Nicholas Murray Spence HBSc thesis abstract

Thesis Title: 
An Interpretation of the Quartz-Hematite Laminations of Mink Mountain, Ontario
Nicholas M.

The quartz-hematite laminations of Mink Mountain, Northwestern Ontario have become the subject of some considerable controversy with respect to the origin of these laminations.  To date, two schools of thought exist regarding the origin of these laminations.  The first concept is that these laminations are the result of hot spring activity producing geyserites or sinter (Walter, 1972).  The second view is that the laminations constitute biogenic results of the growth and preservation of stromatolites.  This thesis presents considerable evidence that indicates the quartz-hematite laminations of Mink Mountain are more likely the result of stromatolite activity and subsequent preservation by cementation and burial.

The quartz-hematite laminations occupy the Upper Algal Chert member of the Gunflint Formation.  A seventy-eight metre long section of the Upper Algal Chert member of Mink Mountain was extensively sampled and these samples were studied in detail by tracings of orthogonal cuts of individual samples and documentation of data into Hofmann's (1969b) stromatolite classification.  In addition, evidence was found to indicate biogenic activity had occurred and that these laminations were formed on a littoral margin.

Through Hofmann's (1969b) classification, it was found that Forms A, C, D, E and G stromatolites exist at Mink Mountain (Hofmann, 1969b).  Microfossils are fairly abundant as filamentous rods similar in appearance to Gunflintia, indicating a biogenic component of the laminations.  The characteristics and configuration of the bioherms suggests these stromatolites thrived in and around tidal pools of a tidal flat on a grainstone substrate.  It is possible that the stromatolite organisms originally secreted carbonate but during the early of late stages of diagenesis, almost total silicification of the bioherms by jaspilitic chert took place.