Rotation of the Colorado Plateau: An analysis of paleomagnetic data

Bryan, Phillip; Gordon, Richard G.

doi:10.1029/tc005i004p00661

Cited by 53 publications

(25 citation statements)

References 7 publications

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“…Despite the fact that both the New Mexico and the Colorado‐Utah sampling sites indicate that the same paleopole prevailed during Summerville and lower Morrison time, the different sites give different actual positions for the paleomagnetic pole of that time. The New Mexico sites are located east of the Rio Grande Rift, presumably part of cratonic North America, whereas the Colorado‐Utah sites reside on the Colorado Plateau which has been shown to have moved independently of the craton [ Steiner , 1984; Irving and Strong , 1985; Steiner , 1986; Bryan and Gordon , 1986; Steiner , 1988; Bryan and Gordon , 1990; Kent and Witte , 1993; Molina‐Garza et al , 1998]. The Colorado Plateau Summerville and lower Morrison poles are displaced clockwise from the cratonic poles, and in an amount similar to other paleopoles derived from coeval strata deposited both on the Colorado Plateau and the North American craton [ Steiner , 1986; Kent and Witte , 1993; Steiner et al , 1994; Molina‐Garza et al , 1998], thus providing yet another data set supporting the clockwise rotation of the Colorado Plateau.…”

Section: Resultsmentioning

confidence: 99%

A cratonic Middle Jurassic paleopole: Callovian‐Oxfordian stillstand (J‐2 cusp), rotation of the Colorado Plateau, and Jurassic North American apparent polar wander

Steiner

2003

Tectonics

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Paleomagnetic results have been obtained from two sequences of the upper Middle Jurassic (upper Callovian) Summerville Formation which are located on the North American craton (north central New Mexico). The thicker of the two sections (Trujillo) exhibits a well‐defined dual‐polarity remanence, forming a magnetostratigraphy of at least 12 relatively short polarity intervals. The high reversal frequency is consistent with that recorded by the oceanic crust at this time. The second section (Romeroville) is thin, gypsiferous, and poorly indurated; consequently, only a short interval (5 m) was successfully sampled. The characteristic magnetization was wholly normal polarity. In the rapid reversals of the thicker section, that thickness of normal polarity is unique and thus forms the basis of magnetostratigraphic correlation between the two sections. A cratonic late Middle Jurassic paleomagnetic pole at 148.2°E, 57.3°N (k = 30.3, α95 = 6.0°) was obtained from the larger Trujillo sequence. Despite large confidence limits, the small sample population of the Romeroville sequence displayed the same pole. Throughout the western United States, the Summerville Formation is overlain with little or no discordance by the Morrison Formation, although the two stratigraphic units are commonly reported to be separated by an unconformity, designated J‐5. The New Mexico paleopoles of the Summerville and overlying lower Morrison Formations are statistically identical at the 95% confidence level; a similar situation exists between Summerville and lower Morrison paleopoles of the Colorado Plateau. The presence of the same geomagnetic field direction in both the Summerville and the lower Morrison Formations suggests that the J‐5 unconformity which separates them may encompass little time, perhaps representing only a minor break in deposition. The two newly investigated Summerville sites are located east of the Rio Grande Rift, hence representative of the North American craton; their paleopoles are displaced counterclockwise relative to those of the Colorado Plateau, and in amounts consistent with other coeval craton‐Colorado Plateau pole pairs. Together, six coeval paleopoles indicate that the Colorado Plateau has rotated clockwise by about 9.0 ± 3° since Late Pennsylvanian time. The cratonic Summerville paleopole also removes the uncertainty over the Jurassic North American apparent polar wander path. The statistically identical Summerville and lower Morrison paleopoles form a substantial data set, five paleopoles, which indicate that NA APW traced a path roughly along 60° latitude. The five paleopoles stand in stark contrast to the paleopole from the slightly older (5–8 Ma) Moat Volcanics. Spreading rates in the central Atlantic do not allow NA plate motion that would include both paleopoles positions. Because the weight of the data, five paleopoles from widely spaced localities and different tectonic blocks, the Moat Volcanics pole cannot be representative of North America in the Middle Jurassic.

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Section: Resultsmentioning

confidence: 99%

A cratonic Middle Jurassic paleopole: Callovian‐Oxfordian stillstand (J‐2 cusp), rotation of the Colorado Plateau, and Jurassic North American apparent polar wander

Steiner

2003

Tectonics

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“…Another possibility is that the structures were developed in a restraining bend along a north-trending, right-lateral, wrench fault (Chapin and Cather, 1981;Harrison and Chapin, 1990). The hypothetical wrench fault is supposedly caused by clockwise rotation of the Colorado Plateau relative to the continental interior; a rotation that is supported by paleomagnetic data (Steiner, 1986;Bryan and Gordon, 1986). However, if the pole of rotation was located in central New Mexico, as suggested by Hamilton (1988 , Fig.…”

Section: Development Of Laramide Structuresmentioning

confidence: 89%

Thick- and thin-skinned Laramide deformation, Fra Cristobal Range, south-central New Mexico

Nelson¹

1993

Geological Society of America Special Papers

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The Fra Cristobal Range in south-central New Mexico exposes different styles of deformation variably affecting Precambrian crystalline rocks and Paleozoic, Mesozoic, and Cenozoic cover strata. Three main structural domains are recognized: I is a thickskinned domain (basement-involved) along the northwest flank of the range; II is a thin-skinned domain along the southwest flank of the range; and III is a combined thickand thin-skinned domain along the east flank of the range. Domains with thick-skinned deformation are characterized by fault-propagation folds cored by basement blocks bounded by reverse or thrust faults. These domains are segmented by transverse faults into two subdomain types: (1) east-vergent, overturned folds cored by a basement block with corners rounded by cataclastic flow; and (2) upright folds overthrust by basement that is imbricated by east-directed thrust faults. Thin-skinned deformation involves only Paleozoic cover strata and is characterized by decollement-style thrust faults, duplexes, and related upright to overturned folds. Assuming a balance of basement shortening along strike, it is likely that a basement uplift formed west of domain II but is now buried in the Rio Grande rift. Domain II structures developed either as thrusting propagated from basement into cover, by out-of-syncline thrusting east of the uplift, or by gravity sliding off the uplift. Domain III is characterized by a large, east-vergent, overturned monocline (probably basement cored at depth); the overturned limb was subsequently overthrust by its western subhorizontal limb (similar to a cross-crestal fold). A two-stage development is suggested: (1) basement-cored fault-propagation folding in domain III, and (2) shortening in domains I and II to the west and late-stage cross-crestal faulting of the domain III fold. Behavior of basement rocks during deformation includes: (1) shortening and uplift of basement by reverse faulting, (2) cataclastic flow of basement on fault-block corners allowing folding of the basement-cover contact, (3) longitudinal segmentation of some domains by transverse faults, and (4) possible control of basement faulting by preexisting weaknesses.

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“… Steiner [1986] argued that comparison of poles from rocks of similar age on and off the plateau indicates 11°±4° of rotation since Late Triassic time. Bryan and Gordon [1986] presented a new method for simultaneously comparing many poles from one or more coeval segments of APW paths from two different crustal blocks. Their method aims to estimate the rotation between the blocks as accurately as possible.…”

Section: Revised Apw Paths Reinterpretations and Implicationsmentioning

confidence: 99%

Paleomagnetic Reference Poles, Apparent Polar Wander Paths, Paleomagnetic Euler Pole Analysis, and True Polar Wander

Geissman

Gordon

1991

Reviews of Geophysics

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Rotation of the Colorado Plateau: An analysis of paleomagnetic data

Cited by 53 publications

References 7 publications

A cratonic Middle Jurassic paleopole: Callovian‐Oxfordian stillstand (J‐2 cusp), rotation of the Colorado Plateau, and Jurassic North American apparent polar wander

A cratonic Middle Jurassic paleopole: Callovian‐Oxfordian stillstand (J‐2 cusp), rotation of the Colorado Plateau, and Jurassic North American apparent polar wander

Thick- and thin-skinned Laramide deformation, Fra Cristobal Range, south-central New Mexico

Paleomagnetic Reference Poles, Apparent Polar Wander Paths, Paleomagnetic Euler Pole Analysis, and True Polar Wander

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