Xiuyin Fu
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M. Sc. Thesis
Controls on the Localization of Mineralization in Abitibi Greenstone Belt Crust: Evidence from the Matheson Area of Ontario, Canada
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The study area is located in the southwest of the Abitibi greenstone belt, in the vicinity of Matheson, which includes ll townships. The purpose of this investigation is to seek spatial relationships between features of the construction of the volcanic sequence and mineralization occurrences.
Field measurements together with data from drill holes and geological maps in the Matheson area indicate that the extrusive sequence of the greenstone belt consists dominantly of two lithological types, basaltic massive and pillow lavas. The formation of the different morphological types of lava flows were largely controlled by eruptive rate. Synconstructional intrusions are considered to be a heat source for hydrothermal circulation and associated mineralization. The proportions of the pillow lavas (i.e., P value = relative thickness of pillowed flows in a section / total extrusions) and of the intrusions (i.e., M value = the area of higher level of magnetic field / total mapped area) are measured in this study as features of construction of the volcanic sequence.
There are 23 Au and Au-associated occurrences, 17 Cu-Zn massive sulfide occurrences, and 8 Ni and Cr occurrences in the study area. Au occurrences in the area are spatially correlated with high P (P > 50%) values. The Cu-Zn group of occurrences occur within the area of low P (P < 50%) and, commonly, high M (M > 75%). These spatial positive, or inverse correlations between the occurrences and the P and/or M values, which have been tested and quantified using logistic regression analysis, suggest that the formation of the occurrences were related to the features of the construction of the volcanic sequence and the heat sources involved.
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Supervisor: James Hall