Metasomatised lower crustal and upper mantle xenoliths from north Queensland: Chemical and isotopic evidence bearing on the composition and source of the fluid phase

Details Metasomatised lower crustal and upper mantle xenoliths from north Queensland: Chemical and isotopic evidence bearing on the composition and source of the fluid phase Metasomatised lower crustal and upper mantle xenoliths from north Queensland: Chemical and isotopic evidence bearing on the composition and source of the fluid phase

Mar 1989

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1989gecoa..53..649s&link_type=abstract

Geochimica et Cosmochimica Acta, vol. 53, Issue 3, pp.649-660

Mathematics

Logic

4

Scientific paper

A diverse range of ultramafic and mafic granulite xenoliths from cone #32, north Queensland display mineralogical and chemical evidence for enhanced fluid activities in the lowermost crust and uppermost mantle. Metasomatism of spinel lherzolite, garnet and spinel websterite and garnet granulite produced variable amounts of amphibole ± mica, locally resulting in development of hornblendite as the end-product of reaction between spinel websterite and C-O-H fluids. In contrast, associated felsic and 2-pyroxene granulite xenoliths have remained relatively unaffected. The garnet granulites and spinel websterites are interpreted as products of underplating of the lower crust by Cenozoic magmatic activity, whereas Nd-Sr isotope systematics for the 2-pyroxene and felsic granulite xenoliths suggest that they may be of Proterozoic age. The development of amphibole and mica in the mafic and ultramafic xenoliths was accompanied by increases in TiO 2 , Na 2 O, K 2 O, A1 2 O 2 , Sr, Ba, Zr, Nb, LREE and Fe 2 O 3 /FeO, and decreased MgO, SiO 2 , Cr and Ni. Virtually anhydrous spinel websterite xenoliths have 87 Sr / 86 Sr and 143 Nd / 144 Nd almost identical to amphibole-rich variants and hornblendite, and very similar values to the host nepheline mugearite and an amphibole megacryst. The chemical and isotopic data suggest that the metasomatism is a relatively young feature caused by oxidized fluids exsolved from alkaline magmas similar to the host as they ascended through the lithosphere. This style of metasomatism is considered a relatively localized phenomenon which is unlikely to provide an important contribution to the source regions of alkali basaltic magmas.

Affiliated with

Also associated with

No associations

Rating

Metasomatised lower crustal and upper mantle xenoliths from north Queensland: Chemical and isotopic evidence bearing on the composition and source of the fluid phase does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Metasomatised lower crustal and upper mantle xenoliths from north Queensland: Chemical and isotopic evidence bearing on the composition and source of the fluid phase, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Metasomatised lower crustal and upper mantle xenoliths from north Queensland: Chemical and isotopic evidence bearing on the composition and source of the fluid phase will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1803375