Geological Science and Engineering

Geological Sciences and Geological Engineering
Geological Sciences and Geological Engineering

Geological Sciences and Geological Engineering Distinguished Speaker Program presents Dr. Sarah Gleeson

On Thursday, November 11, Dr. Sarah Gleeson, Section Leader at Helmholtz-Centre Potsdam - German Research Centre GFZ, will be giving a talk for the Queen's Department of Geological Sciences and Geological Engineering.

Dr. Gleeson will be presenting on: "Early diagenetic controls on the size of Palaeozoic mudstone-hosted Zn deposits ".

Date: Thursday, November 11, 2021

Time: 2:30pm

Zoom link: Email for the Zoom link


Sarah. A. Gleeson12, Joseph M. Magnall1, Merilie A. Reynolds3

1GFZ German Research Centre for Geosciences, Potsdam, 14473, Germany

2Institute for Geological Sciences, Freie Universität, Berlin, 74-100 Malterstrasse, 12249 Berlin

3Northwest Territories Geoscience Office

The North American Cordillera contains a number of large Zn deposits hosted in Devonian and Mississippian biosiliceous, carbonaceous, radiolarian-rich mudstones. Stratabound barite units are associated with the ore deposits, but are also found regionally in correlative sequences which have not been affected by hydrothermal systems. Recent studies have suggested that stratabound barite, pyrite and authigenic carbonate formed in the sediment at the sulphate methane transition zone (SMTZ), and are a product of pre-ore diagenesis.  The radiolarian-rich host rocks, likely initially dominated by Opal A in the top 100s of metres of the sediment, had high porosities and permeabilities that allowed the ore deposits to form in the sub-surface. The hydrothermal fluids were hot, and moderately saline and dissolved pre-existing barite and carbonate, also generating space in the sub-surface.   Therefore, the biosiliceous nature of host rock, and pre-ore diagenetic processes facilitated the emplacement of large Zn deposits below the seafloor.