The 1830 Ma Trans-Hudson hairpin from paleomagnetism of the Wapisu gneiss dome, Kisseynew Domain, Manitoba

2000 ◽  
Vol 37 (6) ◽  
pp. 913-922
Author(s):  
D TA Symons ◽  
M J Harris
Keyword(s):  
Remanent Magnetization ◽  
Amphibolite Facies ◽  
Gneiss Dome ◽  
North Central ◽  
Polar Wander ◽  
Northeastern Part ◽  
Apparent Polar Wander Path ◽  
Peak Metamorphism ◽  
Superior Craton

The Wapisu gneiss dome is located in the northeastern part of the Kisseynew Domain of the Trans-Hudson Orogen (THO) in north-central Manitoba. The dome is circular, about 6 km in diameter, with steeply-dipping flanks. It is composed of upper amphibolite-facies gneisses derived from turbiditic sediments, with leucogranitic sill-like intrusions that were metamorphosed, starting at about 1830 Ma. Alternating field and thermal step demagnetization of 153 specimens from 17 sites around the perimeter of the dome isolated a characteristic remanent magnetization (ChRM) direction of D = 346.6°, I = 78.9° (α95 = 5.3°, k = 46, N = 17) that gives a pole of 119.5° W, 75.8° N (dp = 9.5°, dm = 10.0°). Unblocking temperatures and saturation isothermal remanence analyses show that the ChRM resides mostly in single to pseudosingle domain magnetite or titanomagnetite, with minor hematite commonly present and with minor pyrrhotite present in the leucogranites. The ChRM is found to be postfolding with >>99.9% confidence, indicating acquisition on cooling from peak metamorphism at ~1810 ± 10 Ma. This Wapisu gneiss dome paleopole is the first from the Kisseynew Domain and the first from the 1830 to 1770 Ma interval in the THO. It indicates an ~90° bend or hairpin in the apparent polar wander path for the THO juvenile terranes and Superior craton. It is speculated that the hairpin marks the collisional impact of the Archean Sask craton and (or) Hearne craton, which drove the Paleoproterozoic Kisseynew Domain into the Archean Superior craton.

Age of the Firesand River carbonatite complex from paleomagnetism

1989 ◽  
Vol 26 (11) ◽  
pp. 2401-2405 ◽  
Author(s):  
D. T. A. Symons
Keyword(s):  
Remanent Magnetization ◽  
Pole Position ◽  
Blocking Temperature ◽  
Isothermal Remanent Magnetization ◽  
Carbonatite Complex ◽  
Polar Wander ◽  
Partial Contact ◽  
Apparent Polar Wander Path ◽  
Temperature Spectra ◽  
Middle Proterozoic

The 2.3 km diameter Firesand River complex intrudes Archean volcanics and granites of the Wawa Subprovince in the Superior Province about 8 km east of Wawa, Ontario. It has given differing Middle Proterozoic K–Ar biotite ages of 1018 ± 50 and 1097 Ma. Alternating-field and thermal step demagnetization of specimens from three calcific carbonatite sites, five ferruginous dolomitic carbonatite sites, and one lamprophyre dike site isolated a stable mean direction of 290°, 33 °(α95 = 12°). Isothermal remanent magnetization tests indicate the remanence is held by single-to pseudosingle-domain magnetite and hematite in the carbonatite. The dike remanence is Keweenawan in age, thereby confirming its genetic relationship to the complex, and it gives a positive partial contact test with its host rock, indicating no postintrusive remagnetization. The blocking-temperature spectra indicate that postintrusive uplift has not exceeded about 4 km. The pole position for the complex is 183°E, 27°N (dp = 8°, dm = 13°). This pole lies directly on the well-dated Keweenawan apparent polar wander path, giving an age of 1090 ± 10 Ma, in agreement with the older K–Ar age. It also confirms geologic and aeromagnetic evidence that the complex has not been tectonically tilted since emplacement.

Malley diabase dykes of the Slave craton, Canadian Shield: U–Pb age, paleomagnetism, and implications for continental reconstructions in the early Paleoproterozoic1Geological Survey of Canada Contribution 20110114.

2012 ◽  
Vol 49 (2) ◽  
pp. 435-454 ◽  
Author(s):  
Kenneth L. Buchan ◽  
Anthony N. LeCheminant ◽  
Otto van Breemen
Keyword(s):  
Relative Orientation ◽  
Canadian Shield ◽  
Dyke Swarm ◽  
Slave Craton ◽  
Polar Wander ◽  
Thermal Demagnetization ◽  
Contact Test ◽  
Apparent Polar Wander Path ◽  
Close Proximity ◽  
Superior Craton

The NE-trending Malley dyke swarm, dated herein at 2231 ± 2 Ma (U–Pb baddeleyite), extends from the central Slave craton to the vicinity of the Kilohigok basin, and may continue farther to the northeast as the geochemically similar Brichta dyke swarm, having been offset sinistrally along the prominent Bathurst fault. It carries a characteristic high unblocking temperature paleomagnetic component of single polarity directed up SE (mean direction: D = 138.3°, I = –53.8°), with corresponding paleopole at 50.8°S, 50.0°W. Lower unblocking temperature components, in some cases directed down SE, similar to ca 1.75 Ga post-Hudsonian overprints, are easily removed using combined alternating field (AF) thermal demagnetization, but difficult to remove using AF cleaning alone. The characteristic remanence has not been demonstrated primary, but is significantly older than 2.03 Ga, the age of Lac de Gras dykes, based on a baked contact test at a Lac de Gras – Malley dyke intersection. In addition, an E- to ESE-trending dyke carries a down WNW remanence, typical of 2.19 Ga Dogrib dykes near Yellowknife, suggesting that regional overprinting has not affected the study area since Dogrib emplacement, and that the Malley remanence was acquired at or shortly after Malley emplacement. Comparing Malley and Lac de Gras paleopoles with the 2.22–2.00 Ga Superior craton apparent polar wander path indicates that the two cratons were (i) not in their present relative orientation at 2.23 or 2.03 Ga, and (ii) likely not drifting in close proximity to one another as parts of a single (super)continent throughout the 2.23–2.03 Ga interval.

Paleomagnetism and time-stratigraphic correlation of Proterozoic redbeds of the Labrador Trough and outliers of northern Quebec

1983 ◽  
Vol 20 (11) ◽  
pp. 1725-1737 ◽  
Author(s):  
E. J. Schwarz ◽  
G. N. Freda
Keyword(s):  
Canadian Shield ◽  
Stratigraphic Correlation ◽  
End Points ◽  
Polar Wander ◽  
Northeastern Part ◽  
Apparent Polar Wander Path ◽  
South West ◽  
Group 2 ◽  
Magnetic North ◽  
Group 1

One hundred and forty-two oriented cores were collected from redbeds of the Sakami Formation near LG-4 (85), Dieter (19), Cambrian (18), and Snow-ball (4) lakes, all in Quebec, and from two outliers in Labrador: Evening Lake (6) and Sims Lake (10). A further 73 oriented drill cores were collected from the strongly folded Chakonipau Formation redbeds (44) in the Labrador Trough and undeformed redbeds near Lac Imbault (29) on the western edge of the trough. Thermal demagnetization of the trough redbeds yielded 52 core directions, each of which showed good specimen end points and sufficient homogeneity of magnetization, and 101 such core directions were obtained for the outlier redbeds. In most of these samples, there are no indications that the stable remanence is multi-component, and the fold test yields (for LG-4 Sakami Formation and the Chakonipau Formation) a significant (95% probability) improvement of the dispersion parameter K. Thus, the Chakonipau Formation remanence is probably pre-Hudsonian and the Sakami Formation remanence is probably pre-faulting (not dated). Furthermore, a near reversal (165°) in the Chakonipau Formation suggests that the stable remanence was acquired during or soon after deposition. The pole positions for Circum-Superior orogen rocks, the Proterozoic outliers, and the Sutton Lake inlier suggest: (1) a time-stratigraphic correlation between the LG-4 Sakami, Dieter Lake, Sutton Lake, and the upper part of the Belcher Island sequences; and (2) a time-stratigraphic correlation between the lower part of the Belcher Islands sequence and the Richmond Gulf sequence, which must be substantially older than group 1. The Circum-Superior apparent polar wander path (APWP) is drawn through magnetic North poles from the group 1 poles to the group 2 poles, yielding a slightly lower age for the trough sediments represented by the Chakonipau Formation (two opposing polarities) and the Lac Imbault redbeds. The general North American APWP is simplified by the deletion of the Richmond Gulf South poles, and seems to be positioned as much as about 30° north of the Circum-Superior APWP down to about 1800 Ma ago. This may indicate (pre-) Hudsonian movement between the northeastern part of the Canadian Shield and paleomagnetically better investigated parts to the (south-) west.

Paleomagnetism of Archean rocks from northwestern Ontario: Wabigoon gabbro, Wabigoon Subprovince

1983 ◽  
Vol 20 (12) ◽  
pp. 1805-1817 ◽  
Author(s):  
David J. Dunlop
Keyword(s):  
Remanent Magnetization ◽  
Natural Remanent Magnetization ◽  
Blocking Temperature ◽  
Virtual Geomagnetic Pole ◽  
Polar Wander ◽  
Apparent Polar Wander Path ◽  
Northwestern Ontario ◽  
Paleomagnetic Pole ◽  
Geomagnetic Pole ◽  
Chemical Remanent Magnetization

The Wabigoon gabbro of the Archean Wabigoon greenstone belt in northwestern Ontario preserves a univectorial natural remanent magnetization (NRM) with D = 246°, I = 12° (k = 19.5, α95 = 10.5°, N = 11 sites). The precision is reduced if sample means are averaged, however (k = 9.3, α95 = 9.2°, N = 29 samples). The paleomagnetic pole falls either at 160°W, 11°S (δp = 5.3°, δm = 10.6°), corresponding to an age of ~1300 Ma on the Laurentian apparent polar wander path, or the reverse of this, 20°E, 11° N, corresponding to a late Archean age (~2800 Ma). No ~1300 Ma igneous or metamorphic event is known in the area; a major west-northwest-trending dike about 9 km south of the gabbro yields a virtual geomagnetic pole at 122°W, 45°N and seems to be of Abitibi age (~2150 Ma) rather than Mackenzie age (~1250 Ma). A few gabbro samples and some greenstones from the intrusive baked zone have hybrid remanences in which a higher blocking temperature Kenoran-age (~2600 Ma) NRM is superimposed on the gabbro characteristic NRM. However, the Kenoran component may be a younger chemical remanent magnetization (CRM) residing in hematite. The hypothesis that the gabbro characteristic remanence is itself a hybrid of Kenoran and Keweenawan (~1100 Ma) NRM's, which would explain both the high between-sample scatter and the lack of a ~1300 Ma remagnetizing event, is considered but rejected because fewer than 10% of the gabbro samples exhibit multivectorial swings during alternating field or thermal cleaning. Two geomagnetic field reversals are recorded at interior sites, but only one or none is recorded near the margin of the intrusion. The different cooling histories of margin and interior, as well as the bulk of the other evidence, favour magnetization during initial cooling in late Archean time.

Paleomagnetism of the Wintering Lake pluton and the Early Proterozoic tectonic motion of the Superior Boundary Zone, Manitoba

2006 ◽  
Vol 43 (7) ◽  
pp. 1071-1083
Author(s):  
M J Harris ◽  
D TA Symons ◽  
W H Blackburn ◽  
A Turek ◽  
D C Peck
Keyword(s):  
Coarse Grained ◽  
Boundary Zone ◽  
Polar Wander ◽  
Early Proterozoic ◽  
Apparent Polar Wander Path ◽  
Paleomagnetic Study ◽  
Paleomagnetic Result ◽  
Tectonic Motion ◽  
Host Rocks ◽  
Superior Craton

This Lithoprobe-funded paleomagnetic study of the Early Proterozoic Wintering Lake granitoid body supports tectonic models that suggest continental accretion of the Trans-Hudson Orogen with the Superior Craton occurred at ~1822 Ma. Thermal demagnetization data for the granitoid specimens suggest that the magnetic remanence carriers are coarse-grained magnetite or titanomagnetite, and saturation isothermal remanence tests suggest that the magnetite is mostly multidomain. Six of seven paleomagnetic contact tests were negative, indicating that the host rocks have been remagnetized and that the granitoid body may have been partially remagnetized near its margins. Acceptable site mean remanence directions for 20 of 21 granitic sites yield a paleopole at 46.8°N, 102.2°W (with semi-axes of the 95% ellipse of confidence about the paleopole of dp = 11° and dm = 11°). The paleopole fits on the extrapolated apparent polar wander path (APWP) for the Superior craton at ~1822 Ma, which is the interpreted emplacement age of the pluton close to the peak of the Trans-Hudson orogeny. This is the first well-constrained paleomagnetic result from the Superior Province that provides direct evidence from concordant paleopoles for the Early Proterozoic accretion of the orogen to the craton. Further, the paleomagnetic results from the pluton's host rocks, along with other recent results from the Superior Boundary Zone, fill in a gap in the APWP for the craton between ~1780 and ~1720 Ma. The Superior path is now shown to form a hairpin as the craton moves from mid to polar paleolatitudes from ~1880 to ~1830 Ma, suffers a stillstand from ~1830 to ~1770 Ma during the peak of the Trans-Hudson orogeny, returns to mid-paleolatitudes from ~1770 to ~1740 Ma, and then moves on to subequatorial paleolatitudes by ~1720 Ma.

Paleomagnetism of the Callander Complex and the Cambrian apparent polar wander path for North America

1991 ◽  
Vol 28 (3) ◽  
pp. 355-363 ◽  
Author(s):  
D. T. A. Symons ◽  
A. D. Chiasson
Keyword(s):  
Remanent Magnetization ◽  
Pole Position ◽  
Canadian Shield ◽  
Complete Spectrum ◽  
Isothermal Remanent Magnetization ◽  
Alkaline Complex ◽  
Grenville Province ◽  
Polar Wander ◽  
The Core ◽  
Apparent Polar Wander Path

The 7 km2 circular Callander alkaline complex was emplaced into anorthositic and granitic gneisses of the Grenville Province in the Canadian Shield about 575 ± 5 Ma ago at the start of the Cambrian. The complex has not been subsequently metamorphosed or tilted. Detailed alternating-field and thermal step demagnetization of 252 specimens from 29 sites led to the identification of a characteristic A magnetization component with a direction of D = 82.2°, I = 82.7° (α95 = 3.1°, k = 83, N = 26 sites) in 5 sites of mesocratic to leucocratic syenite from the core of the complex, in 5 sites of fenitized host rock from its aureole, and in 16 sites of lamprophyre from radiating dikes. Isothermal remanent-magnetization tests show that the A component is retained by both magnetite and hematite in a complete spectrum of domain sizes. A reversals test suggests and a contact test shows the A component to be primary. Its pole position at 46.3°S, 121.4°E(dp = 5.9°, dm = 6.1°) does not fall on published but poorly defined Cambrian apparent polar wander paths, leading to speculation on an alternative Cambrian path.

scholarly journals An improved apparent polar wander path for southwest Japan: post-Cretaceous multiphase rotations with respect to the Asian continent

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Koji Uno ◽  
Yuta Idehara ◽  
Daichi Morita ◽  
Kuniyuki Furukawa
Keyword(s):  
Early Cretaceous ◽  
Northeast China ◽  
Remanent Magnetization ◽  
Southwest Japan ◽  
Asian Continent ◽  
Polar Wander ◽  
Apparent Polar Wander Path ◽  
Paleomagnetic Pole ◽  
Tectonic Rotation ◽  
Japanese Islands

AbstractTo construct the Mesozoic apparent polar wander path (APWP) for the inner arc of the southwestern Japanese islands (referred to as southwest Japan) and compare it to that of East Asia, a 110 Ma paleomagnetic pole for southwest Japan was determined. Mudstone and sandstone samples were collected from 16 sites for paleomagnetic analysis in the Lower Cretaceous Inakura Formation of the Inakura area in the central part of southwest Japan. A high-temperature magnetization component, with unblocking temperatures of 670–695 °C, was isolated from 12 sites of red mudstone. Of these, 11 sites revealed a primary remanent magnetization during the Early Cretaceous. The primary directions combined with the previously reported ones provide a new mean direction (D = 79.7°, I = 47.4°, α95 = 6.5°, N = 17), and a corresponding paleomagnetic pole that is representative of southwest Japan (24.6° N, 203.1° E, A95 = 6.8°). The Early Cretaceous paleomagnetic pole, together with the Late Cretaceous and Cenozoic poles, constitute a new APWP for southwest Japan. The new APWP illustrates a standstill polar position during 110–70 Ma, suggesting tectonic quiescence of this region. This standstill was followed by two large tracks during the Cenozoic. We interpret these tracks as clockwise tectonic rotations of southwest Japan that occurred twice during the Cenozoic. The earlier tectonic rotation occurred for a tectonic unit positioned below northeast China, the Liaodong and Korean Peninsulas, and southwest Japan (East Tan-Lu Block) during the Paleogene. The later rotation took place only under southwest Japan during the Neogene. Cenozoic multiphase rifting activity in the eastern margin of the Asian continent was responsible for the tectonic rotations that are observed from the paleomagnetic studies. Intermittent rifting may constitute a series of phenomena due to asthenospheric convection, induced by the growth of the Eurasian mega-continent in the Mesozoic.

Age of emplacement of the Okanogan gneiss dome, north-central Washington

1976 ◽  
Vol 87 (9) ◽  
pp. 1217 ◽  
Author(s):  
K. F. FOX ◽  
C. D. RINEHART ◽  
J. C. ENGELS ◽  
T. W. STERN
Keyword(s):  
Gneiss Dome ◽  
North Central
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