A subvolcanic rock, also known as a hypabyssal rock, is an
intrusive igneous rock that is emplaced at depths less than within the
crust, and has intermediate
grain size and often
porphyritic texture between that of
volcanic rocks and
plutonic rock
Intrusive rock is formed when magma penetrates existing rock, crystallizes, and solidifies underground to form '' intrusions'', such as batholiths, dikes, sills, laccoliths, and volcanic necks.Intrusive RocksIntrusive rocks accessdate: March 2 ...
s. Subvolcanic rocks include
diabase (also known as dolerite) and
porphyry. Common examples of subvolcanic rocks are diabase,
quartz dolerite
Quartz dolerite or quartz diabase is an intrusive rock similar to dolerite (also called diabase), but with an excess of quartz. Dolerite is similar in composition to basalt, which is volcanic, and gabbro, which is plutonic. The differing crystal s ...
,
microgranite
Granite () is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies undergrou ...
, and
diorite.
See also
*
Cone sheet
A cone is a three-dimensional geometric shape that tapers smoothly from a flat base (frequently, though not necessarily, circular) to a point called the apex or vertex.
A cone is formed by a set of line segments, half-lines, or lines con ...
*
Dike (geology)
*
Igneous intrusion
In geology, an igneous intrusion (or intrusive body or simply intrusion) is a body of intrusive igneous rock that forms by crystallization of magma slowly cooling below the surface of the Earth. Intrusions have a wide variety of forms and ...
*
Sill (geology)
References
Igneous petrology
Volcanology
{{Volcanology-stub
he:סלע געשי#סלעים תת-געשיים