Charles C. Walls
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This is Charlie's 1978 B. Sc.
(Physics) grad photo.
M. Sc. Thesis
(PDF - 28 Mb)
The Troodos ophiolite in southwestern Cyprus has commonly been studied as an analogue of oceanic crust. Hydrothermal sulphide mineralization in the Troodos formed from circulating seawater and shows many similarities to that found at mid-ocean ridges. Numerous studies indicate that hydrothermal alteration, also related to the circulation of seawater, radically decreases the magnetization of ophiolitic and oceanic rocks.
This study re-analyses an aeromagnetic survey flown in the 1960's on the northern and eastern flanks of the Troodos ophiolite (Hunting Geology and Geophysics, 1969). Errors in the aeromagnetic data have been considered in detail. The aeromagnetic data has been compared to extensive geological information from a local study area. Samples measurements indicate that the magnetization of the upper Extrusives averages about ten amperes/metre and is not arranged in a regular pattern. Based upon this, the observed magnetic anomalies were modelled with a strongly magnetized layer of unaltered upper extrusives varying from approximately two hundred metres to one kilometre in thickness. This reflects variations in the depth to the top of a hydrothermally altered zone.
Massive sulphide mines in the troodos appear to be grouped into mining districts. The locations of discrete hydrothermal mineralization (mines, mineral prospects, gossans and umbers) were analyzed to determine if they appear regularly along the direction of spreading. No such regularity was found. However, a comparison of the mineralization locations and the aeromagnetic data suggests that some mineralization in the extrusives may occur preferentially in the areas of aeromagnetic lows. The correlation is probably insufficient to be used as a tool to locate mineralization, but may indicate general relationships between hydrothermal activity and a decrease in rock magnetization.
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Pages: 172
Supervisors: James Hall