| Summary: | <p>The purpose of this section is to outline the general development
of this study, and to indicate why certain investigations were carried out,
and why others which might appear to have equal merit were discarded.</p>
<p>In 1959, the Geology Department of the University of Saskatchewan,
in conjunction with the Geology Division of the Saskatchewan Research
Council, decided to co-ordinate a number of research projects and some
future field work in one general area, and selected the Flin Flon area
for this purpose.</p>
<p>Apart from being readily accessible, work which had already been
carried out in the area, notably the mapping of the area surrounding Amisk
Lake, Saskatchewan, to the west of Flin Flon by Dr. A. R. Byers, (Byers
and Dahlstrom, 1954, Byers and Kirkland, 1964), had indicated a variety of
interesting problems which deserved further study. One of these was the
genesis of a number of base metal sulphide deposits.</p>
<p>These deposits seem to fall into two groups. There are a large
number of deposits which consist almost entirely of pyrrhotite or pyrite,
or mixtures of the two, with nominal amounts of other base metal sulphides.
For convenience these will be referred to as the 'barren' deposits. Then
there are a much smaller number of deposits which consist of pyrrhotite or
pyrite or mixtures of the two, with much larger quantities of other base
metal sulphides, particularly chalcopyrite and sphalerite. These deposits,
which may or may not be of commercial value, will be referred to as the
'economic' deposits, and include the main Flin Flon ore body, and a number
of other mines, past and present such as the Coronation and Birch Lake Mines.</p>
<p>Apart from this major difference in quantitative mineralogy the
structural and geological setting of both groups is quite similar in many
respects. A better understanding of the genesis of these sulphides could
have considerable practical value in the search for new 'economic' deposits,
quite apart from any purely theoretical value.</p>
<p>The original purpose of this thesis was to make a study of the
genesis of these sulphide deposits, with emphasis on a general geochemical
approach, to see if there were in fact, other basic differences between the
two groups of sulphide deposits, apart from the obvious difference in
quantitative mineralogy.</p>
<p>This aim was greatly facilitated when the National Advisory
Committee on Research in the Geological Sciences chose Coronation Mine,
some fourteen miles southwest of Flin Flon, as the site of a co-ordinated
research program to be conducted by any interested bodies, under the
general guidance of the Geological Survey of Canada, who in turn assigned
Dr. D. R. E. Whitmore to the task of co-ordinating the various investigations.</p>
<p>It was thus possible to make a detailed collection of samples
from Coronation Mine, as a representative of the 'economic' group, during
the summer of 1960, and on subsequent occasions as mining progressed, as
well as to do underground structural mapping as a contribution to the
Coronation Mine Project. This latter also provided a very necessary
background for the geochemical work.</p>
<p>Samples from the 'barren⢠deposits were represented chiefly by
material previously recovered from exploratory drill core and surface
workings by Dr. A. R. Byers, together with a few samples I was able to
salvage myself. Unfortunately this record is far from complete, as much
of the drill core from a number of prospects has been disposed of, or is
otherwise irrecoverable.</p>
<p>The geochemical work of this thesis resolved itself to some extent,
in that the equipment available limited analytical work to chemicalspectrophotometric
and flame-photometric methods. Due to the inherently
poor productivity of chemical procedures, especially where geological
samples are involved, the geochemical work had to be restricted to a few
studies to which there was the best chance of attaching some geological
significance to the analytical results.</p>
<p>Two possibilities appeared likely to provide the most useful
information:
<OL TYPE="A">
<LI>whole-rock, and trace element studies of ore and altered
wallrocks from Coronation Mine.
<LI>trace element studies of pyrrhotite from both 'economic'
and 'barren' deposits.
</OL>
<p>Even so, considerable preliminary chemical work was necessary to
adapt existing analytical procedures to give reliable results with the
available equipment, and with the particular type of samples involved.</p>
<p>The results ot preliminary whole-rock analyses and some trace
element determinations on altered wallrocks were somewhat disappointing,
in that the conclusions which could be drawn from the results were
essentially negative. It was felt that a detailed study along these lines
would be valuable, but that it would involve an experimental program beyond
the scope of this thesis, and perhaps better suited to more rapid physical
methods of whole-rock analysis. This work was therefore discontinued.</p>
<p>Attention was then concentrated on trace element determinations
of pyrrhotite from both 'economic' and 'barren' deposits. Apart from some
preliminary work on other sulphides, pyrrhotite was chosen for study because
it was common to both groups of deposits, and because it was the most widespread
sulphide in the available sample collection.</p>
<p>The trace elements selected for study were cobalt and nickel,
because it would probably be easier to attach geological significance to
the analytical results than might be the case with cadmium or lead data
for example.</p>
<p>This work in fact, revealed considerable differences between the
two groups of sulphide deposits, and the description of these findings,
and a consideration of their implications form the main portion of this
thesis. Although this purely geochemical work could have stood on its
own, the original intention of the thesis, that of using the geochemical
data to throw light on the genesis of the sulphide deposits, has not been
overlooked.</p>
<p>A consideration of the new data in the light of the available
field evidence shows that a theory for the formation of the 'barren'
sulphide deposits can be proposed which is consistent with the available
data. Difficulties are encountered in finding a satisfactory theory for
the formation of the 'economic' deposits however. These difficulties
chiefly concern the structure and age of the 'economic' mineralization in
the Coronation Mine-Birch Lake area.</p>
<p>Various genetic theories which have been proposed for these
sulphide deposits by other workers or which might have some bearing in
this particular study are briefly reviewed and are also found to be
unsatisfactory or inadequate in one respect or another. It was felt that
some of these difficulties might be resolved if partial remobilization of
the sulphides had occurred and possible evidence in support of remobilization
is briefly considered.</p>
<p>The thesis therefore consists of three main sections. although
there is necessarily some overlap of material dealt with in each section.
There is a brief section on the geological setting and description of the
sulphide deposits, after which follows the main section on the geochemistry,
and the discussion of the results and the genesis of the sulphide deposits.
These are followed by a brief conclusion and some suggestions for further
studies.</p>
<p>A number of appendices contain some additional details or information
on various points which occur in the main text.</p>
|
|---|
