Stratigraphic framework of zinc–lead deposits in the northern Cordillera northeast of the Tintina Trench

1979 ◽  
Vol 16 (2) ◽  
pp. 380-385
Author(s):  
Graeme P. McLaren ◽  
Colin I. Godwin
Keyword(s):  
Sedimentary Rocks ◽  
Minor Element ◽  
Late Cambrian ◽  
Time Space ◽  
Stratigraphic Framework ◽  
Geologic Map ◽  
Carbonate Sequence ◽  
Space Projection ◽  
Host Rocks ◽  
Two Populations

Two major groups of sedimentary rocks hosting zinc–lead deposits in the northern Canadian Cordillera can be distinctly partitioned on the basis of depositional tectonics. A Proterozoic to Early Cambrian succession of carbonates and elastics is separated from a Late Cambrian to Devonian basinal shale and laterally equivalent platformal carbonate sequence by a regional erosional hiatus. This partitioning is emphasized by bimodal minor element distributions in carbonate-hosted sphalerite found throughout these rocks. Two populations of sphalerite, individually contained within the two major groups of host rocks, are separated by a unit that is relatively barren of mineralization. A regional geologic map, diagrammatic cross section, and time–space projection illustrate the stratigraphy, depositional tectonics, and location of sphalerite occurrences, and are presented as a framework for further research.

The Duck Pond and Boundary Cu–Zn deposits, Newfoundland: new insights into the ages of host rocks and the timing of VHMS mineralization

2010 ◽  
Vol 47 (12) ◽  
pp. 1481-1506 ◽  
Author(s):  
Vicki McNicoll ◽  
Gerry Squires ◽  
Andrew Kerr ◽  
Paul Moore
Keyword(s):  
Volcanic Rocks ◽  
Sedimentary Rocks ◽  
Isotopic Data ◽  
Sulphide Ores ◽  
Intrusive Rocks ◽  
Felsic Volcanic ◽  
Host Rocks ◽  
Felsic Volcanic Rocks

The Duck Pond Cu–Zn–Pb–Ag–Au deposit in Newfoundland is hosted by volcanic rocks of the Cambrian Tally Pond group in the Victoria Lake supergroup. In conjunction with the nearby Boundary deposit, it contains 4.1 million tonnes of ore at 3.3% Cu, 5.7% Zn, 0.9% Pb, 59 g/t Ag, and 0.9 g/t Au. The deposits are hosted by altered felsic flows, tuffs, and volcaniclastic sedimentary rocks, and the sulphide ores formed in part by pervasive replacement of unconsolidated host rocks. U–Pb geochronological studies confirm a long-suspected correlation between the Duck Pond and Boundary deposits, which appear to be structurally displaced portions of a much larger mineralizing system developed at 509 ± 3 Ma. Altered aphyric flows in the immediate footwall of the Duck Pond deposit contained no zircon for dating, but footwall stringer-style and disseminated mineralization affects rocks as old as 514 ± 3 Ma at greater depths below the ore sequence. Unaltered mafic to felsic volcanic rocks that occur structurally above the orebodies were dated at 514 ± 2 Ma, and hypabyssal intrusive rocks that cut these were dated at 512 ± 2 Ma. Some felsic samples contain inherited (xenocrystic) zircons with ages of ca. 563 Ma. In conjunction with Sm–Nd isotopic data, these results suggest that the Tally Pond group was developed upon older continental or thickened arc crust, rather than in the ensimatic (oceanic) setting suggested by previous studies.

scholarly journals Satunarcus, a new late Cambrian trilobite genus from southernmost Thailand and a reevaluation of the subfamily Mansuyiinae Hupé, 1955

2020 ◽  
Vol 94 (5) ◽  
pp. 867-880
Author(s):  
Shelly J. Wernette ◽  
Nigel C. Hughes ◽  
Paul M. Myrow ◽  
Apsorn Sardsud
Keyword(s):  
North China ◽  
New Genus ◽  
Sedimentary Rocks ◽  
Cladistic Analysis ◽  
New Genus And Species ◽  
Natural Group ◽  
Middle Cambrian ◽  
Current Definition ◽  
Late Cambrian ◽  
Cambrian Trilobite

AbstractThe Ao Mo Lae Formation of the Tarutao Group crops out on Thailand's Tarutao Island and contains a diverse assemblage of late Furongian trilobite taxa, including several endemic forms. This study presents a new genus and species, Satunarcus molaensis, discovered at two locations on the island. A cladistic analysis of the kaolishaniid subfamily Mansuyiinae in light of Satunarcus and similar genera known from across upper Cambrian equatorial Gondwanan rocks suggests that the subfamily is polyphyletic in its current definition, and thus is not a natural group. Separating Mansuyia Sun, 1924 from the other taxa conventionally placed in Mansuyiinae permits recognition of a previously unrecognized monophyletic subfamily Ceronocarinae new subfamily. As established herein, this kaolishaniid subfamily contains Satunarcus n. gen. and all genera previously recognized as Mansuyiinae. with the exception of Mansuyia itself. Ceronocarinae n. subfam. occur in middle Jiangshanian to middle Cambrian Stage 10 sedimentary rocks from Australia, South China, North China, and Sibumasu, with most genera endemic to Australia.UUID: http://zoobank.org/618c5136-73f0-4912-a7d3-e56559d2a76c

Stratigraphy and lithogeochemistry of rocks from the Nugget Pond Deposit area, Baie Verte Peninsula, Newfoundland

2021 ◽  
Author(s):  
C Mueller ◽  
S J Piercey ◽  
M G Babechuk ◽  
D Copeland
Keyword(s):  
Gold Mineralization ◽  
Sedimentary Rocks ◽  
Mafic Rocks ◽  
Basaltic Rocks ◽  
Late Cambrian ◽  
Lower Unit ◽  
Iapetus Ocean ◽  
Post Archean Australian Shale ◽  
Clastic Sedimentary ◽  
Ocean Ridge

Stratigraphic and lithogeochemical data were collected from selected drill core from the Nugget Pond gold deposit in the Betts Cove area, Newfoundland. The stratigraphy consists of a lower unit of basaltic rocks that are massive to pillowed (Mount Misery Formation). This is overlain by sedimentary rocks of the Scrape Point Formation that consist of lower unit of turbiditic siltstone and hematitic cherts/iron formations (the Nugget Pond member); the unit locally has a volcaniclastic rich-unit at its base and grades upwards into finer grained volcaniclastic/turbiditic rocks. This is capped by basaltic rocks of the Scrape Point Formation that contain pillowed and massive mafic flows that are distinctively plagioclase porphyritic to glomeroporphyritic. The mafic rocks of the Mount Misery Formation have island arc tholeiitic affinities, whereas Scrape Point Formation mafic rocks have normal mid-ocean ridge (N-MORB) to backarc basin basalt (BABB) affinities. One sample of the latter formation has a calc-alkalic affinity. All of these geochemical features are consistent with results and conclusions from previous workers in the area. Clastic sedimentary rocks and Fe-rich sedimentary rocks of the Scrape Point Formation have features consistent with derivation from local, juvenile sources (i.e., intra-basinal mafic rocks). The Scrape Point Formation sedimentary rocks with the highest Fe/Al ratios, inferred to have greatest amount of hydrothermally derived Fe, have positive Ce anomalies on Post-Archean Australian Shale (PAAS)-normalized trace element plots. These features are consistent with having formed via hydrothermal venting into an anoxic/ sub-oxic water column. Further work is needed to test whether these redox features are a localized feature (i.e., restricted basin) or a widespread feature of the late Cambrian-early Ordovician Iapetus Ocean, as well as to delineate the role that these Fe-rich sedimentary rocks have played in the localization of gold mineralization within the Nugget Pond deposit.

Hydrothermal alteration, veining, and fluid-inclusion characteristics of the Kalzas wolframite deposit, Yukon

1989 ◽  
Vol 26 (10) ◽  
pp. 2106-2115 ◽  
Author(s):  
J. V. Gregory Lynch
Keyword(s):  
Hydrothermal Alteration ◽  
Sedimentary Rocks ◽  
Hydrothermal Activity ◽  
Contact Metamorphism ◽  
Quartz Veins ◽  
The Core ◽  
Outer Periphery ◽  
Windermere Supergroup ◽  
Homogenization Temperatures ◽  
Host Rocks

Kalzas is a sheeted vein and stockwork wolframite deposit, crosscutting continental margin sedimentary rocks of the Proterozoic Windermere Supergroup in central Yukon. Mineralization is synchronous with Cretaceous post-tectonic granites of the Selwyn Plutonic Suite.Parallel sets of planar quartz veins contain coarse euhedral wolframite and are generally oriented perpendicular to southeast-plunging fold axes. Widespread alteration of the host rocks and intense stockwork veining surround the veins. Alteration and mineralization show a distinct concentric zonation across a 2.5 km long southeast-trending oval. The core zone is characterized by orthoclase contained within quartz–tourmaline–wolframite veins. Minor phases include apatite, molybdenite, bismuthinite, pyrite, chalcopyrite, and pyrrhotite. Host rocks are prevasively tourmalinized and sericitized. Hydrothermal alteration here at the core of the system overprints early biotitization of the host rocks. The biotitization appears to have been the result of earlier contact metamorphism from a hidden pluton situated beneath the deposit that converted the chloritic groundmass of the metasediments to biotite. At the fringe of wolframite mineralization, cassiterite occurs with quartz, muscovite, and tourmaline, whereas orthoclase is distinctly lacking. The outer periphery of the concentrically zoned sequence features pervasive sericitization, disseminated pyrite, and the disappearance of tourmaline. Here, quartz veins are barren except for minor galena.Three main stages mark the mineralogical evolution of the deposit: (1) early biotitization of the chloritic host rocks in the core area; (2) quartz-dominated veining with internally complex timing relations, hydrothermal alteration, and zoning; and (3) carbonate veining and replacement of wolframite by scheelite.Fluid inclusions within quartz are dominated by H2O and contain variable amounts of CO2 as well as minor CH4 and NaCl. The CO2 content ranges from approximately 0 to 6 mol%. The fluids are generally dilute but locally contain as much as 7 wt.% NaCl equivalent. Homogenization temperatures are variable: for quartz, 160–340 °C; for cassiterite, 280–350 °C; and for apatite, 220–360 °C. Minimum hydrothermal pressures at the time of mineralization are estimated to have been in the range 300–600 bar (1 bar = 100 kPa). Fluctuations in pressure with cooling appear to have resulted in CO2 immiscibility and the formation of late-stage carbonates at the termination of hydrothermal activity.

Stratigraphic framework for the Cambrian–Ordovician rift and passive margin successions from southern Quebec to western Newfoundland

2003 ◽  
Vol 40 (2) ◽  
pp. 177-205 ◽  
Author(s):  
Denis Lavoie ◽  
Elliott Burden ◽  
Daniel Lebel
Keyword(s):  
Sea Level ◽  
Continental Margin ◽  
Passive Margin ◽  
Early Cambrian ◽  
Sea Level Fluctuations ◽  
Late Cambrian ◽  
Head Groups ◽  
Stratigraphic Framework ◽  
Lower Ordovician ◽  
First Time

The Taconian Humber Zone stretches from western Newfoundland to southern Quebec. The Early Cambrian slope succession in Newfoundland is found in the Curling Group, whereas in Quebec, various units were deposited during that first time slice. Biostratigraphic data allow correlation of the Curling Group with the Labrador Group in Newfoundland and with the newly time-constrained slope succession in Quebec. The end of the rift–drift transition is marked by a sea-level lowstand at the end of the Early Cambrian. The Middle Cambrian to latest Early Ordovician passive margin history recorded five cyclic sea-level fluctuations. Three of these cycles are recorded in the shallow-marine Middle to Late Cambrian platform (Port au Port Group) and slope sediments preserved in the Cow Head and Northern Head groups in Newfoundland. The biostratigraphic information assists correlation with Cambrian passive margin units in Quebec. Major sea-level lowstands are recognized along the continental margin in early–middle Late Cambrian (Steptoan) and in late Late Cambrian (Sunwaptan). Even if the Quebec succession can be tied with its Newfoundland correlative, some significant differences in the nature of Upper Cambrian slope conglomerates argue for a tectonic control on the depth of erosion of the Cambrian continental margin. The Lower Ordovician record of the passive margin consists of two depositional cycles (Tremadocian–Arenigian) separated by a sea-level lowstand. This last event is well expressed in platform succession and is also recognized in conglomerate units found in the slope succession.

scholarly journals Petrology and mineralogy of the Ulaan Del Zr-Nb-REE deposit, Lake Zone, Western Mongolia

2020 ◽  
Vol 50 ◽  
pp. 45-62
Author(s):  
Sanjsuren Oyunbat
Keyword(s):  
Fine Grained ◽  
Late Cambrian ◽  
Hydrothermal Processes ◽  
Western Mongolia ◽  
Lake Zone ◽  
High K ◽  
Ore Minerals ◽  
Type Granite ◽  
Host Rocks ◽  
Syenite Porphyry

The Ulaan Del deposit is located in the Lake Zone, Western Mongolia. In the area, middle-late Devonian alkali dykes of the Khalzan Complex are hosted in the middle-late Cambrian granodiorite-tonalite of the Togthohiinshil Complex. The alkali dykes of the Khalzan complex comprise medium- to fine-grained syenite, microsyenite, syenite-porphyry and trachyte, trachyrhyolite, and trachyandesite. The dykes are replaced to silica, sericite, albite, fluorite and are brecciated. They crosscut by quartz and quartz-carbonate veinlets. The dykes contain zircon (>0.19% Zr) with a total of rare earth elements oxides >0.1%. The host rocks of the Togtokhiinshil complex are mid-K, metaluminous, I- type granite, depleted in HFSE. Based on geochemical and mineralogical data, economic REE mineralization is concentrated in syenite and syenite porphyry of calc-alkaline high K to shoshonite series of A- type granite, emplaced at within a plate setting. Syenite dykes are enriched in REE. Ore minerals are zircon, apatite, sphene, monazite, xenotime, synchysite, parisite, fluorite and REE complex minerals, pyrite, rutile and limonite. Magmatic, metasomatic and hydrothermal processes significantly contributed to the formation of Zr, Nb, REE and Y mineralization at the Ulaan Del deposit.

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