Source and timing of gold and other mineralization in the Red Lake area, northwestern Ontario, based on lead-isotope investigations

1993 ◽  
Vol 30 (12) ◽  
pp. 2366-2379 ◽  
Author(s):  
Brian L. Gulson ◽  
Karen J. Mizon ◽  
Brian T. Atkinson
Keyword(s):  
Gold Mineralization ◽  
Volcanic Rocks ◽  
Hydrothermal Activity ◽  
Source Rocks ◽  
Lake Area ◽  
Pb Isotope ◽  
Multistage Processes ◽  
Red Lake ◽  
Felsic Volcanic ◽  
Isotope Analyses

The problems of the timing and source of gold mineralization and the sulfidation mechanism in the Red Lake area, north-western Ontario, have been addressed using more than 300 Pb-isotope analyses of more than 250 samples of sulfides, oxides, gold, and potential source rocks. Base metals and some gold from the Campbell and Dickenson mines are interpreted to have been mainly derived from the mafic–intermediate and felsic volcanic rocks of the lower sequence at ca. 2865 Ma, the model age calculated for samples of gold, chalcopyrite, pyrite, and galena. Other samples of gold are considered to have formed at younger ages, perhaps at ca. 2700 Ma. Differences in isotopic patterns for deposits in possibly different deformation zones but hosted by rocks of the same age and composition, e.g., Campbell–Dickenson, McFinley, Cochenour Willans, are interpreted to mean that some of the deposits formed at different times or from different sources or both (i.e., by multistage processes). The older period of gold mineralization is supported by a 2865 ± 10 Ma Pb–Pb isochron age (mean square of weighted deviates (MSWD) 2.9) for Cu–Ni and Fe sulfides and a similar model age for pyrite from the Bridget Lake prospect in the western sector. Younger mineralization at ca. 2700 Ma is represented by, for example, disseminated sulfides in the Dome stock, Balmer Lake arsenopyrite, the Red Summit mine in the Red Crest stock, sulfides and gold from the McFinley mine, and the model age for the Abino galena. A well-constrained Pb–Pb line for magnetites, mainly from 2700–2730 Ma felsic intrusions, gives an apparent age of 2660 ± 10 Ma (MSWD 3.7). This event may represent late-stage hydrothermal activity. Analyses of gold grains yield very complex isotopic patterns possibly because of remobilization and the very low contents of Pb in the gold grains. In environments such as Red Lake, Pb-isotope analyses of gold appear to give unreliable estimates of genesis and timing.

Geochemistry and U/Pb geochronology of the Williams Brook area, Tobique-Chaleur zone, New Brunswick: stratigraphic and geotectonic setting of gold mineralization

2021 ◽  
Author(s):  
Dennis Sánchez-Mora ◽  
Christopher R.M. McFarlane ◽  
James A Walker ◽  
David R. Lentz
Keyword(s):  
New Brunswick ◽  
Gold Mineralization ◽  
Tectonic Setting ◽  
Volcanic Rocks ◽  
Crustal Contamination ◽  
Volcanic Belt ◽  
Temporal Variations ◽  
Lower Percentage ◽  
Oblique Convergence ◽  
Felsic Volcanic

Gold mineralization at Williams Brook in northern New Brunswick is hosted within the Siluro-Devonian, bimodal, volcano-sedimentary rocks of the Tobique-Chaleur Zone (Wapske Formation). Gold mineralization occurs in two styles: 1) as disseminations (refractory gold) in rhyolite, and 2) in cross-cutting quartz veins (free gold). Dating of the felsic volcanic host rocks by in situ LA-ICP-MS zircon U-Pb geochronology returned ages of 422 ± 3, 409 ± 2, 408 ± 3, 405 ± 2, 401 ± 9 Ma. Zr/Y of subvolcanic felsic intrusion (<8 for syn-mineralization and >8 for post-mineralization) suggests evolution from transitional to more alkalic affinities. Two mineralizing events are recognized; the first is a disseminated mineralization style formed at ~422–416 Ma and the second consists of quartz vein-hosted gold emplaced at 410–408 Ma. Felsic rocks from Williams Brook and elsewhere in the Tobique Group (i.e. Wapske, Costigan Mountain, and Benjamin formations), and the Coastal Volcanic Belt have similar Th/Nb ratios of ~0.1 to 1, reflecting similar levels of crustal contamination, and similar Nb and Y content, suggesting A-type affinities. These data indicate a similar environment of formation. Regionally, mafic rocks show similar within-plate continental signatures and an E-MORB mantle source that formed from partial melts of 10–30%. Mafic volcanic rocks from Williams Brook have a more alkaline affinity (based on Ti/V), and derivation from lower percentage partial melting (~5%). The chemical and temporal variations in the Williams Brook rocks suggest that they were erupted in an evolving transpressional tectonic setting during the oblique convergence of Gondwana and Laurentia.

scholarly journals Geochemistry, geochronology, and fluid inclusion study of the Late Cretaceous Newton epithermal gold deposit, British Columbia

2016 ◽  
Vol 53 (1) ◽  
pp. 10-33 ◽  
Author(s):  
Lijuan Liu ◽  
Jeremy P. Richards ◽  
S. Andrew DuFrane ◽  
Mark Rebagliati
Keyword(s):  
British Columbia ◽  
Gold Deposit ◽  
Late Cretaceous ◽  
Gold Mineralization ◽  
Volcanic Rocks ◽  
Fluid Inclusion Study ◽  
Epithermal Gold ◽  
Epithermal Gold Deposit ◽  
Felsic Volcanic ◽  
Felsic Volcanic Rocks

Newton is an intermediate-sulfidation epithermal gold deposit related to Late Cretaceous continental-arc magmatism in south-central British Columbia. Disseminated gold mineralization occurs in quartz–sericite-altered Late Cretaceous felsic volcanic rocks, and feldspar–quartz–hornblende porphyry and quartz–feldspar porphyry intrusions. The mineralization can be divided into three stages: (1) disseminated pyrite with microscopic gold inclusions, and sparse quartz–pyrite ± molybdenite veins; (2) disseminated marcasite with microscopic gold inclusions and minor base-metal sulfides; and (3) polymetallic veins of pyrite–chalcopyrite–sphalerite–arsenopyrite. Re–Os dating of molybdenite from a stage 1 vein yielded an age of 72.1 ± 0.3 Ma (published by McClenaghan in 2013). The age of the host rocks has been constrained by U–Pb dating of zircon: Late Cretaceous felsic volcanic rocks, 72.1 ± 0.6 Ma (Amarc Resources Ltd., unpublished data, reported by McClenaghan in 2013); feldspar–quartz–hornblende porphyry, 72.1 ± 0.5 Ma; quartz–feldspar porphyry, 70.9 ± 0.5 Ma (Amarc Resources Ltd., unpublished data, reported by McClenaghan in 2013). The mineralized rocks are intruded by a barren diorite, with an age of 69.3 ± 0.4 Ma. Fluid inclusions in quartz–pyrite ± molybdenite ± gold veins yielded an average homogenization temperature of 313 ± 51 °C (number of samples, n = 82) and salinity of 4.8 ± 0.9 wt.% NaCl equiv. (n = 46), suggesting that a relatively hot and saline fluid likely of magmatic origin was responsible for the first stage of mineralization. Some evidence for boiling was also observed in the veins. However, the bulk of the gold mineralization occurs as disseminations in the wall rocks, suggesting that wall-rock reactions were the main control on ore deposition.

Coeval sedimentation, magmatism, and fold-thrust belt development in the Trans-Hudson Orogen: geochronological evidence from the Wekusko Lake area, Manitoba, Canada

1999 ◽  
Vol 36 (2) ◽  
pp. 293-312 ◽  
Author(s):  
Kevin M Ansdell ◽  
Karen A Connors ◽  
Richard A Stern ◽  
Stephen B Lucas
Keyword(s):  
Regional Metamorphism ◽  
Volcanic Rocks ◽  
Sedimentary Rocks ◽  
Detrital Zircons ◽  
Lake Area ◽  
Thrust Belt ◽  
Fold And Thrust Belt ◽  
Minimum Age ◽  
Flin Flon ◽  
Felsic Volcanic

Lithological and structural mapping in the east Wekusko Lake area of the Flin Flon Belt, Trans-Hudson Orogen, suggested an intimate relationship between magmatism, fluvial sedimentation, and initiation of fold and thrust belt deformation. Conventional U-Pb geochronology of volcanic rocks in fault-bounded assemblages provides a minimum age of 1876 ± 2 Ma for McCafferty Liftover back-arc basalts, and ages of between 1833 and 1836 Ma for the Herb Lake volcanic rocks. A rhyolite which unconformably overlies Western Missi Group fluvial sedimentary rocks has complex zircon systematics. This rock may be as old as about 1856 Ma or as young as 1830 Ma. The sedimentary rocks overlying this rhyolite are locally intercalated with 1834 Ma felsic volcanic rocks, and yield sensitive high resolution ion microprobe (SHRIMP) U-Pb and Pb-evaporation detrital zircon ages ranging from 1834 to 2004 Ma. The Eastern Missi Group is cut by an 1826 ± 4 Ma felsic dyke, and contains 1832-1911 Ma detrital zircons. The dominant source for detritus in the Missi Group was the Flin Flon accretionary collage and associated successor arc rocks. The fluvial sedimentary rocks and the Herb Lake volcanic rocks were essentially coeval, and were then incorporated into a southwest-directed fold and thrust belt which was initiated at about 1840 Ma and active until at least peak regional metamorphism.

ARCHAEAN SEDIMENTARY ROCKS OF NORTH SPIRIT LAKE AREA, NORTHWESTERN ONTARIO

1965 ◽  
Vol 2 (6) ◽  
pp. 622-647 ◽  
Author(s):  
J. A. Donaldson ◽  
G. D. Jackson
Keyword(s):  
Volcanic Rocks ◽  
Sedimentary Rocks ◽  
Sole Source ◽  
Lake Area ◽  
Red Lake ◽  
Sedimentary Sequences ◽  
The North ◽  
Northwestern Ontario ◽  
History Of ◽  
Granitoid Rocks

Archaean sedimentary rocks of the North Spirit Lake area show little evidence of having been derived predominantly from associated Archaean volcanic rocks. Instead, compositions of the sediments reflect significant sedimentary and (or) granitoid provenance. A remarkably high content of clastic quartz in thick units of sandstone and conglomerate suggests either reworking of older quartzose sediments, or reduction of the labile constituents in quartz-rich granitoid rocks through prolonged weathering and rigorous transport. Observations for other sedimentary sequences in the region between Red Lake and Lansdowne House suggest that the North Spirit sediments are not unique in the Superior Province. Quartzose sandstones commonly are regarded as atypical of the Archaean, but such rocks arc abundant in northwestern Ontario. Frameworks of many Archaean greywackes actually are richer in quartz than typical greywackes from numerous Proterozoic and Phanerozoic sequences.The concept of rapidly rising volcanic arcs as the sole source of Archaean sedimentary detritus is rejected for the North Spirit area. The volcanies, rather than representing relicts of protocontinents, probably record events removed from initial volcanism in the history of the earth by one or more orogenic cycles. Major unconformities may therefore exist not only between sedimentary and volcanic units, but also between these units and older granitoid rocks.

U–Pb zircon ages for magmatism in the Red Lake greenstone belt, northwestern Ontario

1986 ◽  
Vol 23 (1) ◽  
pp. 27-42 ◽  
Author(s):  
F. Corfu ◽  
H. Wallace
Keyword(s):  
Greenstone Belt ◽  
Volcanic Rocks ◽  
Gold Deposits ◽  
Calc Alkaline ◽  
Red Lake ◽  
Northwestern Ontario ◽  
Igneous Activity ◽  
Felsic Volcanic ◽  
Felsic Volcanic Rocks ◽  
Chemical Sediments

U–Pb dating was carried out on nine volcanic rocks and two felsic intrusions from the Red Lake greenstone belt in order to establish an absolute time framework for the magmatic evolution of the area and yield first indications on the time of deformation and gold mineralization.The data indicate a protracted period of igneous activity spanning at least 270 Ma. Felsic volcanic rocks near the top of the tholeiitic to komatiitic sequence in the eastern part of the belt yield ages of [Formula: see text] and [Formula: see text]. A third unit, dated at [Formula: see text], contains inherited zircons older than 2982 Ma, which casts some uncertainty on the validity of the inferred intercept age. Rocks in the western part of the belt, previously believed to form a relatively young calc-alkalic sequence but now known to be dominantly tholeiitic, are shown to be relatively old, with ages of [Formula: see text] and [Formula: see text]. These two dates also bracket the age of stromatolites occurring in chemical sediments that are under and overlain by the dated units.Another volcanic horizon in the centre of the belt is dated at 2830 ± 15 Ma, and calc-alkaline volcanic sequences on the southern and northern flanks of the belt yield ages of 2739.0 ± 3.0 and [Formula: see text], respectively. An age of [Formula: see text] was determined for tholeiitic pyroclastic rocks near the base of the predominantly calc-alkaline Heyson sequence.The major gold deposits of the Red Lake belt appear to be present dominantly within older supracrustal sequences. On the other hand, they are also associated with late deformation zones that postdate the intrusion of the Dome Stock dated at 2718.2 ± 1.1 Ma ago. The time of an earlier folding event is bracketed by this age and by the age of [Formula: see text] for an isoclinally folded felsic dike.

Metallogenic significance of trace element and U–Pb isotope data for uraninite-rich mineral separates from the Labrador Central Mineral Belt

1993 ◽  
Vol 30 (12) ◽  
pp. 2352-2365 ◽  
Author(s):  
Derek H. C. Wilton ◽  
Henry P. Longerich
Keyword(s):  
Inductively Coupled Plasma ◽  
Genetic Relationships ◽  
Volcanic Rocks ◽  
Analytical Techniques ◽  
Geochronological Data ◽  
Pb Isotope ◽  
Isotope Data ◽  
Mineral Belt ◽  
Felsic Volcanic ◽  
Host Rocks

Thirteen concentrates of uraniferous material were prepared from uranium occurrences in the Central Mineral Belt of Labrador. Host rocks to these occurrences include granitoid rocks of the Archean basement, ca. 2000 Ma metasedimentary rocks of the Lower Aillik Group, and 1860 Ma felsic volcanic rocks of the Upper Aillik Group. Common lead corrected Pb isotope data from inductively coupled plasma mass spectrometry analyses define 207Pb/206Pb ages ranging from 1805 to 1697 Ma for all but one sample, with a mean age of 1752 ± 27 Ma (1 σ). Ages calculated for individual samples are similar to those derived by previous workers using standard analytical techniques. Eleven of these samples define linear trends that intersect the U–Pb concordia at 1741 ± 23 Ma and a Tera-Wasserburg curve at 1740 ± 21 Ma, respectively. These data suggest that the occurrences are epigenetic with respect to host rocks and possibly related to a common metallogenic event, therefore resolving a long-standing controversy about the timing and mode of occurrence of the widespread uranium mineralization in this part of the belt. These ages broadly correlate with a period of migmatization, metamorphism, and granitoid plutonism, as defined by U–Pb zircon geochronological data for regional units. Rare earth element data for uraninite from all concentrates resemble those of uraninite in granite-related deposits. One sample has a distinctly different calculated 207Pb/206Pb age of 495 Ma, indicative of a later remobilization of the ca. 1741 Ma mineralization. The geochemical and geochronological data collectively suggest that the Central Mineral Belt uranium occurrences were related to posttectonic granite magmatism and have no direct genetic relationships with nongranitoid host rocks.

Provenance of igneous clasts in conglomerates of the Archaean Timiskaming Group, Kirkland Lake area, Abitibi greenstone belt, Canada

1994 ◽  
Vol 31 (12) ◽  
pp. 1749-1762 ◽  
Author(s):  
Marc I. Legault ◽  
Keiko Hattori
Keyword(s):  
Greenstone Belt ◽  
Volcanic Rocks ◽  
Hydrothermal Activity ◽  
Tholeiitic Basalt ◽  
Coarse Grained ◽  
Alkaline Magmatism ◽  
Lake Area ◽  
Calc Alkaline ◽  
Intrusive Rocks ◽  
Strike Slip Movement

Four types of igneous clasts from Timiskaming conglomerates of the Kirkland Lake area are identified: calc-alkaline porphyry, trachyte (K2O + N2O > 7.25 wt.%), trondhjemite, and tholeiitic basalt. Clasts derived from quartz–carbonate veins and carbonatized porphyries and komatiites indicate CO2-rich hydrothermal activity along the Larder Lake – Cadillac Fault before sedimentation. Calc-alkaline porphyry, the predominant clast, is similar in appearance to feldspar porphyry intrusions widely exposed in the area, but the two are not related. The porphyry clasts are cogenetic with diorite–granodiorite intrusions and volcanic rocks of the greenstone belt. Andesite clasts are only observed near the base of the assemblage, and the ratio of basalt to andesite increases up stratigraphic sections. The change suggests progressive erosion of arc-related volcanic rocks during sedimentation. Composition, texture, and mineralogy of the trondhjemite clasts are consistent with their derivation from the marginal phases of the Round Lake batholith. Intrusive rocks of the Timiskaming Group (coarse-grained holocrystalline syenitic–monzonitic rocks, biotite-bearing feldspar porphyries, and mica-rich lamprophyres) were not observed in the clasts, which suggests sedimentation prior to unroofing of these rocks. Sedimentation of the conglomerates postdated unroofing of underlying plagioclase porphyry (~2685 Ma), but predated unroofing of Timiskaming intrusions. The distribution of alkaline clasts only in proximity to the fault implies that alkaline magmatism was confined along the fault. Derivation of clasts from both sides of the fault and proximity of inferred sources support a pull-apart basin for sedimentation with minor strike-slip movement during and after the sedimentation.

scholarly journals Tectonics of Volcanogenic Massive Sulphide (VMS) Deposits at Flores Back Arc Basin: A Review

2020 ◽  
Vol 35 (2) ◽  
Author(s):  
Noor CD Aryanto ◽  
Hananto Kurnio
Keyword(s):  
Gold Mineralization ◽  
Tectonic Setting ◽  
Volcanic Rocks ◽  
Hydrothermal Activity ◽  
Basaltic Lava ◽  
Sulphide Deposit ◽  
Volcanogenic Massive Sulphide ◽  
Submarine Ridge ◽  
Vms Deposits ◽  
Back Arc

The bathymetry, petrology, marine magnetic, and seismic-SBP data have identified the northwest-southeast direction submarine ridge that shows hydrothermal activity. This activity occurred through Mount Baruna Komba, Abang Komba, and Ibu Komba. The volcanic rocks are andesite basaltic lava flows, tuff, and pumice. The andesite basaltic lava shows porphyritic, intergranular, intersertal to glomeroporphyritic textures. The rock composes anhedral minerals of k-feldspar, plagioclase, and pyroxene. These minerals present in small-sized, short prismatic dispersed in very fine groundmass minerals or glasses. Most of the volcanic rocks have experienced various degrees of alteration. The k-feldspar and plagioclase are most dominantly transformed into sericite, clay mineral, carbonate, epidote and oxide mineral, opaque mineral, and secondary plagioclase through the albitization process, while pyroxene replaced by chlorite. Other minerals are biotite and quartz, and base metals are present Cu, Zn, Ag, As, Pb, and gold. Mineralization categorizes as the phyllic zone, sub-prophylithic zone, and phyllic-potassic zone that formed at a temperature range of 250-400oC. The submarine hydrothermal alteration in the Komba Ridge is associated with a volcanogenic sulphide deposit controlled by crust thinning due to the crust rifts in the back-arc tectonic setting.

U–Pb zircon ages for the Rice Lake area, southeastern Manitoba

1989 ◽  
Vol 26 (1) ◽  
pp. 23-30 ◽  
Author(s):  
A. Turek ◽  
R. Keller ◽  
W. R. Van Schmus ◽  
W. Weber
Keyword(s):  
Greenstone Belt ◽  
Volcanic Rocks ◽  
Quartz Diorite ◽  
Granitic Rocks ◽  
Lake Area ◽  
The South ◽  
Metasedimentary Rocks ◽  
The North ◽  
Felsic Volcanic ◽  
Felsic Volcanic Rocks

The Archean Rice Lake greenstone belt in southeastern Manitoba is made up of mafic to felsic volcanic rocks and associated intrusive and metasedimentary rocks. The belt is flanked to the north by the Wanipigow River granitic complex and to the south by the Manigotagan gneissic belt. The Ross River quartz diorite pluton is intrusive into the centre of the greenstone belt. U–Pb zircon ages indicate a major volcanic and plutonic event in the area at 2730 Ma. Ages for two volcanic units of the Rice Lake Group are 2731 ± 3 and 2729 ± 3 Ma. The Ross River pluton yields an age of 2728 ± 8 Ma and the Gunnar porphyry gives an age of 2731 ± 13 Ma; both intrude rocks of the Rice Lake Group. Granitic rocks of the Wanipigow River granitic complex give ages of 2731 ± 10 and 2880 ± 9 Ma, while a post-tectonic granite in the Manigotagan gneissic belt has an age of 2663 ± 7 Ma.

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