A conical hill, often steep, formed by accumulation of solidified
fragments of
lava
that fall around the
vent
of a single
basaltic
or
andesitic
eruption. The rock fragments, often called cinders or
scoria, are glassy and contain numerous gas bubbles "frozen" into place
as
magma
exploded into the air and then cooled quickly.
Cinder
cones range in size from tens to hundreds of meters tall.
-
Cinder
cones usually erupt
lava
flows, either through a breach on one side of the crater or
from a
vent
located on a flank.
Lava
rarely issues from the top (except as a fountain) because the
loose, non cemented cinders are too weak to support the
pressure exerted by molten rock as it rises toward the surface
through the central vent.
-
Perhaps the most famous
cinder cone, Paricutin, grew out of a corn field in Mexico in 1943 from
a new
vent. Eruptions continued for 9 years, built the cone to a height
of 424 meters, and produced
lava
flows that covered 25 km2.
-
Cinder
cones are commonly found on the flanks of shield volcanoes,
stratovolcanoes, and calderas. For example, geologists have
identified nearly 100
cinder cones
on the flanks of Mauna Kea, a
shield volcano
located on the Island of Hawai`i (these cones are also
referred to as
scoria
cones and
cinder
and spatter cones).