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.

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.

Geochemistry and origin of the Regan Intrusive Suite and other granitoids in the northeastern Slave Province, northwest Canadian Shield

1985 ◽  
Vol 22 (7) ◽  
pp. 1048-1065 ◽  
Author(s):  
R. A. Frith ◽  
B. J. Fryer
Keyword(s):  
Rare Earth ◽  
Regional Metamorphism ◽  
Volcanic Rocks ◽  
Parental Magma ◽  
Quartz Diorite ◽  
Heavy Rare Earth Elements ◽  
Flow Differentiation ◽  
Felsic Volcanic ◽  
Intrusive Suite ◽  
Host Rocks

The Regan Intrusive Suite of about 100 plutons of tonalite, granodiorite, and quartz diorite intruded the Yellowknife Supergroup and migmatite terrain in the northwest Slave Structural Province 2.59 Ga ago. Rare-earth-element (REE), trace-element, and major-element analyses from 39 representative whole rocks from the suite suggest it was derived by batch melting of the crust, producing a parental magma of tonalitic or granodioritic composition. By analysing REE from different parts of a zoned pluton, it was concluded that REE distribution was controlled by early separation of quartz diorite from the parent magma by flow differentiation and that the bulk of the REE were contained in early, cumulate, accessory apatite and monazite. The residual magma was further fractionated in pipelike magma chambers during ascent into more leucocratic rocks. Chondrite-normalized REE patterns of single-lithology plutons are similar to lithologies in zoned plutons, and it is proposed they initially segregated during ascent. It was found that granites, which were formerly grouped with the suite, formed in three ways, only one of which is related to the Regan Intrusive Suite.Study of 2.67 Ga old synvolcanic tonalite pluton revealed a strong covariance of light REE with those of the bimodal, calc-alkaline Hackett River Group of volcanic rocks. The data imply a common crustal source, but mass balance requires larger volumes of felsic volcanic rocks than are presently preserved, suggesting that much of the erupted felsic pyroclastic rocks were eroded. Partial melts from synvolcanic tonalite during subsequent regional metamorphism differentially depleted host rocks in REE and concentrated Eu and heavy rare-earth elements (HREE) in trondhjemite pegmatites.

scholarly journals New U-Pb geochronological data on the age of volcanic-plutonic assemblage of Oloy belt, Alazey-Oloy fold system (West Chukotka)

2019 ◽  
Vol 487 (6) ◽  
pp. 653-658
Author(s):  
T. V. Kara ◽  
M. V. Luchitskaya ◽  
S. M. Katkov ◽  
E. A. Belousova
Keyword(s):  
Early Cretaceous ◽  
Late Jurassic ◽  
Volcanic Rocks ◽  
Volcanic Belt ◽  
Geochronological Data ◽  
Fold System ◽  
Hypabyssal Intrusions ◽  
Icp Ms ◽  
Age Limits ◽  
Felsic Volcanic

New U-Pb (SIMS and LA-ICP-MS) geochronological data for rocks of Egdygkych complex of hypabyssal intrusions, Nichan and Vukney plutons, and felsic volcanic rocks and tuffs from host strata of Oloy volcanic belt of Alasey-Oloy fold system are obtained. Concordant ages of Egdygkych complex rocks correspond to Early Cretaceous (Berriasian-Valanginian), those for host strata, to the end of Late Jurassic (Tithonian) - beginning of Early Cretaceous (Berriasian). New U-Pb geochronological data allow confidently to distinguish uniform volcanic-plutonic assemblage of Late Jurassic (Tithonian) - Early Cretaceous (Berriasian-Valanginian) age of Oloy volcanic belt. Obtained data more definitely determine age limits of Au-Mo-Cu mineralization, associated with contacts between rocks of Egdydkych complex and host volcanic-sedimentary rocks or contacts of separated intrusive phases.

Isotopic Studies of Ore-Leads in the Hanson Lake-Flin Flon-Snow Lake Mineral Belt Saskatchewan and Manitoba

1972 ◽  
Vol 9 (5) ◽  
pp. 500-513 ◽  
Author(s):  
D. F. Sangster
Keyword(s):  
Volcanic Rocks ◽  
Massive Sulfide ◽  
Good Evidence ◽  
Lake Area ◽  
Sulfide Ores ◽  
Geological Evidence ◽  
Isotopic Studies ◽  
Mineral Belt ◽  
Flin Flon ◽  
Host Rocks

Lead isotope abundances in 4 stratabound sulfide ores are presented and show characteristics of being single-stage lead deposits. Model ages based on these data range from 1780 ± 44 to 1900 ± 44 m.y. and are considered to be close approximations of the time of ore formation. Geological evidence in the massive sulfide deposits suggests they are coeval with their host rocks, which are predominantly volcanics of the Amisk Group. If this assumption is correct the average model lead age of the ores is essentially the age of the enclosing rocks. Within error limits the results are in good agreement with published Rb-Sr ages for Amisk rocks of the Flin Flon area, and with U-Pb ages in zircons of rhyolites, which also contain similar, massive sulfide ores in the Churchill Province of Arizona. This is considered to be good evidence that the Hanson Lake-Flin Flon-Snow Lake volcanic mineral belt, previously regarded as Archean, is Aphebian in part.A previously published Archean, Rb-Sr isochron for volcanic rocks in the Hanson Lake area may indicate that Amisk-type rocks are a folded complex of both Aphebian and Archean lithologies. The suggested Aphebian age of the Amisk-Missi Groups and their equivalents, indicates they are possibly eugeosynclinal equivalents of the miogeosynclinal Hurwitz sediments.

Tectonic evolution of southwestern Newfoundland as indicated by granitoid petrogenesis

1985 ◽  
Vol 22 (7) ◽  
pp. 1080-1092 ◽  
Author(s):  
Derek H. C. Wilton
Keyword(s):  
Fault Zone ◽  
Point Group ◽  
Volcanic Rocks ◽  
Early Carboniferous ◽  
Late Devonian ◽  
Partial Melt ◽  
Show Evidence ◽  
Partial Melts ◽  
Felsic Volcanic ◽  
Host Rocks

Four granitoid suites are recognized in the region of the Cape Ray Fault Zone of southwestern Newfoundland. The two oldest (Ordovician–Silurian (?)) suites represent partial melts of their enclosing host rocks. The Port aux Basques granite is modelled as a partial melt of the gneissic component of its host, Port aux Basques Complex. The Cape Ray granite forms a dominantly tonalitic terrane derived by partial melting of ophiolitic material. The Red Rocks granite and a megacrystic phase of the Cape Ray granite form coherent lines of geochemical descent from the parental tonalite but show evidence of some continental crust contamination.The Late Devonian Windowglass Hill granite is a subvolcanic equivalent of felsic volcanic rocks in the Windsor Point Group. Both units were derived as partial melts of continental crust.The post-tectonic, Late Devonian to Early Carboniferous Strawberry and Isle aux Morts Brook granites constitute the youngest granitoid suite in the region. These A-type granitoids were derived as partial melts of an underlying depleted granulitic (felsic) crust. The depleted nature of the source may have resulted from previous generation of the Windowglass Hill granite and Windsor Point Group. The only possible protolith for the granulitic source is Precambrian Grenvillian gneiss. The presence of this gneiss beneath the Cape Ray Fault Zone of southwestern Newfoundland implies that the complete series of lithologies is allochthonous.

scholarly journals Permian A-type rhyolites of the Muráň Nappe, Inner Western Carpathians, Slovakia: in-situ zircon U–Pb SIMS ages and tectonic setting

2018 ◽  
Vol 69 (2) ◽  
pp. 187-198 ◽  
Author(s):  
Martin Ondrejka ◽  
Xian-Hua Li ◽  
Rastislav Vojtko ◽  
Marian Putis ◽  
Pavel Uher ◽  
...  
Keyword(s):  
Tectonic Setting ◽  
Volcanic Rocks ◽  
Western Carpathians ◽  
Magmatic Activity ◽  
Extensional Tectonics ◽  
Geochronological Data ◽  
Pb Isotope ◽  
Isotope Technique ◽  
Rhyolitic Rock

AbstractThree representative A-type rhyolitic rock samples from the Muráň Nappe of the inferred Silicic Unit of the Inner Western Carpathians (Slovakia) were dated using the high-precision SIMS U–Pb isotope technique on zircons. The geochronological data presented in this paper is the first in-situ isotopic dating of these volcanic rocks. Oscillatory zoned zircon crystals mostly revealed concordant Permian (Guadalupian) ages: 266.6 ± 2.4 Ma in Tisovec-Rejkovo (TIS-1), 263.3 ± 1.9 Ma in Telgárt-Gregová Hill (TEL-1) and 269.5 ± 1.8 Ma in Veľká Stožka-Dudlavka (SD-2) rhyolites. The results indicate that the formation of A-type rhyolites and their plutonic equivalents are connected to magmatic activity during the Permian extensional tectonics and most likely related to the Pangea supercontinent break-up.

scholarly journals Supplemental Material: Tracing fluid evolution in sedimentary basins with calcite geochemical, isotopic and U-Pb geochronological data: Implications for petroleum and mineral resource accumulation in the Nanpanjiang Basin, South China

2021 ◽  
Author(s):  
Xiang Ge ◽  
Chuanbo Shen ◽  
et al.
Keyword(s):  
Mineral Resource ◽  
South China ◽  
Sedimentary Basins ◽  
Geochronological Data ◽  
Pb Isotope ◽  
Isotope Data ◽  
Se Asia ◽  
Icp Ms ◽  
Tectonic Reconstruction

Figure S1: Tectonic reconstruction maps for SE Asia; Table S1: Calcite LA-ICP-MS in situ U-Pb isotope data.

Metallogenic and tectonic implications of Pb isotope data for galena separates from the Labrador Central mineral belt; discussion

1992 ◽  
Vol 87 (8) ◽  
pp. 2180-2184
Author(s):  
Sunil S. Gandhi ◽  
Ralph I. Thorpe
Keyword(s):  
Pb Isotope ◽  
Isotope Data ◽  
Tectonic Implications ◽  
Mineral Belt
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