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TitleTrace elements and oxygen isotope of quartz from the Nashwaak Granite and dykes, and quartz veins related to the Sisson Brook W-Mo-Cu deposit, west-central New Brunswick
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AuthorZhang, W; Lentz, D R; McFarlane, C R M; Thorne, K G
SourceTGI 4 - Intrusion Related Mineralisation Project: new vectors to buried porphyry-style mineralisation; by Rogers, N (ed.); Geological Survey of Canada, Open File 7843, 2015 p. 475-491, https://doi.org/10.4095/296484 (Open Access)
LinksCanadian Database of Geochemical Surveys, downloadable files
LinksBanque de données de levés géochimiques du Canada, fichiers téléchargeables
Year2015
PublisherNatural Resources Canada
Documentopen file
Lang.English
Mediaon-line; digital
RelatedThis publication is contained in Rogers, N; (2015). TGI 4 - Intrusion Related Mineralisation Project: new vectors to buried porphyry-style mineralisation, Geological Survey of Canada, Open File 7843
RelatedThis publication is related to Lang, J R; Duncan, R; Lentz, D; Zhang, W; Bustard, A; McFarlane, C R M; Thorne, K G; (2014). Geological and structural controls on hydrothermal alteration and W-Mo mineralization in the Sisson deposit, New Brunswick, Geological Association of Canada-Mineralogical Association of Canada, Joint Annual Meeting, Abstracts Volume vol. 37
File formatpdf
ProvinceNew Brunswick
NTS21J/02N; 21J/03NE; 21J/06SE; 21J/07SW
AreaSisson
Lat/Long WENS -67.1667 -66.8333 46.5000 46.1667
Subjectseconomic geology; geochemistry; trace element analyses; trace element geochemistry; trace elements; oxygen isotopes; porphyry deposits; porphyry copper; mineral exploration; mineralization; tungsten; molybdenum; copper; gold; granites; dykes; Sisson deposit; Nashwaak Granite; Paleozoic; Devonian; Silurian; Ordovician
Illustrationslocation maps; photomicrographs; photographs; plots
ProgramIntrusion/Porphyry Ore Systems, Targeted Geoscience Initiative (TGI-4)
Released2015 06 11
AbstractThe Sisson Brook W-Mo-Cu deposit, situated in west-central New Brunswick, is hosted by Cambro- Ordovician volcanic and sedimentary rocks of the Miramichi and Tetagouche groups. These rocks have been intruded by the Early Devonian Howard Peak diorite-gabbro, Nashwaak Granite, a phaneritic felsic dyke swarm, and a distinctively younger Late Devonian porphyritic felsic dyke. In order to understand the magma evolution history, the textural and geochemical characteristics of quartz phenocrysts from these felsic rocks were analyzed with the aid of SEM-cathodoluminescence (CL), laser ablation inductively coupled plasma mass spectrometry (LA ICPMS), and secondary ion mass spectrometry (SIMS).
Four intrusive granitic units in the Sisson Brook deposit area: (1) medium-grained, equigranular two-mica granite with brown biotite that is slightly altered to chlorite; (2) biotite- granite with ca. 20 % greenish brown biotite and accessory zircon, apatite, monazite, magnetite, titanite, sulfide and ilmenite; (3) biotite-granite dykes with similar mineralogical features to the biotite-granite; and (4) porphyry dykes with phenocrysts consisting of approximately 23 % plagioclase, 10 % quartz, 8 % biotite, and 7 % K-feldspar.
Quartz phenocyrsts in two-mica granite and biotite-granite plutonic phases is unzoned indicating that it formed at relatively stable magma chamber. Quartz dissolution textures in the dyke phases might be caused by cooling from 600°C to 300°C at pressure below 1 Kbar. Quartz phenocrysts in porphyry dyke samples are oscillatory-zoned. With the assumption that the activity of Ti in these magmas is 0.8 (based on the presence of ilmenite rather than rutile), Ti-In-quartz geothermometry indicates that the porphyry dykes formed at a temperature above 675°C, twomica granite and biotite-granite plutons formed at 600°C to 700°C, and the biotite-granite dykes formed at slightly below 600°C. Higher Ge/Ti ratios reflect greater degrees of magma differentiation. This ratio increases from porpyrhy dykes, two-mica granite and biotite-granite pluton phases to biotite dykes. The highest Al content of quartz measured in two-mica granite is consistent with the highest aluminium saturation index of its whole rock. The oxygen isotope of quartz is from 8-8.5 perthousand for biotite-granite, 9-10 perthousand for biotite dykes and porphyry dykes, and 10-10.5 perthousand for the two-mica granites. The later mineralization quartz veins in the dykes have oxygen isotope values between 8.5 perthousand to 9.5 perthousand, indicating the hydrothermal fluids related to the Sisson Brook deposit are dominantly magmatic fluids.
GEOSCAN ID296484