| Title | Trace 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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| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | Zhang, W; Lentz, D R; McFarlane, C R M; Thorne, K G |
| Source | TGI 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 |
| Links | Canadian Database of Geochemical Surveys, downloadable
files
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| Links | Banque de données de levés géochimiques du Canada,
fichiers téléchargeables
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| Image |  |
| Year | 2015 |
| Publisher | Natural Resources Canada |
| Document | open file |
| Lang. | English |
| Media | on-line; digital |
| Related | This publication is contained in TGI 4 - Intrusion Related
Mineralisation Project: new vectors to buried porphyry-style mineralisation |
| Related | This publication is related to Geological and structural
controls on hydrothermal alteration and W-Mo mineralization in the Sisson deposit, New Brunswick |
| File format | pdf |
| Province | New Brunswick |
| NTS | 21J/02N; 21J/03NE; 21J/06SE; 21J/07SW |
| Area | Sisson |
| Lat/Long WENS | -67.1667 -66.8333 46.5000 46.1667 |
| Subjects | economic 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 |
| Illustrations | location maps; photomicrographs; photographs; plots |
| Program | Targeted Geoscience Initiative (TGI-4) Intrusion/Porphyry Ore Systems |
| Released | 2015 06 11; 2023 03 17 |
| Abstract | The 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. |
| Summary | (Plain Language Summary, not published)
The Targeted Geoscience Initiative (TGI-4) is a collaborative federal geoscience program that provides industry with the next generation of geoscience
knowledge and innovative techniques to better detect buried mineral deposits, thereby reducing some of the risks of exploration. This volume summarises research activities completed under the TGI 4 Intrusion Related Mineralisation Project that
focused on porphyry-style ore systems related to the Cu- and Cu-Mo deposits of South-Central British Columbia and the Sn-W-Mo-In deposits in New Brunswick, Nova Scotia and Newfoundland. |
| GEOSCAN ID | 296484 |
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