Nathan Forslund's Honours thesis abstract

Thesis Title: 
Hydrothermal alteration in the southern felsic volcanics at Marshall Lake, Northwestern Ontario

The Marshall Lake property is a copper-zinc-rich volcanic-hosted massive sulfide (VHMS) deposit located approximately 255km northeast of the city of Thunder Bay, Ontario.  The study area consists of a series of Archean rocks such as volcanics that range in composition from mafic to felsic, and sedimentary units, both clastic and chemical.  These are intruded by Archean intrusions like the Marshall Gabbro and the Summit Lake Pluton, and Proterozoic mafic dikes.

In the past, most work in the area has been concentrated on the northern part of the sequence where most of the mineralization is known to occur.  In 2006, East West Resource Corporation acquired the property, and since this time there has been an increased effort to understand the deposit as a whole; not only the area proximal to the mineralization, but also the distal rocks to the south. 

Mapping and sampling in the area near the southern boundary of the felsic volcanics can reveal patterns related to the distribution of the hydrothermal alteration.  It was noted during this study that the rocks from near the volcanic-sedimentary boundary are characterized by the assemblage garnet-amphibole and are anomalously rich in magnesium and potassium, while depleted in silica and sodium.  This is an important observation since this is a signature that one would expect to see only in certain places in the VHMS model.

Nathan is currently working for East West Resources in Thunder Bay as a project geologist

For more details about this thesis contact Dr. Mary Louise Hill