electron microscopy

This page is very much under construction, as so far I only have BSE images from a limited number of my FKM series thin sections, and X-maps of only one of them (FKM-1).  I look forward to adding more images from the microprobe, but unfortunately, unlike doing quick spot analyses, X-ray maps take a long time and so can be quite costly! Also, I haven’t settled on how I want to format this page, and what kind of additional explanatory information I want to include… so, check back periodically for updates.

 












 




BSE image of the mineralogy in thin section FKM-2, highlighting unusual Sb-rich zones in titanite

 




Norway apatite with astrophyllite aegirine and microcline

 




BSE image of the mineralogy in thin section FKM-171, highlighting zoned tweddillite and piemontite from Prabornaz mine St Marcel Italy

Figure FKM-171-1. Mineralogy and zoning in the tweddillite/piemontite-bearing assemblage in sample FKM-171.
The yellow numbers highlight examples of the following minerals visible in this figure:
(1a) piemontite: this is the location of the “low z core” analysis shown in the composition table.
(1b) tweddillite: this is the location of the “mod-low z core” analysis shown in the composition table.
(1c) tweddillite: this is the location of the “mod z core inner rim” analysis shown in the composition table.
(1d) tweddillite: this is the location of the “high z mid-outer rim” analysis shown in the composition table. This analysis is also the focus of the Normalizing epidote-group minerals in MS Excel YouTube tutorial video.
(1e) piemontite: this is the location of the “v. low z overgrowth” analysis shown in the composition table.
(2) braunite: this location corresponds to the braunite analysis shown in the composition table.
(3) cryptomelane: this location corresponds to the cryptomelane analysis shown in the composition table.
(4) Mn-bearing aluminoceladonite: this is the location for an EDS identification spot; the analyses for this mineral were done elsewhere in the thin section.
(5) K-feldspar: this is the location for an EDS identification spot; the analyses for this mineral were done elsewhere in the thin section.
(6) aegirine: this location corresponds to the aegirine analysis shown in the composition table.
(7) zircon: this is the location for an EDS identification spot; however, zircon was not quantitatively analyzed in this sample.
(8) Mn-bearing phlogopite: this is the location for an EDS identification spot; the analyses for this mineral were done elsewhere in the thin section.

 

BSE image of the mineralogy in thin section FKM-171, highlighting zoned tweddillite and piemontite from Prabornaz mine St Marcel Italy

Figure FKM-171-2. Mineralogy and zoning in the tweddillite/piemontite-bearing assemblage in sample FKM-171.
The yellow numbers highlight examples of the following minerals visible in this figure:
(1a1) piemontite: although from a different grain, this material is similar to the “low z core” analysis shown in the composition table (similar to point 1a in Figure FKM-171-1).
(1a2) piemontite: this material is slightly higher z than the previous “low z core” material shown in point 1a1 but only slightly differs in composition.
(1b) tweddillite: although from a different grain, this material is similar to the “mod-low z core” analysis shown in the composition table (similar to point 1b in Figure FKM-171-1).
(1c) tweddillite: although from a different grain, this material is similar to the “mod z core inner rim” analysis shown in the composition table (similar to point 1c in Figure FKM-171-1).
(1d) tweddillite: although from a different grain, this material is similar to the “high z mid-outer rim” analysis shown in the composition table (similar to point 1d in Figure FKM-171-1, although this particular spot is somewhat less REE-enriched).
(1e) piemontite: although from a different grain, this material is similar to the “v. low z overgrowth” analysis shown in the composition table (similar to point 1e in Figure FKM-171-1).
(2) braunite: this is the location for an EDS identification spot; the analyses for this mineral were done elsewhere in the thin section (see Figure FKM-171-1).
(3) albite: this is the location for an EDS identification spot; the analyses for this mineral were done elsewhere in the thin section.
(4) Mn-bearing aluminoceladonite: this is the location for an EDS identification spot; the analyses for this mineral were done elsewhere in the thin section.
(5) cerianite-(Ce): this location corresponds to the cerianite-(Ce) analysis shown in the composition table.
(6) Mn-bearing phlogopite: this is the location for an EDS identification spot; the analyses for this mineral were done elsewhere in the thin section.

 




BSE image of the mineralogy in thin section FKM-202, highlighting an unusual hibonite + grossite assemblage

Figure FKM-202-1. Texture of the hibonite+grossite assemblage in sample FKM-202.
The orange numbers highlight examples of the following minerals visible in this figure:
(1) diaoyudaoite-like Al-rich oxide: the dark gray enlongated blades and the similarly-shaded irregular area on the right.
(2) hibonite: the slightly paler gray areas both intimately associated with the “diaoyudaoite” and as discrete crystals in the grossite matrix.
(3) grossite: the main homogeneous medium gray matrix hosting the other phases. One example of grossite within a “diaoyudaoite”-hibonite mass is also highlighted.
(4) “Al-V-Mg-oxide”: the light gray generally equant crystals scattered within the grossite matrix.
(5) fluorite: the light gray area infilling a crack between the grossite and a “diaoyudaoite”-hibonite crystal. The white circle adjacent to the number is beam damage in the fluorite.
(6) vanadium metal: the circular and irregular bright white areas are intergrowths of two vanadium alloys. A more detailed look at the numbered grain is shown in Figure FKM-202-3, below.

 

BSE image of the mineralogy in thin section FKM-202, highlighting an unusual hibonite + grossite assemblage

Figure FKM-202-2. Texture of the hibonite+grossite assemblage in sample FKM-202.
The orange numbers highlight examples of the following minerals visible in this figure.
(1) diaoyudaoite-like Al-rich oxide: the dark gray enlongated blades and the similarly-shaded crudely hexagonal crystals.
(2) hibonite: the slightly paler gray areas both included in the “diaoyudaoite” and as larger irregular masses.
(3) grossite: the main homogeneous medium gray matrix hosting the other phases.
(4) gehlenite: the medium-light gray intergrown with fluorite and perovskite in a cavity between larger grossite crystals.
(5) “Al-V-Mg-oxide”: the light gray generally equant crystals scattered within the grossite matrix.
(6) fluorite: the light gray area intergrown with gehlenite and perovskite in a cavity between larger grossite crystals. The fuzzy white circle adjacent to the number is beam damage in the fluorite.
(7) perovskite: the very light gray area intergrown with gehlenite and fluorite in a cavity between larger grossite crystals.
(8) vanadium metal: the small bright white grain adjacent to the number (also similar material in the view).

 

BSE image of the mineralogy in thin section FKM-202, highlighting a vanadium droplet in an unusual hibonite + grossite assemblage

Figure FKM-202-3. Texture of the vanadium “droplets” in the hibonite+grossite assemblage in sample FKM-202.
This grain is the one identified by 6 in Figure FKM-202-1. The orange numbers highlight examples of the following minerals visible in this figure.
(1) crudely equant “low-Fe” vanadium core containing ~1.5 wt% Fe.
(2) dendritic “high-Fe” vanadium containing ~6.3 wt% Fe, surrounding the core.

 









 

 


BSE image of the mineralogy in thin section FKM-212, highlighting cordierite orthopyroxene symplectite, from Mount Riiser-Larsen Antarctica

Figure FKM-212-1. Mineralogy and zoning in the osumilite-bearing assemblage in sample FKM-212.
The yellow numbers highlight examples of the following minerals visible in this figure:
(A) main osumilite-(Mg): the dark thin veinlets and the larger dark area just below the marked spot within the host osumilite are filled with a chlorite-like mixed layer sheet silicate akin to a “Mg-dominant tosudite”.
(5) microperthitic alkali feldspar intermixed with osumilite. This material appears to be very finely-intergrown and only yielded mixed analyses.
(6) “alkali-free osumilite” or potentially a [1 cordierite]+[6 quartz] proportion symplectite: this is the location of the “alkali-free osumilite” analysis shown in the composition table. Note that the analyzed area and similar BSE-shaded areas of the same material appear ostensibly phase-homogeneous, but may alternatively be fine-grained symplectites of essentially non-BSE-differentiable cordierite and quartz.
(7) corderite: this is the location of the cordierite analysis shown in the composition table.
(8) Al-rich orthopyroxene: this is the location of the “most Al-rich enstatite” analysis shown in the composition table.