There’s also a fully searchable index covering the complete thin section set, listing for each sample its locality, the anticipated major minerals, a brief generalized geologic environment description, and where appropriate, the nature of any unusual element enrichments.
Note: Depending on the speed of your internet connection, it could take a minute or two for the images to load. If after the page looks like it’s finished loading but some of the thin section images appear to be missing, reloading the page will typically fix the problem.
left image: unpolarized light; right image: under crossed polarizers; use slider in center to view more of either image
sample: K-65 (covered and yellowing thin section from Univ. Arizona petrology collection [unfortunately, the original billet & hand sample appear to be lost], Krantz collection, sample K-65)
locality: Kaltes Tal, Bad Harzburg, Harz Mtn. region, Niedersachsen, Germany.
rock type: mica peridotite (as small lenses in norite). Also known locally as “glimmerite”.
major mineralogy: Based on petrography, predominately forsterite and red Ti-rich(?) biotite, with gray spinel and minor oxide (believed to be ilmenite).
accompanying videos: Short videos featuring the mineral associations and optical properties of the biotite in this thin section offer a more detailed look at this sample.
| mineral | PPL (lower polar rotation) |
PPL (stage rotation) |
XP (stage rotation) |
optic figure (stage rotation) |
|---|---|---|---|---|
| biotite PPL: pale tan-orange/red-orange/deep brown-red pleochroism, moderate relief; XP: high birefringence largely masked by body color of mineral, mottled extinction; with spinel, forsterite and an opaque oxide (covered thin section) |
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previous page (samples FKM-451 to FKM-475)
This “add photo(s)” image is just a placeholder in advance of adding new samples, so check back periodically to see my progress.
more testing: evaluating a different plugin to do the before-after effect: