Sulphides can be divided into two major groups, those which are of hydrothermal origin and those which are of sedimentary origin. The sulphides of sedimentary origin are found in greatest abundance in bituminous rocks and it is these sulphides that have been investigated in the present work. A study of the sedimentary sulphides is of special importance with respect to ore deposits because the various chemical and geological conditions present at the time of deposition, compaction, and metamorphism of the sediment can have a profound effect on the mineral associations and metal concentrations of the rocks.

At the present time there are no theories of the formation of epigenetic sulphide deposits that are in agreement with chemical and physical facts, theory and experimental results, and which explain all of the field observations that have been made.

This thesis is a study of iron-bearing formations and associated rocks in an area approximately 24 miles SSW of Mount Wright in Central Quebec. During the summer of 1958, the writer bad the opportunity to mar in detail an area of about four square miles. This area is a part of a concession held by Quebec Cartier Mining Company, for whom the survey was undertaken. The mapping roughly followed a series of anomalies outlined by an aero-magnetic survey.

The Abitibi district has been a subject of interest and geological investigation since 1872 when McOuat made a reconnaissance traverse through the area. In 1904 W. A. Parks traversed the country north of Lake Temiakaming. During the years 1908, 1910 and 1911, M. E. Wilson of the Geological Survey of Canada made a general reconnaissance of the western part of the area lying between the Interprovincial Boundary and Kawagama Lake. The results of this work were published as Summary Reports of the Geological Survey of Canada together with a map on a scale of 1/255,400 (Wilson, 1908, 1910, 1911, 1913), and later republished as Memoirs 17 and 39.

The alteration studies discussed in this thesis, were made around sulphide deposits located in the Eastern Townships of the Province of Quebec. The Eastern Townships occupy the hilly part of the province southeast of the St. Lawrence River. Broadly speaking, they extend from the Chaudiere River on the northwest, to the International Boundary on the south. On the northwest, their limit is the Champlain-St-Lawrence fault, or 'Logan's Line'. The area is wholly within the disturbed belt of the Appalachian mountain system.

The nature of the ore forming fluids has long been the foremost scientific problem confronting economic geologists. A study of the literature dealing with ore genesis reveals that there is no general agreement concerning their source, their physical character, their method of transport, and their manner of deposition to form ore deposits. Many of the theories are based upon deductive reasoning rather than experimental evidence.

Following the discovery of lead-zinc deposits in the O'Connor Lake area, N.W.T. during the period 1948-50, the Geological Survey of Canada decided to undertake a programme of geological mapping and examination of mineral occurrences in the area during the year 1952, under the supervision of Dr. A. B. Irwin, the then Resident Geologist of Yellowknife, N.W.T. After a shortwhile however, the present writer assumed full responsibility of the project and the mapping of the area was thence continued through the summers of 1952 and 1953 entirely by the present writer.

The results of investigations on solid specimens of three granites show that, of the three variables, temperature, pressure and time, changes in temperature have the most profound effect on the rates of reactions in the specimens. Variations of both pressure and time also cause differences in the rates of reactions, but, are less important, on the whole than temperature changes. This statement, however, is subject to certain qualifications, depending on the temperature-pressure relationships to the granite liquidus curve. It is also shown that the solid specimens of the three granites begin to melt at almost the same temperature-pressure conditions as finely powdered granites.

The degree of roundness of sand grains, comprising relatively insoluble minerals such as quartz and feldspar, within a specific size range increases with the distance of eolian transport. Roundness indices based on visual recognition and counting of four grain types were used to study sands from the Alfold in Hungary and the Great Sand Hills in Saskatchewan. The Saskatchewan sand showed a significant increase in roundness within about five miles. All the sands in the sand plateau of the Alfold are eolian and increase in roundness with the distance from their source (the Duna (Danube) Valley).

The wall-rocks of the Bridge River gold quartz veins have been hydrothermally altered by warm alkaline mineralizing solutions, containing carbon dioxide, potassium, sulphur and arsenic, which has brought about the partial replacement of the primary constituents of the wall-rocks by such secondary minerals as carbonates, sericite, talc, epidote, chlorite, albite, quartz, pyrite and arsenopyrlte. The dominant process of the alteration has been that of carbonization with up to 75 per cent of the rocks being altered to carbonate. In the more acidic types of wall-rock the carbonate is principally in the form of calcite, while in the more basic varieties, an ankeritic or dolomitic type of carbonate has been the dominant variety developed.