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26 hits

  • Thumbnail for SYH-1CC
    SYH-1CC

    The foliation in this thin section, defined primarily by aligned glaucophane and clinozoisite, as well as strings of euhedral and aggregated sphene, wraps around larger, equant omphacite and glaucophane grains. The grain size is larger than many others in this suite and the foliation weaker.

  • Thumbnail for SYH-1DD
    SYH-1DD

    Glaucophane, muscovite, sphene, and elongate aggregates of epidote-group minerals define the foliation in this thin section. Poikiloblastic garnet and omphacite grains contain inclusions which include glaucophane and rutile.

  • Thumbnail for SYH-3D-1
    SYH-3D-1

    This thin section consists of several zones. The first, a fine-grained glaucophane schist with accessory sphene and zoisite. Microcrenulations cause the boundaries between individual glaucophane crystals to blur. This zone is abruptly cut by a green, omphacite-rich band. In the third zone, the glaucophane fabric is interleaved with elongate aggregates of omphacite and other accessory minerals.

  • Thumbnail for SYH-1GG
    SYH-1GG

    The fabric in this thin section is more disordered than others from this suite. All phases commingle and an alignment of elongate phases amidst many equant phase forms a weak foliation. Garnet and omphacite form porphryclastic, poikiloblastic grains.

  • Thumbnail for SYH-1S
    SYH-1S

    Strongly aligned actinolite crystals define a strongly folded foliation with lenses of subparallel chlorite crystals.

  • Thumbnail for AMA004E
    AMA004E

    The elongate minerals, glaucophane, clinozoisite and muscovite define the foliation in this sample, which is tightly folded in a crenulation cleavage.

  • Thumbnail for SYH-1D-2
    SYH-1D-2

    Glaucophane, muscovite, sphene, and elongate aggregates of epidote-group minerals define the foliation in this thin section. Poikiloblastic garnet and omphacite grains contain inclusions which include glaucophane and rutile and the host minerals show resorption textures.

  • Thumbnail for 0620-1B
    0620-1B

    Strongly aligned, microcrenulated glaucophane is the primary constituent of this blueschist. Sphene and muscovite are much less abundant.

  • Thumbnail for SYH-20
    SYH-20

    This paragonite schist is peppered with euhedral and aggregated clinozoisite. A few phengitic pods with large zoisite grains are found.

  • Thumbnail for GR-05
    GR-05

    The omphacite in this thin section is variably sized. Larger crystals are interspersed with granular aggregates; all are dusty due to alteration to clays. Interstitial muscovite is common and variation in birefringence indicates differing compositions or degrees of alteration of the micaceous phase.

  • Thumbnail for SYH-1E
    SYH-1E

    Glaucophane, muscovite, sphene, and elongate aggregates of epidote-group minerals define the foliation in this thin section. Poikiloblastic garnet and omphacite grains contain inclusions which include glaucophane and rutile.

  • Thumbnail for SYH-1II
    SYH-1II

    Like the other blueschists, aligned glaucophane, clinozoisite, and sphene define the foliation, however, this sample lacks omphacite and garnet, and contains quartz and aragonite instead. These latter two phases are interstitial and occur in minor amounts,

  • Thumbnail for SYH-1BB
    SYH-1BB

    Fine-grained glaucophane, the primary constituent of this blueschist, is aligned to form a foliation. Sphene is visible to the at the macroscopic scale and ranges in grain shape from euhedral diamonds to skeletal masses. Sphene twinning is evident.

  • Thumbnail for SYH-1FF
    SYH-1FF

    This blueschist consists mostly of aligned glaucophane, micas, and sphene. Occasional inclusion-rich porphyroclasts of nephaline are observed.

  • Thumbnail for Syros-unlabeled
    Syros-unlabeled

    Glaucophane, clinozoisite, and muscovite define a spaced foliation with undulose, polycrystalline patches and lenses of quartz. Quartz is relatively equigranular and grain boundaries sutured and showing evidence of bulging.

  • Thumbnail for GR-01
    GR-01

    Anhedral, interlocking calcite crystals growing around aligned, acicular glauconite and muscovite crystals. This thin section is porous and pock-marked. Skeletal garnets with numerous relict calcite inclusions are variably shaped, from beautifully euhedral, to anhedral aggregates.

  • Thumbnail for GR-07
    GR-07

    Aligned muscovite crystals form a foliation with anhedral, interlobate, though elongated grains of quartz and k-feldspar. Grain boundaries are irregularly shaped.

  • Thumbnail for SYH-1EE
    SYH-1EE

    Allotriomorphic omphacite and clinozoisite are intergrown with one another, with clinozoisite occurring frequently as inclusions within the omphacite crystals. The occurrence of muscovite is typically contained to polycrystalline nodes with radiating crystals. The conspicuous rutile grain in the center with radiating veinlets has a rim of plagioclase buffering it from the surrounding material. It contains inclusions of chlorite and sphene. Sphene is abundant as large, subhedral clasts.

  • Thumbnail for SYH-3D-2
    SYH-3D-2

    This thin section consists of several zones. The first, a fine-grained glaucophane schist. The boundaries between individual glaucophane crystals frequently blur. Aggregates of sphene are stretched out lines paralleling the complexly folded foliation. This zone is abruptly cut by a green, omphacite-rich band, bordered on each sided by a greater concentration of sphene. In the third zone, the glaucophane fabric is interleaved with elongate aggregates of omphacite, epidote and sphene.

  • Thumbnail for SYH-1A
    SYH-1A

    This crenulated foliation is defined by elongate omphacite interleaved with clinozoisite, sphene, chlorite, muscovite, and the rarer glaucophane crystals. Euhedral though fractured garnets contain chlorite, muscovite, and omphacite inclusions. Hexagonal porphyroclasts of randomly-oriented chlorite are scattered throughout.

  • Thumbnail for SYH-1R
    SYH-1R

    Aligned, elongate, millimetric-scale actinolite crystals dominate this thin section. Layers of actinolite crystals are interleaved with layers of chlorite. Basal sections of actinolite, which show fabulous amphibole cleavage are strongly plucked, leaving patchy void spaces throughout the thin section.

  • Thumbnail for SYH-1HH
    SYH-1HH

    Strongly aligned, microcrenulated glaucophane and muscovite define the tightly folded foliation of this rock. Sphene is skeletal with inclusions of both aforementioned phases.

  • Thumbnail for 0621-4
    0621-4

    This fine grained sample is fairly monomineralic. The small, feathery crystals are aligned to form a weak foliation. Opaques are plentiful though sphene much less so.

  • Thumbnail for SYH-3A-3
    SYH-3A-3

    This rock grades from an omphacite-rich zone into a muscovite-rich zone, and yet again into a glaucophane and chlorite-rich zone. The transitions between each section is rather abrupt. Micaceous phases are strongly aligned to define a foliation. Sphene is noticeably less abundant than in other samples. A k-feldspar porphyroclast surrounded by radiating chlorite is observed in the chlorite-glaucophane region.

  • Thumbnail for SYH-1M
    SYH-1M

    Randomly oriented, irregularly-shaped omphacite crystals comprise a boudin within the blueschist. In cracks within this boudin are aligned muscovite, glaucophane, and chlorite crystals. In one corner of the thin section, a titanite aggregate forms a reddish inclusion.