Transient rifting north of the Galápagos Triple Junction

Mitchell, G. A.; Montési, Laurent G. J.; Zhu, Wenlu; Smith, Deborah; Schouten, Hans

doi:10.1016/j.epsl.2011.05.027

Cited by 6 publications

(14 citation statements)

References 41 publications

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“…A succession of transient, east-west trending rifts north and south of C-N Rift at the Galapagos triple junction, has been explained by a simple crack interaction model (Mitchell et al, 2011;Schouten et al, 2008). The rifts initiate at the EPR and their locations at the EPR are controlled by tensile stresses generated by two major, interacting cracks: one crack representing the north-south trending EPR, and the other the large, westward propagating C-N Rift, whose tip does not meet the EPR.…”

Section: Discussionmentioning

confidence: 99%

“…According to the model, transient rifts are generated by stresses associated with the tip of the propagating C-N Rift which remains separated from the EPR (Mitchell et al, 2011;Schouten et al, 2008;Smith et al, 2011).…”

Section: Discussionmentioning

confidence: 99%

“…They suggested that when the tip of the C-N Rift moves closer to the EPR, the transient rifts jump rapidly south, and when the tip remains stationary with respect to the EPR, the transient rifts are stable growing westward as they maintain contact with EPR. Mitchell et al (2011) expanded on the Schouten et al (2008) model to show how a sequence of rapidly jumping rifts and triple junctions could form.…”

Section: Background -Identifying Paleo Triple Junctions On the Cocos mentioning

confidence: 99%

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The recent history of the Galapagos triple junction preserved on the Pacific plate

Smith¹,

Schouten²,

Montési³

et al. 2013

Earth and Planetary Science Letters

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At the Galapagos triple junction, the Cocos and Nazca plates are broken by a succession of transient rifts north and south of the Cocos-Nazca (C-N) Rift. Modeling has suggested that each rift initiated at the East Pacific Rise (EPR), its location controlled by the distance of the C-N Rift tip from the EPR. Evidence on the Pacific plate confirms that each transient rift formed a true RRR triple junction with the EPR and clarifies the history of the region. At ~1.5 Ma the triple junctions began jumping rapidly toward C-N Rift suggesting that the C-N Rift tip moved closer to the EPR. Pacific abyssal hills became broad and shallow indicating enhanced magma supply to the region. At ~1.4 Ma, the Galapagos microplate developed when extension became fixed on the southern transient rift to form the South scarp of the future Dietz rift basin. Lavas flooded the area and a Galapagos-Nazca magmatic spreading center initiated at the EPR. We suggest that a hotspot was approaching the southern triple junction from the west. The hotspot crossed to the Nazca plate ~1.25 Ma. Dietz seamount formed within the young spreading center, dikes intruded Dietz rift basin, and eruptions built volcanic ridges. Since ~0.8 Ma magmatic spreading has jumped northward twice, most recently to Dietz volcanic ridge. Amagmatic extension to the east has formed the large North scarp of Dietz rift basin. Northward jumping of the southern triple junction has maintained the microplate boundary close to the proposed hotspot.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Background -Identifying Paleo Triple Junctions On the Cocos mentioning

confidence: 99%

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The recent history of the Galapagos triple junction preserved on the Pacific plate

Smith¹,

Schouten²,

Montési³

et al. 2013

Earth and Planetary Science Letters

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“…Thus, the crust exposed at the Hess Deep Rift likely formed within a short segment, perhaps at a segment end (Lonsdale 1988). Reconstructions of the EPR flanks indicate several episodes of migrating offsets in the recent past and suggest that the crust now exposed in the Hess Deep Rift formed on the western margin of the EPR (Lonsdale, 1989;Smith et al, 2011;Mitchell et al, 2011). Multichannel seismic reflection profiling along the EPR flanks north of the Northern Escarpment indicates a crustal thickness of 5-5.5 km, with a seismic Layer 3 thickness of 3.0-3.5 km (Zonenshain et al, 1980).…”

Section: Geological Settingmentioning

confidence: 99%

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2012

IODP Scientific Prospectus

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“…The Galapagos microplate has developed to the south and has been stable for ∼1 Ma. At the time of the Schouten et al [2008] and Mitchell et al [2011] studies, no bathymetry data existed to determine whether transient cracks mirroring those to the north had formed to the south prior to the establishment of the microplate.…”

Section: Introductionmentioning

confidence: 99%

Distributed deformation ahead of the Cocos-Nazca Rift at the Galapagos triple junction

Smith

Schouten

Zhu

et al. 2011

Geochem. Geophys. Geosyst.

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The Galapagos triple junction is not a simple ridge‐ridge‐ridge (RRR) triple junction. The Cocos‐Nazca Rift (C‐N Rift) tip does not meet the East Pacific Rise (EPR). Instead, two secondary rifts form the link: Incipient Rift at 2°40′N and Dietz Deep volcanic ridge, the southern boundary of the Galapagos microplate (GMP), at 1°10′N. Recently collected bathymetry data are used to investigate the regional tectonics prior to the establishment of the GMP (∼1.5 Ma). South of C‐N Rift a band of northeast‐trending cracks cuts EPR‐generated abyssal hills. It is a mirror image of a band of cracks previously identified north of C‐N Rift on the same age crust. In both areas, the western ends of the cracks terminate against intact abyssal hills suggesting that each crack initiated at the EPR spreading center and cut eastward into pre‐existing topography. Each crack formed a short‐lived triple junction until it was abandoned and a new crack and triple junction initiated nearby. Between 2.5 and 1.5 Ma, the pattern of cracking is remarkably symmetric about C‐N Rift providing support for a crack interaction model in which crack initiation at the EPR axis is controlled by stresses associated with the tip of the westward‐propagating C‐N Rift. The model also shows that offsets of the EPR axis may explain times when cracking is not symmetric. South of C‐N Rift, cracks are observed on seafloor as old as 10.5 Ma suggesting that this triple junction has not been a simple RRR triple junction during that time.

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Transient rifting north of the Galápagos Triple Junction

Cited by 6 publications

References 41 publications

The recent history of the Galapagos triple junction preserved on the Pacific plate

The recent history of the Galapagos triple junction preserved on the Pacific plate

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Distributed deformation ahead of the Cocos-Nazca Rift at the Galapagos triple junction

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