Rockwood Park

Rocks

The park is appropriately named. The rocks found in Rockwood Park are quite diverse. They include Precambrian marble, Precambrian gneiss, Precambrian to Cambrian igneous rocks (granite), tonalite, granodiorite and dacite and Devonian sandstone and conglomerate. Two geologic terranes are found in the park. The Caledonian Terrane includes the McBrien Lake Formation dacite and the Cambrian Saint John Group, found just outside the park. Northwest of the dacite, rocks belong to the Brookville Terrane. The Devonian rocks are a later cover sequence of younger sedimentary rocks.

A major fault called the Caledonia Fault separates the terranes. The main road past the Lily Lake Pavilion follows the fault line.

A Long History

Rockwood Park has had a long history of scientific study and geological exploration. The Natural History Society of New Brunswick examined the geology of the park in the late 1800s. Rock specimens Society members collected from the park are found in the New Brunswick Museum collection. Howes Cave in the Ashburn Formation marble was discovered in the 1860s and described in the Society Bulletin in 1904. Even earlier in the 1800s a graphite mine operated near the outlet of Lily Lake.

Geocaching

Rockwood Park has many trails that allow opportunities to explore the geology on foot, on a mountain bike, or on horseback. Get up-close by rock climbing with a guide. In the winter it is a great place to explore on cross-county skis or snowshoes.

Access:
Access:
Disabled Friendly:
Hours:
Dawn Till Dusk
Location:
Address:
10 Fisher Lake Drive
Saint John, New Brunswick
Canada
GPS:
45.3039657, -66.0594638

St. Martins

Rocks

The rocks of St. Martins are Permian-Triassic age, about 250 million years old, and belong to the Honeycomb Point, Quaco and Echo Cove formations. The sea caves are in the red Honeycomb Point Formation. The coarse boulder conglomerate is part of the Quaco Formation. The contact of the two formations is easily seen at the east end of the beach in front of the restaurants. Very few fossils are found in these rocks. Poorly preserved plant fossils were found in the Echo Cove Formation many decades ago.

Bay of Fundy Rocks

The Permian-Triassic rocks seen at St. Martins dip under the Bay of Fundy and emerge on the Nova Scotia side of the bay near Parrsboro and Blomidon. Nova Scotia’s fossil history includes the oldest dinosaurs in North America found in Triassic age rocks. Rocks in Nova Scotia include fossils similar to Coelophysis. Our rocks are too old to have dinosaur fossils.

The Triassic rocks in New Brunswick represent the oldest part of the time period, and may even extend back in geologic time to the Permian Period. Permian rocks in Prince Edward Island have produced reptile fossils like Bathygnathus. Possible reptile footprints have been seen here!

Sea Caves

Waves on the Bay of Fundy pound relentlessly on the coastal cliffs. The harbour at St. Martins has beautiful examples of sea caves, shallow features carved into sandstone and conglomerate. Sea caves are caused by physical erosion, unlike chemical solution caves in karst landscapes where carbonate bedrock has been dissolved by natural acids in rain and groundwater. In sedimentary rocks like these the caves may form along rock layers. You can see this where the boulder conglomerate meets the red sandstone. The cave floor is on the same angle as the rock layers.

Access:
Access:
Disabled Friendly:
Hours:
Dawn Till Dusk
Location:
Address:
Highway 111
St. Martins, New Brunswick
Canada
GPS:
45.348151, -65.5556239
Phone:

Irving Nature Park

Rocks

The geology of the Irving Nature Park includes both Devonian to Carboniferous bedrock (359 to 346 million years old) exposed on Taylors Island and at Sheldon Point and overlying sand, gravel and clay deposited during the last ice age less than 15,000 years ago. The age of the older volcanic and sedimentary rocks has been hard to determine.

Although they have many interesting features, this note will focus on the ice age geology of the Irving Nature Park. This is one of the best places in Stonehammer to see this part of the geologic record. The ice age geology is made up of “unconsolidated” sediments. They are not rock yet, they are too young.

Climate Change

The end of the ice age was a time of rapid climate change especially during the “Younger Dryas” cold interval. About 11,000 years ago temperatures plummeted about 7˚C in a decade. Sub-arctic insects re-invaded the Maritimes for hundreds of years until temperature warmed again. A peat bog on the hill at Saints Rest Beach records this rapid climate event.

Glaciers

At a time geologists call the “Last Glacial Maximum”, about 20,000 years ago, continental glaciers covered most of North America, including the Maritimes. By 10,000 years ago New Brunswick was probably “ice-free”. As the glaciers retreated they left piles of sand and gravel along their margin. Called “moraines” and “outwash”, these piles of sediment are easily seen on the modern landscape. We often use them as sand and gravel quarries. The quarry on Sand Cove Road above the beach is an example. About 15,000 years ago the front of the glacier stood here at the Irving Nature Park. It is called a tidewater glacier since the glacier ice was up against the ocean. The red clay along the beach cliffs is composed of layers of ocean sediment. Occasionally fossils of snails, clams, sea urchins and starfish can be found in the clay. As the glacier continued to retreat it left a series of moraines where it stood still for a period of time. Looking northwest from the beach you can see Manawagonish Road on the hill. The road is built on the Manawagonish Moraine. This moraine acted as a dam and forced the St. John River to flow through the Reversing Rapids.

Access:
Access:
Disabled Friendly:
Hours:
Location:
West Saint John
Address:
1379 Sand Cove Road
Saint John, New Brunswick
E2L 4M3 ~ Canada
GPS:
45.2257772, -66.1175892
Stonehammer UNESCO Global Geopark