Petrogenetic evaluation of the Cape Spencer gold deposit system, southern New Brunswick, Canada
| dc.contributor.advisor | Lentz, David R. | |
| dc.contributor.author | Cardenas Vera, Alan Fernando | |
| dc.date.accessioned | 2024-07-23T13:09:21Z | |
| dc.date.available | 2024-07-23T13:09:21Z | |
| dc.date.issued | 2024-06 | |
| dc.description.abstract | The Cape Spencer gold deposit, southeast of Saint John, New Brunswick, presents features and characteristics of orogenic gold deposits with gold mineralization and associated alteration concentrated along strongly faulted and sheared contacts between the deformed lithologies in the Cape Spencer area. Although the fundamental controls of the late faults and thrust in the region are known, further constraints on the metals’ source, fluid channels, and timing of ore deposition were necessary to better understand the distribution of gold mineralization and the link with the development of the northern Appalachians and its related tectonic activity. U-Pb geochronology of monazite from leucocratic dykes that crosscut the various deformation fabrics associated with the gold mineralization provided an upper constraint age of 273.7 ± 1.3 Ma to ore deposition. Further study of these dykes indicated they were the result of partial melting of a crustal source with assimilation of Meguma metasedimentary rocks and/or Avalonian sedimentary rocks, based on their Nd-Hf isotopic signatures and whole-rock geochemistry composition. In situ 40Ar/39Ar and Rb-Sr geochronology was performed on illites linked to the alteration associated with the gold mineralization, and the geochronology results indicated different illite populations resulting from continuous recrystallization events occurring below the closure temperature for illite. Therefore, an age around ~300 Ma seems reasonable as a main illite crystallization event that further constrains the illitic alteration associated with the gold mineralization to ~ 300 – 318 Ma, when considering the age of the Lancaster Formation, the youngest unit affected by the hydrothermal fluid. Three generations of hydrothermal pyrite (Py1, Py2, and Py3) showing distinct textural, mineral paragenetic characteristics, and elemental compositions were identified in the ore bodies. In situ S and bulk pyrite Pb isotope analyses indicated the involvement of both Avalonian and Meguma intrusive and metasedimentary rocks as sources for the hydrothermal fluids and metals in the Cape Spencer gold deposit. The evolution of the ore-forming fluids is characterized by a decrease of δ34S values from the first pyrite generation (Py1) towards the last identified pyrite generation (Py3) that result from wall-rock sulphidation and phase separation as the main gold precipitation mechanisms. | |
| dc.description.copyright | © Alan Fernando Cardenas Vera, 2024 | |
| dc.format.extent | xviii, 328 | |
| dc.format.medium | electronic | |
| dc.identifier.uri | https://unbscholar.lib.unb.ca/handle/1882/38058 | |
| dc.language.iso | en | |
| dc.publisher | University of New Brunswick | |
| dc.relation | New Brunswick Department of Natural Resources and Energy Development (NB-DNRED) | |
| dc.relation | New Brunswick Innovation Foundation (NBIF) | |
| dc.rights | http://purl.org/coar/access_right/c_abf2 | |
| dc.subject.discipline | Earth Sciences | |
| dc.title | Petrogenetic evaluation of the Cape Spencer gold deposit system, southern New Brunswick, Canada | |
| dc.type | doctoral thesis | |
| oaire.license.condition | other | |
| thesis.degree.discipline | Earth Sciences | |
| thesis.degree.grantor | University of New Brunswick | |
| thesis.degree.level | doctorate | |
| thesis.degree.name | Ph.D. |