A Robust Estimation of the 3‐D Intraplate Deformation of the North American Plate From GPS

ABSTRACT Naturally occurring asbestos (NOA) is being discovered in a widening array of geologic environments. The complex geology of the state of California is an excellent example of the variety of geologic environments and rock types that contain NOA. Notably, the majority of California rocks were emplaced during a continental collision of eastward-subducting oceanic and island arc terranes (Pacific and Farallon plates) with the westward continental margin of the North American plate between 65 and 150 MY BP. This collision and accompanying accretion of oceanic and island arc material from the Pacific plate onto the North American plate, as well as the thermal events caused by emplacement of the large volcanic belt that became today's Sierra Nevada mountain range, are the principal processes that produced the rocks where the majority of NOA-bearing units have been identified.

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Bryozoa of the Mission Argillite (Permian), northeastern Washington

Journal of Paleontology ◽

10.1017/s0022336000032704 ◽

2000 ◽

Vol 74 (4) ◽

pp. 545-570 ◽

Cited By ~ 2

Author(s):

Ernest H. Gilmour ◽

Edward M. Snyder

Keyword(s):

New Species ◽

Pacific Ocean ◽

North American ◽

Type Species ◽

New Genus ◽

Western Pacific ◽

North American Plate ◽

Western Pacific Ocean ◽

Late Permian ◽

The North

Fifteen species of Late Permian bryozoans occur in a biohermal bank in the Mission Argillite of northeastern Washington. These include two species conspecific with species described from Japan and 13 new species, one of which is the type species of a new genus. The presence of two species, Dyscritella iwaizakiensis Sakagami, 1961, and Hayasakapora cf. erectoradiata Sakagami, 1960, previously reported from Japan, and the similarity of new species with those previously described from Japan, China and Russia supports the idea that these rocks were originally deposited in the southeastern or central western Pacific Ocean and subsequently accreted to the North American Plate.Bryozoans and previously reported fusulinids indicate that the biohermal bank is latest Wordian (Kazanian).Newly described bryozoans include the new genus and type species Sakagamiina easternensis belonging to the Timanodictyidae. Other new species are Fistuliramus pacificus, Meekoporella inflecta, Neoeridotrypella missionensis, Coeloclemis urhausenii, Tabulipora colvillensis, Rhombotrypella kettlensis, Pamirella oculus, Pinegopora petita, Wjatkella nanea, Alternifenestella vagrantia, Polypora arbusca, and Mackinneyella stylettia.

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The southern Mexico block: main boundaries and new estimation for its Quaternary motion

BSGF - Earth Sciences Bulletin ◽

10.2113/gssgfbull.179.2.209 ◽

2008 ◽

Vol 179 (2) ◽

pp. 209-223 ◽

Cited By ~ 27

Author(s):

Louis Andreani ◽

Xavier Le Pichon ◽

Claude Rangin ◽

Juventino Martínez-Reyes

Keyword(s):

North American ◽

Triple Junction ◽

Strike Slip ◽

North American Plate ◽

Southern Mexico ◽

Active Deformation ◽

Lateral Strike Slip ◽

Counterclockwise Rotation ◽

The North ◽

Slip Partitioning

Abstract Numerous studies, mainly based on structural and paleomagnetic data, consider southern Mexico as a crustal block (southern Mexico block, SMB) uncoupled from the North American plate with a southeast motion with respect to North America, accommodated by extension through the central Trans-Mexican volcanic belt (TMVB). On the other hand, the accommodation of this motion on the southeastward boundary, especially at the Cocos–Caribbean–North American triple junction, is still debated. The boundary between the SMB and the North American plate is constituted by three connected zones of deformation: (1) left-lateral transtension across the central TMVB, (2) left-lateral strike-slip faulting along the eastern TMVB and Veracruz area and (3) reverse and left-lateral strike-slip faulting in the Chiapas area. We show that these three active deformation zones accommodate a counterclockwise rotation of the SMB with respect to the North American plate. We specially discuss the Quaternary motion of the SMB with respect to the surrounding plates near the Cocos–Caribbean–North American triple junction. The model we propose predicts a Quaternary counterclockwise rotation of 0.45°/Ma with a pole located at 24.2°N and 91.8°W. Finally we discuss the geodynamic implications of this counterclockwise rotation. The southern Mexico block motion is generally assumed to be the result of slip partitioning at the trench. However the obliquity of the subduction is too small to explain slip partitioning. The motion could be facilitated by the high thermal gradient and gravitational collapse that affects central Mexico and/or by partial coupling with the eastward motion of the Caribbean plate.

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Micropaleontological Dating of the Collision between the North American Plate and the Greater Antilles Arc in Western Cuba

Palaios ◽

10.2307/3515303 ◽

1997 ◽

Vol 12 (2) ◽

pp. 133 ◽

Cited By ~ 32

Author(s):

Timothy J. Bralower ◽

Manuel A. Iturralde-Vinent

Keyword(s):

North American ◽

North American Plate ◽

Greater Antilles ◽

The North

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Geochronology of the North American Midcontinent rift in western Lake Superior and implications for its geodynamic evolution

Canadian Journal of Earth Sciences ◽

10.1139/e17-039 ◽

1997 ◽

Vol 34 (4) ◽

pp. 476-488 ◽

Cited By ~ 84

Author(s):

D. W. Davis ◽

J. C. Green

Keyword(s):

North American ◽

Lake Superior ◽

Flood Basalt ◽

North American Plate ◽

Rift System ◽

Midcontinent Rift ◽

Subsidence Rate ◽

The North ◽

Western Lake ◽

Midcontinent Rift System

Volcanism in the Midcontinent rift system lasted between 1108 and 1086 Ma. Rates of flood-basalt eruption and subsidence in the western Lake Superior region appear to have been greatest at the beginning of recorded activity (estimated 5 km/Ma subsidence rate at 1108 Ma) and rapidly waned over a period of 1–3 Ma during a magnetically reversed period. The age of the paleomagnetic polarity reversal is now constrained to be between 1105 ± 2 and 1102 ± 2 Ma. A resurgence of intense volcanism began at 1100 ± 2 Ma in the North Shore Volcanic Group and lasted until 1097 ± 2 Ma. This group contains a ca. 7 Ma time gap between magnetically reversed and normal volcanic sequences. A similar disconformity appears to exist in the upper part of the Powder Mill Group. The average subsidence rate during this period was approximately 3.7 km/Ma. Latitude variations measured from paleomagnetism on dated sequences indicate that the North American plate was drifting at a minimum rate of 22 cm/year during the early history of the Midcontinent rift. An abrupt slowdown to approximately 8 cm/year occurred at ca. 1095 Ma. These data support a mantle-plume origin for Midcontinent rift volcanism, with the plume head attached to and drifting with the continental lithosphere. Resurgence of flood-basalt magmatism at 1100 Ma may have been caused by extension of the superheated lithosphere following continental collision within the Grenville Orogen to the east.

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