An integrated study of magnetism, magmatic Ni-Cu sulphide mineralization and metallogeny in the Umiakoviarusek Lake Region, Labrador, Canada

• Main Author: Piercey, Stephen John
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 1998
• Subjects: Canada; Nain
• Online Access: https://research.library.mun.ca/6578/; https://research.library.mun.ca/6578/1/StephenJohnPiercey.pdf; https://research.library.mun.ca/6578/3/StephenJohnPiercey.pdf

The OKG prospect in the Umiakoviarusek Lake region of Labrador provides an excellent laboratory to study anorthosite-mangeric-charnockite-granite (AMCG) magmatism, pyroxenite-leucotroctolite hosted magmatic Ni-Cu sulphide mineralization and metallogeny. This thesis has used a combined field, geochemical and isotopic approach to assess the following problems: 1) what is the geology and nature of mineralization at the OKG prospect; 2) what are the isotopic and geochemical attributes of the anorthositic and granitoid rocks, and do they display any similarities to the Nain Plutonic Suite (NPS); 3) what is the nature and style of magmatic Ni-Cu sulphide mineralization; and 4) what are the chemical and isotopic controls on the genesis of the OKG Ni-Cu sulphide mineralization. -- The geology of the OKG prospect consists largely of anorthositic (sensu lato) and granitoid rocks, with lesser Archean gneisses and mineralized pyroxenitic (sensu lato) rocks. The Archean gneisses are predominantly amphibolitic/mafic granulite and subequal metatonalitic to quartzofeldspathic gneisses. The anorthositic and granitoid rocks of the property are predominantly anorthositic and leuconoritic and occur both north and south of Umiakoviarusek Lake and as a northwesterly trending body in the eastern portion of the property. Granitoid rocks are in roughly subequal proportions to the anorthositic rocks and range from mozonite, quartz momzonite, syenite, quartz syenite, alkali feldspar granite and granite. Traditionally these anorthositic and granitoid rocks have been assigned to the Nain Plutonic Suite (NPS)- however, recent work in this region has shown that much of the rocks in this region actually, and likely Paleoproterozoic and exhibit evidence of deformation and metamorphic influence from the ca. 1.86-1.74 Ga Torngat Orogen. These features include: 1) localized sinistral strike-slip and ductile (mylonitic) faulting and related folding; 2) the presence of foliations within the granitoid rocks that mirror the grain of the Archean ...