2024-03-29T11:25:05Zhttps://research-repository.st-andrews.ac.uk/oai/requestoai:research-repository.st-andrews.ac.uk:10023/124722022-04-08T10:30:48Zcom_10023_1940com_10023_24com_10023_879com_10023_878col_10023_1941col_10023_880
Cloutier, Jonathan
Piercey, Stephen J.
Lode, Stefanie
Vande Gutche, Michael
Copeland, David A.
2018-01-13T00:31:53Z
2018-01-13T00:31:53Z
2017-04
Cloutier , J , Piercey , S J , Lode , S , Vande Gutche , M & Copeland , D A 2017 , ' Lithostratigraphic and structural reconstruction of the Zn-Pb-Cu-Ag-Au Lemarchant volcanogenic massive sulphide (VMS) deposit, Tally Pond group, central Newfoundland, Canada ' , Ore Geology Reviews , vol. 84 , pp. 154-173 . https://doi.org/10.1016/j.oregeorev.2017.01.010
0169-1368
PURE: 248982587
PURE UUID: 67522308-af92-46a4-87e3-fe5ce6599dcf
Scopus: 85009942081
ORCID: /0000-0002-9432-9880/work/29708389
WOS: 000397361900009
http://hdl.handle.net/10023/12472
https://doi.org/10.1016/j.oregeorev.2017.01.010
The Lemarchant volcanogenic massive sulphide (VMS) deposit (1.24 Mt grading at 0.58% Cu, 5.38% Zn, 1.19% Pb, 1.01g/t Au, and 59.17g/t Ag) is a bimodal-felsic VMS deposit hosted within the Late Cambrian ($513–509 Ma) Tally Pond group of the Exploit Subzone in central Newfoundland, Canada. The deposit is hosted by andesitic volcaniclastic and volcanic rocks with subordinate dacite flows. The mineralisation is hosted by the dacites and is overlain by pillowed and massive basalts.Four structural breaks offset the local stratigraphic sequences including: 1) the LJ syn-volcanic shear zone; 2) the KJ syn-volcanic shear zone; 3) the Lemarchant thrust; and 4) the Bam normal fault. Deformation of the Lemarchant likely occurred during the Penobscot orogeny (486–478 Ma). Early deformation is marked with the local deformation of the LJ and KJ syn-volcanic shear zones during NW-SE compression which coincided with the development of the Lemarchant thrust. A late (<465Ma) east trending normal fault, the Bam fault, affected the central portion of the Lemarchant area and down-faulted the southern portion of the study area relative to the northern portion.Immobile element systematics of all the sequences from the Lemarchant deposit are tholeiitic with transitional Zr/Y ratios (1.9–6.6), Lan/Smn ratios <1 (normalised to upper crust), and have primitive mantle extended rare earth elements profiles with slight light rare earth element (LREE)-enriched pat- terns with flat heavy REE (HREE), and weak to strong negative Nb, Zr, and Ti anomalies. Together, these geochemical features, coupled with an FIIIa signature, and existing mineralogical and Nd-Pb iso- tope data, are consistent with the rocks at the Lemarchant deposit having formed within a shallow (<1500 m) arc or migrating cross-arc seamount chain located within a young peri-continental rifted arc along the margin of Ganderia, within the Iapetus Ocean. The estimated shallow water emplace- ment of the deposit likely allowed boiling near or at the rock-sea water interface, ultimately resulting in precious metal enrichment of the Lemarchant deposit. It is suggested that cross-arcs within rifted arc environments may represent favourable exploration targets for precious metal-enriched VMS deposits.
eng
© 2017 Elsevier B.V. All rights reserved. This work has been made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at: https://doi.org/10.1016/j.oregeorev.2017.01.010
Precious metal enriched VMS deposits
Lemarchant deposit
Tally Pond
Stratigraphic reconstruction
Structural reconstruction
Appalachian tectonic evolution
Economic Geology
NDAS
Lithostratigraphic and structural reconstruction of the Zn-Pb-Cu-Ag-Au Lemarchant volcanogenic massive sulphide (VMS) deposit, Tally Pond group, central Newfoundland, Canada
Journal article
oai:research-repository.st-andrews.ac.uk:10023/92342022-04-08T08:30:25Zcom_10023_1940com_10023_24com_10023_879com_10023_878col_10023_1941col_10023_880
Cloutier, Jonathan
Piercey, Stephen J.
Layne, Graham
Heslop, John
Hussey, Andrew
Piercey, Glenn
2016-07-31T23:31:12Z
2016-07-31T23:31:12Z
2015-08
Cloutier , J , Piercey , S J , Layne , G , Heslop , J , Hussey , A & Piercey , G 2015 , ' Styles, textural evolution, and sulfur isotope systematics of Cu-rich sulfides from the Cambrian Whalesback volcanogenic massive sulfide deposit, central Newfoundland, Canada ' , Economic Geology , vol. 110 , no. 5 , pp. 1215-1234 . https://doi.org/10.2113/econgeo.110.5.1215
0361-0128
PURE: 211292354
PURE UUID: 3d081197-e965-4cca-803a-ffd626d1ea74
Scopus: 84938398342
ORCID: /0000-0002-9432-9880/work/29685350
http://hdl.handle.net/10023/9234
https://doi.org/10.2113/econgeo.110.5.1215
The Whalesback Cu-rich volcanogenic massive sulfide deposit in the Newfoundland Appalachians is a highly deformed deposit found on a steep limb of a closed and boudinaged overturned fold. The deposit was intensely deformed at low temperature but medium pressure (>175 MPa) during the accretion of the composite Lushs Bight oceanic tract-Dashwoods terrane onto the Humber margin at ca. 480 Ma. The ore mineralogy consists of chalcopyrite, pyrrhotite, and pyrite with lesser sphalerite and trace Ag, Bi, and Hg tellurides. Four styles of sulfide mineralization are present: (1) disseminated (5%); (2) vein (50%); (3) breccia (25%); and (4) semimassive to massive (20%). Independent of mineralization style, massive pyrite and pyrrhotite (and some chalcopyrite) are commonly parallel to main S2 schistosity in the deposit, whereas late chalcopyrite piercement veins occur at a high angle to S2. The progressive increase in pressure and temperature produced a remobilization sequence wherein sphalerite was the first sulfide phase to cross the brittle-ductile boundary, followed by pyrrhotite and, finally, chalcopyrite. Maximum temperature was not high enough for the pyrite to cross the brittle-ductile boundary. Instead, pyrite grains were incorporated and transported by pyrrhotite and chalcopyrite during the ductile remobilization events, rounding and fracturing them. Remobilization of the sulfides occurred mainly by plastic flow, but some solution transport and reprecipitation is locally observed. In situ secondary ion mass spectrometry sulfur isotope geochemistry of sulfides yielded values of δ34S ranging from 2.7‰ to 4.7‰ for pyrite, 2.1‰ to 4.0‰ for pyrrhotite, and 1.3‰ to 4.7‰ for chalcopyrite. Sulfur isotope modeling suggests that at least 60% of the sulfur was derived from leaching of igneous rocks (i.e., basalts), with the remainder derived from thermochemical sulfate reduction of seawater sulfate during alteration of the basalts by seawater. At the deposit scale, sulfur isotopes retained their original signature and did not reequilibrate during the secondary deformation and remobilization events.
eng
© 2015 Society of Economic Geologists. This work is made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at https://dx.doi.org/10.2113/econgeo.110.5.1215
Economic Geology
Sulphur Isotopes
VMS deposit
QE Geology
NDAS
Styles, textural evolution, and sulfur isotope systematics of Cu-rich sulfides from the Cambrian Whalesback volcanogenic massive sulfide deposit, central Newfoundland, Canada
Journal article
oai:research-repository.st-andrews.ac.uk:10023/89082023-04-25T23:44:55Zcom_10023_1940com_10023_24com_10023_71com_10023_879com_10023_878col_10023_1941col_10023_72col_10023_880
Jones, S
Diem, Torsten
Huaraca Quispe, L
Cahuana, A
Reay, D
Meir, P
Teh, Yit Arn
2016-06-01T11:30:04Z
2016-06-01T11:30:04Z
2016-01-27
Jones , S , Diem , T , Huaraca Quispe , L , Cahuana , A , Reay , D , Meir , P & Teh , Y A 2016 , ' Drivers of atmospheric methane uptake by montane forest soils in the southern Peruvian Andes ' , Biogeosciences , vol. 9 , no. 12 , pp. 1-31 . https://doi.org/10.5194/bg-2016-16
1726-4170
PURE: 242457215
PURE UUID: 0bee4f06-d4c0-4912-b13b-a148a179dabc
Scopus: 84979517918
http://hdl.handle.net/10023/8908
https://doi.org/10.5194/bg-2016-16
http://www.biogeosciences-discuss.net/bg-2016-16/bg-2016-16-supplement.pdf
NE/H006583/1
The soils of tropical montane forests can act as sources or sinks of atmospheric methane (CH4). Understanding this activity is important in regional atmospheric CH4 budgets, given that these ecosystems account for substantial portions of the landscape in mountainous areas like the Andes. Here we investigate the drivers of CH4 fluxes from premontane, lower and upper montane forests, experiencing a seasonal climate, in southeastern Peru. Between February 2011 and June 2013, these soils all functioned as net sinks for atmospheric CH4. Mean (standard error) net CH4 fluxes for the dry and wet season were −1.6 (0.1) and −1.1 (0.1) mg CH4 – C m−2 d−1 in the upper montane forest; −1.1 (0.1) and −1.0 (0.1) mg CH4 – C m−2 d−1 in the lower montane forest; and −0.2 (0.1) and −0.1 (0.1) mg CH4 – C m−2 d−1 in the premontane forest. Variations among forest types were best explained by available nitrate and water-filled pore space, indicating that nitrate inhibition of oxidation or diffusional constraints imposed by changes in water-filled pore space on methanotrophic communities represent important controls on soil-atmosphere CH4 exchange. Seasonality in CH4 exchange varied among forests with an increase in wet season net CH4 flux only apparent in the upper montane forest. Net CH4 flux was inversely related to elevation; a pattern that differs to that observed in Ecuador, the only other extant study site of soil-atmosphere CH4 exchange in the tropical Andes. This may result from differences in rainfall patterns between the regions, suggesting that attention should be paid to the role of rainfall and soil moisture dynamics in modulating CH4 uptake by the organic-rich soils typical of high elevation tropical forests.
eng
© Author(s) 2016. This work is distributed under the Creative Commons Attribution 3.0 License.
GE Environmental Sciences
NDAS
SDG 13 - Climate Action
Drivers of atmospheric methane uptake by montane forest soils in the southern Peruvian Andes
Journal article