Joe Umanetz, enrichment teacher for the Bruce-Grey Catholic School Board and Peter Russell presented a one hour workshop titled "Geology for Beginners." to over 30 participants at this year's Science Teacher's Association of Ontario meeting at the Regal Constellation Hotel in early November. The focus was on local geology. Joe pointed out 10 basic concepts to be understood they are The Rock Cycle, Living on a Layercake, The Earth Moves, Up and Down Upheaval and Subduction, Sideways Tectonics, Sedimentation Coral Reefs, Glaciation, Weathering of Rocks and Minerals and Bedrock vs Gravel. He encouraged teachers to purchase geological maps of Ontario and learn about the geology near home.
Participants were provided with sets of mineral and rock samples - the kit contained samples of quartz, feldspar, mica and calcite and the rocks granite, gneiss, conglomerate, limestone, shale as well as concrete. This slimmed-down rock and mineral kit is best to keep the focus on locally derived rocks and minerals. Granite and Gneiss are composed of feldspar, mica and quartz. The conglomerate contained grains of quartz and feldspar in limestone. Limestone is mainly calcite derived from the skeletons of creatures that lived at the time of deposition in a warm, shallow salt sea. Shale is formed of clay minerals derived from the weathering of minerals such as mica and feldspar. Shale may contain fossils and our sample of Collingwood shale smells of oil when a piece is scratched or broken off. The layercake activity described below was also presented to the group.
Southern Ontario is made of different layers of sedimentary rocks overlying the Precambrian basement. A way to bring this concept alive is to have students paint styrofoam or paper plates to represent the different ages present beneath your feet in your home town. for example, the rocks under Waterloo includes the Precambrian, Cambrian, Ordovician and Silurian. These rocks are overlain by glacial deposits covered by evidence of human activity.
All these layers are coloured and pictures of fossils painted on. Paint each plate bright colours. On the Quaternary plate, mammoths and mastodons may represent the fossils of the ice-age. The final plate is a simple map of the area around the school. The plates are then stacked on top of each other from oldest to youngest. Between each layer of stacked plates is an unconformity, or break in deposition. Erosion of some of the previously deposited rocks occurred, before deposition of new sediments resumed. The Precambrian rocks are usually metamorphic rocks with intrusions of igneous rocks, they should be represented by dynamic swirling of the folded metamorphic rocks and red or pink blobs representing intrusions of magma which formed granite and other intrusive rocks.
To make the stack of plates look like the map of southern Ontario illustrated below the plates should be cut back "eroded" to expose the older rocks below. The ice-age layer covers these older rocks and holes may be cut in this plate to allow the rocks to be seen below. This stack then represents the geology of southern Ontario. Note the different older rocks present under our feet! These layers may also be made of plasticene. "Drilling" with a straw will show the layering found by drilling the rocks under your community.
The book Rock Ontario is an excellent resource for teaching about Ontario rocks and their formation. This book is available from the Ontario Mines and Minerals Information Centre 1-800-665-4480, price $14.95. They also provide free teacher information kits and copies of a 8.5" x 11," "Geology of Ontario" maps.