Chemical and isotopic constraints on water/rock interactions at the Lost City hydrothermal field, 30°N Mid-Atlantic Ridge

Foustoukos, Dionysis I.; Savov, Ivan P.; Janecky, David R.

doi:10.1016/j.gca.2008.07.035

Cited by 83 publications

(61 citation statements)

References 111 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These are consistently lower than the B content of seawater and endmember hydrothermal fluids have been determined to 0.34-0.55 lg/g (31-51 lmol/kg), 2.57 lg/g (238 lmol/kg), and 3.62 lg/g (335 lmol/kg) for Lost City, Rainbow, and Logatchev, respectively (Schmidt et al 2007;Foustoukos et al 2008;Boschi et al 2008;Seyfried et al 2011Seyfried et al , 2015. Boron isotopic data for ultramafic-hosted vent fluids are not yet available, but have been estimated to þ 25 to +30‰ (Foustoukos et al 2008;Boschi et al 2008).…”

Section: Hydrothermal Vent Fluidsmentioning

confidence: 90%

Boron Isotopes in the Ocean Floor Realm and the Mantle

Marschall

2017

Advances in Isotope Geochemistry

View full text Add to dashboard Cite

This chapter reviews the boron isotopic composition of the ocean floor, including pristine igneous oceanic crust such as mid-ocean ridge basalts and ocean island basalts and their implications for the B isotopic composition of the mantle. The chapter further discusses the B isotopic effects of assimilation of altered crustal materials in mantle-derived magmas. The systematics of seawater alteration on oceanic rocks are discussed, including sediments, igneous crust and serpentinization of ultramafic rocks and the respective marine hydrothermal vent fluids. The chapter concludes with a discussion of the secular evolution of the B isotopic composition of seawater.

show abstract

Section: Hydrothermal Vent Fluidsmentioning

confidence: 90%

Boron Isotopes in the Ocean Floor Realm and the Mantle

Marschall

2017

Advances in Isotope Geochemistry

View full text Add to dashboard Cite

show abstract

“…Although the abundant seafloor basalt outcrops and axial location of the vent field support reaction with basaltic substrate as the dominant control on Piccard fluid chemistry, determination of fluid B abundance, and comparison with Von Damm, Lost City (FOUSTOUKOS et al, 2008), and Rainbow fluid B contents (SEYFRIED et al, 2012), could identify a possible ultramafic influence at Piccard. The nature of water/rock reaction at Piccard could also be further examined by examining H 2 production in water/rock reaction experiments conducted at higher temperatures than previous efforts, which are usually run at temperatures ≤ 400°C.…”

Section: Concluding Remarks and Future Research Directionsmentioning

confidence: 99%

Geochemistry of deep-sea hydrothermal vent fluids from the Mid-Cayman Rise, Caribbean Sea

McDermott¹

2015

View full text Add to dashboard Cite

THESIS ABSTRACTThis thesis examines the controls on organic, inorganic, and volatile species distributions in hydrothermal fluids venting at Von Damm and Piccard, two recently discovered vent fields at the ultraslow spreading Mid-Cayman Rise, Earth's deepest mid-ocean ridge. A wide variety of possible temperatures and substrates for fluid/rock reaction exist at ultraslow spreading ridges. The flux of chemicals delivered to the ocean by circulating vent fluids exerts a major control on mass transfer into and out of the oceanic crust and supports chemosynthetic ecosystems. In Chapter 2, abiotic organic synthesis is shown to occur via two distinct mechanisms in the serpentinizing Von Damm system. Longstanding questions concerning the spatial, temporal, and mechanistic nature of carbon transformations in deep-sea hot springs are addressed. In contrast with the current paradigm, CH 4 is not actively forming during circulation of H 2 -rich vent fluids, but instead is derived from fluid inclusions in the host rocks. Chapters 3 and 4 present in-depth studies of the chemical and isotopic compositions of aqueous species in vent fluids at Von Damm and Piccard to elucidate the role of reaction temperature, pressure, substrate composition, and water/rock mass ratios during the chemical evolution of hydrothermal fluids at oceanic spreading centers. At Von Damm, sequential reaction of gabbroic and peridotite substrates at intermediate temperatures can explain generation of the observed fluids. Geochemical modeling shows that talc-quartz assemblage is expected to precipitate during fluid mixing with seawater at the seafloor. At Piccard, extremely high temperature subsurface water/rock reaction results in high temperature fluids that are richer in dissolved H 2 than any previously observed fluids worldwide. At both locations, high-H 2 conditions promote the abiotic reduction of ΣCO 2 to formate species, which may fuel a subsurface biosphere. In Chapter 5, multiple sulfur isotopes were measured on metal sulfide deposits, S 0 , and fluid H 2 S to constrain sulfur sources and the isotopic systematics of precipitation in a wide variety of seafloor hydrothermal vents. Areas studied include the eastern Manus Basin and Lau Basin back-arc spreading centers, the unsedimented basalt-hosted Southern East Pacific Rise, and the sediment-hosted Guaymas Basin mid-ocean ridge spreading centers. Limited isotope fractionation between fluid H 2 S and precipitating chalcopyrite implies that sulfur isotopes in a chimney lining may record past hydrothermal activity. ACKNOWLEDGEMENTSFirst, I would like to thank my co-advisor, Jeff Seewald, whose limitless scientific creavitity and sunny outlook have been a continual source of encouragement throughout the 5 years of my doctoral education and research. Jeff's gift for simultaneously challenging and motivating me has taught me many lasting lessons. His limitless optimism and imagination have left permanent impressions on my approach to scientific research, and will not be far from mind when I mentor oth...

show abstract

“…Based on the endmember ethane and H 2 concentrations reported by Proskurowski et al (2008), these ethene concentrations are in excess of values predicted for equilibrium with ethane at the measured vent temperatures (≤91ºC), requiring instead temperatures >300°C. There is extensive evidence, however, to suggest that Lost City fluids have cooled conductively during upflow and are considerably hotter (in the vicinity of ~250°C) at depth Proskurowski et al, 2006;Foustoukos et al, 2008). This suggests that chemical equilibrium in the ethane-ethene reaction may record higher temperatures deeper in the hydrothermal reservoir, as has been observed in the Middle…”

Section: H / 1 H Ratios and Abiogenesis In Igneous Environmentsmentioning

confidence: 99%