Tucker Park

Rocks

The rocks at Tucker Park are part of a distinctive formation in the Saint John area. They comprise the Kennebecasis Formation, named for the river where they are seen in outcrop. These are the oldest ‘cover rocks’ in the park, meaning they lie on top of the older geological terranes that amalgamated by the process of plate tectonics. The red Devonian age rocks are about 370 million years old.

Rivers of Rock

Kennebecasis Formation rocks might be described as ‘Rivers of Rock’ since they are layers of sediment that accumulated in riverbeds. The sand, mud and boulders were once sweeping down fast flowing rivers, eroding the mountains that had been created as the older terranes collided. Spectacular examples of these Devonian rocks can be seen around the north end of Saint John in Millidgeville and near UNBSJ. The Memramcook Formation seen further east near Hampton is a related formation and formed in a similar environment.

The Age of Fishes

The Devonian Period of geologic time is often called ‘The Age of Fishes’. During this Period many of the groups of fish we now know flourished. Some of the dominant fish of the Devonian also became extinct. Bony fish and sharks evolved rapidly during this time and are still here today. Acanthodians, placoderms, cephalaspids, thelodonts and others are gone. The Devonian is also the time that animals called tetrapods evolved. A tetrapod is an animal with four legs (or two legs and two arms in our case). A fossil fish often found with Devonian tetrapod fossils is the lobefin fish Holoptychius. Recently a fossil of this fish was found in the Kennebecasis Formation not far from Tucker Park. The scales and jaw are distinctive and indicate that these rocks are most likely Devonian age, a support the idea these are freshwater, or non-marine sediments.

Access:
Access:
Disabled Friendly:
Hours:
Dawn Till Dusk
Location:
Address:
Kennebecasis Drive
Saint John, New Brunswick
Canada
GPS:
45.3113292, -66.0987850
Phone:

Dominion Park

The Rocks

Green Head Island is the “Type Locality” for the Green Head Group that includes a Late Precambrian marble about 750 million to 1.2 billion years old. Marble is a metamorphic rock created from limestone. It has been subjected to heat and pressure that causes the limestone to transform and recrystallize. The limestone was once sediment on the floor of a warm shallow sea.

The Martinon Formation is also part of the Green Head Group. It is often seen as a sandstone or conglomerate rock. This formation is believed to be about the same age as the marble, but it represents deeper water sediment formed on the underwater slopes leading to the deeper ocean.

The Geologic Period

Precambrian is the name given to a very long period of geologic time. As the name suggests it is everything before the Cambrian Period, and encompasses the time from the formation of the Earth 4.6 billion years ago to the start of the Cambrian 542 million years ago. Four billion years is a long time and to call it all Precambrian simplifies a complex period of Earth history. In the 1800s fossils were one of the only tools to distinguish Precambrian from younger rocks. Cambrian rocks often contain abundant fossils such as trilobites. The first presumed Precambrian fossil was discovered in the 1860s and was part of an intense search for the first record of Precambrian life. This first discovery was discounted by the end of the 19th century. Meanwhile Saint John geologist George Matthew described a fossil in 1890, not far from Dominion Park. His identification of the stromatolite Archaeozoon acadiense has withstood scientific scrutiny and is now known as the first Precambrian stromatolite fossil described in scientific literature.

What’s Nearby

The Green Head lime quarry in Saint John includes remains of built structures and quarries preserving one of the last historic lime kiln operations in southern New Brunswick. It includes remains of the quarry, kiln foundations, wharf timbers and foundation walls of homes. During the 1800s the lime business was booming in the region with as many as nineteen kiln sites in operation. Quarries are located in the Precambrian Ashburn Formation marble of the Green Head Group. The Green Head quarry was operated for many years by Joseph and Frank Armstrong whose lime product was known throughout the Maritimes for its quality. Lime produced at the Armstrong Quarry was used locally. Buildings constructed in Uptown Saint John after the Great Fire of 1877 were mortared using Green Head lime. Joseph Armstrong was a pioneer in the development of the lime industry which was worth almost $100,000 in export trade by 1889. The quarry operation is a historic reminder of a mining industry that supported southern New Brunswick’s economy throughout much of the nineteenth century.

Access:
Year Round
Access:
Disabled Friendly:
Yes
Hours:
Dawn Till Dusk
Location:
Corner of Dominion Park Road & Tippett Drive
Address:
GPS:
45.2691391, -66.123868

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