Structure of hydrothermal plumes at the Logatchev vent field, 14°45′N, Mid-Atlantic Ridge: evidence from geochemical and geophysical data

Sudarikov, S. M.; Roumiantsev, A.B

doi:10.1016/s0377-0273(00)00174-8

Cited by 39 publications

(32 citation statements)

References 8 publications

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“…35 miles south of the Fifteen-Twenty Fracture zone (44°58 0 N 14°45 0 W, Sudarikov and Roumiantsev, 2000), the Logatchev hydrothermal field is located on the rift flank. It was discovered during several Russian expeditions in the 90s.…”

Section: Geological Settingmentioning

confidence: 99%

The Lithium, Boron and Beryllium content of serpentinized peridotites from ODP Leg 209 (Sites 1272A and 1274A): Implications for lithium and boron budgets of oceanic lithosphere

Vils¹,

Pelletier²,

Kalt³

et al. 2008

Geochimica et Cosmochimica Acta

118

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Despite the key importance of altered oceanic mantle as a repository and carrier of light elements (B, Li, and Be) to depth, its inventory of these elements has hardly been explored and quantified. In order to constrain the systematics and budget of these elements we have studied samples of highly serpentinized (>50%) spinel harzburgite drilled at the Mid-Atlantic Ridge (FifteenTwenty Fracture zone, ODP Leg 209, Sites 1272A and 1274A). In-situ analysis by secondary ion mass spectrometry reveals that the B, Li and Be contents of mantle minerals (olivine, orthopyroxene, and clinopyroxene) remain unchanged during serpentinization. B and Li abundances largely correspond to those of unaltered mantle minerals whereas Be is close to the detection limit. The Li contents of clinopyroxene are slightly higher (0.44-2.8 lg g À1 ) compared to unaltered mantle clinopyroxene, and olivine and clinopyroxene show an inverse Li partitioning compared to literature data. These findings along with textural observations and major element composition obtained from microprobe analysis suggest reaction of the peridotites with a mafic silicate melt before serpentinization. Serpentine minerals are enriched in B (most values between 10 and 100 lg g À1 ), depleted in Li (most values below 1 lg g À1 ) compared to the primary phases, with considerable variation within and between samples. Be is at the detection limit. Analysis of whole rock samples by prompt gamma activation shows that serpentinization tends to increase B (10.4-65.0 lg g À1 ), H 2 O and Cl contents and to lower Li contents (0.07-3.37 lg g À1 ) of peridotites, implying that-contrary to alteration of oceanic crust-B is fractionated from Li and that the B and Li inventory should depend essentially on rock-water ratios. Based on our results and on literature data, we calculate the inventory of B and Li contained in the oceanic lithosphere, and its partitioning between crust and mantle as a function of plate characteristics. We model four cases, an ODP Leg 209-type lithosphere with almost no igneous crust, and a Semail-type lithosphere with a thick igneous crust, both at 1 and 75 Ma, respectively. The results show that the Li contents of the oceanic lithosphere are highly variable (17-307 kg in a column of 1 m Â 1 m Â thickness of the lithosphere (kg/col)). They are controlled by the primary mantle phases and by altered crust, whereas the B contents (25-904 kg/col) depend entirely on serpentinization. In all cases, large quantities of B reside in the uppermost part of the plate and could hence be easily liberated during slab dehydration. The most prominent input of Li into subduction zones is to be expected from Semail-type lithosphere because most of the Li is stored at shallow levels in the plate. Subducting an ODP Leg 209-type lithosphere would mean only very little Li contribution from the slab. Serpentinized mantle thus plays an important role in B recycling in subduction zones, but it is of lesser importance for Li.

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Section: Geological Settingmentioning

confidence: 99%

The Lithium, Boron and Beryllium content of serpentinized peridotites from ODP Leg 209 (Sites 1272A and 1274A): Implications for lithium and boron budgets of oceanic lithosphere

Vils¹,

Pelletier²,

Kalt³

et al. 2008

Geochimica et Cosmochimica Acta

118

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show abstract

“…1) and covers an area of ∼ 1 km 2 . The Logatchev vent site comprises 3 active high-temperature (∼ 350°C) hydrothermal sites associated with at least 15 smaller structures, such as smoking craters, diffuse flow sites, inactive vents and lowtemperature hydrothermal deposits (Sudarikov and Roumiantsev, 2000;Cherkashev et al, 2000;Douville et al, 2002;Kuhn and HYDROMAR scientific Party, 2004). Mineral deposits from the high-temperature vents are composed of massive chalcopyrite chimneys, massive pyrite crusts, silicified breccias and abundant secondary Cu-sulphides and Fe-Mn oxy-hydroxides (Kuhn and HYDROMAR scientific Party, 2004).…”

Section: Logatchev Sitementioning

confidence: 99%

Tracing dust input to the Mid-Atlantic Ridge between 14°45′N and 36°14′N: Geochemical and Sr isotope study

et al. 2008

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“…The "14 o N Segment" has faulted volcanic morphology, while the segments to the north and south have irregular and blocky topography and core complexes. The peridotite-hosted Logatchev hydrothermal vent field 18 A bathymetric map of the MAR between the Fifteen-Twenty and the Marathon fracture zones (Fig. 1) shows an alternation in the morphology of the spreading axis.…”

mentioning

confidence: 99%

Widespread active detachment faulting and core complex formation near 13° N on the Mid-Atlantic Ridge

Smith

Cann

Escartı́n

2006

Nature

257

266

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Oceanic core complexes are massifs in which lower crustal and upper mantle rocks are exposed at the sea floor 1-3 . They form at mid-ocean ridges through slip on detachment faults rooted below the spreading axis 2-6 . To date, most studies of core complexes have been based on isolated inactive massifs that have spread away from ridge axes. A new survey of the Mid-Atlantic Ridge (MAR) near 13°N reveals a segment in which a number of linked detachment faults extend for 75 km along one flank of the spreading axis. The detachment faults are apparently all currently active and at various stages of development. A field of extinct core complexes extends away from the axis for at least 100 km. The new data document the topographic characteristics of actively-forming core complexes and their evolution from initiation within the axial valley floor to maturity and eventual inactivity. Within the surrounding region there is a strong correlation between detachment fault morphology at the ridge axis and high rates of hydroacoustically-recorded earthquake seismicity. Preliminary examination of seismicity and seafloor morphology farther north along the MAR suggests that active detachment faulting is occurring in many segments and that detachment faulting is more important in the generation of ocean crust at this slow-spreading ridge than previously suspected.

show abstract

Structure of hydrothermal plumes at the Logatchev vent field, 14°45′N, Mid-Atlantic Ridge: evidence from geochemical and geophysical data

Cited by 39 publications

References 8 publications

The Lithium, Boron and Beryllium content of serpentinized peridotites from ODP Leg 209 (Sites 1272A and 1274A): Implications for lithium and boron budgets of oceanic lithosphere

The Lithium, Boron and Beryllium content of serpentinized peridotites from ODP Leg 209 (Sites 1272A and 1274A): Implications for lithium and boron budgets of oceanic lithosphere

Tracing dust input to the Mid-Atlantic Ridge between 14°45′N and 36°14′N: Geochemical and Sr isotope study

Widespread active detachment faulting and core complex formation near 13° N on the Mid-Atlantic Ridge

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