A nonfoliated metamorphic rock that is typically formed by contact metamorphism around igneous intrusions.
A hard, dark-colored, dense metamorphic rock that forms from the intrusion of magma into shale or basalt.
A nonfoliated metamorphic rock of uniform grain size, formed by high-temperature metamorphism, typically formed by contact metamorphism around igneous intrusions.
a high temperature, low pressure metamorphic rock typically with an equant texture (no foliation or lineation).
A high-temperature metamorphic rock of uniform grain size showing no foliation. Usually formed by contact metamorphism.
Fine grained silicate rock produced by metamorphism.
A fine-grained contact metamorphic rock.
a fine-grained metamorphic rock formed by the action of heat on clay rocks
a term used to describe a fine-grained, granular metamorphic rock.
A dark, very fine-grained metamorphic rock produced by the recrystallization of a fine-grained rock by heat from a nearby igneous intrusion. From the German, meaning horn rock.
a fine-grained rock composed of a mosaic of equidimensional grains without preferred orientation (foliation) and typically formed by contact metamor-phism.
A fine grained metamorphic rock, sometimes with isolated larger crystals, formed when a clay has been recrystallised by heat but with little pressure. Hornfelses are common in contact metamorphism. For example, around the Dartmoor granite, the great heat released by the granite mass as it cooled baked all of the surrounding rocks out to a distance of several kilometers but did not place them under any great pressure.
A fine-grained rock with a mosaic of equidimensional grains.
a compact, fine-grained metamorphic rock composed of quartz, feldspar, mica and other minerals, formed by the contact action of intrusive rock upon shale or other sedimentary rock. [AHDOS
Rock that undergoes metamorphism simply because of a change in temperature, without being subjected to differential stress.
Hornfels (German, meaning "hornstone") is the group designation for a series of contact metamorphic rocks that have been baked and indurated by the heat of intrusive igneous masses and have been rendered massive, hard, splintery, and in some cases exceedingly tough and durable. Most hornfelses are fine-grained, and while the original rocks (such as sandstone, shale and slate, limestone and diabase) may have been more or less fissile owing to the presence of bedding or cleavage planes, this structure is effaced or rendered inoperative in the hornfels. Though they may show banding, due to bedding, etc., they break across this as readily as along it; in fact, they tend to separate into cubical fragments rather than into thin plates.
