Tagged: geology

Fossil hunting at Macoun Marsh

by Richard Singhroy

Richard Singhroy is a student at the University of Ottawa. As part of the university’s Community Service Learning program, he has volunteered to report on several OFNC outings and meetings. On November 7, he joined the Geology Interest Group to look for fossils.

Coral fossils spotted at Macoun Marsh

Coral fossils spotted at Macoun Marsh (click for larger image)

Now, it wasn’t digging for dinosaurs, but something equally interesting.

First a bit about Macoun Marsh. It is a small patch of trees near a tiny stream next to Beechwood Cemetery – a truly a beautiful place. The rocks that were brought to the marsh were quarried at Labreton flats next to the Ottawa River.

These limestone rocks are 458 million years old. They were formed during the upper Ordovician period. To give you some context, during this period, our area was almost entirely ocean, and most of the world’s land was a supercontinent known as Gondwana. Throughout the Ordovician period, Gondwana shifted toward the South Pole and much of it was submerged underwater. The Ordovician is best known for its diverse marine invertebrates, including graptolites, trilobites, brachiopods, and the conodonts.

Now for the good part. What did we find? Well, brachiopods were the first thing. Brachiopods are a phylum of small marine shellfish, sometimes called lampshells. They are not common today, but in the Palaeozoic period they were one of the most common types. They lived near the shore (littoral zone), but now they have been pushed into deeper water by competition from bivalve molluscs. Like mussels they have shells, but the shells do differ.

Sponge fossil found at Macoun Marsh

Sponge fossil found at Macoun Marsh (click for larger image)

We also found sponges and coral fossils (see photos). These are more widely known than brachiopods.

Next we found an orthocone. An orthocone is a long straight shell of a nautiloid cephalopod. During the 18th and 19th centuries, all shells of this type were named Orthoceras, but it is now known that many groups of nautiloids developed or retained this type of shell. An orthocone is like a nautilus shell, but straight and uncoiled. It was previously believed that these represented the most primitive form of nautiloid, but it is now known that the earliest nautiloids had shells that were slightly curved.

I found the last to be the most interesting. Trace fossils are literally what you think they might be, a fossil that an animal left behind, like a footprint. I’m amazed how a path left behind millions of years ago can still be seen today.

I really enjoyed my morning and learning the geology of the distant past. The setting was nice and the fossils were very intresting. I would definitely recommend that you visit Macoun Marsh if you get a chance.


Staying connected from Algonquin to the Adirondacks

By Natalie Sopinka with geologic descriptions by Ken Buchan

Larose Forest guide now on sale!

Larose Forest guide now on sale!

At the club’s second last meeting before summer, Linda Burr (Education & Publicity Committee) unveiled the OFNC’s first bilingual publication The Larose Forest, a Naturalist’s Guide. On sale now for $4, the guide includes a description of the forest’s history and habitats by OFNC member Christine Hanrahan, species lists of birds, mammals, herps, butterflies, odonates and vascular plants, plus a colour map of the forest trails. Birding (June 8), mothing (June 13) and butterfly (June 22) walks will be held in the Larose Forest next month. Event details are on the OFNC website.

Emma Kirke, one of the OFNC award winners at the Ottawa Regional Science Fair, was also at the meeting and shared her display on tree crown shape and wind resistance.

Murray Citron captivated the audience with his poetic memories of the “seaside spectacle” that is Newfoundland. While relating tectonic plates to Titans, Murray noted that “where there is geology, there is Greek mythology.”

Where there is geology there may also be a geophysicist like Ken Buchan. In between canoe trips, Ken is a dedicated board member of the Algonquin to Adirondacks (A2A) Collaborative and spoke to OFNC members about the group’s conservation efforts.

The A2A Collaborative’s mission is to “protect, restore, enhance and maintain” connections for wildlife that inhabit and move within the Algonquin to Adirondacks region. The region has a rich geological history that Ken shared. He described how, starting 1300 million years ago, continental collisions formed the Grenville Mountains along the southeastern margin of the Precambrian Canadian Shield. Over hundreds of millions of years they were eroded and partly covered with flat-lying sedimentary rocks to produce the landscape we see today in the A2A region. The Algonquin Highlands and the Adirondack Mountains, as well as the Frontenac Arch which connects them, are part of the Canadian Shield. Although valiant efforts were made to farm on the Arch in the 19th century, it proved unsuitable for agriculture and much of the area has since been reforested. Immediately to the southeast of the A2A region, the Appalachian Mountains were formed during a later series of continental collisions beginning at about 450 million years ago.

The cities of Ottawa and Gatineau are located within the Algonquin to Adirondacks region. Map by Ken Buchan.

The cities of Ottawa and Gatineau are located within the Algonquin to Adirondacks region. Map by Ken Buchan.

Working alongside Canadian and American NGOs, universities, land trusts, naturalist clubs, government agencies and cottage associations, the A2A Collaborative is:

1. Identifying A2A connections in forests, wetlands, rivers and island chains with comprehensive mapping. Whether it’s large mammals moving through forested landscapes, lake sturgeon migrating within river systems or small mammals and birds utilizing island chains, identifying and recording A2A connections can help ensure they are not severely altered.

2. Identifying threats to A2A connections. Habitat fragmentation, roads/highways, aquatic pollution, hydroelectric dams, proposed tar sands pipelines, climate change, urban sprawl, inappropriate recreational use and wind turbine placement can all compromise the integrity of A2A connections.

3. Maintaining and restoring A2A connections. The collaborative is working with its partners on a number of research and monitoring projects including ones that focus on protecting species at risk (e.g., in watersheds and important bird areas), habitat restoration and road ecology along Highway 401.

4. Developing an online database. To facilitate collaboration and sharing of important information among partners, the collaborative is in the process of creating an online database to catalog data for use by organizations working in the A2A region.

Be sure to visit the A2A Collaborative’s website to learn more about its projects and how you can get involved and support the A2A initiative.

A view from the Precambrian Canadian Shield on the Eardley Escarpment in Gatineau Park, looking east over the Paleozoic sedimentary rocks and farmland of the Ottawa River valley. Photo by Ken Buchan.

A view from the Precambrian Canadian Shield on the Eardley Escarpment in Gatineau Park, looking east over the Paleozoic sedimentary rocks and farmland of the Ottawa River valley. Photo by Ken Buchan.

Here we are, with Paul Keddy

Paul Keddy, with OFNC friends Paul Catling and Dan Brunton

Paul Keddy (left), with OFNC friends Paul Catling and Dan Brunton

by Lynn Ovenden

Dr. Paul Keddy drove to Ottawa last Tuesday from his home deep in the forest of Lanark County to speak to a large meeting of OFNC members in the Neatby Building. He drove from forest on the marble and gneiss of a Precambrian continent, across the Ordivician limestone of an ancient sea, to the recent sediments of a post-glacial delta and seabed that underlie Ottawa. He then described the wetlands and forests in Lanark County 200 years ago, subsequent human impacts on the landscape, and some special places that remain.

Earth, Water, Fire is the title of his book on Lanark County and code for a 3-part approach to “knowing where we are” – that is, familiarity with the geology, vegetation, and human history of an area. Paul Keddy encouraged all of us, as field-naturalists, to develop this kind of authority on our home turf. Note to self: “Scientific Foundations for Conservation in the Ottawa Valley” is a reading list compiled by Paul Keddy, Dan Brunton, Don Cuddy and Paul Catling for biologists and others interested in natural heritage conservation, who want to know something about the Ottawa Valley.

Dr. Keddy recommended four biologically “special places” to explore in Lanark County:

  • The fire barrens of the western side, including the Christie Lake fire barrens; these are areas of little soil, scattered jack pine, oak, lichens, and prairie warblers
  • The Hackberry Forest in Carleton Place beside the Mississippi River
  • Innisville Wetland, a huge alluvial swamp at the south end of Mississippi Lake, penetrable by canoe or kayak; the Mississippi Valley Field-Naturalists’ club has explored part of it from the boat launch in Ferguson Falls
  • The fourth is the Burnt Lands Alvar near Almonte

Paul’s talk, recorded by Cathy Keddy, will soon be available to all on his website – have a look. Also check out accounts of the Mississippi Valley Field Naturalists’ forays into Lanark County’s special places. There is much to delight and lead us astray…