Microplate tectonics along a superfast seafloor spreading system near Easter Island

Hey, R. N.; Naar, David F.; Kleinrock, Martin C.; Morgan, W. Jason; Morales, Ethel; Schilling, Jean-Guy

doi:10.1038/317320a0

Cited by 110 publications

(36 citation statements)

References 36 publications

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“…Also, the developtrent and subsequent accretion of a microplate to a neighboring major plate may be one method by which In addition to the edge-driven model a variety of other possible models have been suggested for microplate kinematics. The first models described mid-ocean ridge microplates as the lithosphere being transferred by a large-scale propagating rift system [Hey et al, 1980;Handschumacher et al, 1981] and were advanced subsequently to include the processes of dual rift propagation and microplate rotation about Euler poles located proximal to propagator rift tips [Engeln and Stein, 1984;Hey et al, 1985]. Finally, nonrigid behavior (e.g., intmplate deformation, rapidly migrating boundaries) was considered with respect to these models [Hey et al, 1985;Engeln et al, 1988;Hey, 1989a, 1991].…”

Section: Introductionmentioning

confidence: 99%

Plate tectonic reconstructions of the Juan Fernandez microplate: Transformation from internal shear to rigid rotation

Bird¹,

Naar²,

Larson³

et al. 1998

J. Geophys. Res.

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Section: Introductionmentioning

confidence: 99%

Plate tectonic reconstructions of the Juan Fernandez microplate: Transformation from internal shear to rigid rotation

Bird¹,

Naar²,

Larson³

et al. 1998

J. Geophys. Res.

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“…The evidence for their kinematics is best preserved in the oceans and at their margins, where they are often shown to have had a brief, simple, existence governed by local complications to the major plate pattern (e.g. plate boundary jumps or migration of triple junctions) [1,2]. Within deforming continental regions, where the age of each kinematic indicator must be independently assessed, the process of microplate formation is poorly understood (e.g.…”

Section: Introductionmentioning

confidence: 99%

Kinematics of the Danakil microplate

Eagles

Gloaguen

Ebinger

2002

Earth and Planetary Science Letters

107

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A refinement and extrapolation of recent motion estimates for the Danakil microplate, based on ancient kinematic indicators in the Afar region, describes the evolution of a microplate in the continental realm. The Danakil horst is an elevated part of this microplate, exposing a Precambrian basement within the Afar depression, the site of the NubiaŜ omalia^Arabia triple junction. We compare evidence for strike-or oblique-slip faults in data from the Afar depression and southern Red Sea to small circles about published poles of rotation for the Danakil microplate with respect to Nubia. A reconstruction about the preferred pole reunites lengths of a Precambrian shear zone on the Nubia and Danakil sides and preserves a uniform basement fabric strike through Nubia, Danakil and Yemen. Since at least magnetic chron C5 (V11 Ma) Danakil rotated about a different pole with respect to Nubia than either Somalia or Arabia, but between chrons C5 and C2A Nubia^Danakil motion was a close approximation to NubiaŜ omalia motion. Since C2A relative motions of the Danakil microplate have been independent of movements on any of the neighbouring plate boundaries. We relate this to the onset of oceanic-type accretion within Afar. The resulting eastwards acceleration of Danakil was accommodated by westwards propagation of the Gulf of Aden rift that became the new, discrete, plate boundary between the Danakil microplate and the Somalia plate. Present-day activity suggests that the Red Sea and Aden rifts will link through Afar, thereby isolating the Danakil horst as a microcontinent on the Arabian margin. ß

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“…Thus the probable age of Easter Island may be as great as 4.5 Ma, which is similar to the estimated age of the Easter Microplate. Hey et al (1985) identified the east ridge of the microplate as being composed of at least two northward propagating rifts. Studies of the relationship between propagating rifts and near axis hotspots in other areas suggest that propagating rifts may propagate away from bathymetric highs on ridge crests near hotspots (Hey et al 1980;Phipps Morgan and Parmentier, 1985;Naar and Hey, 1986).…”

Section: Tectonic Implications Of Recent Volcanismmentioning

confidence: 99%

“…This change in spreading fabric orientation is characteristic of propagating rifts. A pseudofault with an orientation that could be projected to pass through Easter Island was delineated by Hey et al (1985) north of 25 ~ S.…”

Section: Tectonic Implications Of Recent Volcanismmentioning

confidence: 99%

A SeaMARC II survey of recent submarine volcanism near Easter Island

et al. 1990

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Abstract. SeaMARC II side-scan sonar data reveal that a large area of seafloor north and west of Easter Island has been disrupted by recent submarine volcanism. A large volcanic area begins approximately 60 km WNW of the island and extends for over 130 km to the west. The volcanic field is characterized by high backscatter intensity in the side-scan sonar records and is elevated 400 1000 m above the N-S seafloor fabric that surrounds it. This field, the Ahu Volcanic Field, covers at least 2500 km 2 and appears to consist of recent lava flows and small volcanoes. Backscatter intensity of the Ahu Volcanic Field is similar to that of the adjacent ridge flank which is less than 0.4 Ma, suggesting a similar age for its formation.Two additional areas of high backscatter immediately north of Easter Island cover a combined area of over 300 km 2. The sidescan sonar records show that these features are clearly of volcanic origin and are not debris flows from the nearby island. The flows are nearly 300 m thick and are morphologically similar to subaerial pahoehoe lava shields. Their high backscatter indicates that they are also the products of relatively recent submarine volcanic activity.The presence of these large areas of recent volcanism in the vicinity of Easter Island has important implications for the various models that have been proposed to explain the origin of the Easter Seamount Chain. In addition, the similar ages of Easter Island and the Easter Microplate suggest that the presence of a hotspot near or beneath this fast-spreading portion of the East Pacific Rise about 4.5 m.y. ago may have initiated the large-scale rift propagation that created the microplate.

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Microplate tectonics along a superfast seafloor spreading system near Easter Island

Cited by 110 publications

References 36 publications

Plate tectonic reconstructions of the Juan Fernandez microplate: Transformation from internal shear to rigid rotation

Plate tectonic reconstructions of the Juan Fernandez microplate: Transformation from internal shear to rigid rotation

Kinematics of the Danakil microplate

A SeaMARC II survey of recent submarine volcanism near Easter Island

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