Onaping fault system: age constraints on deformation of the Kapuskasing structural zone and units underlying the Sudbury Structure

1994 ◽  
Vol 31 (7) ◽  
pp. 1197-1205 ◽  
Author(s):  
Kenneth L. Buchan ◽  
Richard E. Ernst
Keyword(s):  
Fault System ◽  
Dyke Swarm ◽  
Superior Province ◽  
Time Marker ◽  
Aeromagnetic Anomalies ◽  
Gneiss Complex ◽  
Sudbury Structure ◽  
Important Time ◽  
Lateral Offset ◽  
Age Constraints

The deformation of the Matachewan dyke swarm of the Superior Province, which includes a 60 km right-lateral offset and moderate uplift localized along the Kapuskasing structural zone, represents an important time marker in the evolution of the zone. However, the age of this deformation is poorly constrained. Here, it is shown that the prominent Mattagami River – Upper Wanapitei River fault of the Onaping fault system, which offsets 2167 Ma Biscotasing dykes south of the Kapuskasing structural zone, can be aligned with a fault of similar offset north of the zone after the Matachewan swarm is restored to its predeformational configuration. Thus, the deformation of the Matachewan swarm in the vicinity of the Kapuskasing structural zone must postdate the 2167 Ma emplacement and the subsequent faulting of the Biscotasing dykes. Southward extensions of faults of the Onaping fault system appear to offset aeromagnetic anomalies associated with highly magnetic units in the basement beneath the Sudbury Structure and Huronian sediments of the Southern Province, but do not substantially offset the Sudbury Structure itself. This suggests that the 1850 Ma Sudbury Structure was emplaced after most of the displacement on Onaping faults, while the unit underlying it, variously interpreted as the Archean Levack Gneiss Complex or a hidden ultramafic body of unknown age, predates Onaping faulting.

Characterization of the Benny deformation zone, Sudbury, Ontario

1996 ◽  
Vol 33 (9) ◽  
pp. 1256-1267 ◽  
Author(s):  
R. L. Kellett ◽  
B. Rivard
Keyword(s):  
High Resolution ◽  
Greenstone Belt ◽  
Deformation Zone ◽  
Fault System ◽  
Magnetic Data ◽  
Dyke Swarm ◽  
Radar Images ◽  
Sudbury Structure ◽  
Tectonically Active ◽  
Wrench Fault

Remote sensing imagery and geophysical data are well known as valuable tools for reconnaissance mapping in unknown areas, but they can also be used to reinterpret existing regional geological maps. A combination of airborne magnetic data and synthetic aperture radar images, at both a regional and a detailed scale, have been used to identify a wrench-fault system on the Canadian Shield north of the Sudbury structure. The 3–4 km wide deformation zone comprises a set of subparallel vertical faults bounding blocks of Archean granites, Archean metavolcanics of the Benny greenstone belt, and Paleoproterozoic metasediments of the Huronian supergroup. Using high-resolution airborne radar and magnetic data, the fault zone is found to extend for 40 km along the southern margin of the Benny greenstone belt. The wrench-fault system may have been tectonically active during several episodes throughout the Proterozoic. An interpretation of these data, supported by additional field mapping, indicates that the 1240 Ma Sudbury dyke swarm has been intruded through the deformation zone after its most active period of movement. Overprinting of Sudbary impact breccia at the southern edge of the deformation zone suggests that some movement occurred on the faults postdating the 1850 Ma meteorite impact. Lineaments that correlate spatially with the wrench-fault system can be traced across the southern Superior Province and the Cobalt Embayment on the regional images. However, more high-resolution studies are required to establish the same overprinting relationships along the length of the lineaments.

Geophysical evidence for a pre-impact Sudbury dome, southern Superior Province, Canada

2005 ◽  
Vol 42 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Stephen A Prevec ◽  
Duncan R Cowan ◽  
Gordon RJ Cooper
Keyword(s):  
Thermal Regime ◽  
Superior Province ◽  
Geochronological Data ◽  
Subsequent Evolution ◽  
Igneous Complex ◽  
Sudbury Igneous Complex ◽  
Gneiss Complex ◽  
Sudbury Structure ◽  
Abitibi Subprovince

New filtering of aeromagnetic images of the Sudbury area indicates the existence of a large, elliptical feature that appears to underlie the deformed Sudbury Structure in the region of the exposed Levack Gneiss Complex, such that the two features have long axes which are significantly orthogonal to one another. A north–south-oriented ellipse appears to be crosscut by that of the Sudbury Structure and does not correspond to known local lithological or structural trends. The magnetic images, combined with existing tectonic, petrological, geothermometric and geobarometric, and geochronological data, are used to suggest the existence of a pre-impact crustal dome in the southernmost Abitibi subprovince, probably related to ca. 2450 Ma rifting and magmatism in the area. This is consistent with existing petrological and tectonic evidence from a variety of sources. Although the doming is itself unrelated to the ca. 1850 Ma Sudbury event, it may have affected the thermal regime existing at the time of impact, which would have profound implications for the subsequent evolution of the Sudbury Igneous Complex.

Age of the Grenville dyke swarm, Ontario–Quebec: implications for the timing of lapetan rifting

1995 ◽  
Vol 32 (3) ◽  
pp. 273-280 ◽  
Author(s):  
S. L. Kamo ◽  
T. E. Krogh ◽  
P. S. Kumarapeli
Keyword(s):  
Long Range ◽  
Volcanic Rocks ◽  
Canadian Shield ◽  
Dyke Swarm ◽  
Alkaline Complex ◽  
Southeastern Part ◽  
Time Marker ◽  
Continental Breakup ◽  
Iapetus Ocean

U–Pb baddeleyite and zircon ages for three diabase dykes from widely spaced localities within the Grenville dyke swarm indicate a single age of emplacement at [Formula: see text] Ma. The 700 km long Grenville dyke swarm, located in the southeastern part of the Canadian Shield, was emplaced syntectonically with the development of the Ottawa graben. This graben may represent a plume-generated lapetan failed arm that developed at the onset of the breakup of Laurentia. Other precisely dated lapetan rift-related units, such as the Callander Alkaline Complex and the Tibbit Hill Formation volcanic rocks, indicate a protracted 36 Ma period of rifting and magmatism prior to volcanism along this segment of the lapetan margin. The age of the Grenville dykes is the youngest in a progression of precisely dated mafic magmatic events from the 723 Ma Franklin dykes and sills to the 615 Ma Long Range dykes, along the northern and northeastern margins of Laurentia, respectively. Thus, the age for these dykes represents a key time marker for continental breakup that preceded the formation of the Iapetus ocean.

Hafnium-Neodymium isotope, trace element and U-Pb zircon age constraints on the petrogenesis of the 3.44–3.46 Ga Dwalile greenstone remnant, Ancient gneiss Complex, Swaziland

2020 ◽  
Vol 351 ◽  
pp. 105970
Author(s):  
J. Elis Hoffmann ◽  
Emmanuel Musese ◽  
Alfred Kröner ◽  
Kathrin P. Schneider ◽  
Jean Wong ◽  
...  
Keyword(s):  
Trace Element ◽  
Zircon Age ◽  
Gneiss Complex ◽  
Age Constraints

Chapter 3 The Scourie Dyke Suite

2002 ◽  
Vol 26 (1) ◽  
pp. 21-28
Keyword(s):  
Central Region ◽  
Southern Region ◽  
Dyke Swarm ◽  
Southwestern Part ◽  
Gneiss Complex ◽  
Igneous Origin ◽  
Relationship Of

The Scourie dyke suite has only been securely dated in the Central Region, and no emplacement ages have been published from the dykes in the Southern Region. In view of the possibility that the Central and Southern Regions may not have coalesced until after the dyke emplacement, the equivalence of the swarms in the two regions has not been proved. Nevertheless, the dyke swarm in the Southern Region has traditionally been referred to as the 'Scourie dykes' and for convenience, this nomenclature is adopted here.Amphibolite bodies attributed to the Scourie dyke suite are abundant within the Scourian gneiss complex of the Gairloch district. Several sill-like amphibolite sheets of doubtful affinity occur within the Loch Maree Group; however, these are chemically distinct from the Scourie dykes (see Section 4.9.2) and no bodies that can be identified as Scourie dykes cut the rocks of the LMG.The dykes weather dark grey to almost black and contrast sharply with the much paler acid gneisses. They are generally sheetlike in form, although many show considerable irregularity of shape. The igneous origin and intrusive relationship of these bodies to the host gneisses can be widely demonstrated, and are particularly clearly displayed in the eastern part of the Tollie area, for example on Creag Mhor Thollaidh, and in the southwestern part of the district, around Loch Braigh Horrisdale. In both these areas, the dykes are grossly discordant to the banding of the host gneisses (see map). However, in the two belts of gneisses adjoining the

Paleomagnetism and U–Pb geochronology of the 2.17 Ga Biscotasing dyke swarm, Ontario, Canada: evidence for vertical-axis crustal rotation across the Kapuskasing Zone

2004 ◽  
Vol 41 (3) ◽  
pp. 255-269 ◽  
Author(s):  
Henry C Halls ◽  
Donald W Davis
Keyword(s):  
Vertical Axis ◽  
Paleomagnetic Data ◽  
Dyke Swarm ◽  
Superior Province ◽  
Hudson Bay ◽  
Short Period ◽  
Western Half ◽  
Eastern Half

U–Pb dates on baddeleyite yield ages of 2167.8 ± 2.2 and 2171.6 ± 1.2 Ma on two northeast-trending dykes west of the Kapuskasing Zone in Ontario, Canada. These ages identify the dykes as belonging to the Biscotasing dyke swarm east of the Kapuskasing Zone, which was previously dated at 2166.7 ± 1.4 Ma by U–Pb on baddeleyite and zircon. The new dates show that the Biscotasing swarm was emplaced over an area of at least 300 000 km2, much larger than hitherto suspected, and in a geologically short period of time of about 5 million years. A comparison of paleomagnetic data from Biscotasing and 2.45 Ga Matachewan dykes on either side of the Kapuskasing Zone suggests that the western half of the Superior Province has rotated about 10°–20° counterclockwise relative to the eastern half across the Kapuskasing Zone. This movement may have been accompanied by rifting farther north which ultimately led to the Paleoproterozoic embayment, underlying Hudson Bay, that gives the Superior Province its characteristic butterfly-shaped outline.

Paleomagnetism and U-Pb geochronology of diabase dyke swarms of Minto block, Superior Province, Quebec, Canada

1998 ◽  
Vol 35 (9) ◽  
pp. 1054-1069 ◽  
Author(s):  
Kenneth L Buchan ◽  
James K Mortensen ◽  
Kenneth D Card ◽  
John A Percival
Keyword(s):  
Collaborative Study ◽  
Sedimentary Rocks ◽  
Dyke Swarm ◽  
Superior Province ◽  
Mafic Dyke ◽  
Magnetization Direction ◽  
Virtual Geomagnetic Pole ◽  
Southern Province ◽  
Geomagnetic Pole ◽  
Dyke Swarms

In the first collaborative study of paleomagnetism and precise U-Pb geochronology in the Minto block of the Superior Province, mafic dyke swarms with three widely divergent paleomagnetic signatures and isotopic ages have been identified. The 2505 ± 2 Ma Ptarmigan dykes trend north to northeast and have a virtual geomagnetic pole at 42°S, 220°E, similar to that of 2473-2446 Ma Matachewan dykes of the southern Superior Province. The ca. 2230 Ma Maguire dykes trend west to northwest and yield a paleopole at 9°S, 267°E, similar to those for 2216+8-4 Ma Senneterre dykes and 2217-2210 Ma Nipissing sills of the southern Superior and Southern provinces, respectively. The 2209 ± 1 Ma Klotz dykes trend west-northwest, but do not carry a consistent magnetization direction. Finally, 1998 ± 2 Ma Minto dykes of west-northwest to northwest trend, identical in age to the 1998 Ma ± 2 Ma Purtuniq ophiolite of the Cape Smith Belt, have a paleopole at 38°N, 174°E. The similarity of paleopoles for the ca. 2.23-2.21 Ga Maguire dykes of the Minto block, Senneterre dykes of the southern Superior, and Nipissing sills of the Southern Province demonstrates that these regions were in their present relative latitudes and orientations at that time. Likewise, the similarity of the Ptarmigan virtual geomagnetic pole and the Matachewan paleopole suggests little relative latitudinal movement or rotation of the two regions since ca. 2.5 Ga. The Maguire, Senneterre, and Klotz dykes form a roughly radiating pattern and may represent one quadrant of a giant radiating dyke swarm centred southeast of Ungava Bay, whose focus marks the location of a mantle plume responsible for ca. 2.22 Ga breakup along the eastern margin of the Superior Province. If so, the coeval Nipissing sills that intrude sedimentary rocks of the Huronian Supergroup of the Southern Province may have been fed laterally by Senneterre dykes from the Ungava plume centre.

Thermal history of thrust sheets in an orogenic wedge: 40Ar/39Ar data from the polymetamorphic Seve Nappe Complex, northern Swedish Caledonides

2000 ◽  
Vol 137 (4) ◽  
pp. 437-446 ◽  
Author(s):  
OLAF M. SVENNINGSEN
Keyword(s):  
Shear Zones ◽  
Passive Margin ◽  
Fault System ◽  
Dyke Swarm ◽  
Slow Cooling ◽  
Nappe Complex ◽  
Thrust Sheets ◽  
Seve Nappe Complex ◽  
The Baltic ◽  
The Individual

The Seve Nappe Complex in the Scandinavian Caledonides contains the fragmented late Precambrian continent–ocean transition between Baltica and the Iapetus Ocean. This passive margin was fragmented and thrust eastwards over the Baltic Shield during Caledonian orogenesis. The individual thrust sheets in the Seve Nappe Complex went through different P–T–t evolutions, resulting in dramatic metamorphic contrasts: eclogite-bearing nappes are juxtaposed with nappes showing no evidence of Caledonian deformation or metamorphism in their interiors. Strain localization to the marginal parts of the thrust sheets left records of both pre-orogenic (rift) and early orogenic (subduction and subsequent uplift) processes in the thrust sheets of the Seve Nappe Complex. Even though it has been transported several hundred kilometres, only the margins of the eastern part of the Sarektjåkkå Nappe are affected by penetrative Caledonian deformation. This part of the Sarektjåkkå Nappe is dominated by pristine tholeiitic dykes and cross-bedded sandstones. The dykes are 608±1 Ma old and make up 70–80% of the nappe. Widely spaced thin shear zones of the Ruopsok fault system represent the only Caledonian penetrative deformation in the interior of the nappe. Previously published Ar–Ar dates indicate cooling below the closure temperature of hornblende at c. 470 Ma, but numerous ages have been recorded. Ar dating of biotite and muscovite from a cross-laminated metapsammite in the Sarektjåkkå Nappe gave well-defined ages of 428.5±3.6 and 432.4±3.8 Ma, respectively. Muscovite from a shear zone in the Ruopsok Fault System gave 428.2±4.0 Ma, whereas hornblende from the same locality did not yield interpretable data. The results indicate that these rocks were completely degassed at some unknown time, presumably at the emplacement of the dyke swarm. No subsequent excess argon contamination can be detected. A likely candidate for the degassing event is the emplacement of the dykes at 608 Ma. The interior of the nappe, and thus the entire nappe complex, cooled below ∼ 350 °C at around 430 Ma. Cooling from more than 500 °C at c. 470 Ma to 350 °C at c. 430 Ma suggests an average cooling rate of [les ] 4 °C/Ma. A prolonged period of slow cooling (≈exhumation?) following the initial, rapid uplift of the eclogite-bearing nappes and Early Ordovician construction of the Seve Nappe Complex is suggested.

New age constraints on the Lan Sang gneiss complex, Thailand, and the timing of activity of the Mae Ping shear zone from in-situ and depth-profile zircon and monazite U-Th-Pb geochronology

2019 ◽  
Vol 181 ◽  
pp. 103886 ◽  
Author(s):  
Jürgen E. Österle ◽  
Urs Klötzli ◽  
Daniel F. Stockli ◽  
Markus Palzer-Khomenko ◽  
Pitsanupong Kanjanapayont
Keyword(s):  
Shear Zone ◽  
Depth Profile ◽  
New Age ◽  
Gneiss Complex ◽  
Age Constraints
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