During the early Palaeozoic Ross Orogeny, the Wilson Terrane of northern Victoria Land was extensively intruded by felsic and mafic magmas. Plutons resulting from this igneous activity include an intrusive complex that crops out along the coast of northern Victoria Land at Terra Nova Bay which has been the subject of a detailed field, petrographic, petrologic, geochemical, isotopic and geochronologic work. This paper and the attached map summarize the results of this work on the composite Terra Nova Intrusive Complex. The complex evolved by multiple emplacement pulses that can be recognised by differences in internal structures and intrusive relationships. Generally, each major magmatic episode is characterized by mafic as well as felsic rocks, which commonly show textures indicative of intermingling and mixing. The different units and their internal variations (mafic, intermediate and felsic bodies) were identified and distinguished from each other in the field and then validated with petrographic-petrologic studies, thus yielding a geopetrographic map. Field data indicate strong variations in the stress regime during emplacement of the various magmatic units, with decreasing intensity of deformation and shallowing of emplacement level with time.
The Terra Nova Intrusive Complex, Victoria Land, Antarctica (with 1:50,000 geopetrographic map)
ROCCHI, SERGIO;
2004-01-01
Abstract
During the early Palaeozoic Ross Orogeny, the Wilson Terrane of northern Victoria Land was extensively intruded by felsic and mafic magmas. Plutons resulting from this igneous activity include an intrusive complex that crops out along the coast of northern Victoria Land at Terra Nova Bay which has been the subject of a detailed field, petrographic, petrologic, geochemical, isotopic and geochronologic work. This paper and the attached map summarize the results of this work on the composite Terra Nova Intrusive Complex. The complex evolved by multiple emplacement pulses that can be recognised by differences in internal structures and intrusive relationships. Generally, each major magmatic episode is characterized by mafic as well as felsic rocks, which commonly show textures indicative of intermingling and mixing. The different units and their internal variations (mafic, intermediate and felsic bodies) were identified and distinguished from each other in the field and then validated with petrographic-petrologic studies, thus yielding a geopetrographic map. Field data indicate strong variations in the stress regime during emplacement of the various magmatic units, with decreasing intensity of deformation and shallowing of emplacement level with time.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
