Echo Bay Research Articles

Dawn singing of Eastern Phoebes varies with breeding stage and brood number

The dawn chorus is a daily period of continuous singing by male songbirds that begins prior to sunrise. It is relatively less studied than daytime singing, and particularly in suboscine birds. We analyzed dawn singing of 14 Eastern Phoebes (Sayornis phoebe) in Echo Bay, Ontario over the 2011–2012 breeding seasons. We measured time of first song, length of dawn bout, time of final song, average song rate, and peak song rate and compared these characteristics among breeding stages. Results indicated that breeding stage was a significant predictor of all five dawn song features. Our results suggest that dawn singing of Eastern Phoebes is directly related to female fertility. We show that males begin singing significantly earlier when females are fertile. Males sang significantly longer during fertile and incubation stages than while feeding young. Males began singing later and sang for the shortest duration during the pre-breeding period. Song rates were higher in first broods than in second broods. We showed that suboscine dawn signaling patterns vary across breeding seasons in ways similar to oscine songbirds.

P–T composition and evolution of paleofluids in the Paleoproterozoic Mag Hill IOCG system, Contact Lake belt, Northwest Territories, Canada

The Echo Bay stratovolcano complex and Contact Lake Belt of the Great Bear Magmatic Zone, Northwest Territories, host a series of coalescing Paleoproterozoic hydrothermal systems that affected an area of several hundred square kilometers. They were caused by intrusion of synvolcanic diorite–monzodioritic plutons into andesitic host rocks, producing several characteristic hydrothermal assemblages. They include early and proximal albite, magnetite–actinolite–apatite, and potassic (K-feldspar) alteration, followed by more distal hematite, phyllic (quartz–sericite–pyrite), and propylitic (chlorite–epidote–carbonate±sericite±albite±quartz) alteration, and finally by late-stage polymetallic epithermal veins. These alteration types are characteristic of iron oxide copper–gold deposits, however, with distal and lower-temperature assemblages similar to porphyry Cu systems. Magnetite–actinolite–apatite alteration formed from high temperature (up to 560 °C) fluids with average salinity of 12.8 wt% NaCl equivalent. The prograde propylitic and phyllic alteration stages are associated with fluids with temperatures varying from 80 to 430 °C and a wide salinity range (0.5–45.6 wt% NaCl equivalent). Similarly, wide fluid temperature (104–450 °C) and salinity (4.2–46.1 wt% NaCl equivalent) ranges are recorded for the phyllic alteration. This was followed by Cu–Ag–U–Zn–Co–Pb sulfarsenide mineralization in late-stage epithermal veins formed at shallow depths and temperatures from 270 °C to as low as 105 °C. The polymetallic veins precipitated from high salinity (mean 30 wt% NaCl equivalent) dense fluids (1.14 g/cm3) with a vapor pressure of 3.8 bars, typical of epithermal conditions. Fluid inclusion evidence indicates that mixed fluids with evolving physicochemical properties were responsible for the formation of the alteration assemblages and mineralization at Mag Hill. An early high temperature, moderate salinity, and magmatic fluid was subsequently modified variably by boiling, mixing with cooler low-salinity meteoric water, and simple cooling. The evidence is consistent with emplacement of the source plutons and stocks into an epithermal environment within ~1 km of surface. This generated near-surface high-temperature alteration in a dynamic hydrothermal system that collapsed (telescoped) resulting in widespread evidence of boiling and epithermal mineralization superimposed on earlier stages of alteration.

To Hedge or Not to Hedge…That Is the Question Empirical Evidence from the North American Gold Mining Industry 1996–2000

To Hedge or Not to Hedge…That Is the Question Empirical Evidence from the North American Gold Mining Industry 1996–2000

English

Limnologic and water chemistry data from Echo Bay Mineral's Key West and Equinox Resources' Van Stone mines were collected between August, 2000 and September, 2001. Pit lake elevations, areas and depths are 1,318 and 1,050 m; 1.1 and 1.9 ha; and 28 and 31 m, respectively. Depth profiles of temperature, pH, specific conductivity, oxidation-reduction potential (ORP), and dissolved oxygen were collected on a monthly basis during this period. Results indicate that both water bodies are oligotrophic and dimictic, experiencing complete mixing during the spring and fall. Seasonal water temperatures range between near 0° and 22° C and ice covers the lakes approximately 5 months per year. Thermal stratification becomes well developed in both water columns during late summer. The dissolved oxygen profile at Key West is clinograde, ranging from 8-10 mg/l at the surface to 1-2 mg/l at total depth, except during turnover. Van Stone displays an orthograde oxygen profile with relatively high concentrations (>6 mg/l) at lake bottom through out the year. Values for pH tend to fall with depth in both lakes. Waters in Key West and Van Stone pits are slightly alkaline (7-8.5), calcium-sulfate types. TDS concentrations average 628 mg/l at Key West and 386 mg/l at Van Stone; likewise sulfate currently averages about 336 mg/l and 138 mg/l, respectively. Metal concentrations are low in both waters. Contrary to expectation, sulfate concentrations in Key West lake waters have decreased over time, despite abundant sulfide minerals in the pit wall. Also unanticipated, were diminished concentrations of dissolved zinc, arsenic, molybdenum, antimony and selenium concentrations in the oxygen deficient hypolimnion at Key West. The observations and empirical data from Key West and Van Stone pit lakes are useful for, and should be considered, when developing, calibrating, and validating water quality models for circum-neutral mine pit lakes in temperate climates.

Forty Years of Northern Non-Renewable Natural Resource Development

Northern Canada is endowed with abundant non-renewable natural resources, and exploration and development of those resources have increased steadily since World War II. Particularly during the past 20 years new regulatory controls have been emplaced in response to elevated concerns about the possible impact of resource development on the environment. During the past 40 years gold, silver, copper, lead, zinc, nickel, asbestos, tungsten, uranium, coal and other minor commodities have been produced from more than 30 mines in the northern mainland, but at the present time only 6 mines are producing gold, silver, lead and zinc in that area: Con, Giant Yellowknife, Echo Bay, Mount Skukum, United Keno Hill and Faro mines. Lead and zinc are being produced at the world's most northerly mine. Polaris, on Little Cornwallis Island, and lead, zinc and silver are mined at Nanisivik on Baffin Island. At least 375 oil and gas wells have been drilled north of the Arctic Circle in the northern mainland since 1947, and 42 oil and gas fields have been discovered in the Beaufort Sea-Mackenzie Delta area alone. Total discovered and undiscovered resources in the latter area approximate 2131 billion cu m gas and 1.35 billion cu m oil. From 1961, 176 wells were drilled in the Arctic Islands and 17 oil and gas fields were discovered. Discovered and undiscovered resources approximate 2257 billion cu m gas and 686 million cu m oil. Key words: minerals, oil, gas, coal, Beaufort Sea, Mackenzie Delta, Arctic Islands, weather stations, transportation

Oxygen, hydrogen, and carbon isotopic studies of the Great Bear Lake silver deposits, Northwest Territories

The native-silver-bearing deposits of the Great Bear Lake region occur within two separate domains, namely the Echo Bay sector and the Camsell River sector. In all these deposits, native silver occurs in veins, associated with a wide range of Ni-, Co-, and Fe- arsenides, Cu-, Fe-, Ni-, and Co-sulfides, and pitchblende in gangues of quartz, calcite, dolomite, siderite, rhodochrosite, and fluorite. The host rocks of the veins are for the most part Aphebian volcano-sedimentary roof pendants within the Great Bear batholithic complex. The carbonates (calcite, dolomite, siderite, and rhodochrosite) show a wide range of δ18O (6.8 to 22.5‰, SMOW) and δ13C (−2.7 to −13.3‰, PDB) values. A single analysis of quartz gave a δ18O value of 16.54‰ (SMOW). The δD of water in fluid inclusions in quartz, dolomite, and calcite shows a range from −62.2 to −98.5‰ (SMOW). The δD of present-day meteoric waters from the region shows a range of −146.5 to −165.2‰ (SMOW). The δ18O of the hydrothermal fluids (0.47 to 9.12‰, SMOW) was calculated from the δ18O values of the quartz, calcite, and dolomite belonging to different paragenetic sequences. The δ13C of carbon (−2.8 to −8.6‰, PDB) in the hydrothermal fluid was calculated from the δ13C values of the calcites. The oxygen, carbon, and hydrogen isotopic values indicate that in the early stages of mineralization, magmatic water and carbon from a magmatic source were predominant. During the late stages of mineralization, the influence of meteoric water became more pronounced.

Electron microprobe analyses of native silver and associated arsenides from the Great Bear Lake silver deposits, Northwest Territories, Canada

The Great Bear Lake silver deposits in the Northwest Territories of Canada occur within two separate domains, namely the Echo Bay sector and the Camsell River sector. In these deposits, native silver occurs in veins, associated with a wide range of Ni-, Co-, and Fe-arsenides, sulphides, and pitchblende in gangues of quartz, calcite, dolomite, rhodochrosite, and fluorite. The host rocks of the veins are for the most part Aphebian volcano-sedimentary roof pendants within the Great Bear batholithic complex. Native silver, nickeline (niccolite), maucherite, safflorite, rammelsbergite, pararammelsbergite, loellingite, skutterudite, cobaltite, gersdorffite, and arsenopyrite were analyzed on the electron microprobe to determine any local or regional chemical variations. Mercury and antimony were found to occur in significant quantities in the majority of the native-silver samples. The silver samples from the Camsell River sector were found to be generally more enriched in mercury than those of the Echo Bay sector. Nickeline, cobaltite, and gersdorffite were found to be enriched in arsenic in the ores of the Camsell River sector, versus those of the Echo Bay sector. Such variations are probably related to differing magmatic sources for the hydrothermal fluids or even to precursor metallo-organic associations and are not due to different rocks hosting the silver-bearing veins.

Results of Seepage Meter and Mini‐Piezometer Study, Lake Mead, Nevada

ABSTRACTThe seepage meter and the mini‐piezometer were utilized in an attempt to evaluate ground‐water reservoir interactions over a 12‐month period at Echo Bay in Lake Mead. In conjunction with these techniques three standard piezometers, refraction seismic data, and water chemistry data were utilized to interpret seepage device results. During a four‐month period, from December 1979 to March 1980, an 8 ft (2.5 m) rise in reservoir stage, the reservoir contributed water to Echo Wash bank storage at rates of up to 0.29 gpd/ft2 (12 lpd/m2). Ground‐water discharge occurred for the remainder of the project, during a stage decline from April 1980 to May 1980, a rise in June 1980, and leveling off and slight decline for the remainder of the year, July 1980 to December 1980. The maximum seepage meter ground‐water discharge rate of 3.0 gpd/ft2 (122 lpd/m2) was recorded in December 1980. Seepage meter water chemistry data for June were similar to Lake Mead water chemistry and were interpreted to be previously recharged Lake Mead water. September water chemistry data showed two possible components of ground‐water discharge, a high SpC calcium sulfate Echo Wash ground water and a lower SpC Lake Mead recharged bank storage water. December ground‐water chemistry data showed discharge to be a high SpC calcium sulfate water similar to Echo Wash ground‐water quality which was apparently unaffected by Lake Mead inflow. Mini‐piezometer data were collected at each seepage meter site. However, these data usually did not provide correlative results with seepage meter data probably because of suspended sediment in the piezometer water column and plugging of the perforated tip. Seepage meters were successfully utilized to characterize reservoir ground‐water interaction in Echo Bay.

The geochronology of uranium deposits in the Great Bear batholith, Northwest Territories

The oldest uranium mineralisation found in the Great Bear batholith during this study may be hydrothermal pitchblende–hematite veins at Hottah Lake. Their apparent age of 2058 ± 34 Ma can also be explained by the contamination of deposits only 440 ± 57 Ma old, which is the age of pitchblende veins nearby. Numerous pendants of metamorphosed, uraninite-bearing "black sand" placers in a north-trending belt west of the Wopmay Fault are 1860 ± 20 Ma old, the age of the granites that intrude them. Mineralisation at Echo Bay is from 1500 ± 10 to 1424 ± 29 Ma old, and extends up to 30 km north and 40 km south of Echo Bay. The JD claims contain small quartz vein deposits dated at 535 ± 164 and 1092 ± 115 Ma. At Mountain Lake, pitchblende in Helikian sandstones overlying the batholith is 1076 ± 96 Ma old. Polymetallic veinlets at Mazenod Lake are 457 ± 26 Ma old. Pitchblende in a giant quartz vein at the Rayrock mine is 511 ± 86 Ma old. Small pitchblende veins east of the batholith along the Coppermine River are between 400 and 660 Ma old.All the deposits are either between ~395 and 660 Ma old, or indicate remobilization during this interval. These events may be related to a marine transgression and regression approximately 600 and 350 Ma ago, respectively.

Zooplankton Communities in Two Inshore Areas of Great Bear Lake, N.W.T., Canada

The composition, structure, and seasonal development of zooplankton communities in Great Bear Lake were determined from monthly collections made between April and October 1978. Samples were taken 2 km off shore near Echo Bay and Conjuror Bay in the upper 40 m of the water column. There were 20 species found in the plankton, of which 10 were crustaceans, 7 were rotifers, and 3 were protozoans. The most common crustaceans in both areas were Diaptomus sicilis, Cyclops scutifer, and Holopedium gibberum; dominant rotifers included Keratella cochlearis, Kellicottia longispina, and Asplanchna priodonta; and the prevalent protozoan was Codonella cratera. Crustaceans reached a total maximum density of 3.1 x 103 animals m-3 in August whereas the combined totals for rotifers and protozoans were 10.5 x 103 and 13.2 x 103 animals m-3, respectively. These densities and the total number of species are among the lowest recorded for freshwaters and are- probably re

Lead Isotope Evidence on the Genesis of the Silver-Arsenide Vein Deposits of the Cobalt and Great Bear Lake Areas, Canada

Silver veins of Proterozoic age in the Cobalt area, Ontario, are associated with the thick Nipissing diabase sheet, and those at Great Bear Lake, N.W.T., are also, in part, associated with a diabase sheet. Host rocks in the Cobalt area are flat-lying Aphebian sedimentary rocks, steeply dipping Archean volcanic and associated sedimentary rocks, and diabase, while host rocks in the Great Bear Lake area are intermediate and felsic volcanic rocks and tuffs of the Echo Bay group.Model-lead ages for ordinary galenas are about 1,630 and 2,280 m.y. for the Great Bear Lake and Cobalt veins, respectively, whereas the pitchblende U-Pb age for the Great Bear Lake veins is about 1,445 m.y., and the apparent Rb-Sr age for the Cobalt veins is about 2,160 m.y. An Rb-Sr isochron age of 1,425 + or - 48 m.y. has been obtained for the diabase sill in the Port Radium area, Great Bear Lake.In the Cobalt area essentially identical lead isotope compositions were obtained for interflow base metal mineralization in Archean volcanic rocks, galena along bedding in sedimentary rocks of the Cobalt group, and some late-stage sulfide veins. One interflow sample with a more primitive composition has a model age of at least 2,805 m.y. Mineralization, including deposition of most of the lead in Archean interflow beds, is interpreted to have taken place at about 2,160 m.y. and to be genetically related to the Nipissing diabase. In addition, two anomalous lead lines are defined, one of which suggests an age of 3,260 + or - 100 m.y. for Archean volcanic rocks. A shallow line, represented in only late-stage sulfide veins, is difficult to interpret but could be due to the late addition of a radiogenic component during Paleozoic or younger events not normally considered as causing mineralization, or even from ground water.Leads from the Great Bear Lake area could represent a single anomalous lead line with a slope of 0.1085 + or - 0.0070, and thus have a maximum possible age of 1,130 m.y. Geological events younger than this are known in the Bear Province, but not in the vicinity of the veins, and the same problems of interpretation exist as for the Cobalt area.The source of lead is not defined in either area. However, a source with homogeneous lead is required and the lack of extensive wall-rock alteration suggests that the lead was not leached from the country rocks. The diabase is tentatively favored as the source, but a connate brine or other source is possible.

Stable Isotope Geochemistry and the Origin of the Great Bear Lake Silver Deposits, Northwest Territories, Canada

Within the Bear Province, the Echo Bay Group of sediments and volcanics (~1800 m.y.) are intruded by Hudsonian granites and later diabases. Northeasterly trending fracture zones contain vein type U–Ag–Bi–Co–Ni–As–Cu deposits. Samples from the Terra, Norex, Silver Bay, and El Bonanza mines give a general paragenetic sequence of uraninite + hematite; Co–Ni arsenide minerals and silver; dolomite and sulfides; and sulfosalts with bismuth. The vein mineralogy is consistent with an ore fluid of high oxidation potential, low sulfur content (10−3 m) and low pH (~4).Dolomite δ 13C and δ 18O values of around −4‰ (PDB) and +15‰ (SMOW) respectively from all stages reflect a relatively constant temperature of deposition, which from mineralogical and other data is estimated at 200 °C. A δ 18O value of +2‰ (SMOW) is calculated for the ore fluid. The bulk of the sulfide δ 34S values are around +1‰ (CDT), which suggests a magmatic sulfur source. However, an equilibrium model is presented whereby the sulfur is derived from Precambrian sea-water sulfate and the carbon from limestones. The embryo ore fluid (connate sea water?) probably circulated both through the Echo Bay Group and the intrusives, and underwent chemical changes before moving into dilatant zones of mineral deposition.

Mineralogy, Fluid Inclusions, and Stable Isotopes of the Echo Bay U-Ni-Ag-Cu Deposits, Northwest Territories, Canada

At the Echo Bay mine, vein type U-Ni-Ag-Cu deposits occur along NE-SW-trending fracture zones in ca. 1,800 m.y. old andesitic tuffs. The temperatures of mineralization suggested by the occurrence of native bismuth and mckinstryite, the fluid inclusion filling temperatures, the sulphur isotopic compositions of coexisting sphalerite and galena, and the oxygen isotopic compositions of coexisting quartz and hematite were: around 120 degrees C for the first four stages, about 200 degrees C for stages 5 and 6, and below about 95 degrees C for the last stage. Data on the mineralogy, temperature, and the sulphur and carbon isotopic compositions of the hydrothermal minerals were used to evaluate the chemistry of hydrothermal fluids. The delta O 18 H2O and delta S 34 (sub sigma S) values and the initial high oxidation state of the hydrothermal fluids possibly reflect an origin as surface water. A model which involves the circulation and boiling of sea water caused by the intrusion of diabase at about 1,450 m.y. ago is presented to explain the concentration of salts, enrichment of O 18 , reduction of oxidation state, decreasing of pH of the fluids, and leaching of heavy metals from volcanic rocks.

The Camsell River–Conjuror Bay Area, Great Bear Lake, N.W.T.

Roof pendants of a late Aphebian (~1800 m.y.) volcano–sedimentary complex, within Hudsonian granites, outcrop on the eastern shore of Great Bear Lake. The volcano–sedimentary complex is similar to, and may be correlated with, the Echo Bay Group which outcrops farther to the north.The volcanic rocks are interbedded with immature volcanoclastic sedimentary rocks and with thinner units of calcargillite and dolomite. A unit of conglomerate, tuff, and siltstone, previously correlated with the Cameron Bay Group, is assigned to the 'Balachey Unit', until its relationships with other groups in the area are more clearly understood.Hudsonian granitic stocks and batholiths (~ 1750 m.y.) intruded the complex. Sharp contacts and narrow aureoles characterize these as high level intrusions. Zones of sulfide replacement are common in the aureoles. Porphyry dikes and stocks of similar age to the granites and rare, pegmatitic magnetite–apatite–actinolite bodies, also intrude the volcano–sedimentary complex.Three sets of diabase intrusions are identified, and related to three distinct fault directions. Giant quartz veins and mineralization of the U–Ag–Ni, Co arsenide – Bi type are found in zones of northeast-striking dextral faults.The volcano–sedimentary complex is interpreted as the molasse phase of the rising orogen of the Coronation Geosyncline, and is related to earlier deposits (the Snare and Epworth Groups) closer to the craton in the eastern part of the geosyncline.

The Geology and Geochronology of the Echo Bay Area, Northwest Territories, Canada

In the Echo Bay region of Great Bear Lake the Echo Bay Group has been intruded by Precambrian granites, granodiorites, aplites, and diabases. This group, which has undergone zeolite-facies regional metamorphism, has a lower dominantly sedimentary-pyroclastic sequence (about 1320 m thick) and an upper volcanic sequence (> 1500 m thick). The Lower Echo Bay sub-Group consists of tuffs and cherts with a 190 m thick intermediate lava flow and occasional thin limestones. A sequence of andesites and pyroclastics comprises the Upper Echo Bay sub-Group. Contact metamorphism of the hornblende hornfels and albite–epidote hornfels facies has been induced by the granitic intrusions. A Rb–Sr isochron for the Upper Echo Bay sub-group volcanics gives an age of 1770 ± 30 m.y. K–Ar apparent ages for the granite, granodiorite, and volcanics average around 1650 m.y., possibly reflecting local argon loss up to this date. Mineralized veins with a pitchblende-Co,Ni arsenide-silver-Fe, Cu, Ag, Bi, Zn. Pb sulfide para genesis are mainly confined to the sedimentary-pyroclastic horizons of the Lower Echo Bay sub-Group. It is possible that the mineralization was effected by fluids generated during the low-grade regional metamorphism and that some contribution was made to ore genesis by the thermal regime developed during the diabase intrusion.

Mckinstryite from the Echo Bay Mine, N.W.T., Canada

Mckinstryite occurs as late-stage, primary sulfide in the U = Co-Ni-Ag-Bi deposit of the Echo Bay Mine, N.W. Territories, accompanying niccolite, rammelsbergite, chalcopyrite, bornite, covelite and early dolomite. Electron microprobe analyses reveal an composition of Cu (sub 0.72) Ag (sub 1.28) S (sub 0.91) . A variable excess of Ag and S deficiency are probably due to a nonstoichiometric defect structure of the Schottky type. The mineral has an average S.G. of 6.64+ or -0.04, is light gray, weakly bireflectant, strongly anisotropic and biaxial positive. The reflectance at 470nm = 30.8% (av. min), 36.7% (av. max); at 546nm = 29% (av. min), 32.8% (av. max); at 589nm = 23.8% (av. min), 30.7% (av. max); at 650nm = 30.1% (av. min), 29.1% (av. max). VHN 20 gm = 50.1 to 67.1 (av. 55.7). Powder diffraction fives a = 13.962 + or -0.001A, b = 15.675+ or -0.002A, c = 7.775+ or -0.002A and Z = 32, delta S 34 values of +23 to +27 per thousand exhibited by the mckinstryite are interpreted as being due to the late formation of the mineral at 94.4 degrees C.

Musellifer sublitoralis, a New Genus and Species of Gastrotricha from the San Juan Archipelago, Washington

Musellifer sublitoralis n. g., n. sp. is described as a marine gastrotrich. Diagnosis of the family Chaetonotidae Zelinka, 1889 is emended to include this new genus. Diagnosis of the genus Musellifer: Chaetonotidae with head drawn out into a muzzle; caudal furca elongate, having neither joints nor annulations; muzzle surrounded by a ciliary band; cuticle thickened into scales; oral opening terminal. The type species is characterized by subcircular dorsal scales, each bearing a short anterior keel fitted with a posteriorly directed seta, and by the persistence of scales to the furcal tips. Holotype metrics (measurements in JLm): lengths-total 330, muzzle 14, pharynx 63 intestine 123, furca 101; widths-head 33.5, neck 28, trunk 50. Habitat: epibenthic mud, 10-12 m depth, Echo Bay, Seucia Island, San Juan Archi­ pelago, Washington. In each of two summers, 1962 and 1963, I received a single gastrotrich found by John C. Boykin in samples of sublittoral epibenthic mud from the San Juan Archipelago, Washington. Despite intensive sampling of similar habi­ tats during both summers, only two sp,ecimens were found. Although they were collected from stations sep,arated by 30 km of water, the two specimens were of nearly identical morphology. One specimen was collected from the mouth of Echo Bay, Seucia Island (10-12 m depth) and the other from the middle of East Sound, off Rosario Point, Orcas Island (30-32 m depth). These circum­ stances suggest a species of low density and sporadic occurrence. The sp'ecimens represent a new species whose taxonomic characteristics warrant the establish­ ment of a new genus. Order Chaetonotida Remane, 1925 Family Chaetonotidae Zelinka, 1889 EMENDED DIAGNOSIS: Head rounded, lobate, or drawn out into a muzzle; neck somewhat constricted; trunk more or less inflated an,d extended posteriorly into a caudal furca; body without adhesive tubes other than those associated with the posterior end. Two longitudinal bands of normal ventral cilia extend from the head or neck onto the trunk; head with one or two tufts of dorso- or ventro­ lateral cilia or, if a muzzle is present, with a ciliary band surrounding the muzzle; body often with one or two pairs of dorsal bristles. Cuticle smooth or variously thickened, often forming scales or spines. Oral opening terminal or subterminal.

Mineragraphy of the ores of Great Bear Lake

Research Article| June 30, 1935 Mineragraphy of the ores of Great Bear Lake † D. F. KIDD; D. F. KIDD §Assistant Geologist, Geological Survey of Canada, Department of Mines, Ottawa. Search for other works by this author on: GSW Google Scholar M. H. HAYCOCK M. H. HAYCOCK ‡Mineragrapher, Mines Branch, Department of Mines, Ottawa. Search for other works by this author on: GSW Google Scholar Author and Article Information D. F. KIDD §Assistant Geologist, Geological Survey of Canada, Department of Mines, Ottawa. M. H. HAYCOCK ‡Mineragrapher, Mines Branch, Department of Mines, Ottawa. Publisher: Geological Society of America Received: 20 Feb 1934 First Online: 02 Mar 2017 Online Issn: 1943-2674 Print Issn: 0016-7606 © 1935 Geological Society of America GSA Bulletin (1935) 46 (6): 879–960. https://doi.org/10.1130/GSAB-46-879 Article history Received: 20 Feb 1934 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation D. F. KIDD, M. H. HAYCOCK; Mineragraphy of the ores of Great Bear Lake . GSA Bulletin 1935;; 46 (6): 879–960. doi: https://doi.org/10.1130/GSAB-46-879 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract INTRODUCTIONThe silver and pitchblende ores at Great Bear Lake have attracted wide attention. Great Bear Lake is on the Arctic Circle, east of the Mackenzie River, and the deposits are at Echo Bay on the east side of the lake.Since the original find in May, 1930, the geology of the region and of the mineral deposits have been described by a number of geologists and engineers. A list of these papers is given in the accompanying bibliography.After spending two months in 1931 examining the mineral deposits and making a reconnaissance of the areal geology, Kidd published a brief account1 of the geology and mineralization at the Eldorado mine, the most important deposit in the district. In 1932, he spent six months making further field studies of the mineral occurrences and conducting a broad reconnaissance over 3000 square miles of geologically unknown territory. The results of this work . . . This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

TESTS FOR MESOTHORIUM IN RADIUM FROM LABINE POINT, GREAT BEAR LAKE

A sample containing 50 mgm. of radium bromide, prepared from ore obtained from the Echo Bay deposits in Canada, was tested for mesothorium impurity by the gamma ray absorption method. The material was found to be free from mesothorium within the limits of the experimental error, 0.2% radiation equivalent.As a confirmatory test a number of samples of the ore were analyzed for thorium in the National Research Laboratories, Ottawa. Quantities of thorium up to 0.07% of the uranium content were found, indicating a possible mesothorium impurity in the finished radium of 0.021% radiation equivalent.

The Discoveries of Pitch-Blende at Great Bear Lake

Prospectors are gifted with a fondness for adventure; otherwise Gilbert LaBine would not have left the comparative comfort of mineral-bearing areas in sou them Canada to trek the sub-Arctic regions in search of new wealth. They are observant by intuition; otherwise the indications of radium and silver ores at LaBine Point, on the shore of Echo Bay, Great Bear Lake, might easily have been missed. Thanks to these traits, possessed by a man who had already established a reputation in Canadian mining circles, the Dominion may now be regarded as an important source of radium.