Paleomagnetism of the Dockum Group (Upper Triassic), northwest Texas: Further evidence for the J-1 cusp in the North America apparent polar wander path and implications for rate of Triassic apparent polar wander and Colorado plateau rotation

Paleomagnetic sampling of the Lawrenceton Formation of the Silurian Botwood Group in northeastern Newfoundland was combined with detailed structural mapping of the area in order to determine the deformation history and make adequate structural corrections to the paleomagnetic data.Structural analysis indicates that the Lawrenceton Formation experienced at least two folding events: (i) a regional northeast–southwest-trending, Siluro-Devonian folding episode that produced a well-developed axial-plane cleavage; and (ii) an episode of local north-trending folding. Bedding – regional cleavage relationships indicate that the latter event is older than the regional folding.Thermal demagnetization of the Lawrenceton Formation yielded univectorial southerly and shallow directions (in situ). A fold test on an early mesoscale fold indicates that the magnetization of the Botwood postdates this folding event. However, our results, combined with an earlier paleomagnetic study of nearby Lawrenceton Formation rocks, demonstrate that the magnetization predates the regional folding. Therefore, we conclude that the magnetization occurred subsequent to the local folding but prior to the period of regional folding.While a tectonic origin for local folding cannot be entirely excluded, the subaerial nature of these volcanics, the isolated occurrence of these folds, and the absence of similar north-trending folds in other areas of eastern Notre Dame Bay suggest a syndepositional origin. Consequently, the magnetization may be nearly primary. Our study yields a characteristic direction of D = 175°, I = +43°, with a paleopole (16°N, 131 °E) that plots near the mid-Silurian track of the North American apparent polar wander path. This result is consistent with an early origin for the magnetization and supports the notion that the Central Mobile Belt of Newfoundland was adjacent to the North American craton, in its present-day position, since the Silurian.

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Paleomagnetism of the komatiitic basalts of the Ottawa Islands, N.W.T.

Canadian Journal of Earth Sciences ◽

10.1139/e85-056 ◽

1985 ◽

Vol 22 (4) ◽

pp. 553-566 ◽

Cited By ~ 2

Author(s):

K. L. Buchan ◽

W. R. A. Baragar

Keyword(s):

North American ◽

Hudson Bay ◽

The West ◽

Magnetization Direction ◽

Polar Wander ◽

The North ◽

Dominant Component ◽

Apparent Polar Wander Path

The komatiitic basalts of the Ottawa Islands in eastern Hudson Bay are on strike with and believed to form a continuation of similar units of the Cape Smith Belt 150 km to the northeast. Units sampled in the Ottawa Islands all dip gently to the west and hence are not suitable for an internal fold test of their age of magnetization. However, before correcting for the tilt of the lavas, the dominant magnetization direction (D = 207.6°, I = 61.9°, k = 168, α95 = 3.7°) does not differ significantly from the uncorrected magnetization direction reported from the steeply dipping, northwest-facing units at Cape Smith (D = 218°, I = 60°, k = 47, α95 = 4°). This negative fold test suggests that the remanence at both locations was acquired after folding. Comparison with the North American Precambrian apparent polar wander path implies that overprinting is related to the Hudsonian Orogeny.A second stable magnetization directed to the west with a shallow inclination is superimposed on the dominant component at a number of sampling sites. Its direction is poorly defined and no fold test is possible. However, magnetic evidence suggests that this component was probably acquired as an overprint after the dominant magnetization, perhaps during a mild reheating associated with the Elsonian Orogeny.

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Palaeomagnetic evidence for Proterozoic continental development

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences ◽

10.1098/rsta.1981.0110 ◽

1981 ◽

Vol 301 (1461) ◽

pp. 265-277 ◽

Cited By ~ 16

Keyword(s):

North America ◽

High Latitude ◽

Baltic Shield ◽

Continental Drift ◽

Polar Wander ◽

Late Proterozoic ◽

Apparent Polar Wander Path ◽

Orogenic Uplift ◽

The Baltic ◽

Opening And Closing

The palaeomagnetic record of continental drift during the Proterozoic is reasonably complete for North America (including Greenland and the Baltic Shield), less complete for Africa and Australia, and fragmentary elsewhere. Palaeomagnetic poles of similar age from different cratons or structural provinces of any one continent tend to fall on a common apparent polar wander path (a.p.w.p.), indicating no major (> 1000 km) intercratonic movements. On this evidence, Proterozoic orogens and mobile belts are essentially ensialic in origin. However, the palaeomagnetic record has systematic gaps. In highly metamorphosed orogens (amphibolite grade and above), remagnetization dating from post-orogenic uplift and cooling is pervasive. Collisional and ensialic orogenesis cannot then be distinguished. Palaeopoles from different continents do not follow a common a.p.w.p. They record large relative rotations and palaeolatitude shifts. A recurrent pattern appears in the late Proterozoic drift of North America. At approximately 200 Ma intervals (at about 1250, 1050, 850 and 600 Ma B.P .), the continent returned to the same orientation and (equatorial) latitudes from various rotations and high-latitude excursions. Lacking detailed a.p.w.ps. from other continents, it is not possible to say if these motions represent Wilson cycles of ocean opening and closing in the Phanerozoic style, but they do require minimum drift rates of 50—60 mm/a, comparable to the most rapid present-day plate velocities.

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The Apparent Polar Wander Path For the North China Block Since the Jurassic

Geophysical Journal International ◽

10.1111/j.1365-246x.1991.tb02492.x ◽

1991 ◽

Vol 104 (1) ◽

pp. 29-40 ◽

Cited By ~ 57

Author(s):

Zhong Zheng ◽

Masaru Kono ◽

Hideo Tsunakawa ◽

Gaku Kimura ◽

Qingyun Wei ◽

...

Keyword(s):

North China ◽

North China Block ◽

Polar Wander ◽

The North ◽

Apparent Polar Wander Path

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Upper Triassic Invertebrates from the Antimonio Formation, Sonora, Mexico

Journal of Paleontology ◽

10.1017/s0022336000062284 ◽

1994 ◽

Vol 68 (S36) ◽

pp. 1-33 ◽

Cited By ~ 12

Author(s):

George D. Stanley ◽

Carlos González-León ◽

Michael R. Sandy ◽

Baba Senowbari-Daryan ◽

Peter Doyle ◽

...

Keyword(s):

North America ◽

North American ◽

Weak Link ◽

Upper Triassic ◽

Marine Fauna ◽

Western Tethys ◽

The North ◽

Tethys Realm ◽

First Occurrence ◽

North American Craton

A diverse Upper Triassic tropical marine fauna from northwestern Sonora, Mexico, includes 31 taxa of tropical invertebrates including scleractinian corals, spongiomorphs, disjectoporoids, “hydrozoans,” thalamid and nonthalamid sponges, spiriferid and terebratulid brachiopods, gastropods, bivalves, coleoids, and anomuran microcoprolites. They occur within the late Karnian to Norian part of the Antimonio Formation (Antimonio terrane), which is juxtaposed against a fragmented portion of the North American craton. Most of the fauna is also known from the Tethys region. Sixteen Sonoran taxa co-occur in the western Tethys and five have never been known outside this region. Four additional taxa (one identified only at genus level) are geographically widespread. Some taxa occur in displaced terranes of North America, especially in west-central Nevada (Luning Formation). A weak link exists with the California Eastern Klamath terrane but stronger ties exist with Peru. Among Sonoran sponges,Nevadathalamia polystomawas previously recognized only from the Luning Formation, western Nevada. SpongesCinnabaria expansa, Nevadathalamia cylindrica, and a coral,Astraeomorpha sonorensisn. sp., are also known from Nevada. The coralsDistichomeandra austriaca, Chondrocoenia waltheri, Pamiroseris rectilamellosa, andAlpinophyllia flexuosaco-occur in central Europe. Two new taxa, a spongiomorph hydrozoan,Stromatoporidium lamellatumn. sp., and a disjectoporoid,Pamiropora sonorensisn. sp., have distinct affinities with the Tethys. The geographically widespread North American brachiopod,Spondylospira lewesensis, andPseudorhaetina antimoniensisn. gen. and sp. are among the Sonoran fauna. The Sonoran coleoid (aulacocerid)Dictyoconites(Dictyoconites) cf.D. reticulatumoccurs in the Tethys realm andCalliconitescf.C. drakeiis comparable with a species from the Eastern Klamath terrane.Calliconites millerin. sp. is the first occurrence of the genus outside Sicily. The bivalvesMyophorigonia jaworskii, M. salasi, andPalaeocardita peruvianaare known from Sonora and Peru. Eight gastropod taxa includeGuidoniacf.G. intermediaandG.cf.G. parvula, both previously known from Peru, andEucycloscala subbisertusfrom the western Tethys. The gastropods are unlike those already known from other North American terranes.

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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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Paleomagnetism of the Lac St-Jean anorthosite and related rocks, Grenville Province, Quebec

Canadian Journal of Earth Sciences ◽

10.1139/e83-022 ◽

1983 ◽

Vol 20 (2) ◽

pp. 246-258 ◽

Cited By ~ 8

Author(s):

K. L. Buchan ◽

W. F. Fahrig ◽

G. N. Freda ◽

R. A. Frith

Keyword(s):

North American ◽

Regional Metamorphism ◽

The Other ◽

Central Portion ◽

Grenville Province ◽

Polar Wander ◽

Thermal Demagnetization ◽

The North ◽

Apparent Polar Wander Path ◽

Normal Polarity

Alternating field and thermal demagnetization study of the Lac St-Jean anorthosite and related rock units in the central portion of the exposed Grenville Province reveals two components of magnetization, one of reversed and the other of normal polarity. Both components are thought to have been acquired during the last regional metamorphism, which was sufficiently intense in this area (mostly amphibolite grade) to reset any earlier magnetization. Corresponding paleopoles at 193°W, 8°S (dm = 7.3°, dp = 4.6°) and 213°W, 19°S (dm = 10.5°, dp = 8.5°) lie along the 950–900 Ma segment of the recently calibrated Grenville track of the North American apparent polar wander path, a track that has thus far been defined largely by results from rock units of the western Grenville.

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Paleomagnetism of the Moenkopi and Chinle Formations in central New Mexico: Implications for the North American Apparent Polar Wander Path and Triassic magnetostratigraphy

Journal of Geophysical Research Atmospheres ◽

10.1029/91jb00644 ◽

1991 ◽

Vol 96 (B9) ◽

pp. 14239-14262 ◽

Cited By ~ 49

Author(s):

Roberto S. Molina-Garza ◽

John W. Geissman ◽

Rob Van der Voo ◽

Spencer G. Lucas ◽

Steve N. Hayden

Keyword(s):

New Mexico ◽

North American ◽

Polar Wander ◽

The North ◽

Apparent Polar Wander Path

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The occurrence of the hydrozoan genus Cassianastraea from Upper Triassic (Carnian) rocks of Williston Lake, British Columbia, Canada

Journal of Paleontology ◽

10.1666/10-044.1 ◽

2011 ◽

Vol 85 (1) ◽

pp. 29-31

Author(s):

George D. Stanley ◽

John-Paul Zonneveld

Keyword(s):

British Columbia ◽

North America ◽

Coral Reefs ◽

North American ◽

Upper Triassic ◽

Geological Survey ◽

The North ◽

Lake Region ◽

First Occurrence ◽

North American Craton

Cassianastraea is an enigmatic colonial Triassic cnidarian first described as a coral but subsequently referred to the Hydrozoa. We report here the first occurrence in Canada of fossils we designate as Cassianastraea sp. from the Williston Lake region of British Columbia. The specimens come from older collections of the Geological Survey of Canada, collected in Upper Triassic (Carnian) strata assigned to either the Ludington or Baldonnel Formations. While well known in reef associations of the former Tethys region, Cassianiastraea is relatively rare in North America. The Carnian Baldonnel Formation contains the earliest coral reefs from the North American craton and we suspect that Cassianastraea sp. also came from this reef association.

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