Gold mineralisation in Darlot gold mine
the lighter slightly dipping veins are mineralised
core of vein
alteration zones include:
close to vein, proximal: hematite-pyrite-Albite-Au, talc
intermediate: chlorite
distal: epidote,garnet
in this one is no visible gold, i.e. the Au is inclosed in the pyrite
click on it for magnification
Banded Iron Formation (Bif)
Bif in Hamersley Range, Tom Price, located on the Pilbara Craton. blueish layeres are richer in
hematite/martite, while lighter layers are richer in chert. sometimes small knobs can be spotted
(stromatolites) or wave ripples. (the blob in the lower part of the photo is probaly just some disturbance)
Stromatolite in Bif
You can see circular rings in the middle of the fossile.
blue-grey mineral is hematite or martite (hematite after magnetite), yellow mineral is quartz
Pillow basalt
Spinifex texture in Komatiite
On top of picture are banded meta-sediments, in the lower part needle-like spinifex texture
Magmatic Flows in the Archean with high MG content (>18wt%). They must have been very hot (1500C)
and the viscosity was similar to water. On the surface of the flow Olivine and Clinopyroxene
crystallized and intergrew to Spinifex texture, which was altered is to tremolite and chlorite.
click on it for magnification
