Geological and geophysical signatures of the East Pacific Rise 8°–10°N

Vithana, M.V.P.; Xu, Min; Zhao, Xu; Zhang, Maochuan; Luo, Yu

doi:10.1016/j.sesci.2019.04.001

Cited by 7 publications

(2 citation statements)

References 103 publications

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“…2). Experiments of Angiboust et al (2012), Gerya (2014a), andRuh et al (2015) have shown that extensive oceanic mantle serpentinization is a prerequisite for involvement of the oceanic-plate lower crust into the accretionary edifice, which is generally not the case for most circum-Pacific seafloor material where a thick (5-10 km) basaltic oceanic crust prevails (e.g., Vithana et al, 2019).…”

Section: Research Papermentioning

confidence: 99%

The rise and demise of deep accretionary wedges: A long-term field and numerical modeling perspective

2021

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Several decades of field, geophysical, analogue, and numerical modeling investigations have enabled documentation of the wide range of tectonic transport processes in accretionary wedges, which constitute some of the most dynamic plate boundary environments on Earth. Active convergent margins can exhibit basal accretion (via underplating) leading to the formation of variably thick duplex structures or tectonic erosion, the latter known to lead to the consumption of the previously accreted material and eventually the forearc continental crust. We herein review natural examples of actively underplating systems (with a focus on circum-Pacific settings) as well as field examples highlighting internal wedge dynamics recorded by fossil accretionary systems. Duplex formation in deep paleo–accretionary systems is known to leave in the rock record (1) diagnostic macro- and microscopic deformation patterns as well as (2) large-scale geochronological characteristics such as the downstepping of deformation and metamorphic ages. Zircon detrital ages have also proved to be a powerful approach to deciphering tectonic transport in ancient active margins. Yet, fundamental questions remain in order to understand the interplay of forces at the origin of mass transfer and crustal recycling in deep accretionary systems. We address these questions by presenting a suite of two-dimensional thermo-mechanical experiments that enable unravelling the mass-flow pathways and the long-term distribution of stresses along and above the subduction interface as well as investigating the importance of parameters such as fluids and slab roughness. These results suggest the dynamical instability of fluid-bearing accretionary systems causes either an episodic or a periodic character of subduction erosion and accretion processes as well as their topographic expression. The instability can be partly deciphered through metamorphic and strain records, thus explaining the relative scarcity of paleo–accretionary systems worldwide despite the tremendous amounts of material buried by the subduction process over time scales of tens or hundreds of millions of years. We finally stress that the understanding of the physical processes at the origin of underplating processes as well as the forearc topographic response paves the way for refining our vision of long-term plate-interface coupling as well as the rheological behavior of the seismogenic zone in active subduction settings.

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Section: Research Papermentioning

confidence: 99%

The rise and demise of deep accretionary wedges: A long-term field and numerical modeling perspective

2021

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“…The surrounding islands were formed by upper Jurassic to lower Cretaceous volcanic activity (Clouard and Bonneville, 2005). The seafloor between the Clarion Fracture Zone and the Clipperton Fracture Zone is characterized by long, northsouth-trending hills, ridges, intervening valleys, and furrows (Vithana et al, 2019;Maciąg and Harff, 2020). Sediments in the area are characterized by organic carbon-starved siliceous clay (Mewes et al, 2016).…”

Section: Sample and Preparationmentioning

confidence: 99%

Classification of a Complexly Mixed Magnetic Mineral Assemblage in Pacific Ocean Surface Sediment by Electron Microscopy and Supervised Magnetic Unmixing

Liu

et al. 2020

Front. Earth Sci.

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Unambiguous magnetic mineral identification in sediments is a prerequisite for reconstructing paleomagnetic and paleoenvironmental information from environmental magnetic parameters. We studied a deep-sea surface sediment sample from the Clarion Fracture Zone region, central Pacific Ocean, by combining magnetic measurements and scanning and transmission electron microscopic analyses. Eight titanomagnetite and magnetite particle types are recognized based on comprehensive documentation of crystal morphology, size, spatial arrangements, and compositions, which are indicative of their corresponding origins. Type-1 particles are detrital titanomagnetites with micron- and submicron sizes and irregular and angular shapes. Type-2 and -3 particles are well-defined octahedral titanomagnetites with submicron and nanometer sizes, respectively, which are likely related to local hydrothermal and volcanic activity. Type-4 particles are nanometer-sized titanomagnetites hosted within silicates, while type-5 particles are typical dendrite-like titanomagnetites that likely resulted from exsolution within host silicates. Type-6 particles are single domain magnetite magnetofossils related to local magnetotactic bacterial activity. Type-7 particles are superparamagnetic magnetite aggregates, while Type-8 particles are defect-rich single crystals composed of many small regions. Electron microscopy and supervised magnetic unmixing reveal that type-1 to -5 titanomagnetite and magnetite particles are the dominant magnetic minerals. In contrast, the magnetic contribution of magnetite magnetofossils appears to be small. Our work demonstrates that incorporating electron microscopic data removes much of the ambiguity associated with magnetic mineralogical interpretations in traditional rock magnetic measurements.

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Stable Sn isotope signatures of Mid-ocean ridge basalts

She

Kubik

et al. 2023

Chemical Geology

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Geological and geophysical signatures of the East Pacific Rise 8°–10°N

Cited by 7 publications

References 103 publications

The rise and demise of deep accretionary wedges: A long-term field and numerical modeling perspective

The rise and demise of deep accretionary wedges: A long-term field and numerical modeling perspective

Classification of a Complexly Mixed Magnetic Mineral Assemblage in Pacific Ocean Surface Sediment by Electron Microscopy and Supervised Magnetic Unmixing

Stable Sn isotope signatures of Mid-ocean ridge basalts

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