Two separate areas which are located in the southern portion of the Coppermine River area were surveyed by the author during the summer of 1957. The area under investigation is underlain by the upper part of the Epworth Series and the lower part of the Coppermine River Series. Because of the lack of fossils in these series, they are presumed to be of late Precambrian age. The upper part of Epworth Series is represented by dolomite and interbedded quartzite. The lower part of the Coppermine River Series is represented by a series of basalt flows which are typical tholeiites, and interbedded sandstone in its upper part. A monzonite dyke crosses the basalt flows and sandstone at a high angle and is parallel to the main basaltic dyke swarm seen in the Takiyuak Lake area. The common structural feature is a series of tension faults trending from N10°E to N45°E and N10°W to N20°W, This is believed to have originated by the compressive force from the north induced by the Caledonian movement. The ore minerals, mainly chalcocite, occur in quartz-carbonate veins in feeder dykes and flow tops of basalt. Flakes of native copper are occasionally found in the fractures of the basalt flows. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

An intrusive complex in the Coppermine River Area, Northwest Territories appears to be a greatly elongated lopolith approximately 5 miles wide and 60 miles long. Multiple intrusion and magmatic differentiation have combined to produce layers of rocks which range in composition from dunite to granophyre within the lopolith. The acid rocks of the complex were emplaced as a number of separate injections of magma after the crystallization and cooling of the basic and ultrabasic rocks. The structural relations of the acid and basic rocks indicate that the acid intrusions were accompanied by faulting and subsidence of a part of the northern end of the lopolith. A prominent textural feature of the granophyre, an oscillatory mantling of nuclei of graphic quartz and potash feldspar by quartz-free potash feldspar and plagioclase, is believed to be the result of fluctuations in water vapour pressure during crystallization of the magma. The fragments in a breccia cemented by granophyre were probably, in part, formed by fault movements which accompanied the intrusion of the acid magma. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

A geochemical survey was undertaken in the vicinity of massive sulphides at Anne-Cleaver and Camp Lakes to assess secondary geochemical dispersion within the zone of continuous permafrost. Samples were collected at several depths within the active layer together with snow-melt runoff, seepage, pit and lake waters and sediments. For each element (Ag, Cd, Cu, Fe, Mn, Pb and Zn) geochemical patterns are similar in all three soil layers (L-F-H 0 to 14 and 14 to 25 inch depths); therefore, sample depth does not appear to be critical. Ag, Fe and Pb display similar, well developed patterns and, except for Fe, possess high geochemical contrast. Conversely, Cd, Cu and Zn patterns are poorly developed and have low contrast, particularly in mineral soil. In areas of low pH, high levels of Ag, Fe and Pb can be found while Cu and Zn values are low and often form negative anomalies. High Zn levels are usually confined to areas of relatively high pH. Relative to total patterns, partial extraction (0.05M EDTA and 1.0M HCl) patterns provide little additional information; however, low partial to total ratio patterns are well developed, which suggests clastic dispersion. Because Pb is immobile, it can be used as a model for glacial dispersion of sulphides. Dispersion of Pb is in narrow thin zones of sulphide-rich till which rise at low (<2°) angles 1000 to 2000 feet down ice from the source. Anomalous metal concentrations and gossan are detectable in excess of 4000 feet down ice. Cu and Zn, although dispersed initially the same as Pb, have subsequently been subjected to extensive hydromorphic dispersion as a result of intensive oxidation and leaching in the acidic, water-rich soils of the active layer. Consequently, high levels of Cu and, in particular, Zn with high geochemical contrast are found in the surrounding waters and sediments. Relative to Cu and Zn, Pb is much more restricted and less concentrated in sediments and waters. This is because Cu and Zn enter the lake largely as dissolved species while Pb enters as a sorbed constituent on clay-sized particulate matter. High Cu-Pb-Zn levels in sediments and waters are restricted to lakes lying down drainage from mineralization and/or down ice in areas of metal-rich till. Within individual lakes, sediments display erratic metal levels with fluctuations often ≥10x. Conversely, lake waters are homogeneous but possess more limited dispersion halos relative to center-lake sediments. Pb is more likely than Cu and Zn to locate mineralization in all sample media; however, in waters, Cu and Zn are more easily detected and offer a much larger target than Pb. The effects of permafrost on geochemical dispersion are minimal. Hydromorphic and clastic dispersion patterns are well developed, perhaps better developed than in temperate climates. Significant inhibiting or complicating factors, with regard to geochemical dispersion are not present. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

No description available.

The Taglu is introduced as a new member of the Reindeer Formation. Its type section is in the Taglu G-33 well and its age is Eocene. This member conformably overlies the Aklak Member and underlies the "Un-named shale" or the "Kugmallit" member. The thickness of the Taglu varies from well to well but in the type section it is 800 ft. (268 m). Correlation of the Taglu Member is difficult due to facies changes, similarity in composition of successive facies, faulting, and the absence of marker beds or diagnostic fauna. Correlation, however, was accomplished through seismic interpretation, sedimentary megacycles, trace elements, biology, gamma-ray logs and logic. The Taglu Member was deposited under cool but occasionally warm temperate climatic conditions and is composed of two main deltaic sequences, each represented by a regressive phase overlain by a transgressive phase. Each sequence includes environments such as prodelta, delta front, distributary mouth bars, marshes and swamps, and finally distributary channels on top. The depositional basin during accumulation was undergoing moderate subsidence and receiving a high influx of sediments. Both the Richardson Mountains and the Eskimo Lakes Arch supplied, at least in part, the Taglu sediments. Occasional presence of volcanic rock fragments may indicate a third source, possibly well to the south. Based on its composition, the Taglu sandstone can be classified as quartz arenite and sublitharenite. It consists of quartz, chert, feldspar, mica, rock fragments, woody herbaceous matter, and cementing material. The cementing material includes non-ferroan calcite, ferroan and non-ferroan dolomite, siderite, silica and authigenic clay minerals. The cement, which is mainly controlled by the environment of deposition, is eodiagenetic and in places mesodiagenetic.

A study of Precambrian sedimentary rocks belonging to Division three of the Yellowknife group has been made. Samples for this study were obtained from an area 2 miles north of the northeast arm of Russel Lake near the granite contact. The rocks are greywacke, arkose and phyllite that have suffered low grade regional metamorphism. Shear zones that parallel the strike of the sediments have provided channelways for mineralizing solutions so that these zones now constitute mineral deposits important for their gold content. The shear zones contain, in addition to quartz and sulphides, an intergrowth of grunerite and hornblende similar to that found in the iron-bearing district of Lake Superior. This amphibole intergrowth is particularly well developed in an assemblage of thinly banded sediments containing a narrow (about 4") iron formation. Although Almandite garnet is found to a small extent in the shear zones, it is the characteristic wall rock alteration of these zones. An attempt has been made to show that the elongated "quartz pebbles” which occur in the shear zones, are of hydrothermal origin. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

This thesis presents the results of a general geological study of a belt of Archean rocks in the Indin Lake district, N.W.T. The summary results of a summer's field work are incorporated with a brief petrographical investigation of different rock types. Intermediate to acidic lava flows and pyroclastic rocks overlain conformably (?) by a succession of clastic sediments are invaded by minor acidic intrusives and a plexus of basic dykes and sills. Isoclinal folds in sediments, broader flexures in volcanics, bedded shear zones, and regional foliation and lineation are all attributed to a single system of powerful tangetial forces that affected all stratiform rocks in the area. Zones of weakness at contacts are imputed, to differential competence between volcanic and sedimentary rocks, and a. theory of folding of rock units of differing competency is applied in modified form to the origin of the Indin "break" - a gold-bearing shear zone close to a major contact. Evidence is presented to suggest that “cross-faults” clean-cut dislocations that transect the regional structural trend - and emplacement of late basic intrusives are quasi-contemporaneous events that progressed over a protracted interval of time and may have been consequent upon a single deformational-pattern. An attempt to explain the propinquity, and thus the possible structural relation, of gold mineralization to cross-faults is embodied in a theory relating the control of mineralization "by channeling of ore-solutions in structures developed during the period of strain accumulation that culminated in cross-faulting. An almost completely reconstituted mineral assemblage is ascribed to a moderate grade of regional metamorphism consisting of dynamic metamorphism during orogeny and relatively minor effects of superimposed thermal and retrograde metamorphism. Metacrysts of ankeritic carbonate, believed to be hydro-thermal, are discussed, and their superficial genetic or structural association with gold mineralization is offered as a possible guide to future ore discovery. Rather detailed descriptions are submitted of ankeritic carbonate, an unusual "hornblende" occurring in amphibolite, and a green mica, tentatively called phengitic-muscovite, from a carbonate zone. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

No description available.

No description available.

The Akaitcho property borders the northern claims of the Giant Yellowknife property. Diamond drilling has revealed an ore body lying along a terrace in a steeply-dipping mineralized shear zone. The shear is contained in Pre-cambrian volcanic rocks all of which have been more or less regionally metamorphosed. Adjacent to the ore, the rocks contain much introduced quartz, calcite, and pyrite. Sulphide mineralization is sparse but the ore is quite complex with an abundance of pyrite, arsenopyrite, stibnite, and sulpho-salts present. The gold is very fine-grained, the largest particle observed microscopically being 150 microns in diameter. It is disseminated in a quartz-carbonate gangue and is also closely associated with sulphides especially arsenopyrite and veinlets of sulpho-salts. Based upon the mineral assemblage, the alteration zone, and the general nature of the ore, the deposits would be classed as mesothermal. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate