Canadian Rockhound: Roadside Geology of Ontario: North Shore of Lake Superior

If you've ever wondered about the interesting and unique geology and scenery of northwestern Ontario, you will be pleased to learn about a new guidebook by Edgar G. Pye that was published in 1997. The book, "Roadside Geology of Ontario: North Shore of Lake Superior," will be appreciated by rockhounds who intend to explore the region along Lake Superior's northern shore between Thunder Bay and Sault Ste. Marie, Ontario.

Book cover.

This pocket-sized guidebook is divided into five parts. Each part is nicely illustrated with many attractive colour maps, diagrams, and photographs of scenery and geological features. The maps are simple and easy to understand, and reveal the basic underlying geology of northwestern Ontario.

The first part of the guide book summarizes the general geology of the Lake Superior region and it is organized into two main sections. The section on the Precambrian focuses on the Canadian Shield. Geologists have divided the Canadian shield into several geological provinces, which in turn have been subdivided into smaller units. For example, the Superior Province consists of 12 subprovinces, each differing in age, composition and structure. The section on the Proterozoic Eon describes the various rock groups and formations within the Southern Province, and tables provide the age of each group. Different rock types, such as volcanic, sedimentary, and intrusive rocks are found in northern Ontario, and these are covered as well. Other topics, such as folding, faulting and gold deposits are mentioned. A section on the Phanerozoic Eon briefly describes the Paleozoic, Mesozoic and Cenozoic rocks found, and the Great Ice Age.

Sample pages from the guidebook.

The second part of the guidebook is divided into 12 trip sections that cover the route between Thunder Bay and Sault Ste. Marie. Each trip provides a list of important geological and scenic features of interest to rockhounds, accompanied by explanations and maps showing the underlying geology. Trips include tours to nearby falls, mines, ridges, mesas, gorges, and outcrops. The famous amethyst deposits are also described in one of the trips to the Nipigon area. Overall, Part 2 gives the reader lots of useful and interesting information.

A list of common rocks and minerals found in northern Ontario is provided in Part 3 of the guidebook. For each mineral there is a description, which includes the localities where the mineral is found. Access to collecting sites is discussed in a separate section. Mineral collectors and rockhounds will also find a useful directory of rock shops and amethyst mines, complete with addresses and telephone numbers.

Part 4 of the guidebook provides a glossary of geological terms, which will be of help to readers with no background in geology. A number of common minerals, such as agate, calcite, and gypsum are also defined.

More serious collectors will appreciate the list of selected references to geological literature in Part 5. References on gold deposits, fossil sites, mineralogy, mineral localities, and geological features pertaining to northern Ontario are provided.

Readers with little or no background in geology will not feel lost while reading the first part of this guide book. Rockhounds will also appreciate the user friendly, spiral-bound format of the guidebook. You can have the book open while driving, or while collecting in the field, since it can be laid flat on the ground or a level surface.

Overall, I enjoyed reading this guidebook by Edgar Pye. It is well written, easy to understand and very interesting. I gained a much better understanding of the geology of the Lake Superior region. Many Canadians are unaware of some of the secrets that lurk in this region. For example, I was surprised to learn that Lake Superior sits on top of an ancient mid-continental rift, which is believed to be the deepest known in the world.

If you plan to collect minerals or make a scenic tour of the Lake Superior region, I strongly recommend purchasing this excellent guidebook, which is available in Canada for $16.95. You can purchase it from the following sources:

Purchase Sources:

Mines and Minerals Information Centre
Room MS-17, Macdonald Block
900 Bay St.
Toronto, Ontario M7A 1C3
Tel: 1-800-665-4480 (within Ontario)
Tel: 416-314-3800
Fax: 416-314-3797
Publication Sales
933 Ramsey Lake Rd.,
Sudbury, Ontario P3E 6B4
Tel: 705-670-5691 (collect calls accepted)
Fax: 705-670-5770
E-mail: pub_sales@torv05.ndm.gov.on.ca

Reference:

Pye, E.G. 1997. Roadside Geology of Ontario: North Shore of Lake Superior; Ontario GEOServices Centre, ROCK ON Series 2, 164 p.

Permission is given to freely reprint this article from the Canadian Rockhound for non-commercial and educational purposes, provided the author and the Canadian Rockhound are acknowledged, and that the website URL address of the Canadian Rockhound is given. The article may not be edited or rewritten to change its meaning or substance without the author's permission. To contact the author, please use the e-mail address provided.