Art meets geology in this series of postcards designed for the ‘Geology at the Edge’ residency on Fogo Island, Nfld.

In the spring of 2017 I spent a month on Fogo island as a ‘Geology at the Edge’ resident. During my tenure, I shared my digital mapping knowledge and led geological hikes with the help of summer student Maggie Whelan. After weeks of field trips, we discussed the need for a set of visual tools to illustrate the more abstract concepts presented in the field and proceeded to lay out the foundation for this project. Back at home I created the cards in stages over the following year and a half with Maggie’s invaluable input via email as she completed her geology undergrad. This set of educational postcards will be available this spring (2020) to visitors at the Geology Centre on Fogo Island. Thanks to Maggie Whelan for her conceptual input and feedback, and to the folks at ‘Geology at the Edge’ for their work on the over-side texts and print layout.

The geological development of Newfoundland from 490 million years ago to the present is shown through Plate tectonic models1. Fogo Island and Change Islands are part of Newfoundland’s Central Zone (C), which represents the remnants of the Iapetus Ocean that separated the ancient continents of Laurentia and Gondwana. Plate tectonics and convergence led to the development of a subduction zone, volcanic island arcs, and the eventual closing of the Iapetus Ocean. Fogo and Change Islands’ rocks are the latest phase of this ocean closing and the related intrusion of magma derived from within the earth’s hot mantle.

1 Tectonic Models based on: Colman-Sadd, S. P., and Scott, S. A., (1994), Newfoundland and Labrador: Traveller’s Guide to the Geology and Guidebook to Stops of Interest. Canada-Newfoundland Cooperative Agreement on Mineral Development.

Artwork: Copyright © Suzanne Nacha 2019
Concept: Suzanne Nacha & Maggie Whelan

The bedrock types exposed on Fogo Island preserve evidence of a magma chamber which formed more than 400 million years ago during the Silurian Period. Similar colours have been given to the simplified geology map and the idealized volcanic model to illustrate relative relationships between the deformed and eroded rocks found at the surface today, and the original magma chamber and related volcanism.

Artwork: Copyright © Suzanne Nacha 2019
Concept: Suzanne Nacha & Maggie Whelan

Igneous rocks, abundant on Fogo Island are the products of hot magma generated within the earth’s mantle over 400 million years ago. The rock cycle on the upper right shows plate tectonics as the principal force behind the creation of new magma and Igneous rocks. On the left, a simplified volcanic model shows a lower intrusive magma chamber (a) and upper extrusive volcanic rocks (b). On the right, the classification scheme shows common igneous rocks organized by texture, composition, and relative mineral abundance1.

1 Igneous Classification after: Carla W. Montgomery (2011). Environmental geology (9th ed). Dubuque, IA McGraw-Hill.

Artwork: Copyright © Suzanne Nacha 2019
Concept: Suzanne Nacha & Maggie Whelan