RUSTENBURG LAYERED SUTE
Photomicrographs of selected thin sections
All photographs have a horizontal field of 6mm, except where
individually given in the caption
LZ = Lower Zone (ultramafic cumulates), LCZ = Lower Critical
Zone (chromite seams in ultramafic cumulates), UCZ = Upper Critical
Zone (chromite seams in norites and anorthosites), MZ = Main Zone (mainly
gabbronorites), UZ = Uper Zone (magnetite gabbonorites) |
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LZ - Dunite, olivine cumulate, partly
serpentinised - PPL |
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LZ - Dunite, olivine cumulate, partly
serpentinised - XP |
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LZ - Peridotite, olivine + opx adcumulate - PPL |
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LZ - Peridotite, olivine + opx adcumulate - XP |
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LZ - Pyroxenite, opx adcumulate - PPL |
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LZ - Pyroxenite, opx adcumulate - XP |
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LZ - Pyroxenite, opx orthocumulate with intercumulus cpx
- XP |
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LZ - Pyroxenite, opx orthocumulate with intercumulus plag
- PPL |
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LCZ - Chromite pyroxenite, chrom + opx cumulate
- PPL |
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LCZ - Chromite pyroxenite, chrom + opx orthocumulate with
intercumulus
plag - PPL |
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LCZ - Chromite pyroxenite, chrom + opx orthocumulate
with intercumulus
plag - XP |
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LCZ - Pyroxenite, opx + minor chrom orthocumulate with
intercumulus plag
- PPL |
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LCZ - Pyroxenite, opx + minor chrom orthocumulate
with intercumulus plag
- XP |
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LCZ - Pyroxenite, opx adcumulate with trace chromite
- PPL |
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LCZ - Pyroxenite, opx adcumulate - PPL |
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LCZ - Pyroxenite, opx adcumulate - XP |
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UCZ - Chromite pyroxenite, chrom + opx orthocumulate with
intercumulus plag - PPL |
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UCZ - Chromite pyroxenite, chrom + opx adcumulate - PPL |
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UCZ - Chromite pyroxenite, chrom + opx adcumulate
- XP |
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UCZ - Chromite pyroxenite, basal chromite adcumulate grading
up into chrom
+ opx orthocumulate - 3mm - PPL |
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UCZ - Chromite cumulate grading up into chrom +
opx cumulate - 3mm - PPL |
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UCZ - Chomite orthocumulate with intercumulus opx and plag
- 3mm - PPL |
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UCZ - Pyroxenite, opx orthocumulate with intercumulus
plag and trace chromite
- PPL |
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UCZ - Pyroxenite, opx orthocumulate with intercumulus
plag and trace chromite
- PPL |
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UCZ
- Norite, opx + plag cumulate - PPL |
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UCZ
- Norite, opx + plag cumulate - XP |
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UCZ
- Leuconorite, plag + opx cuulate - PPL |
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UCZ
- Leuconorite, plag + opx cuulate - XP |
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UCZ - Spotted Anorthosite, plag orthocumulate with intercumulus
opx - PPL |
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UCZ - Spotted Anorthosite, plag orthocumulate with intercumulus
opx - XP |
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UCZ - UG1 Chromite Anorthosite, alternating chrom and
plag cumulates -
PPL |
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UCZ - UG1 Chromite Anorthosite, alternating chrom
and plag cumulates -
PPL |
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UCZ - UG2 Chromite Seam, bright grey chromite embedded
in dark grey intercumulus
plag - Reflected Light - 2mm - PPL |
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Merensky Reef - Bottom chromite seam overlain by sulphide
pyroxenite -
3mm - PPL |
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Merensky Reef - bottom chromite seam overlain by sulphide
+ phlogopite
pyroxenite - 3mm - PPL |
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Merensky Reef - bottom chromite seam overlain by sulphide
+ phlogopite
pyroxenite - 3mm - XP |
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Merensky Reef - bottom chromite seam, chromite orthocumulate
with intercumulus
plag + opx - 3mm - PPL |
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Merensky Reef - bottom chromite seam, chromite partly recrystallised
into
aggregates - 3mm - PPL |
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Merensky Reef - bottom chromite seam with sulphide
inclusions - Reflected
Light - 2mm - PPL |
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Merensky Reef - interstitial magmatic sulphide surrounded
by euhedral cumulate
opx - PPL |
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Merensky Reef - interstitial magmatic sulphide surrounded
by euhedral cumulate
opx - XP (thick section) |
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MZ
- Gabbronorite, plag + opx + cpx cumulate - PPL |
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MZ
- Gabbronorite, plag + opx + cpx cumulate - XP |
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MZ
- Gabbronorite, plag + opx + cpx cumulate - PPL |
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MZ
- Gabbronorite, plag + opx + cpx cumulate - XP |
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MZ - Gabbronorite, plag + inverted pigeonite+ cpx
cumulate, plag has dusty
inclusions (Belfast "black granite") - PPL |
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MZ - Gabbronorite, inverted pigeonite with typical
herringbone exsolution
texture - 3mm - XP |
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MZ - Gabbronorite, interstitial granophyric intergrowth
of quartz and alkali
feldspar - 3mm - XP |
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UZ - Magnetite gabbronorite,
plag + opx + cpx + minor mt cumulate - PPL |
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UZ - Magnetite gabbronorite, plag + opx + cpx +
mt cumulate - PPL |
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UZ - Magnetite gabbronorite, plag + opx + cpx +
minor mt cumulate, elongate plag shows preferred orientation in plane
of layering - PPL |
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UZ - Magnetite gabbronorite, plag + opx + cpx + minor mt
cumulate, elongate plag shows preferred orientation in plane of layering
- XP |
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UZ - Magnetite anorthosite, plag cumulate with abundant
intercumulus mt
- PPL |
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UZ - Magnetite anorthosite, plag + mt cumulate with intercumulus
cpx +
opx, distinct lamination of prismatic plag - 20mm - PPL |