metamorphism – מילון אנגלי-אנגלי
metamorphism
n.
metamorphosis; change in form or structure due to natural agencies (Geology)
Metamorphism
Metamorphism is the change of
minerals or
geologic texture (distinct arrangement of minerals) in pre-existing
rocks (
protoliths), without the protolith melting into liquid
magma (a
solid-state change). The change occurs primarily due to heat, pressure, and the introduction of chemically active fluids. The
chemical components and
crystal structures of the minerals making up the rock may change even though the rock remains a
solid. Changes at or just beneath Earth's surface due to
weathering and/or
diagenesis are not classified as metamorphism. Metamorphism typically occurs between diagenesis 200°C, and
melting 850°C.
metamorphism
Noun
1. change in the structure of rock by natural agencies such as pressure or heat of introduction of new chemical substances
(hypernym) geological process, geologic process
(hyponym) anamorphism
Metamorphism
(n.)
The state or quality of being metamorphic; the process by which the material of rock masses has been more or less recrystallized by heat, pressure, etc., as in the change of sedimentary limestone to marble.
Webster's Revised Unabridged Dictionary (1913), edited by Noah Porter.
About
metamorphism
The process by which conditions within the Earth, below the zone of diagenesis, alter the mineral content, chemical composition, and structure of solid rock without melting it. Igneous, sedimentary, and metamorphic rocks may all undergo metamorphism.
