On Cathodoluminescence and Rare Earth Minerals Exploration
Cathodoluminescence photomicrograph of carbonatite with manganoan calcite (orange-red), primary apatite (purple), hydrothermal apatite (yellow-green), and ferric-iron-bearing orthoclase (pink-red, bottom of image). Horizontal dimension of photo is 1.59 mm. 10 kV, 0.5 mA beam. (Courtesy of Adrian Van Rythoven, Rare Element Resources, Inc.)