U-PB zircon age of quartz porphyry from the Kolmozero-Voronja greenstone belt, Kola Peninsula, Russia

1998 ◽  
Vol 43 (S1) ◽  
pp. 69-69
Author(s):  
N. M. Kudryashov ◽  
E. A. Apanasevich
Keyword(s):  
Kola Peninsula ◽  
Greenstone Belt ◽  
Quartz Porphyry ◽  
Zircon Age

U–Pb zircon ages for rocks from the Island Lake greenstone belt, Manitoba

1986 ◽  
Vol 23 (1) ◽  
pp. 92-101 ◽  
Author(s):  
A. Turek ◽  
T. M. Carson ◽  
Patrick E. Smith ◽  
W. R. Van Schmus ◽  
W. Weber
Keyword(s):  
Greenstone Belt ◽  
Quartz Diorite ◽  
Superior Province ◽  
Intrusive Complex ◽  
Quartz Porphyry ◽  
Zircon Age ◽  
Metasedimentary Rocks ◽  
Intrusive Rocks ◽  
Granitoid Rocks

The Archean Hayes River Group of the Island Lake greenstone belt (Superior Province, Sachigo Subprovince) comprises mafic to felsic metavolcanics, subvolcanics, and associated metasedimentary rocks. The Hayes River Group is intruded by granitoid rocks belonging to the early intrusive complex. One such pluton, the Bella Lake tonalite, is intrusive into the metabasalt of the Hayes River Group and has a U–Pb zircon age of 2886 ± 15 Ma. Similar intrusives of this complex, either internal or marginal to the greenstone belt, yield zircon ages of 2801 ± 8 Ma (Pipe Point tonalit) and 2768 ± 22 Ma (Linklater Island prophyry). This suggests that the early intrusive complex was emplaced over an ~ 120 Ma long interval by at least three separate intrusive episodes.Subsequent to the emplacement of the early intrusive complex, the isoclinally folded Hayes River Group and the early intrusive complex were uplifted, eroded, and followed by the unconformable deposition of the Island Lake Group, comprising fluvial to marine metasedimentary rocks. The stratigraphically lower part of the Island Lake Group is bracketed by the 2768 ± 22 Ma age of the Linklater Island porphyry and the 2729 ± 3 Ma age obtained for the late tectonic suite—the Pipe Point quartz diorite and feldspar porphyry. A feldspar quartz porphyry belonging to the post-tectonic intrusive rocks intrudes higher stratigraphic levels and has been dated at 2699 ± 4 Ma (Horseshoe Island quartz feldspar porphyry).

U–Pb ages and tectonic significance of late Archean alkalic magmatism and nonmarine sedimentation: Timiskaming Group, southern Abitibi belt, Ontario

1991 ◽  
Vol 28 (4) ◽  
pp. 489-503 ◽  
Author(s):  
F. Corfu ◽  
S. L. Jackson ◽  
R. H. Sutcliffe
Keyword(s):  
Greenstone Belt ◽  
Early Stage ◽  
Sedimentary Rocks ◽  
Detrital Zircons ◽  
Geochemical Data ◽  
Lake Area ◽  
Quartz Porphyry ◽  
Bear Lake ◽  
Lake Formation ◽  
Dominant Period

The paper presents U–Pb ages for zircons of the calc-alkalic to alkalic igneous suite and associated alluvial–fluvial sedimentary rocks of the Timiskaming Group in the late Archean Abitibi greenstone belt, Superior Province. The Timiskaming Group rests unconformably on pre-2700 Ma komatiitic to calc-alkalic volcanic sequences and is the expression of the latest stages of magmatism and tectonism that shaped the greenstone belt. An age of 2685 ± 3 Ma for the Bidgood quartz porphyry, an age of about 2685–2682 Ma for a quartz–feldspar porphyry clast in a conglomerate, and ages ranging from 2686 to 2680 Ma for detrital zircons in sandstones appear to reflect an early stage in the development of the Timiskaming Group. The youngest detrital zircons in each of three sandstones at Timmins, Kirkland Lake, and south of Larder Lake define maximum ages of sedimentation at about 2679 Ma; the latter sandstone is cut by a porphyry dyke dated by titanite at [Formula: see text], identical to the 2677 ± 2 Ma age for a volcanic agglomerate of the Bear Lake Formation north of Larder Lake. Similar ages have previously been reported for syenitic to granitic plutons of the region. The dominant period of Timiskaming sedimentation and magmatism was thus 2680–2677 Ma. Xenocrystic zircons found in a porphyry and a lamprophyre dyke have ages of 2750–2720 Ma, which correspond to the ages of the oldest units in the belt, predating the volumetrically dominant ca. 2700 Ma greenstone sequences. The presence of these xenocrysts and the onlapping of the Timiskaming Group on all earlier lithotectonic units of the southern Abitibi belt support the concept that the 2700 Ma ensimatic sequences were thrust onto older assemblages during a phase of compression that culminated with the generation of tonalite and granodiorite at about 2695–2688 Ma. Published geochemical data for the Timiskaming igneous suite, notably the enrichments in large-ion lithophile elements and light rare-earth elements and the relative depletion of Nb, Ta, and Ti compare with the characteristics of suites at modern convergent settings such as the Eolian and the Banda arcs and are consistent with generation of the melts from deep metasomatized mantle in the final stages of, or after cessation of, subduction. Late- and post-Timiskaming compression caused north-directed thrusting and folding. Turbiditic sedimentary units of the Larder Lake area which locally structurally overly the alluvial–fluvial sequence and were earlier thought to be part of the Timiskaming Group, appear to be older "flyschoid" sequences, possibly correlative with sedimentary rocks deposited in the Porcupine syncline at Timmins between 2700 and 2690 Ma.

First U–Pb zircon ages of granitoid plutons from the La Grande greenstone belt, James Bay area, New Quebec

1989 ◽  
Vol 26 (5) ◽  
pp. 1068-1073 ◽  
Author(s):  
Karen St. Seymour ◽  
Andrew Turek ◽  
Ronald Doig ◽  
Stephen Kumarapeli ◽  
Robert Fogal
Keyword(s):  
Greenstone Belt ◽  
The Other ◽  
Superior Province ◽  
Present Level ◽  
James Bay ◽  
Zircon Age ◽  
Maximum Deformation ◽  
The Third ◽  
Bay Area ◽  
Greenstone Belts

Zircon ages from three granitoid plutons are the first to be reported from the La Grande greenstone belt. Two of the dated samples are from highly tectonized, early tectonic plutons that at the present level of erosion are just outside the greenstone belt proper. Their zircon ages of ca. 2740 Ma are emplacement ages or alternatively represent the age of maximum deformation of the greenstone belt. The third sample is from a mildly deformed late tectonic pluton within the greenstone belt. Its zircon age of ca. 2670 Ma probably represents the emplacement age. The above dates and the relationships of the dated plutons to the greenstone belt as a whole suggest that the bulk of the volcanism in the La Grande belt is older than 2.7 Ga. This limiting age indicates that the age of the La Grande "supracrustals" is similar to those of the other greenstone belts in the Superior Province.

scholarly journals Mustard Gold in the Oleninskoe Gold Deposit, Kolmozero–Voronya Greenstone Belt, Kola Peninsula, Russia

Minerals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 786 ◽  
Author(s):  
Arkadii A. Kalinin ◽  
Yevgeny E. Savchenko ◽  
Ekaterina A. Selivanova
Keyword(s):  
Kola Peninsula ◽  
Gold Deposit ◽  
Greenstone Belt ◽  
Noble Metals ◽  
Fennoscandian Shield ◽  
Silver Deposit ◽  
Partial Removal ◽  
Gold Silver ◽  
The Matrix ◽  
Gold Bearing

The Oleninskoe intrusion-related gold–silver deposit is the first deposit in the Precambrian of the Fennoscandian Shield, where mustard gold has been identified. The mustard gold replaces küstelite with impurities of Sb and, probably, gold-bearing dyscrasite and aurostibite. The mosaic structure of the mustard gold grains is due to different orientations and sizes of pores in the matrix of noble metals. Zonation in the mustard gold grains is connected with mobilization and partial removal of silver from küstelite, corresponding enrichment of the residual matter in gold, and also with the change in the composition of the substance filling the pores. Micropores in the mustard gold are filled with iron, antimony or thallium oxides, silver chlorides, bromides, and sulfides. The formation of mustard gold with chlorides and bromides shows that halogens played an important role in the remobilization of noble metals at the stage of hypergene transformation of the Oleninskoe deposit.

scholarly journals 3.3Ga SHRIMP U–Pb zircon age of a felsic metavolcanic rock from the Mundo Novo greenstone belt in the São Francisco craton, Bahia (NE Brazil)

2002 ◽  
Vol 15 (3) ◽  
pp. 363-373 ◽  
Author(s):  
J.J Peucat ◽  
J.F Mascarenhas ◽  
J.S.F Barbosa ◽  
S.L de Souza ◽  
M.M Marinho ◽  
...  
Keyword(s):  
Greenstone Belt ◽  
Metavolcanic Rock ◽  
Zircon Age

U–Pb zircon geochronology in the southwestern Abitibi greenstone belt, Superior Province

1989 ◽  
Vol 26 (9) ◽  
pp. 1747-1763 ◽  
Author(s):  
F. Corfu ◽  
T. E. Krogh ◽  
Y. Y. Kwok ◽  
L. S. Jensen
Keyword(s):  
Greenstone Belt ◽  
Gold Mineralization ◽  
Superior Province ◽  
Zircon Geochronology ◽  
Zircon Age ◽  
The Past ◽  
Sedimentary Sequences ◽  
Lake Region ◽  
Apparent Age ◽  
Stratigraphic Thickness

The Abitibi Belt is the largest continuous greenstone belt in the Superior Province of the Canadian Shield. It comprises several composite komatiitic–tholeiitic–calc-alkalic and sedimentary sequences that are folded, transected by major faults, and intruded by various generations of plutonic rocks. Precise U–Pb geochronology has been carried out in the belt for the past decade to solve chronostratigraphic and metallogenetic problems. This paper presents new zircon ages and reassesses previously published ones, now refined by the addition of abraded and concordant zircon analyses.Volcanic and subvolcanic units of the Timmins area yield the following ages: 2727 ± 1.5 Ma for a tuff of the upper Deloro Formation; 2703 ± 1.5 Ma for a tuff of the upper Tisdale Formation; and 2698 ± 4 Ma for the Krist fragmental, assigned to the top of the Tisdale Formation. The age of a dunite intrusive into the upper Deloro Formation is revised at 2707 ± 3 Ma, whereas the Aquarius diorite east of Timmins yields a poorly defined age of 2705 ± 10 Ma. In the Lake Abitibi – Kirkland Lake region, the following dates were obtained: 2713 ± 2 Ma for a porphyritic unit of the Hunter Mine Group; 2714 ± 2 Ma for a rhyolite at the base of the mainly tholeiitic to komatiitic Stoughton–Roquemaure Group; 2701 ± 2 Ma for porphyritic rhyolite of the Blake River Group; 2701 ± 2 Ma for a tuff of the Skead Group; and [Formula: see text] for a pyroclastic unit at the base of the Larder Lake Group. These data are generally consistent with the earlier proposed stratigraphic subdivisions and correlations. However, there are apparent age reversals, for example between the Larder Lake and Skead groups, that could support the concept of thrusting and tectonic thickening to explain particular lithologic relationships and the considerable stratigraphic thickness of the supracrustal sequences in the Abitibi Belt.One part of the study was dedicated to the problem of gold mineralization in the Timmins area. The zircon age of 2690 ± 2 Ma for the Paymaster porphyry, a less well defined but probably identical age for the Preston porphyry, and dates of 2689 ± 1 Ma for the Pearl Lake porphyry, 2691 ± 3 Ma for the Millerton porphyry, and 2688 ± 2 Ma for the Crown porphyry show that these intrusions were formed during a well-defined, short-lived episode unrelated to volcanism; furthermore, a date of [Formula: see text] for an albitite, which predates Au mineralization, demonstrates that Au is spatially but not genetically related to the porphyries.Finally, two ages are reported for late tectonic potassic intrusions: a refined age of 2678 ± 2 Ma for the Garrison stock east of Matheson and a precise zircon (and titanite) age of 2680 ± 1 Ma for the Otto stock near Kirkland Lake.

Sign in / Sign up

Export Citation Format

Share Document