Structure and topography of the Siqueiros transform fault system: Evidence for the development of intra-transform spreading centers

Fornari, Daniel J.; Gallo, David G.; Edwards, Margo H.; Madsen, John A.; Perfit, Michael R.; Shor, Alexander

doi:10.1007/bf00282579

Cited by 109 publications

(89 citation statements)

References 72 publications

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“…A similar interval was estimated from the spacing of abandoned ridge tips associated with the 11º45 0 N OSC [46]. Structures along the northern boundary of the Siqueiros Fracture Zone have been interpreted to reflect a 300-500 ka episodicity in the volcanic and tectonic processes in this region [47].…”

Section: Origin Of Temporal Chemical Variationsmentioning

confidence: 65%

Variations in the geochemistry of magmatism on the East Pacific Rise at 10°30′N since 800 ka

Regelous

Niu

Wendt

et al. 1999

Earth and Planetary Science Letters

145

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Section: Origin Of Temporal Chemical Variationsmentioning

confidence: 65%

Variations in the geochemistry of magmatism on the East Pacific Rise at 10°30′N since 800 ka

Regelous

Niu

Wendt

et al. 1999

Earth and Planetary Science Letters

145

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“…The age offset of the Clipperton fracture zone (1.5 Myr) is among the smallest of all the large fracture zones in the world's oceans [e.g., Fornari et al, 1989]. From bathymetry data and crustal magnetization models, Perram and Macdonald [ 1990] and Carbotte and Macdonald [1992] The travel time picks of the seismic refractions were done visually to avoid mislabeling phases and were then optimized by cross-correlating roughly 10 traces at a time to establish relative time shifts [VanDecar and Crosson, 1990].…”

Section: Clipperton Fracture Zonementioning

confidence: 99%

A two‐dimensional tomographic study of the Clipperton transform fault

Avendonk¹,

et al. 1998

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Abstract. From the marine refraction data recorded on five instruments during the Clipperton Area Seismic Survey to Investigate Compensation (CLASSIC) experiment in 1994 we construct a compressional velocity model for a 108 km long profile across the Clipperton transform. We apply a new seismic tomography code that alternates between ray tracing and linearized inversions to find a smooth seismic velocity model that fits the observed refraction travel times. The solution to the forward ray-tracing problem is a hybrid of the graph (or shortest path) method and a ray-bending method. The inversion is performed with least squares penalties on the data misfit and first derivatives of the seismic structure. Starting with a one-dimensional compressional velocity model for oceanic crust, the misfit in the normalized travel time residuals is reduced by 96%, decreasing the median travel time residual from 110 to 25 ms. The compressional velocity structure of the Clipperton transform is characterized by anomalously low velocities, about 1.0 km/s lower than average, beneath the median ridge and parallel troughs of the transform domain. The low compressional velocities can be explained by an increased porosity due to fracturing of the oceanic crust. We found crustal thicknesses of 5.6-5.9 km under the transform fault to produce the best fit of the Prop phase arrivals and Pg/Pn crossovers. Since the crust is not thin beneath the transform parallel troughs and the velocity anomaly is not confined to the median ridge, we find uplift by serpentinite diapirs unlikely as an explanation for the relief of the median ridge. A median ridge that is the result of brittle deformation due to compression across the transform domain is, however, compatible with our results. The upper crust is thicker to the north of the transform than to the south, which is likely a consequence of the contrast in temperature structure of these two spreading segments.

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“…Several examples of transform-rift interaction may be related to case (ii), such as at the intersection of the East Pacific Rise with the Tamayo Transform Fault (Gallo et al, 1984), the Siqueiros Transform fault system with the East Pacific Rise (Fornari et al, 1989), the Vema Fracture Zone (Mamaloukas-Frangoulis et al, 1991), the Oceanographer Transform fault with the Mid-Atlantic Ridge, and several other sites (review iņ Sengör, 2014). This type of configuration is stable with the slip vector of the rift coinciding with the slip vector of the transform fault, especially if simplified as the scheme of Figure 1C.…”

Section: Introductionmentioning

confidence: 99%

Interaction between Transform Faults and Rift Systems: A Combined Field and Experimental Approach

2016

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We present a detailed field structural survey of the area of interaction between the active NW-striking transform Husavik-Flatey Fault (HFF) and the N-S Theystareykir Fissure Swarm (TFS), in North Iceland, integrated by analog scaled models. Field data contribute to a better understanding of how transform faults work, at a much higher detail than classical marine geophysical studies. Analog experiments are conducted to analyse the fracture patterns resulting from different possible cases where transform faulting accompanies or postpones the rift motions. Different tectonic block configurations are also considered and results are compared with field data in order to study as thoroughly as possible the interaction between the HFF and the TFS as well as the possible prolongation of the HFF into the TFS. West of the intersection between the transform fault (HFF) and the rift zone (TFS), the former splays with a gradual bending giving rise to a leading extensional imbricate fan. The westernmost structure of the rift, the N-S Gudfinnugja Fault (GF), is divided into two segments: the southern segment makes a junction with the HFF and is part of the imbricate fan; north of the junction instead, the northern GF appears right-laterally offset by about 20 m. Southeast of the junction, along the possible prolongation of the HFF across the TFS, the strike of the rift faults rotates in an anticlockwise direction, attaining a NNW-SSE orientation. Moreover, the TFS faults north of the HFF prolongation are fewer and have smaller offsets than those located to the south. Through the comparison between the structural data collected in the field at the HFF-TFS connection zone and a set of scaled experiments, we confirm a prolongation of the HFF through the rift, although here the transform fault has a much lower slip-rate than west of the junction. Our data suggest that transform fault terminations may be more complex than previously known, and propagate across a rift through a modification of the rift pattern.

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Structure and topography of the Siqueiros transform fault system: Evidence for the development of intra-transform spreading centers

Cited by 109 publications

References 72 publications

Variations in the geochemistry of magmatism on the East Pacific Rise at 10°30′N since 800 ka

Variations in the geochemistry of magmatism on the East Pacific Rise at 10°30′N since 800 ka

A two‐dimensional tomographic study of the Clipperton transform fault

Interaction between Transform Faults and Rift Systems: A Combined Field and Experimental Approach

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