Colorado College Logo

  DigitalCC

Use AND (in capitals) to search multiple keywords.
Example: harmonica AND cobos

16 hits

  • Thumbnail for PS-2a-pgr
    PS-2a-pgr

    A granitic inequigranular diorite with graphically intergrown, sericitized k-feldspar and quartz, and chloritized hornblende. Clinozoisite and sphene are accessory minerals found throughout the thin section.

  • 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 ERB-09a
    ERB-09a

    Grain boundaries between the quartz and feldspar phases in this sample are consistently lobate, often with finer-grained subgrains rimming each crystal. Quartz in undulatory. The mica phases are subhedral and often resorbed, with kink bands causing undulose extinction along the length of the grain. Along one edge of the thin section is a seam dominated by clinozoisite. A hematite stain gives a dusty orange appearance to the feldspars and fractures within the sample contain higher concentrations of the phase.

  • 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-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 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 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 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-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-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 A-6-7
    A-6-7

    A continuous foliation for this sample is defined by aligned hornblende, micas, elongate quartz grains and granular aggregates of epidote and clinozoisite. Quartz is either equant or elongate with a granular texture. The hornblende phase is generally subhedral in shape, as are biotite crystals, which appear to be pseudomorphing an earlier mineral phase as evidenced by abundant inclusions. Radiation halos can be found in this sample though their occurrance is rare.

  • Thumbnail for 27-2A
    27-2A

    A continuous foliation in this sample is defined by aligned hornblende grains. Altered biotites are poikiloblastic and have kink bands causing undulose extinction. The aligned hornblende grains are juxtaposed against equigranular polygonal-interlobate quartz and aggregates of altered and decussate muscovite and clinozoisite.

  • Thumbnail for J-9-4
    J-9-4

    Strongly aligned hornblende grains define a continuous foliaiton in this thin section. Interspersed among these grains are polygonal quartz and fine-grained aggregates of clinozoisite and anhedral muscovite.

  • 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-1F
    SYH-1F

    A contact between blueshist and an omphacite boudin is captured in this thin section. The blueschist side is strongly foliated due to aligned glaucophane with interspersed sphene and minor muscovite and chlorite. The contact itself is an aggregate of sphene with interstitial chlorite and clinozoisite. Omphacite is the dominant mineral on the other side of the contact, though some glaucophane, muscovite, sphene, and clinozoisite is present. Quartz rims surround reddish opaques.