Other
Scientific paper
Dec 1986
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1986gecoa..50.2693l&link_type=abstract
Geochimica et Cosmochimica Acta, Volume 50, Issue 12, p. 2693-2705.
Other
4
Scientific paper
Hydrothermally altered andesites in the upper member of the Amulet formation at Buttercup Hill, Noranda, Quebec represent part of the aquifer and cap of a self-sealing geothermal system that focussed the discharge of hydrothermal fluids during the formation of massive Cu-Zn sulfide deposits. Five alteration facies are recognizedpervasive greenschist faciés regional metamorphism (least-altered andesite)epidotization-silicificationalbitization-silicificationchloritizationsericitization-silicification. Alteration is localized on permeable zones such as amygdules, fractures, flow tops, discordant breccia dikes, and conformable breccia horizons.Epidotized-silicified andesite is enriched in Ca-Sr-Eu and depleted in Mg and first transition series metals (FTSM) relative to least-altered andesite. Albitized-silicified andesite is significantly enriched in Na and depleted in most FTSM relative to least-altered andesite. The abundances and inter-element ratios of the rare-earth elements (REE) and most high field-strength elements (HFS: Y, Zr, Th, U, Hf, Ta) are similar in least-altered, epidotized-silicified and albitized-silicified andesites. The most silicified andesites are strongly enriched in Na-Si, strongly depleted in Mg and divalent FTSM and slightly but systematically depleted in REE and most HFS elements. Serialized andesites were previously silicified; they are very strongly enriched in K-Rb-Cs-Ba, very strongly depleted in Na-Ca-Sr-Eu and slightly depleted in light REE relative to silicified andesite. Chloritized andesitic rocks exhibit heavy REE and HFS element ratios similar to those of leastaltered andesite, but are relatively strongly enriched in Mg and divalent FTSM, strongly depleted in Si and large ion lithophile (LIL) elements and slightly depleted in light REE.The coupled behavior of the heavy REE and most HFS elements during epidotization, albitization, silicification, chloritization and serialization suggests that they were inert during hydrothermal modification of the andesite. Mass balance calculations suggest that volume was conserved during epidotization-silicification and albitization-silicification, but that intense silicification was accompanied by volume increases up to 30 percent.
Campbell Ian H.
Gibson H. L.
Lesher Michael C.
No associations
LandOfFree
Composition-volume changes during hydrothermal alteration of andesite at Buttercup Hill, Noranda District, Quebec 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 Composition-volume changes during hydrothermal alteration of andesite at Buttercup Hill, Noranda District, Quebec, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Composition-volume changes during hydrothermal alteration of andesite at Buttercup Hill, Noranda District, Quebec will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1123842