By means of a multivariate analysis of the Tyrrhenian and peri-Tyrrhenian Late Miocene to Quaternary igneous rocks, performed through a statistical routine known as SIMCA (Soft Independent Modelling of Classes Analogy) and based on the Principal Components Analysis, it has been possible to distinguish, from an initially unstructured data set, seven minimum-variance subsets (classes). By analyzing the petrological meaning of these classes in the frame of the tectonic setting of the Tyrrhenian intra-continental eastward-migrating extensional lithospheric strain field, a tectonomagmatic model of the area is proposed which stresses the role played by the extending lithosphere in controlling the magmatism. This magmatism can be interpreted as being related to a limited number of parental magmas generated at well defined structural levels: continental crust, mantle lithosphere and metasomatized mantle asthenosphere. The large variety of rock types with different chemical compositions, which outcrop all over the studied area, can be considered to derive from these melts through a complex evolutionary history involving immiscibility, crystal fractionation and mixing among different bacsthes of magmas.
The Tyrrhenian zone: a case of lithosphere extension control of intra-continental magmatism
LAVECCHIA, Giuseppina;STOPPA, Francesco
1990-01-01
Abstract
By means of a multivariate analysis of the Tyrrhenian and peri-Tyrrhenian Late Miocene to Quaternary igneous rocks, performed through a statistical routine known as SIMCA (Soft Independent Modelling of Classes Analogy) and based on the Principal Components Analysis, it has been possible to distinguish, from an initially unstructured data set, seven minimum-variance subsets (classes). By analyzing the petrological meaning of these classes in the frame of the tectonic setting of the Tyrrhenian intra-continental eastward-migrating extensional lithospheric strain field, a tectonomagmatic model of the area is proposed which stresses the role played by the extending lithosphere in controlling the magmatism. This magmatism can be interpreted as being related to a limited number of parental magmas generated at well defined structural levels: continental crust, mantle lithosphere and metasomatized mantle asthenosphere. The large variety of rock types with different chemical compositions, which outcrop all over the studied area, can be considered to derive from these melts through a complex evolutionary history involving immiscibility, crystal fractionation and mixing among different bacsthes of magmas.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
