On pole position: causes of dispersion of the paleomagnetic poles behind apparent polar wander paths

Paleomagnetic results from 55 sampling sites throughout the Stark Formation are reported. The known stratigraphic sequence of these sites enables the behaviour of the geomagnetic field in these remote times (1750 m.y.) to be elucidated. Two polarity reversals are identified and these represent potentially useful correlative features in strata devoid of index fossils. One of these is investigated in detail and indicates that behaviour of the geomagnetic field during polarity reversals was essentially the same in the early Proterozoic as it has been over the last few million years. The pole position (145°W, 15°S, dp = 3.5, dm = 6.9) lies far to the west of that anticipated from earlier results, implying further complexity of the North American polar wander curve. Possible alternatives to this added complexity are discussed.

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Age of the Firesand River carbonatite complex from paleomagnetism

Canadian Journal of Earth Sciences ◽

10.1139/e89-205 ◽

1989 ◽

Vol 26 (11) ◽

pp. 2401-2405 ◽

Cited By ~ 4

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.

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Magnetic Anomalies on the Pacific Plate Reveal True Polar Wander

Eos ◽

10.1029/2019eo117729 ◽

2019 ◽

Vol 100 ◽

Author(s):

Aaron Sidder

Keyword(s):

Magnetic Anomalies ◽

Pacific Plate ◽

Standard Approach ◽

Polar Wander ◽

True Polar Wander ◽

The Pacific ◽

New Locations ◽

Paleomagnetic Poles

A new study rebuffs the standard approach to paleomagnetism and offers an updated methodology and new locations of paleomagnetic poles.

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Paleomagnetism of igneous rocks from the Belcher Islands, Northwest Territories, Canada

Canadian Journal of Earth Sciences ◽

10.1139/e80-081 ◽

1980 ◽

Vol 17 (7) ◽

pp. 807-822 ◽

Cited By ~ 22

Author(s):

P. W. Schmidt

Keyword(s):

North America ◽

Northwest Territories ◽

Igneous Rock ◽

Pole Position ◽

Igneous Rocks ◽

Hudson Bay ◽

Plate Model ◽

Polar Wander ◽

Apparent Polar Wander Path ◽

Paleomagnetic Pole

Paleomagnetic results from igneous rock units on the Belcher Islands, Hudson Bay, are described. Fold tests for all units studied, as well as a contact test for the intrusive bodies, indicate that both primary (initial), and secondary (post-folding) magnetizations are present.The paleomagnetic pole position from primary directions of the oldest unit studied, the Eskimo volcanics, is situated at 40°S, 002°E (A95 = 12°) and is similar to that derived from equivalent volcanics on the mainland. The younger volcanic unit studied, the Flaherty volcanics, yielded a pole position from primary directions at 0°, 244°E (A95 = 7°). The Haig intrusions, associated with these younger volcanics, yields an almost identical pole position at 1°N, 247°E (A95 = 6°), being derived from directions which are shown to be not only pre–folding but also date from initial cooling. The Eskimo volcanics, which have been more deeply buried than the Flaherty (upper) volcanics, carry substantial components of secondary (post-folding) magnetization which yield a pole position at 19°N, 243°E (A95 = 15°), about 20° north of the pole positions derived from the youngest units.It is argued that the apparent polar wander path (APWP) constructed for the Belcher Islands is representative of the mainland Ungava Craton. Comparison with the equivalent APWP from elsewhere in North America shows that the two APWP's are at variance. Although a two-plate model could be advanced, perhaps a more conservative interpretation is to extend the existing North American APWP eastward to include the Belcher–Ungava APWP, that is, to favour a one-plate model.

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Paleomagnetic Results from the Jurassic Topley Intrusions near Endako, British Columbia

Canadian Journal of Earth Sciences ◽

10.1139/e73-095 ◽

1973 ◽

Vol 10 (7) ◽

pp. 1099-1108 ◽

Cited By ~ 11

Author(s):

D. T. A. Symons

Keyword(s):

British Columbia ◽

Lower Cretaceous ◽

Remanent Magnetization ◽

Upper Jurassic ◽

Pole Position ◽

Upper Triassic ◽

Polar Wander ◽

Quartz Monzonite ◽

Reversed Polarity ◽

North American Craton

The Upper Jurassic Topley Intrusions intrude rocks of the tectonically stable Interior Plateau in central British Columbia. A stable primary remanent magnetization of both normal and reversed polarity was isolated after a.f. demagnetization in 19 of 22 sites (109 cores; 208 specimens) representing several of the plutonic units present in this sialic complex of quartz monzonite affinity near Endako, B.C. The unit mean remanence directions support some petrological correlations suggested by Carr, Bright, and White et al., but do not support others. The pole position derived from 13 sites representing 6 plutonic units with a K–Ar radiomelric age of 139 ± 4 m.y. (White et al.) is 128.6 °E, 70.0 °N(δm = 14.4°; δp = 11.4°). This position indicates a smooth polar wander path during the Jurassic between the well defined Upper Triassic and Lower Cretaceous pole positions. It also indicates that the northern Interior Plateau has not been tectonically rotated or translated since emplacement relative to the stable North American craton.

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The analysis of Meso–Cenozoic paleomagnetic poles and the apparent polar wander path of Siberia

Izvestiya Physics of the Solid Earth ◽

10.1134/s1069351315050043 ◽

2015 ◽

Vol 51 (5) ◽

pp. 674-688 ◽

Cited By ~ 4

Author(s):

A. N. Didenko

Keyword(s):

Polar Wander ◽

Apparent Polar Wander Path ◽

Paleomagnetic Poles

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MANICOUAGAN, QUEBEC, PALEOMAGNETIC RESULTS

Canadian Journal of Earth Sciences ◽

10.1139/e67-041 ◽

1967 ◽

Vol 4 (4) ◽

pp. 641-649 ◽

Cited By ~ 49

Author(s):

W. A. Robertson

Keyword(s):

North American ◽

Remanent Magnetization ◽

Thermal Studies ◽

Pole Position ◽

The Mean ◽

Paleomagnetic Poles

The remanent magnetization of dacitic material from Manicouagan, Quebec, was examined. Laboratory thermal studies support the view that viscous buildup in situ was small and secondary components insignificant. A pole position of 89 °E., 57 °N. is calculated from the mean direction of 6 sites. Comparison with other North American paleomagnetic poles points to a possible Triassic age for the formation of the material.

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Paleomagnetic data of the Siberian Mesoproterozoic rocks (Udzha Uplift, Northern Siberia)

10.5194/egusphere-egu2020-9315 ◽

2020 ◽

Author(s):

Aleksandr Pasenko ◽

Aleksandr Savelev ◽

Sergey Malyshev

Keyword(s):

Siberian Platform ◽

Paleomagnetic Data ◽

Russian Science ◽

Polar Wander ◽

Late Precambrian ◽

Apparent Polar Wander Path ◽

The Earth ◽

Isotope Studies ◽

Paleomagnetic Poles ◽

Olenek Uplift

In spite of the fact, that during the last two decades some number of new paleomagnetic poles, more or less meeting the modern standards of quality [Van der Voo, 1993], have been obtained for Mesoproterozoic of Siberia [Evans et al., 2016]. The problem of the Precambrian segment of the apparent polar wander path (APWP) for Siberia, rests still to be far from its solution.The latter, obviously, hampers the elaboration of Precambrian paleogeographic reconstructions, solution of numerous other important tasks of the Earth Sciences.The Late Precambrian key section of the Udzha Uplift seemed to be one of the most promising object to elaborate the Mesoproterozoic segment of APWP of the Siberian platform. Until recently, the rocks composing this section have been considered to be of the Mesoproterozoic and Vendian age.As a result of isotope studies in recent years, the age of formations of the Udzha Uplift has been significantly increased (1386&#177;30 Ma, apatite, U-Pb, [Malyshev et al., 2018]). In particular, age of the Udzha Fm, which forms the uppermost part of the Udzha riphean sequence is considered currently to be Mesoproterosoic. On the base of our new paleomagnetic data this formation has been formed about the same time as the Khaypakh Fm from the Olenek Uplift (NE Siberia), whose Mesoproterozoic age has been established earlier from independent isotopic data [Zaitseva et al., 2017].During last several years we have carried out the paleomagnetic studies of Late Precambrian rocks of the Udzha Uplift including the Mesoproterozoic Udzha and Unguokhtakh formations as well as intrusions representing two Mesoproterozoic magmatic events.In this abstract we present new paleomagnetic poles for the Mesoproterosoic rocks (1500 Ma, ca.1400 Ma, 1385 Ma) of the Siberian platform.These paleomagnetic poles significantly complement the Mesoproterozoic segment of APWP of the Siberian Platform.The studies were supported by the Russian Science Foundation project &#8470; 19-77-10048.

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