LE3 .A278 2001

2001

Stanley, Cliff

Acadia University

Master of Science

Masters

Geology

Earth & Environmental Sciences

The Halfmile Lake South Deep zone (HMLSDZ), Bathurst Mining Camp, New Brunswick, was discovered by Noranda Inc (Exploration) as a result of a 3-D seismic survey. Mineralization consists of Pb-Zn-Cu and hosted by an overturned Lower Tetagouche Group volcano-sedimentary package. Epiclastic rocks are interbedded with subordinate fine-grained felsic pyroclastic rocks that dominate the structural hangingwall. Locally crystal rich felsic tuffs and subordinate epiclastic rocks comprise the immediate structural footwall. This sequence was intruded by quartz-feldspar porphyritic intrusions and cut by intermediate to basaltic dykes. The host rocks to the deposit have suffered sub-greenschist facies metamorphism, polyphase deformation, and are variably hydrothermally altered. The host rocks can be geochemically discriminated using trace element ratios such as Zr/TiO2, Nb/TiO2, 'etc'. These ratios indicate that four volcanic compositions existence at the HMLSDZ: rhyolite, dacite, andesite, and basalt. The aphyric and feldspar quartz phyric volcanic rocks are rhyolitic and dacitic in composition whereas the epiclastic rocks are predominantly dacitic. Pearce element ratio (PER) diagrams, molar element ratio (MER) diagrams, and petrographic examination demonstrate that hydrothermal activity involved muscovite, chlorite, and minor carbonate formation. A lateral and vertical zone (200-300 m) of intense alteration is developed in the immediate structural hangingwall to the HMLSDZ. This alteration halo is characterized by additions of Fe, H and variable K, and losses of Na and minor Ca, due to hydrothermal activity. Results from this study demonstrate that metamorphism and deformation have not significantly obscured hydrothermal alteration signatures.

The author retains copyright in this thesis. Any substantial copying or any other actions that exceed fair dealing or other exceptions in the Copyright Act require the permission of the author.

https://scholar.acadiau.ca/islandora/object/theses:2776