cavities locally comprise up to 20% of the rock, and in places, contain the same hydrothermal mineral assemblage as the stockwork veins, including quartz, magnetite, chalcopyrite and trace bornite.
The quartz in stage IV is characterized by milky veins or miarolitic
cavities, associated with white calcite and purple fluorite (Fig.
Ores textures are varied and include euhedral-subhedral crystals, metasomatic dissolution features, banding, veins, disseminations, and fillings of miarolitic
cavities (Figures 3(e)-3(h)).
Muraoka, "Three-dimensional shape analysis of miarolitic
cavities and enclaves in the Kakkonda granite by X-ray computed tomography," Journal of Structural Geology, vol.
The abundance of aligned miarolitic
cavities parallel to primary flow fabric suggests that these bodies were emplaced at high levels.
are the goethite, blue-green microcline ("amazonite") and smoky quartz from miarolitic
pockets in granite exposed at many sites in the Pikes Peak batholith of central Colorado.
A leucocratic foliated granite with miarolitic
cavities 15 km south in Fiordo Peel showed a ca 150 Ma U-Pb zircon age (unpubl.
The only member of the beryl family with more Fe is stoppaniite, which occurs in miarolitic
cavities in volcanic ejecta at Latium, Italy, and contains up to 19.30 wt.% [Fe.sub.2][O.sub.3] (Della Ventura et al., 2000).
The groundmass is granophyric, partly spherulitic, and contains miarolitic
The presence of quartz and feldspar ph enocrysts, as well as miarolitic
cavities, requires the melt composition (the opposing end of the lever) to lie on the quartz- feldspar boundary line.
The main ore structures consist of massive, disseminated, banded, veined, stockwork, miarolitic
, and brecciated structures (Figure 3).
Just in time for the show, Marshall received a shipment of about 20 flats of beautiful specimens of aquamarine/schorl/feldspar, newly dug from miarolitic
cavities in the granite of the Erongo Mountains, Namibia.