Evidence for deep fluid circulation and gas hydrate dissociation using boron and boron isotopes of pore fluids in forearc sediments from Costa Rica (ODP Leg 170)

Kopf, Achim J; Deyhle, Annette; Evelyn, Zuleger

doi:10.1016/s0025-3227(00)00026-8

Cited by 45 publications

(35 citation statements)

References 55 publications

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“…Observations of sedimentary B contribution in pore waters have been reported at numerous convergent margins (You et al 1993a, b;Kopf et al 2000), as well as in laboratory experiments . In high sedimentation regions, sufficient burial stresses may cause smectite-to-illite or opal-A-CT transformation to occur at shallow depths.…”

mentioning

confidence: 89%

“…3e). Gas hydrate dissociation is a possible candidate for causing low B in pore waters (Kastner et al 1995;Sample and Kopf 1995;Kopf et al 2000). Other likely fresh water sources are clay dehydration water (e.g., smectite-illite transformation) and continental inputs.…”

Section: Boron Contents and B Isotopesmentioning

confidence: 99%

“…3c, d) being observed at the sandy turbidite zones. Boron and δ 11 B are sensitive tracers for sedimentary diagenesis that might influence pore water geochemistry , as well as fluids processes at convergent margins (Brumsack and Zuleger 1992;You et al 1993a;You et al 1995;Kopf et al 2000;. Possible mechanisms that affect B and B isotope signatures in pore waters are briefly summarized as follow: (1) De-sorption of exchangeable B in clays, resulting in elevated B with low δ 11 B.…”

Section: Factors Controlling Chemical Distribution In Pore Watersmentioning

confidence: 99%

“…Work during the Deep Sea Drilling Project (DSDP) and the Ocean Drilling Program (ODP) in the past three decades has obtained a broad spectrum of high quality chemical data of interstitial waters in various marine environments. These studies, in particular, have shed light on sediment dewatering processes in the frontal part of accretionary wedges around the world and have provided information on potential return flux of volatiles into the ocean at convergent margins (You et al 1993a,b;Zuleger et al 1996;Kopf et al 2000;. On the contrary, only a little attention has been focused on pore water chemical characteristics in a newly occurring spreading region, e.g., Okinawa spreading center.…”

Section: Introductionmentioning

confidence: 99%

“…Other important B and δ 11 B applications are oceanic crust alteration Spivack et al 1990;Smith et al 1995), environmental pollution (Gabler and Bahr 1999), and pH reconstruction in past oceans (Spivack et al 1993;Sanyal et al 1997;Palmer and Pearson 2003). Recent studies also demonstrate that B and δ 11 B provide crucial information on the study of fluid origin and the degree of water/ sediment interaction at depth, as well as methane hydrates formation (Brumsack and Zuleger 1992;You et al 1993a;You et al 1995You et al 1996Kopf et al 2000;Deyhle and Kopf 2002).…”

Section: Introductionmentioning

confidence: 99%

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Geochemistry of Major Constituents, Boron and Boron Isotopes in Pore Waters from ODP Site 1202, Okinawa Trough

Huang¹,

You²,

Shen³

et al. 2005

Terr. Atmos. Ocean. Sci.

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mentioning

confidence: 89%

Section: Boron Contents and B Isotopesmentioning

confidence: 99%

Section: Factors Controlling Chemical Distribution In Pore Watersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Geochemistry of Major Constituents, Boron and Boron Isotopes in Pore Waters from ODP Site 1202, Okinawa Trough

Huang¹,

You²,

Shen³

et al. 2005

Terr. Atmos. Ocean. Sci.

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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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Styles and Productivity of Mud Diapirism along the Middle American Margin

Moerz

Kopf

Brueckmann

et al.

NATO Science Series

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Abstract:We present sedimentological and structural data and conceptual models for the evolution of two types of diapiric mud moundss offshore Costa Rica. Dozens of exposed mud mounds are found in the smooth domain of the margin with Mound Culebra being the most prominent example. Mound Culebra is a fault controlled feature with steep flanks (~10-20°) and a lack of recent mud flows. The extruded material consists of overcompacted silty clay with signs of intense brittle deformation, brecciation, hydrofracturing and secondary perforation by closely spaced conduits. The southern rough domain is characterized by numerous local tectonic regimes linked to seamount subduction and the collision of the Cocos ridge all associated with diverse forms of venting. Diapirism seems to play only a minor role and Mound 11 and 12 are examples of fault controlled, low relief mud volcanoes with shallow-dipping flanks. Mud flow sequences, vent debris and the presence of gas hydrates in the shallow subsurface favor an episodic, gas driven eruption behavior.

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Evidence for deep fluid circulation and gas hydrate dissociation using boron and boron isotopes of pore fluids in forearc sediments from Costa Rica (ODP Leg 170)

Cited by 45 publications

References 55 publications

Geochemistry of Major Constituents, Boron and Boron Isotopes in Pore Waters from ODP Site 1202, Okinawa Trough

Geochemistry of Major Constituents, Boron and Boron Isotopes in Pore Waters from ODP Site 1202, Okinawa Trough

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

Styles and Productivity of Mud Diapirism along the Middle American Margin

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