Volcanism in Central Italy started from late Pliocene in extensional regime related to the opening of the Tyrrhenian back arc basin, involving the emplacement of acid dome complexes both in subaqueous (Northern Pontine Archipelago) and subaerial environments (Tolfa, Ceriti, Manziate, and Cimini dome complexes), and than allowing, during late Pleistocene, the emplacement of several alkali-potassic volcanic districts. The acid character of the dome complexes is generally interpreted as originated by mantle magmas metasomatized by crustal materials, whereas the alkali-potassic character of the districts is directly related to mantle hybrid magmas. We present the results of researches concerning the acid dome complexes, useful for the comprehension of the relationship between the structural setting of the basement and volcanism.All the acid dome complexes emplaced inside NE-oriented transversal grabens. The Tolfa and the Cerite-Manziate dome complexes emplaced inside half-grabens with the main extensional NE-trending faults at the northern margin. The Cerite-Manziate dome complex developed in a half graben at the southern margin of the Tolfa Mts. sedimentary structural high. The extrusive domes aligned along NE-trending fracture systems with a space-time evolution from west to east to which corresponds a change of the chemical composition from rhyolites (to the west) to trachydacites (to the east) and of the morphology of the domes from upheaved plug domes to the west, to coulee (or low lava domes) to the east. On the opposite, the Tolfa dome complex developed in a half graben constrained inside the Tolfa Mts. sedimentary structural high. It emplaced as a large cryptodome with a homogeneous trachydacitic composition. The Cimini dome complex shows a similar evolution: it developed as a cryptodome at the contact between the Mesozoic-Cenozoic calcareous units with the Pliocene-Pleistocene clay sediments, causing the uplift of the area. The local swelling produced radial and tangential fracture systems along which several domes emplaced with morphological characteristics related to their different location respect to the central area. The subaqueous Pontine dome complex developed on the continental Tyrrhenian shelf. Domes show different characteristics of the hyaloclastic facies in relationship to their location respect to important regional lineaments conditioning the structural setting of the coastal platform.
Cimarelli, C., DE RITA, D. (2004). The influence of the structural setting of the basement in the emplacement of submarine and subaerial dome complexes: the case of the Latian dome complexes (Central Italy)..
The influence of the structural setting of the basement in the emplacement of submarine and subaerial dome complexes: the case of the Latian dome complexes (Central Italy).
CIMARELLI, CORRADO;DE RITA, Donatella
2004-01-01
Abstract
Volcanism in Central Italy started from late Pliocene in extensional regime related to the opening of the Tyrrhenian back arc basin, involving the emplacement of acid dome complexes both in subaqueous (Northern Pontine Archipelago) and subaerial environments (Tolfa, Ceriti, Manziate, and Cimini dome complexes), and than allowing, during late Pleistocene, the emplacement of several alkali-potassic volcanic districts. The acid character of the dome complexes is generally interpreted as originated by mantle magmas metasomatized by crustal materials, whereas the alkali-potassic character of the districts is directly related to mantle hybrid magmas. We present the results of researches concerning the acid dome complexes, useful for the comprehension of the relationship between the structural setting of the basement and volcanism.All the acid dome complexes emplaced inside NE-oriented transversal grabens. The Tolfa and the Cerite-Manziate dome complexes emplaced inside half-grabens with the main extensional NE-trending faults at the northern margin. The Cerite-Manziate dome complex developed in a half graben at the southern margin of the Tolfa Mts. sedimentary structural high. The extrusive domes aligned along NE-trending fracture systems with a space-time evolution from west to east to which corresponds a change of the chemical composition from rhyolites (to the west) to trachydacites (to the east) and of the morphology of the domes from upheaved plug domes to the west, to coulee (or low lava domes) to the east. On the opposite, the Tolfa dome complex developed in a half graben constrained inside the Tolfa Mts. sedimentary structural high. It emplaced as a large cryptodome with a homogeneous trachydacitic composition. The Cimini dome complex shows a similar evolution: it developed as a cryptodome at the contact between the Mesozoic-Cenozoic calcareous units with the Pliocene-Pleistocene clay sediments, causing the uplift of the area. The local swelling produced radial and tangential fracture systems along which several domes emplaced with morphological characteristics related to their different location respect to the central area. The subaqueous Pontine dome complex developed on the continental Tyrrhenian shelf. Domes show different characteristics of the hyaloclastic facies in relationship to their location respect to important regional lineaments conditioning the structural setting of the coastal platform.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
