Late Cretaceous paleomagnetism of the Tucson Mountains: Implications for vertical axis rotations in south central Arizona

1991 ◽  
Vol 96 (B10) ◽  
pp. 16069 ◽  
Author(s):  
Jonathan T. Hagstrum ◽  
Peter W. Lipman
Keyword(s):  
Late Cretaceous ◽  
Vertical Axis ◽  
South Central ◽  
Central Arizona

New paleomagnetic data for the Triassic Guichon batholith of south-central British Columbia and their bearing on Terrane I tectonics

1983 ◽  
Vol 20 (8) ◽  
pp. 1340-1344 ◽  
Author(s):  
D. T. A. Symons
Keyword(s):  
British Columbia ◽  
Late Cretaceous ◽  
Vertical Axis ◽  
Pole Position ◽  
Primary Component ◽  
Paleomagnetic Data ◽  
Clockwise Rotation ◽  
North American Cordillera ◽  
Thermal Demagnetization ◽  
South Central

The 198 Ma Guichon batholith outcrops in the southern end of the Intermontane Belt or composite Terrane I of the western North American Cordillera. Thermal demagnetization of specimens from 19 sites at 200, 450, and 560 °C isolates a stable primary component at 560 °C in 13 sites, giving a pole position of 347°W, 52°N (δp = 5°, δm = 9°). These data support earlier results obtained by the author that indicate the batholith has undergone a clockwise rotation about a vertical axis of ~43 ± 7°. They also show that the batholith has undergone northward motion of 13 ± 6°, which supports recent arguments that the terrane underwent 14 ± 2° of northward translation between Late Cretaceous and pre-Miocene time.

Timing of magnetization and vertical-axis rotations of the Cotiella massif (Late Cretaceous, South Central Pyrenees)

2015 ◽  
Vol 425 (1) ◽  
pp. 213-232 ◽  
Author(s):  
Miguel Garcés ◽  
Jesús García-Senz ◽  
Josep Antón Muñoz ◽  
Berta López-Mir ◽  
Elisabet Beamud
Keyword(s):  
Late Cretaceous ◽  
Vertical Axis ◽  
South Central ◽  
Central Pyrenees

Paleomagnetism of the Triassic Nikolai Greenstone, McCarthy Quadrangle, Alaska

1977 ◽  
Vol 14 (11) ◽  
pp. 2578-2592 ◽  
Author(s):  
J. W. Hillhouse
Keyword(s):  
British Columbia ◽  
High Temperature ◽  
North America ◽  
Vertical Axis ◽  
Upper Triassic ◽  
Present Position ◽  
Stable Component ◽  
South Central ◽  
Early Mesozoic ◽  
Lamellar Texture

Paleomagnetic evidence indicates that the extensive early Mesozoic basalt field near McCarthy, south-central Alaska, originated far south of its present position relative to North America. Results obtained from the Middle and (or) Upper Triassic Nikolai Greenstone suggest that those basalts originated within 15° of the paleoequator. This position is at least 27° (3000 km) south of the Upper Triassic latitude predicted for McCarthy on the basis of paleomagnetic data from continental North America. The Nikolai pole, as determined from 50 flows sampled at 5 sites, is at 2.2° N, 146.1° E (α95 = 4.8°). The polarity of the pole is ambiguous, because the corresponding magnetic direction has a low inclination and a westerly declination. Therefore, the Nikolai may have originated near 15° N latitude or, alternatively, as far south as 15° S latitude. In addition to being displaced northward, the Nikolai block has been rotated roughly 90° about the vertical axis. A measure of the reliability of this pole is provided by favorable results from the following tests: (1) Within one stratigraphic section, normal and reversed directions from consecutive flows are antipolar. (2) Consistent directions were obtained from sites 30 km apart. (3) Application of the fold test indicated the magnetization was acquired before the rocks were folded. (4) The magnetizations of several pilot specimens are thermally stable up to 550 °C. The stable component is probably carried by magnetite with lamellar texture, a primary feature commonly acquired by a basalt at high temperature during initial cooling of the magma. Geologic and paleomagnetic evidence indicates that the Nikolai is allochthonous to Alaska and that, together with associated formations in southern Alaska and British Columbia, it is part of a now disrupted equatorial terrane.

Late Cretaceous Angiosperm Woods from the McRae Formation, South-Central New Mexico, USA: Part 2

2018 ◽  
Vol 179 (2) ◽  
pp. 136-150 ◽  
Author(s):  
Emilio Estrada-Ruiz ◽  
Elisabeth A. Wheeler ◽  
Garland R. Upchurch ◽  
Greg H. Mack
Keyword(s):  
New Mexico ◽  
Late Cretaceous ◽  
South Central
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