-
biotite and hornblende.
Other dacites,
especially pyroxene-bearing
dacites, are
darker colored. In thin section,
dacites may have an
aphanitic to porphyritic...
-
although the
majority are of
intermediate composition (such as Santiaguito,
dacite-andesite,
present day) The
characteristic dome
shape is
attributed to high...
-
percentage (>63%) of silica, the lava is
described as felsic.
Felsic lavas (
dacites or rhyolites) are
highly viscous and are
erupted as
domes or short, stubby...
-
magmas have a
silica content greater than 63%. They
include rhyolite and
dacite magmas. With such a high
silica content,
these magmas are
extremely viscous...
-
called the
Pagosa Peak
Dacite, made of
dacite that is very
similar to that of the Fish
Canyon Tuff. The
Pagosa Peak
Dacite,
which has characteristics...
- 'slate' or 'bluestone', a
metamorphic phyllite rock, with both
andesite and
dacite mineral composition.
Dacitic phyllite is a
predominant type of rock found...
-
characteristic mixture of
dacite and andesite,
while modern lava is very
diverse (ranging from
olivine basalt to
andesite and
dacite).: 214 St. Helens started...
-
erupt from the vent were hornblende-pyroxene
andesites with a
hornblende dacite dome at its summit.
Glacial erosion has
since modified its shape.[citation...
-
Paleozoic and
Mesozoic rocks. The city's
Mount Elden is a lava dome made of
dacite,
Sunset Crater is the
youngest feature of the San
Francisco volcanic field...
-
working in the area were not there. By the time of the
climactic eruption,
dacite magma intruding into the
volcano had
forced the
north flank outward nearly...
