Geochronology of detrital zircons from the Elzevir and Frontenac terranes, Central Metasedimentary Belt, Grenville Province, Ontario

1993 ◽  
Vol 30 (3) ◽  
pp. 465-473 ◽  
Author(s):  
E. Anne Sager-Kinsman ◽  
R. R. Parrish
Keyword(s):  
Detrital Zircons ◽  
Time Interval ◽  
Adirondack Mountains ◽  
Sedimentary Sequence ◽  
Grenville Province ◽  
Clastic Rocks ◽  
Metavolcanic Rocks ◽  
Group A ◽  
Clastic Sedimentary ◽  
Detrital Zircon Ages

The Central Metasedimentary Belt (CMB) of the Grenville Province contains metasedimentary sequences belonging to a number of distinct tectono-stratigraphic terranes whose depositional ages are poorly known. This study provides information on not only the provenance, but also the maximum age of clastic rocks in two of these terranes, the Elzevir Terrane on the northwest and the Frontenac Terrane to its southeast, adjacent to the Adirondack Mountains of New York.The Flinton Group, a component of the Elzevir Terrane, is a distinctive, mostly clastic, sedimentary sequence that unconformably overlies igneous and metavolcanic rocks of the main part of Elzevir Terrane of the CMB. Analyzed zircons from quartzose metasediments of the Flinton Group are 0–2% discordant and range in age from 1150 to 1335 Ma, with older rounded grains at 1461 ± 5 and 1877 ± 3 Ma. The quartzite was therefore deposited after ca. 1150 Ma, indicating that the Flinton Group is more than 100 Ma younger than the intrusion of the underlying Elzevir batholith. We speculate that 1150–1180 Ma zircons within the Flinton Group were derived from plutons in the Frontenac Terrane to the southeast, implying that the Elzevir and Frontenac terranes were contiguous during Flinton Group deposition. Subsequent metamorphism of the Flinton Group occured between 1150 and 1080 Ma.The high-grade Frontenac Terrane of the CMB lies southeast of Elzevir Terrane, and contains marble associated with pelitic gneiss and quartzite, as well as granitic intrusive rocks; it resembles a metamorphosed continental margin sedimentary sequence. U–Pb analyses of zircons from quartzites from two different localities are generally less than 5% discordant, but show stronger evidence for Grenvillian Pb loss than zircons from the Flinton Group. 207Pb/206Pb ages range from 1493 to 2580 Ma, with one analysis (2% discordant) at 1306 ± 16 Ma, another at 3185 ± 3 Ma, and a cluster of ages between 1745 and 1892 Ma. Detrital zircon ages are, for the most part, distinctly older than in the Flinton Group. The age of this quartzite sequence is tentatively regarded as less than ca. 1300 Ma (based on one grain), but is certainly less than 1500 Ma. It could therefore have been deposited during the same time interval as the 1.2–1.3 Ga metasedimentary and metavolcanic rocks of the Elzevir Terrane. Although Frontenac Terrane experienced metamorphism along with Elzevir Terrane around 1.1 Ga, the principle metamorphic culmination in the Frontenac occurred prior to 1170 Ma.

A fault-bounded outlier of Archean clastic rocks near Thunder Bay, Ontario

1988 ◽  
Vol 25 (1) ◽  
pp. 152-157
Author(s):  
M. M. Kehlenbeck
Keyword(s):  
Sedimentary Sequence ◽  
Clastic Rocks ◽  
Basin Structure ◽  
Thunder Bay ◽  
Crenulation Cleavage ◽  
Metavolcanic Rocks ◽  
Internal Disruption ◽  
Clastic Sedimentary

A fault-bounded clastic sedimentary sequence occurs as an outlier in contact with a terrane of Archean metavolcanic rocks. In addition to a regional penetrative fabric, the rocks of the clastic sequence possess a crenulation cleavage that is axial planar to a set of minor, north-plunging folds. Abundant faulting of the clastic rocks has resulted in significant internal disruption of the sequence as a whole and suggests it is a down-faulted block of a basin structure.

U–Pb age constraints on arenaceous and volcanic rocks of the Wakeham Group, eastern Grenville Province

2005 ◽  
Vol 42 (10) ◽  
pp. 1677-1697 ◽  
Author(s):  
O van Breemen ◽  
L Corriveau
Keyword(s):  
Volcanic Rocks ◽  
Detrital Zircons ◽  
Morphological Evidence ◽  
Ionization Mass ◽  
Grenville Province ◽  
Metavolcanic Rocks ◽  
Southeastern Margin ◽  
Depositional Age ◽  
Age Constraints ◽  
Group Yield

Combined sensitive high-resolution ion microprobe (SHRIMP) and thermal ionization mass spectrometry (TIMS) U–Pb zircon data from a tightly constrained stratigraphic context of the Wakeham Group provide a precise depositional age for sedimentation within this extensive basin of the Grenville Province. Metavolcanic rocks at the eastern exposure of the Wakeham Group yield ages of 1511 ± 13, 1506 ± 11, 1502 ± 9, and 1491 ± 7 Ma. A crosscutting 1493 ± 10 Ma porphyry vein marks the end of volcanism. The older two volcanic rocks rest stratigraphically above metasediments, with a 1517 ± 20 Ma maximum age of sedimentation derived from the youngest detrital zircons of an arenite. Five 1.61–1.55 Ga inherited zircons in the volcanics, reinforced by coeval inheritance in nearby plutons, indicate a Labradorian basement source to the supracrustals. The predominant arenite detrital zircons dates are in the 1.95–1.75 Ga range, however, and feature both trace element and morphological evidence for metamorphism in the source terrane. Together with zircons as old as 2.95 Ga, the detrital age spectrum is consistent with a circum-Superior provenance. The ages obtained imply that Wakeham Group volcanism and sedimentation were, at least in part, coeval with the onset of 1.52–1.46 Ga Pinwarian plutonism along the southeastern margin of Laurentia. U–Pb zircon analyses record a late Grenvillian metamorphic event around 1019 Ma. U–Pb monazite analyses from one sample yield 1010–1000 Ma ages, and the end of Grenvillian metamorphism is marked by 990 Ma U–Pb titanite ages.

scholarly journals Permo-Carboniferous conglomerates in the Trinity Peninsula Group at View Point, Antarctic Peninsula: sedimentology, geochronology and isotope evidence for provenance and tectonic setting in Gondwana

2011 ◽  
Vol 149 (4) ◽  
pp. 626-644 ◽  
Author(s):  
JOHN D. BRADSHAW ◽  
ALAN P. M. VAUGHAN ◽  
IAN L. MILLAR ◽  
MICHAEL J. FLOWERDEW ◽  
RUDOLPH A. J. TROUW ◽  
...  
Keyword(s):  
Antarctic Peninsula ◽  
Detrital Zircon ◽  
Tectonic Setting ◽  
Detrital Zircons ◽  
View Point ◽  
Transport Distance ◽  
Clastic Sedimentary ◽  
Detrital Zircon Ages ◽  
The Antarctic ◽  
The Trinity

AbstractField observations from the Trinity Peninsula Group at View Point on the Antarctic Peninsula indicate that thick, southward-younging and overturned clastic sedimentary rocks, comprising unusually coarse conglomeratic lenses within a succession of fine-grained sandstone–mudstone couplets, are the deposits of debris and turbidity flows on or at the foot of a submarine slope. Three detrital zircons from the sandstone–mudstone couplets date deposition at 302 ± 3 Ma, at or shortly after the Carboniferous–Permian boundary. Conglomerates predominantly consist of quartzite and granite and contain boulders exceeding 500 mm in diameter. Zircons from granitoid clasts and a silicic volcanic clast yield U–Pb ages of 466 ± 3 Ma, 373 ± 5 Ma and 487 ± 4 Ma, respectively and have corresponding average εHft values between +0.3 and +7.6. A quartzite clast, conglomerate matrix and sandstone interbedded with the conglomerate units have broadly similar detrital zircon age distributions and Hf isotope compositions. The clast and detrital zircon ages match well with sources within Patagonia; however, the age of one granite clast and the εHf characteristics of some detrital zircons point to a lesser South Africa or Ellsworth Mountain-like contribution, and the quartzite and granite-dominated composition of the conglomerates is similar to upper Palaeozoic diamictites in the Ellsworth Mountains. Unlike detrital zircons, large conglomerate clasts limit possible transport distance, and suggest sedimentation took place on or near the edge of continental crust. Comparison with other upper Palaeozoic to Mesozoic sediments in the Antarctic Peninsula and Patagonia, including detrital zircon composition and the style of deformation, suggests deposition of the Trinity Peninsula Group in an upper plate basin on an active margin, rather than a subduction-related accretionary setting, with slow extension and rifting punctuated by short periods of compression.

The transition from dyke to sill in the Otish Mountains, Quebec; relations to host-rock characteristics

1987 ◽  
Vol 24 (1) ◽  
pp. 110-116 ◽  
Author(s):  
E. H. Chown ◽  
Guy Archambault
Keyword(s):  
Host Rock ◽  
Sedimentary Basin ◽  
Superior Province ◽  
Sedimentary Sequence ◽  
Grenville Province ◽  
Clastic Rocks ◽  
The North ◽  
Dyke Swarms ◽  
East West

The Otish gabbro sills intrude Aphebian clastic rocks lying uncanformably on the Archean rocks of the Superior Province close to its juncture with the Grenville Province. The sills are undated but by inference may be ca. 1750 Ma. Two dyke swarms are known in the vicinity, the 1950 Ma, northwest-trending Mistassini dykes and a northeast-trending swarm of unknown age extending 600 km from Senneterre to the Otish Mountains and possibly another 300 km to the northeast. The trends of feeder dykes to the Otish sills are physically compatible with the dominant northeast dykes, which are therefore considered to be the feeders and should be called the Otish dykes.The Otish sills appear to be a unique occurrence along the 900 km dyke trend, possibly, but not entirely because of the chances of preservation. The general form of the Otish sill complex is a triangle bounded on the north by the east–west lip of the sedimentary basin, on the southwest by a northwest-trending Otish feeder dyke, and on the southeast by the underlying northeast feeder dykes. These dykes segment the sills into a series of four or five separate intrusive complexes, small in the northwest and becoming larger to the southeast. The regular inclination of tension fractures in the basal chilled margin of the sills suggests a crude pattern of flow from the feeder dykes inward to the centre of the sheets.Interpretation of the sedimentary sequence indicates that the Otish clastics were deposited higher on the paleoslope than the Mistassini carbonates. Although few dykes intrude the deeper basin, the magma rose and formed sills within the higher sequence. This variation may be explained by the different mechanical character of the two types of cover rock controlling the dyke behaviour. The relatively plasto-viscous Mistassini carbonate–shale sequence resisted the formation of tension fractures, whereas the brittle elastics opened easily, allowing the magma to rise into the stratified sequence, forming the sill complexes.

Petrology of Metavolcanic Rocks in the Bishop Corners – Donaldson Area, Grenville Province, Ontario

1973 ◽  
Vol 10 (5) ◽  
pp. 589-614 ◽  
Author(s):  
K. Sethuraman ◽  
John M. Moore Jr.
Keyword(s):  
Alkali Basalt ◽  
Bulk Composition ◽  
Metamorphic Grade ◽  
Chemical Analyses ◽  
Grenville Province ◽  
Clastic Rocks ◽  
Carbonate Sedimentation ◽  
Metavolcanic Rocks ◽  
Apparent Thickness ◽  
Mineral Assemblages

A calc-alkalic suite, with an apparent thickness of 7 km, varies from alkali basalt and tholeiite composition in the lowest part exposed, through andesite flows and pyroclastic rocks, to rhyodacite pyroclastics at the top. Sixty-two chemical analyses demonstrate a single volcanic cycle. Volcanism was succeeded by carbonate sedimentation and intrusion of granodiorite plutons. After deposition of clastic rocks, the entire succession was deformed and metamorphosed in the amphibolite facies.Isograds divide the metavolcanic rocks into five mineral zones: chlorite, biotite, blue-green hornblende, green hornblende, and diopside. Equivalent zones in the pelites are: chloritoid–staurolite, kyanite–staurolite, and sillimanite–muscovite.Fe in epidote, Ca in plagioclase, K and Na in hornblende, and ferric/ferrous ratio in rocks, biotite, and hornblende all increase in mafic and intermediate rocks, with increasing metamorphic grade. In biotite and hornblende, octahedral Al decreases with grade, whereas other chemical variables are related to bulk composition. Mineral assemblages and hornblende compositions indicate metamorphic conditions between Abukuma and classical Barrovian facies series.

Geochemistry of the felsic metavolcanic rocks of the Wakeham Group: a metamorphosed peralkaline suite from the eastern Grenville Province, Quebec, Canada

1986 ◽  
Vol 23 (7) ◽  
pp. 978-984 ◽  
Author(s):  
James H. Bourne
Keyword(s):  
Incompatible Trace Element ◽  
White Mica ◽  
Low Grade ◽  
Textural Features ◽  
Chemical Analyses ◽  
Grenville Province ◽  
Metavolcanic Rocks ◽  
Group A ◽  
Grenvillian Orogeny ◽  
Acid Volcanics

The Wakeham Group is a suite of low-grade (greenschist facies) rocks located in the eastern Grenville Province. In order of volumetric importance, it consists of sandstones, acid volcanics, and gabbro dykes and sills. This report deals with the acid volcanic member of the group. Primary textural features have in large part been preserved. The minerals present include stilpnomelane, white mica, albite, titanite, and zircon. Calculations using 33 chemical analyses show that 29 of the compositions have normative corundum. The rocks would therefore appear to be predominantly peraluminous; however, incompatible trace-element data show affinities with other anorogenic, peralkaline suites. It is proposed that alkali loss, probably during the subsequent Grenvillian orogeny, imposed a peraluminous composition on originally peralkaline rocks. The Wakeham Group cannot be definitively correlated with other metavolcanic rocks found in the region.

scholarly journals Precambrian Basement and Late Paleoproterozoic to Mesoproterozoic Tectonic Evolution of the SW Yangtze Block, South China: Constraints from Zircon U–Pb Dating and Hf Isotopes

Minerals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 333 ◽  
Author(s):  
Wei Liu ◽  
Xiaoyong Yang ◽  
Shengyuan Shu ◽  
Lei Liu ◽  
Sihua Yuan
Keyword(s):  
South China ◽  
Tectonic Evolution ◽  
Detrital Zircons ◽  
Geochemical Data ◽  
Precambrian Basement ◽  
Yangtze Block ◽  
Two Stage ◽  
Clastic Rocks ◽  
Columbia Supercontinent ◽  
Isotopic Analyses

Zircon U–Pb dating and Hf isotopic analyses are performed on clastic rocks, sedimentary tuff of the Dongchuan Group (DCG), and a diabase, which is an intrusive body from the base of DCG in the SW Yangtze Block. The results provide new constraints on the Precambrian basement and the Late Paleoproterozoic to Mesoproterozoic tectonic evolution of the SW Yangtze Block, South China. DCG has been divided into four formations from the bottom to the top: Yinmin, Luoxue, Heishan, and Qinglongshan. The Yinmin Formation, which represents the oldest rock unit of DCG, was intruded by a diabase dyke. The oldest zircon age of the clastic rocks from the Yinmin Formation is 3654 Ma, with εHf(t) of −3.1 and a two-stage modeled age of 4081 Ma. Another zircon exhibits an age of 2406 Ma, with εHf(t) of −20.1 and a two-stage modeled age of 4152 Ma. These data provide indirect evidence for the residues of the Hadean crustal nuclei in the Yangtze Block. In combination with the published data, the ages of detrital zircons from the Yinmin Formation yielded three peak ages: 1.84, 2.30 and 2.71 Ga. The peaks of 1.84 and 2.71 Ga are global in distribution, and they are best correlated to the collisional accretion of cratons in North America. Moreover, the peak of 1.84 Ga coincides with the convergence of the global Columbia supercontinent. The youngest age of the detrital zircon from the Yinmin Formation was 1710 Ma; the age of the intrusive diabase was 1689 ± 34 Ma, whereas the weighted average age of the sedimentary tuff from the Heishan Formation was 1414 ± 25 Ma. It was presumed that the depositional age for DCG was 1.71–1.41 Ga, which was in accordance with the timing of the breakup of the Columbia supercontinent. At ~1.7 Ga, the geochemical data of the diabase were characterized by E-MORB and the region developed the same period A-type granites. Thus, 1.7 Ga should represent the time of the initial breakup of the Yangtze Block. Furthermore, the Yangtze Block continues to stretch and breakup until ~1.4 Ga, which is characterized by the emergence of oceanic island, deep-sea siliceous rock and flysch, representing the final breakup. In brief, the tectonic evolution of the Yangtze Block during the Late Paleoproterozoic to Mesoproterozoic coincided with the events caused by the convergence and breakup of the Columbia supercontinent, because of which, the Yangtze Block experienced extensive magmatic activity and sedimentary basin development during this period.

Detrital zircon geochronology of Neoproterozoic to Permian miogeoclinal strata in British Columbia and Alberta

1998 ◽  
Vol 35 (12) ◽  
pp. 1380-1401 ◽  
Author(s):  
George E Gehrels ◽  
Gerald M Ross
Keyword(s):  
British Columbia ◽  
Detrital Zircon ◽  
Isotopic Signature ◽  
Detrital Zircons ◽  
Detrital Zircon Geochronology ◽  
Salmon River ◽  
Western Canada Sedimentary Basin ◽  
Cordilleran Margin ◽  
Peace River Arch ◽  
Detrital Zircon Ages

U-Pb ages have been determined on 250 detrital zircon grains from Neoproterozoic through Permian miogeoclinal strata in British Columbia and Alberta. Most of the grains in these strata are >1.75 Ga and are interpreted to have been derived from nearby basement provinces (although most grains were probably cycled though one or more sedimentary units prior to final deposition). Important exceptions are Ordovician sandstones that contain grains derived from the Peace River arch, and upper Paleozoic strata with detrital zircons derived from the Franklinian orogen, Salmon River arch (northwestern U.S.A.), and (or) Grenville orogen. These provenance changes resulted in average detrital zircon ages that become progressively younger with time, and may also be reflected by previously reported shifts in the Nd isotopic signature of miogeoclinal strata. In addition to the grains that have identifiable sources, grains of ~1030, ~1053, 1750-1774, and 2344-2464 Ma are common in our samples, but igneous rocks of these ages have not been recognized in the western Canadian Shield. We speculate that unrecognized plutons of these ages may be present beneath strata of the western Canada sedimentary basin. Collectively, our data provide a record of the ages of detrital zircons that accumulated along the Canadian Cordilleran margin during much of Paleozoic time. Comparisons between this reference and the ages of detrital zircons in strata of potentially displaced outboard terranes may help reconstruct the paleogeography and accretionary history of the Cordilleran orogen.

scholarly journals PHYSICAL-MECHANICAL PROPERTIES OF METAVOLCANIC ROCKS OF THE MOUNTAIN CRIMEA

2018 ◽  
Vol 13 (4-5) ◽  
pp. 36-51
Author(s):  
J. V. Frolova ◽  
V. V. Ladygin ◽  
E. M. Spiridonov ◽  
G. N. Ovsyannikov
Keyword(s):  
Mechanical Properties ◽  
Magnetic Susceptibility ◽  
Volcanic Rocks ◽  
Low Grade ◽  
Secondary Mineral ◽  
Grade Metamorphism ◽  
Clastic Rocks ◽  
Metavolcanic Rocks ◽  
Physical Density ◽  
Characteristic Values

The article considers the petrogenetic features of the volcanogenic rocks of the Middle Jurassic age of the Mountain Crimea and analyzes their influence on physical (density, porosity, water absorption, and magnetic susceptibility) and physical-mechanical properties (strength, modulus of elasticity, and Poisson's ratio). Among volcanogenic strata there are subvolcanic, effusive and volcanogenic-clastic rocks. All volcanic rocks were altered under the influence of the regional low-grade metamorphism of the zeolite and prehnite-pumpellyite facies, which resulted in a greenstone appearance. Among the secondary mineral the most common are albite, chlorite, quartz, adularia, sericite, calcite, pumpellyite, prenite, zeolites, epidote, sphene, and clay minerals. It is shown that low-grade metamorphism is characterized by heterogenious transformations: there are both slightly modified, practically fresh differences, and fully altered rocks. Tuffs are usually altered to a greater extent than effusive and subvolcanic rocks. In general, effusive and volcanogenic-clastic rocks differ markedly in their physicalmechanical properties, which is due to the peculiarities of their formation: the former are substantially more dense and stronger, less porous and compressible. However, these differences are leveled as a result of intensive changes in mineral composition and porosity in the process of low-grade metamorphism. The most characteristic values of metavolcanite properties were revealed. It is shown that among all studied parameters, the magnetic susceptibility most clearly correlates with the degree of rocks alteration.

scholarly journals Crustal thickness of the Grenville orogen: A Mesoproterozoic Tibet?

Geology ◽  
2021 ◽  
Author(s):  
Adam Brudner ◽  
Hehe Jiang ◽  
Xu Chu ◽  
Ming Tang
Keyword(s):  
Crustal Thickness ◽  
Detrital Zircons ◽  
Crustal Thickening ◽  
Geochemical Data ◽  
Geochronological Data ◽  
Grenville Province ◽  
Crustal Thinning ◽  
Paleoenvironmental Evolution ◽  
Orogenic Plateau ◽  
St Lawrence River

The Grenville Province on the eastern margin of Laurentia is a remnant of a Mesoproterozoic orogenic plateau that comprised the core of the ancient supercontinent Rodinia. As a protracted Himalayan-style orogen, its orogenic history is vital to understanding Mesoproterozoic tectonics and paleoenvironmental evolution. In this study, we compared two geochemical proxies for crustal thickness: whole-rock [La/Yb]N ratios of intermediate-to-felsic rocks and europium anomalies (Eu/Eu*) in detrital zircons. We compiled whole-rock geochemical data from 124 plutons in the Laurentian Grenville Province and collected trace-element and geochronological data from detrital zircons from the Ottawa and St. Lawrence River (Canada) watersheds. Both proxies showed several episodes of crustal thickening and thinning during Grenvillian orogenesis. The thickest crust developed in the Ottawan phase (~60 km at ca. 1080 Ma and ca. 1045 Ma), when the collision culminated, but it was still up to 20 km thinner than modern Tibet. We speculate that a hot crust and several episodes of crustal thinning prevented the Grenville hinterland from forming a high Tibet-like plateau, possibly due to enhanced asthenosphere-lithosphere interactions in response to a warm mantle beneath a long-lived supercontinent, Nuna-Rodinia.

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