The Sila and Serre granitoids of Calabria were emplaced in the late Carboniferous at depths ranging from 6 to 23 km in a postcollisional extensional regime. Their fabric, which developed during and after final crystallization up to the solid state, strongly increases in intensity with emplacement depth, This relationship is attributed to the thermal history of the Calabrian basement. Cooling histories of granitoids, constrained by geological data and Rb-Sr cooling ages on micas, demonstrate that residence times of rocks at temperatures greater than those of the brittleductile transition vary greatly as a function of initial emplacement depth. This explains why shallow-level granitoids, that remained for about 10 Myr at temperatures above those of the brittle domain, retain their original magmatic fabric, By contrast, the strong fabrics of the deep-seated granitoids are explained by solid-state strain overprint that lasted more than 100 Myr at temperatures above those of the brittle domain.
Thermal history vs. fabric anisotropy in granitoids emplaced at different crustal levels: an example from Calabria, southern Italy
CAGGIANELLI, Alfredo;
2000-01-01
Abstract
The Sila and Serre granitoids of Calabria were emplaced in the late Carboniferous at depths ranging from 6 to 23 km in a postcollisional extensional regime. Their fabric, which developed during and after final crystallization up to the solid state, strongly increases in intensity with emplacement depth, This relationship is attributed to the thermal history of the Calabrian basement. Cooling histories of granitoids, constrained by geological data and Rb-Sr cooling ages on micas, demonstrate that residence times of rocks at temperatures greater than those of the brittleductile transition vary greatly as a function of initial emplacement depth. This explains why shallow-level granitoids, that remained for about 10 Myr at temperatures above those of the brittle domain, retain their original magmatic fabric, By contrast, the strong fabrics of the deep-seated granitoids are explained by solid-state strain overprint that lasted more than 100 Myr at temperatures above those of the brittle domain.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
