Lawsonitebearing
Lawsonitebearing refers to rocks or mineral assemblages that contain lawsonite, a hydrous calcium aluminum silicate with the approximate formula CaAl2Si2O7(OH)2·H2O. Lawsonite is a characteristic mineral of high-pressure, low-temperature metamorphism and is a key indicator of subduction-zone processes. Consequently, lawsonitebearing assemblages are most commonly associated with blueschist facies metamorphism, though they can occur in other HP–LT settings.
Lawsonite is stable at relatively high pressures and relatively low temperatures, conditions typical of subduction zones.
Geological significance: The presence of lawsonite constrains pressure–temperature conditions and helps reconstruct P–T paths in subduction
Occurrence: Lawsonitebearing rocks have been reported in blueschist and related high-pressure belts worldwide, including the Franciscan
See also: Blueschist facies, subduction zone metamorphism, glaucophane, dehydration reactions.
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