Mechanisms of mud extrusion on the Mediterranean Ridge Accretionary Complex

Kopf, Achim J; Robertson, Alastair H.F.; Clennell, M.B.; Flecker, Rachel

doi:10.1007/s003670050058

Cited by 60 publications

(45 citation statements)

References 12 publications

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“…Yassir [1989] found plasticities of Trinidad muds of ϳ30%, but of Ͻ20% for the Taiwan features (with Ͻ35 wt % clay; see above). The sample with the highest clay content (71.6 wt % at Digity MV in Trinidad) had the highest plasticity (47.8 %), in agreement with maximum values of 41 wt % clay and 42 % plasticity at Napoli MV on the Mediterranean Ridge [Kopf et al, 1998]. …”

Section: Mechanical Aspects Mud Flux and Episodicity/ Durationmentioning

confidence: 57%

“…Undrained strength determined with a torsionvane shear apparatus showed values well below 100 kPa for both marine clays and serpentinite diapiric clays [Phipps and Ballotti, 1992]. Drained shear strength tests (1.2 MPa) on muds from Mediterranean Ridge MVs using a standard geotechnical shear box had peak values of 200 -380 kPa at friction angles typical for smectiterich material [Kopf et al, 1998]. The mud was found to Figure 6a.…”

Section: Mechanical Aspects Mud Flux and Episodicity/ Durationmentioning

confidence: 99%

“…Although plausible in an environment of hydrate stability entrained by a (warmer) fluid from depth (thus destroying the hydrate cap), the physical properties of gas hydrates are only incompletely understood [e.g., Stoll and Bryan, 1979;Zhang et al, 1999]. On the Mediterranean Ridge (Figure 7), where the fluids triggering MVism may be either ancient pore waters or mineral water from near the backstop, the mélange-type breccias are believed to be the product of efficient removal of the fault breccia by the ascending mud [Kopf et al, 1998]. The release mechanism for excess mud pressures is tectonic forces, which episodically unlock the shear zone juxtaposed by the MV (Figures 5b, 6b, and 8).…”

Section: Diapiric and Other Modelsmentioning

confidence: 99%

“…They generally comprise a variety of clasts and rock fragments in a clay mineral-rich matrix. The ratio of clasts to matrix covers the entire spectrum from clast-supported deposits to virtually clastfree homogeneous muds (the latter are often related to the final phase of an eruptive cycle, when loose wall rock along the conduit has already been removed by the ascending mud [e.g., Kopf et al, 1998]). The most common terms used for the ejecta of MVs as well as of diapirs are mud breccia or conglomerate (depending on the shape of the fragments), olistostromes/olistoliths, mud debris flow deposits, scaly clay (here the fragments are sheared, strongly dewatered matrix material), diapiric mélange [e.g., Orange, 1990], or argille scaliose [e.g., Agar et al, 1988].…”

Section: General Relationships and Terminologymentioning

confidence: 99%

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Significance of Mud Volcanism

Kopf

2002

Reviews of Geophysics

747

646

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Mud volcanism and diapirism have puzzled geoscientists for ∼2 centuries. They have been described onshore and offshore in many places on Earth, and although they occur in various tectonic settings, the majority of the features known to date are located in compressional tectonic scenarios. This paper summarizes the main thrusts in mud volcano research as well as the various regions in which mud volcanism has been described. Mud volcanoes show variable geometry (up to tens of kilometers in diameter and several hundred meters in height) and a great diversity regarding the origin of the fluid and solid phases. Gas (predominantly methane), water, and mud may be mobilized at subbottom depth of only a few meters but, in places, can originate from several kilometers depth (with minor crustal or mantle input). The possible contribution of mud extrusion to global budgets, both from quiescent fluid emission and from the extrusive processes themselves, is important. In regions where mud volcanoes are abundant, such as the collision zones between Africa and Eurasia, fluid flux through mud extrusion exceeds the compaction‐driven pore fluid expulsion of the accretionary wedge. Also, quiescent degassing of mud volcanoes may contribute significantly to volatile budgets and, hence, to greenhouse climate.

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Section: Mechanical Aspects Mud Flux and Episodicity/ Durationmentioning

confidence: 57%

Section: Mechanical Aspects Mud Flux and Episodicity/ Durationmentioning

confidence: 99%

Section: Diapiric and Other Modelsmentioning

confidence: 99%

Section: General Relationships and Terminologymentioning

confidence: 99%

See 2 more Smart Citations

Significance of Mud Volcanism

Kopf

2002

Reviews of Geophysics

747

646

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“…This shift probably occurred during the short but intense compressional phase of 1 to 0.7 Ma that prevailed between two extensional regimes (Sorel et al, 1992). The initiation of mud volcanism in Milano and Napoli volcanoes is dated to ~1.5 Ma (Kopf et al, 1998). The activity of both centers along the western and eastern branches of the Mediterranean Ridge was probably triggered by these changes in stress regime rather than from the on-going process of subduction.…”

Section: Helenic and Calabrian Arcsmentioning

confidence: 99%

Early-to-mid Pleistocene Tectonic Transition Across the Eastern Mediterranean Influences the Course of Human History

Schattner¹

2011

New Frontiers in Tectonic Research - At the Midst of Plate Convergence

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Boron desorption and fractionation in Subduction Zone Fore Arcs: Implications for the sources and transport of deep fluids

Saffer

Kopf

2016

Geochem Geophys Geosyst

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At many subduction zones, pore water geochemical anomalies at seafloor seeps and in shallow boreholes indicate fluid flow and chemical transport from depths of several kilometers. Identifying the source regions for these fluids is essential toward quantifying flow pathways and volatile fluxes through fore arcs, and in understanding their connection to the loci of excess pore pressure at depth. Here we develop a model to track the coupled effects of boron desorption, smectite dehydration, and progressive consolidation within sediment at the top of the subducting slab, where such deep fluid signals likely originate. Our analysis demonstrates that the relative timing of heating and consolidation is a dominant control on pore water composition. For cold slabs, pore water freshening is maximized because dehydration releases bound water into low porosity sediment, whereas boron concentrations and isotopic signatures are modest because desorption is strongly sensitive to temperature and is only partially complete. For warmer slabs, freshening is smaller, because dehydration occurs earlier and into larger porosities, but the boron signatures are larger. The former scenario is typical of nonaccretionary margins where insulating sediment on the subducting plate is commonly thin. This result provides a quantitative explanation for the global observation that signatures of deeply sourced fluids are generally strongest at nonaccretionary margins. Application of our multitracer approach to the Costa Rica, N. Japan, N. Barbados, and Mediterranean Ridge subduction zones illustrates that desorption and dehydration are viable explanations for observed geochemical signals, and suggest updip fluid migration from these source regions over tens of km.

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Mechanisms of mud extrusion on the Mediterranean Ridge Accretionary Complex

Cited by 60 publications

References 12 publications

Significance of Mud Volcanism

Significance of Mud Volcanism

Early-to-mid Pleistocene Tectonic Transition Across the Eastern Mediterranean Influences the Course of Human History

Boron desorption and fractionation in Subduction Zone Fore Arcs: Implications for the sources and transport of deep fluids

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