Pre-eruption history of enriched MORB from the Menez Gwen (37°50′N) and Lucky Strike (37°17′N) hydrothermal systems, Mid-Atlantic Ridge

被引：14

作者：

Marques, Ana Filipa A. ^{[1
,2
]}

Scott, Steven D. ^{[1
]}

Gorton, Michael P. ^{[1
]}

Barriga, Fernando J. A. S. ^{[2
]}

Fouquet, Yves ^{[3
]}

机构：

[1] Univ Toronto, Dept Geol, Scotiabank Marine Geol Res Lab, Toronto, ON M5S 3B1, Canada

[2] Univ Lisbon, Fac Ciencias, Dept Geol, CREMINER LA ISR, P-1749016 Lisbon, Portugal

[3] IFREMER, Ctr Brest, F-29280 Plouzane, France

来源：

LITHOS | 2009年 / 112卷 / 1-2期

基金：

加拿大自然科学与工程研究理事会;

关键词：

Menez Gwen; Lucky Strike; MORB; Mid-Atlantic Ridge; Melt inclusion; Plagioclase; SEA EXPLOSIVE ACTIVITY; MAGMA CHAMBER BENEATH; EAST PACIFIC RISE; BACK-ARC BASIN; MELT INCLUSIONS; BASALT GLASSES; CARBON-DIOXIDE; GEOCHEMICAL CHARACTERISTICS; CRUSTAL THICKNESS; DISSOLVED CARBON;

D O I：

10.1016/j.lithos.2009.05.026

中图分类号：

P3 [地球物理学]; P59 [地球化学];

学科分类号：

0708 ; 070902 ;

摘要：

The Menez Gwen (37 degrees 50'N) and Lucky Strike (37 degrees 17'N) seafloor hydrothermal systems on the Mid-Atlantic Ridge are influenced by the Azores plume, which results in a geochemically enriched character of the host basalts. Two groups of highly plagioclase phyric lavas can be identified at Menez Gwen. Group I lavas are highly vesicular and highly enriched in incompatible elements with high (La/SM)(N), Nb/Zr, Ba/Nb, Zr/Y and Nb/Y ratios. The enriched group I lavas resemble those at the Lucky Strike site. Group II porphyritic lavas are less vesicular, less enriched in incompatible elements with low (La/SM)N, Nb/Zr. Ba/Nb, Zr/Y and Nb/Y ratios. These differences between group I and II lavas can be explained either by melting-induced mixing of a two-component mantle or mixing between two melts. Furthermore, the presence of identical assemblages of plagioclase phenocrysts in both groups is strong evidence for mantle heterogeneities. Silicate melt inclusions, hosted in plagioclase phenocrysts, exhibit small metallic precipitates of Fe + Ni + Cu +/- Zn (+/- Co +/- As) +/- S +/- Cl within the vapour bubbles. The heterogeneous trapping of distinct coexisting phases during plagioclase growth indicates that a high temperature ore-metal rich immiscible fluid must have been exsolved from the magma prior to eruption. On the other hand, lava vesicularities are remarkably different between the group I and group 11 lavas. They indicate ubiquitous degassing of magmatic volatiles, particularly in group I lavas that underwent significant pre-eruptive degassing. The presence of an ore-metal-rich fluid being exsolved from the magma chamber in conjunction with pre-eruptive degassing is a strong indicator of direct magmatic contribution of metals and volatiles to the seafloor hydrothermal systems. At the Menez Gwen site, timing of degassing and the enriched chemistry of lavas proved to be crucial factors contributing to the exsolution of a metal-rich fluid prior to magma eruption. (C) 2009 Elsevier B.V. All rights reserved.

引用

页码：18 / 39

页数：22

共 35 条

[1] Enriched basalts at segment centers: The Lucky Strike (37°17′N) and Menez Gwen (37°50′N) segments of the Mid-Atlantic Ridge
Gale, Allison
Escrig, Stephane
Gier, Elizabeth J.
Langmuir, Charles H.
Goldstein, Steven L.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS, 2011, 12
[2] Population structure and recruitment in mytilid bivalves from the Lucky Strike and Menez Gwen hydrothermal vent fields (37°17′ N and 37°50′ N on the Mid-Atlantic Ridge)
Comtet, T
Desbruyeres, D
MARINE ECOLOGY PROGRESS SERIES, 1998, 163 : 165 - 177
[3] Distribution of dissolved sulfide, methane, and manganese near the seafloor at the Lucky Strike (37°17′N) and Menez Gwen (37°50′N) hydrothermal vent sites on the mid-Atlantic Ridge
Radford-Knoery, J
Charlou, JL
Donval, JP
Aballea, M
Fouquet, Y
Ondreas, H
DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS, 1998, 45 (2-3) : 367 - 386
[4] Compared geochemical signatures and the evolution of Menez Gwen (37°50′N) and Lucky Strike (37°17′N) hydrothermal fluids, south of the Azores Triple Junction on the Mid-Atlantic Ridge
Charlou, JL
Donval, JP
Douville, E
Jean-Baptiste, P
Radford-Knoery, J
Fouquet, Y
Dapoigny, A
Stievenard, M
CHEMICAL GEOLOGY, 2000, 171 (1-2) : 49 - 75
[5] Distribution of dissolved sulfide, methane, and manganese near the seafloor at the Lucky Strike (37°17 prime N) and Menez Gwen (37°50 prime N) hydrothermal vent sites on the mid-Atlantic Ridge
Radford-Knoery, Joel
Charlou, J.-L.
Donval, J.-P.
Aballea, M.
Fouquet, Y.
Ondreas, H.
Deep-Sea Research, Part 1: Oceanographic Research Papers, 1998, 45 (2-3): : 367 - 386
[6] Hydrothermal anomalies in the Lucky Strike segment on the Mid-Atlantic Ridge (37 degrees 17'N)
Wilson, C
Charlou, JL
Ludford, E
Klinkhammer, G
Chin, C
Bougault, H
German, C
Speer, K
Palmer, M
EARTH AND PLANETARY SCIENCE LETTERS, 1996, 142 (3-4) : 467 - 477
[7] Subseafloor phase equilibria in high-temperature hydrothermal fluids of the Lucky Strike Seamount (Mid-Atlantic Ridge, 37°17′N)
Pester, Nicholas J.
Reeves, Eoghan P.
Rough, Mikaella E.
Ding, Kang
Seewald, Jeffrey S.
Seyfried, William E., Jr.
GEOCHIMICA ET COSMOCHIMICA ACTA, 2012, 90 : 303 - 322
[8] Mixing two enriched and distinct mantle sources beneath Lucky Strike segment, 37° N on the Mid-Atlantic Ridge
Ferreira, PL
Murton, BJ
Boulter, C
GEOCHIMICA ET COSMOCHIMICA ACTA, 2005, 69 (10) : A102 - A102
[9] Geotectonic setting of hydrothermal activity on the summit of Lucky Strike Seamount (37°17′N, Mid-Atlantic Ridge) -: art. no. 1049
Humphris, SE
Fornari, DJ
Scheirer, DS
German, CR
Parson, LM
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS, 2002, 3
[10] Plagioclase-phyric basalts of Menez Gwen and Lucky Strike (Mid-Atlantic Ridge): pre-eruptive history from melt inclusion studies
Marques, A. F. A.
Scott, S. D.
Barriga, F. J. A. S.
Fouquet, Y.
DIGGING DEEPER, VOLS 1 AND 2: DIGGING DEEPER, 2007, : 1033 - 1036

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