Brecciated Serpentinite – Location 17

  Sample : Photo location 17
  Rock name : Brecciated Serpentinite (Turner, 1982)

 

Megascopic description:

Highly fractured serpentinized peridotite / dunite with olivine relicts. Brown-creamy materials / mass are commonly found throughout. Fractures are filled with whithish minerals. Overall groundmass is dark blue-black (prograde to blueschist?)

Microscopic description:

The thin section of serpentinite shows the intensively fracturing to form the brecciated texture that their fractures are filled by carbonate and silica (chalcedony). The present of spinel and relic of olivine and pyroxene, anhedral to subhedral in shape, up to 3.5 mm in crystals size, it indicated that their protolith is a peridotite rocks, it has been metamorphosed (serpentinized) until to form the talk mineral (medium graded metamorphism). Olivine and pyroxene usually present to form sea and island texture and mesh structures, Some of talk minerals show the foliation structure in the some area of thin section and they folded to form microfold.

MACRO PHOTOGRAPH

MICRO PHOTOGRAPH

Sample: Photo location 17

PPL

XPL

The thin section of serpentinite shows the intensively fracturing to form the brecciated texture that their fractures are filled by carbonate and silica (chalcedony). The relic mineral of olivine and pyroxene still present to form the sea and island texture and mesh structure.

MICRO PHOTOGRAPH

Sample: Photo location 17

PPL

XPL

The thin section of serpentinite still shows the relic mineral of olivine and pyroxene to form the sea and island texture and mesh structure, anhedral in shape, medium to coarse in crystals size. The presence of talc mineral indicated the medium graded metamorphism.

MICRO PHOTOGRAPH

Sample: Photo location 17

PPL

XPL

The thin section of serpentinite shows the foliation structure serpentine and talk minerals and they folded to form the microfold.

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