Buck Creek dunite - serpentinized and chloritized

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Polished slab of partially serpentinized and chloritized dunite. Buck Creek ultramafic body, Blue Ridge Mountains, Clay County, western North Carolina. Optical scan at 1524 pixels/cm (600 dpi). Original width 3400 pixels, reduced by Blogger to 1600 pixels at maximum magnification. Slab dimensions 8 cm x 14.5 cm. Below is a higher-resolution image (6096 pixels/cm.) of the 3.5-cm-by-3.5-cm area outlined in the larger image.

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Serpentine meshwork in Josephine peridotite

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Josephine peridotite, partially serpentinized. A component of the Josephine ophiolite sequence. Serpentine meshwork occupies space between grains and along fractures within individual grains. Because serpentine can't accommodate the iron given up by the olivine, this is taken up as hematite, which gives the meshwork its brown color. Josephine County, southwest Oregon. XPL Imaged area 1.3 mm x 2 mm.

Josephine peridotite - hand samples

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Polished section (left) and rough hand sample (right) of Josephine peridotite, a component of the Josephine ophiolite sequence, southwest Oregon and northwest California. Dark grains in polished section (also slightly darker grains in rough hand sample) are orthopyroxene, remainder is olivine. Light areas around edges are weathered rind; white lines are saw marks. Josephine County, Oregon. Scale in centimeters.

Josephine peridotite (harzburgite) - Full thin section in cross-polarized light

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It looks much better close up.                      Photo © Daniel R. Snyder

Josephine peridotite, a component of the Josephine ophiolite sequence. Small, brightly colored grains are olivine, larger grains in shades of gray are orthopyroxene.  Josephine County, southwest Oregon. XPL macrophotograph of entire thin section. Imaged area 18 mm x 38 mm.

Josephine peridotite - digital mosaic

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In this image: mostly olivine (bright colors) with incipient serpentinization, and a few large (gray) grains of orthopyroxene. Josephine peridotite, a component of the Josephine ophiolite sequence. Klamath Mountains, Josephine County, southwest Oregon. Digital mosaic of four 2x-objective images. XPL. Imaged area 5.1 mm x 7.6 mm.

Josephine peridotite (harzburgite) - pyroxene

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Josephine peridotite (partially serpentinized harzburgite), a component of the Josephine ophiolite sequence. Gray grain at left is pyroxene, large gray grain in center is partially serpentinized pyroxene (bastite texture). Brightly colored grains are olivine. Klamath Mountains, Josephine County, southwest Oregon.  XPL. Imaged area 1.3 mm x 2 mm.

Serpentinite exposure

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Serpentinite exposure adjacent to an extensive occurrence of Josephine peridotite.  Because serpentine can't accommodate the iron in the peridotite protolith, much of this is taken up as hematite, visible as  brick-red layers in the exposure. Road cut opposite Eight Dollar Mountain, Josephine County, SW Oregon. Rock hammer for scale is in the white circle at the bottom of the photograph.