Volatiles in Basaltic Glasses from the Easter‐Salas y Gomez Seamount Chain and Easter Microplate: Implications for Geochemical Cycling of Volatile Elements

Kyla Simons; Jacqueline Dixon; Jean‐Guy Schilling; Richard Kingsley; Robert Poreda

doi:10.1029/2001GC000173

Volatiles in Basaltic Glasses from the Easter‐Salas y Gomez Seamount Chain and Easter Microplate: Implications for Geochemical Cycling of Volatile Elements

Kyla Simons, Jacqueline Dixon, Jean‐Guy Schilling, Richard Kingsley, Robert Poreda

Research output: Contribution to journal › Article › peer-review

Abstract

We present H 2 O, CO 2 , and Cl concentrations in 66 basaltic glasses from the Easter Microplate (EMP) and Easter&hyphen;Salas y Gomez Seamount Chain (ESC) system in the southeastern Pacific. The EMP&hyphen;ESC system is characterized by binary mixing between a depleted mid&hyphen;ocean ridge basalt (MORB) mantle source (DMM) and an incompatible element and radiogenic isotope enriched source, the Salas y Gomez mantle plume (SyG). Plume material is channeled toward the ridge crest centered at &sim;27°S on the east rift of the microplate. Water concentrations on the EMP are highest on the east rift at &sim;27°S and become progressively lower to the north and south, following the spatial pattern of other geochemical tracers. EMP basalts have not lost H 2 O to degassing but have assimilated variable quantities of a Cl&hyphen;rich hydrothermal component. In contrast, some seamount basalts have lost water by shallow degassing, but very few have gained Cl, indicating little assimilation of Cl&hyphen;rich materials. Several ESC seamount glasses may have assimilated a hydrous component, for example, serpentinized harzburgite, during magma ascent through the lithosphere. On the basis of samples unaffected by shallow processes, the main plume component has H 2 O/Ce of &sim;210 ± 20 and is neither preferentially enriched nor depleted in H 2 O relative to other similarly incompatible elements. The depleted MORB source has H 2 O/Ce of &sim;150 ± 10. Estimated mantle volatile concentrations are 750 ± 210 ppm H 2 O and 40 ± 11 ppm Cl for the SyG source, 120 ± 27 ppm H 2 O and 4.5 ± 1.4 ppm Cl for an average EPR source, and 54 ± 12 ppm H 2 O and 1.7 ± 0.4 ppm Cl for the DMM source. The coupled behavior of H 2 O and Cl with similarly incompatible elements, coupled with elevated 3 He/ 4 He ratios, suggests that the volatiles are dominantly juvenile, representative of a component common to mantle plumes, with minor contribution from recycled lithospheric components.

Original language	American English
Journal	Geochemistry, Geophysics, Geosystems
Volume	3
DOIs	https://doi.org/10.1029/2001GC000173
State	Published - Jul 1 2002
Externally published	Yes

Keywords

Easter
mantle plume
volatiles
water
chlorine
basalt

Disciplines

Life Sciences

Access to Document

10.1029/2001GC000173License: CC BY

Volatiles in Basaltic Glasses from the Easter Salas y Gomez SeamoFinal published version, 751 KBLicense: CC BY

Cite this

@article{a28ef47b3da94df59c233e227b533bdc,

title = "Volatiles in Basaltic Glasses from the Easter‐Salas y Gomez Seamount Chain and Easter Microplate: Implications for Geochemical Cycling of Volatile Elements",

abstract = " We present H 2 O, CO 2 , and Cl concentrations in 66 basaltic glasses from the Easter Microplate (EMP) and Easter&hyphen;Salas y Gomez Seamount Chain (ESC) system in the southeastern Pacific. The EMP&hyphen;ESC system is characterized by binary mixing between a depleted mid&hyphen;ocean ridge basalt (MORB) mantle source (DMM) and an incompatible element and radiogenic isotope enriched source, the Salas y Gomez mantle plume (SyG). Plume material is channeled toward the ridge crest centered at &sim;27°S on the east rift of the microplate. Water concentrations on the EMP are highest on the east rift at &sim;27°S and become progressively lower to the north and south, following the spatial pattern of other geochemical tracers. EMP basalts have not lost H 2 O to degassing but have assimilated variable quantities of a Cl&hyphen;rich hydrothermal component. In contrast, some seamount basalts have lost water by shallow degassing, but very few have gained Cl, indicating little assimilation of Cl&hyphen;rich materials. Several ESC seamount glasses may have assimilated a hydrous component, for example, serpentinized harzburgite, during magma ascent through the lithosphere. On the basis of samples unaffected by shallow processes, the main plume component has H 2 O/Ce of &sim;210 ± 20 and is neither preferentially enriched nor depleted in H 2 O relative to other similarly incompatible elements. The depleted MORB source has H 2 O/Ce of &sim;150 ± 10. Estimated mantle volatile concentrations are 750 ± 210 ppm H 2 O and 40 ± 11 ppm Cl for the SyG source, 120 ± 27 ppm H 2 O and 4.5 ± 1.4 ppm Cl for an average EPR source, and 54 ± 12 ppm H 2 O and 1.7 ± 0.4 ppm Cl for the DMM source. The coupled behavior of H 2 O and Cl with similarly incompatible elements, coupled with elevated 3 He/ 4 He ratios, suggests that the volatiles are dominantly juvenile, representative of a component common to mantle plumes, with minor contribution from recycled lithospheric components.",

keywords = "Easter, mantle plume, volatiles, water, chlorine, basalt",

author = "Kyla Simons and Jacqueline Dixon and Jean‐Guy Schilling and Richard Kingsley and Robert Poreda",

year = "2002",

month = jul,

day = "1",

doi = "10.1029/2001GC000173",

language = "American English",

volume = "3",

journal = "Geochemistry, Geophysics, Geosystems",

}

TY - JOUR

T1 - Volatiles in Basaltic Glasses from the Easter‐Salas y Gomez Seamount Chain and Easter Microplate: Implications for Geochemical Cycling of Volatile Elements

AU - Simons, Kyla

AU - Dixon, Jacqueline

AU - Schilling, Jean‐Guy

AU - Kingsley, Richard

AU - Poreda, Robert

PY - 2002/7/1

Y1 - 2002/7/1

N2 - We present H 2 O, CO 2 , and Cl concentrations in 66 basaltic glasses from the Easter Microplate (EMP) and Easter&hyphen;Salas y Gomez Seamount Chain (ESC) system in the southeastern Pacific. The EMP&hyphen;ESC system is characterized by binary mixing between a depleted mid&hyphen;ocean ridge basalt (MORB) mantle source (DMM) and an incompatible element and radiogenic isotope enriched source, the Salas y Gomez mantle plume (SyG). Plume material is channeled toward the ridge crest centered at &sim;27°S on the east rift of the microplate. Water concentrations on the EMP are highest on the east rift at &sim;27°S and become progressively lower to the north and south, following the spatial pattern of other geochemical tracers. EMP basalts have not lost H 2 O to degassing but have assimilated variable quantities of a Cl&hyphen;rich hydrothermal component. In contrast, some seamount basalts have lost water by shallow degassing, but very few have gained Cl, indicating little assimilation of Cl&hyphen;rich materials. Several ESC seamount glasses may have assimilated a hydrous component, for example, serpentinized harzburgite, during magma ascent through the lithosphere. On the basis of samples unaffected by shallow processes, the main plume component has H 2 O/Ce of &sim;210 ± 20 and is neither preferentially enriched nor depleted in H 2 O relative to other similarly incompatible elements. The depleted MORB source has H 2 O/Ce of &sim;150 ± 10. Estimated mantle volatile concentrations are 750 ± 210 ppm H 2 O and 40 ± 11 ppm Cl for the SyG source, 120 ± 27 ppm H 2 O and 4.5 ± 1.4 ppm Cl for an average EPR source, and 54 ± 12 ppm H 2 O and 1.7 ± 0.4 ppm Cl for the DMM source. The coupled behavior of H 2 O and Cl with similarly incompatible elements, coupled with elevated 3 He/ 4 He ratios, suggests that the volatiles are dominantly juvenile, representative of a component common to mantle plumes, with minor contribution from recycled lithospheric components.

AB - We present H 2 O, CO 2 , and Cl concentrations in 66 basaltic glasses from the Easter Microplate (EMP) and Easter&hyphen;Salas y Gomez Seamount Chain (ESC) system in the southeastern Pacific. The EMP&hyphen;ESC system is characterized by binary mixing between a depleted mid&hyphen;ocean ridge basalt (MORB) mantle source (DMM) and an incompatible element and radiogenic isotope enriched source, the Salas y Gomez mantle plume (SyG). Plume material is channeled toward the ridge crest centered at &sim;27°S on the east rift of the microplate. Water concentrations on the EMP are highest on the east rift at &sim;27°S and become progressively lower to the north and south, following the spatial pattern of other geochemical tracers. EMP basalts have not lost H 2 O to degassing but have assimilated variable quantities of a Cl&hyphen;rich hydrothermal component. In contrast, some seamount basalts have lost water by shallow degassing, but very few have gained Cl, indicating little assimilation of Cl&hyphen;rich materials. Several ESC seamount glasses may have assimilated a hydrous component, for example, serpentinized harzburgite, during magma ascent through the lithosphere. On the basis of samples unaffected by shallow processes, the main plume component has H 2 O/Ce of &sim;210 ± 20 and is neither preferentially enriched nor depleted in H 2 O relative to other similarly incompatible elements. The depleted MORB source has H 2 O/Ce of &sim;150 ± 10. Estimated mantle volatile concentrations are 750 ± 210 ppm H 2 O and 40 ± 11 ppm Cl for the SyG source, 120 ± 27 ppm H 2 O and 4.5 ± 1.4 ppm Cl for an average EPR source, and 54 ± 12 ppm H 2 O and 1.7 ± 0.4 ppm Cl for the DMM source. The coupled behavior of H 2 O and Cl with similarly incompatible elements, coupled with elevated 3 He/ 4 He ratios, suggests that the volatiles are dominantly juvenile, representative of a component common to mantle plumes, with minor contribution from recycled lithospheric components.

KW - Easter

KW - mantle plume

KW - volatiles

KW - water

KW - chlorine

KW - basalt

UR - https://digitalcommons.usf.edu/msc_facpub/1326

U2 - 10.1029/2001GC000173

DO - 10.1029/2001GC000173

M3 - Article

VL - 3

JO - Geochemistry, Geophysics, Geosystems

JF - Geochemistry, Geophysics, Geosystems

ER -

Volatiles in Basaltic Glasses from the Easter‐Salas y Gomez Seamount Chain and Easter Microplate: Implications for Geochemical Cycling of Volatile Elements

Abstract

Keywords

Disciplines

Access to Document

Other files and links

Cite this