Magmatic processes under mid-ocean ridges: A detailed mineralogic study of lavas from East Pacific Rise 9 degrees 30 ' N, 10 degrees 30 ' N, and 11 degrees 20 ' N

doi:10.1029/2002GC000309

IOCAS-IR > 海洋地质与环境重点实验室

	Magmatic processes under mid-ocean ridges: A detailed mineralogic study of lavas from East Pacific Rise 9 degrees 30 ' N, 10 degrees 30 ' N, and 11 degrees 20 ' N
	Pan, YC ; Batiza, R
	2003-11-01
发表期刊	GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
卷号	4
文章类型	Review
摘要	[1] Detailed petrologic study has been made for lavas from the northern East Pacific Rise (EPR) 9degrees30'N, 11degrees20'N, and 10degrees30'N. 9degrees30'N and 11degrees20'N have robust magma supply and a shallow melt lens while 10degrees30'N has nonrobust magma supply and no shallow melt lens. Lavas from all three localities are sparsely phyric and glassy, containing plagioclase +/- olivine +/- pyroxene. Typically, the lavas contain several to many ( up to seven) distinct chemical groups of plagioclase that are not always distinct texturally. The lavas may also contain up to three chemically distinct groups of olivine and two groups of pyroxene. The lavas contain both individual crystals and groups comprising reticulate and dendritic clots that we interpret to represent bits of crystal networks forming in mushy zones of an axial magma chamber. 21 of the 23 samples studied in detail have diverse crystal compositions and require mixing, which most likely occurs when mostly liquid magma passes through mushy zones. We find no significant systematic differences between robust and nonrobust segments in terms of their crystal content, proportion of texturally distinct xenocrysts, crystal size, aspect ratio, roundness, modal abundance, magma residence time, number of diverse mineral-chemical groups, and characteristics of mixing like the total range of composition of disequilibrium minerals present, and the magnitude of the chemical gaps between disequilibrium and equilibrium compositions. This unexpected and remarkable similarity suggests that the presence or absence of a seismically imaged shallow melt lens has essentially no effect on the mineralogy of erupted lavas. We conclude that the fundamentally important magmatic process under mid-ocean ridges, from slow to fast, is the formation of crystal networks and their subsequent compaction; the seismically detected shallow melt lenses likely contain highly evolved magma, formed by expelled interstitial melt during crystal network compaction, and play very little role in crustal accretion. Our conclusion implies that the thick (> 3 km) low velocity zone near the base of the crust produces the thin (< 30 m) shallow melt lenses, not the other way around.
关键词	Mid-ocean Ridge Magma Chamber East Pacific Rise Crystal Network Shallow Melt Lens Segregation Vein Marine Geology And Geophysics : Midocean Ridge Processes Seismology : Oceanic Crust TectonoPhysics : Physics Of Magma And Magma Bodies Volcanology : Physics And Chemistry Of Magma Bodies
DOI	10.1029/2002GC000309
收录类别	SCI
语种	英语
WOS记录号	WOS:000186394400001
引用统计	被引频次：23[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/33001
专题	海洋地质与环境重点实验室
作者单位	1.Chinese Acad Sci, Inst Oceanol, Qingdao 266071, Peoples R China 2.Univ Hawaii, Dept Geol & Geophys, Honolulu, HI 96822 USA 3.Natl Sci Fdn, Arlington, VA 22230 USA
推荐引用方式 GB/T 7714	Pan, YC,Batiza, R. Magmatic processes under mid-ocean ridges: A detailed mineralogic study of lavas from East Pacific Rise 9 degrees 30 ' N, 10 degrees 30 ' N, and 11 degrees 20 ' N[J]. GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS,2003,4.
APA	Pan, YC,&Batiza, R.(2003).Magmatic processes under mid-ocean ridges: A detailed mineralogic study of lavas from East Pacific Rise 9 degrees 30 ' N, 10 degrees 30 ' N, and 11 degrees 20 ' N.GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS,4.
MLA	Pan, YC,et al."Magmatic processes under mid-ocean ridges: A detailed mineralogic study of lavas from East Pacific Rise 9 degrees 30 ' N, 10 degrees 30 ' N, and 11 degrees 20 ' N".GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS 4(2003).

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