- diameter.
Phenocrysts below this level, but
still larger than the groundm**** crystals, are
termed microphenocrysts. Very
large phenocrysts are termed...
-
plagioclase phenocrysts and/or
rounded corroded quartz phenocrysts.
Subhedral hornblende and
elongated biotite grains are present.
Sanidine phenocrysts and augite...
- gl**** in texture. They
often contain clasts of
other rocks and
phenocrysts.
Phenocrysts are
crystals that are
larger than the
matrix and are identifiable...
-
composition first. This
forms large, well-shaped
euhedral phenocrysts. If
these phenocrysts are
different in
density to the
remaining melt, they usually...
-
visibly crystalline,
though not as
large as the
phenocrysts. The
crystallization of the
phenocrysts during fractional crystallization changes the composition...
-
Rhomb porphyry is an
example with
usually large porphyritic rhomb shaped phenocrysts embedded in a very fine-grained matrix. Some of the best
known trachytes...
-
rocks – An ultramafic, ultrapot****ic
intrusive rock
dominated by
mafic phenocrysts in a
feldspar groundm**** Latite – Type of
volcanic rock – A silica-undersaturated...
-
crystals (
phenocrysts) of
plagioclase formed prior to the
extrusion that
brought the
magma to the surface,
embedded in a finer-grained matrix.
Phenocrysts of...
- texture, but may be porphyritic,
containing larger mineral crystals (
phenocrysts) in an
otherwise fine-grained groundm****. The
mineral ****emblage is predominantly...
-
crystals (
phenocrysts)
formed prior to the
extrusion that
brought the
magma to the surface,
embedded in a finer-grained matrix.
These phenocrysts usually...
