Ottawa-Bonnechere Graben

Mattawa FaultOttawa ValleyOttawa-Bonnechere
The Ottawa-Bonnechere Graben (also known as the Ottawa Graben) is a geological structure that coincides with a 55 km wide topographic depression extending from near Montréal through Ottawa.wikipedia
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Mattawa River

MattawaMattawa River Provincial Park
Since then, it has been traced west to Lake Nipissing, and northwestwards from the confluence of the Mattawa and Ottawa Rivers up the valley of the latter stream to Lake Timiskaming and the Montreal River valley.
This valley is an offshoot arm of ancient rift valley, called the Ottawa-Bonnechere Graben, which still causes minor earthquakes in the area.

Saint Lawrence rift system

Saint Lawrence rift
On the east, it joins the Saint Lawrence rift system, a half-graben which extends more than 1000 km along the Saint Lawrence River valley and links the Ottawa and Saguenay Graben.
The rift system trends northeast and southwest and forms a half-graben that links the Ottawa-Bonnechere and the Saguenay grabens.

Lake Nipissing

Lake Nippising
The Ottawa-Bonnechere Graben runs from the Montreal area on the east to near Sudbury and Lake Nipissing on the west.
Lake Nipissing lies in the Ottawa-Bonnechere Graben, a Mesozoic era rift valley that formed 175 million years ago.

Timiskaming Graben

This latter branch is the Timiskaming Graben.
It is a northwesterly extension of the Ottawa-Bonnechere Graben, a failed arm of the Saint Lawrence rift system which is related to the opening of the Iapetus Ocean.

Graben

grabenshalf grabenhalf-graben
The 200 km segment of the Ottawa-Bonnechere Graben west of Ottawa was the first to be recognized as a graben.

Ottawa River

OttawaOttawa valleya major waterway
Since then, it has been traced west to Lake Nipissing, and northwestwards from the confluence of the Mattawa and Ottawa Rivers up the valley of the latter stream to Lake Timiskaming and the Montreal River valley.
The Ottawa River lies in the Ottawa-Bonnechere Graben, which is a Mesozoic rift valley that formed 175 million years ago.

Manitou Islands (Lake Nipissing)

Manitou IslandsManitou Islands Provincial Park
Since the Late Proterozoic to Early Paleozoic, erosion has removed the volcanic peaks, exposing a number of relic volcanic pipes, such as Callander Bay and the Manitou Islands in Lake Nipissing.
The Manitou Islands lie inside the Ottawa-Bonnechere Graben and are part of an eroded volcanic pipe, leaving the multiple islands.

Lake Timiskaming

Lake TemiskamingLake TemiscamingTimiskaming
Since then, it has been traced west to Lake Nipissing, and northwestwards from the confluence of the Mattawa and Ottawa Rivers up the valley of the latter stream to Lake Timiskaming and the Montreal River valley.
It is the northern extension of the Ottawa-Bonnechere Graben, which is part of the Saint Lawrence rift system.

Aulacogen

failed armfailed riftfailed
The graben has been interpreted as a Late Proterozoic to Early Paleozoic failed arm of the Iapetus Ocean, the precursor to the Atlantic Ocean.
An example of a reactivated aulacogen is the East African Rift or the Ottawa-Bonnechere Graben in Ontario and Quebec, Canada, an ancient aulacogen that reactivated during the breakup of Pangaea.

Gatineau Hills

Eardley EscarpmentCamp Fortune
Along the northern side of the Ottawa-Bonnechere Graben lies a dramatic escarpment that forms the southern edge of the Gatineau Hills.
The Gatineau Hills (Collines de la Gatineau) are a geological formation in Canada that makes up part of the southern tip of the Canadian Shield, and acts as the northern shoulder of the Ottawa Valley.

Grenville dike swarm

This volcanism was probably coeval with the emplacement of the Grenville dike swarm.
The Ottawa-Bonnechere Graben is associated with the Grenville dike swarm, as some of its features date from that time.

Great Lakes

North American Great LakesGreat Lakethe Great Lakes
The depressions formed by the graben across the rugged Canadian Shield were a spillway for the Great Lakes after the last Ice Age.

Escarpment

scarpscarpsescarpments
Along the northern side of the Ottawa-Bonnechere Graben lies a dramatic escarpment that forms the southern edge of the Gatineau Hills.

Brent crater

BrentBrent impact crater
On or near a branch of the Ottawa-Bonnechere Graben lies the Brent impact crater.
The crater lies in the Ottawa-Bonnechere Graben, a 452 million year old rift valley.

Crust (geology)

crustEarth's crustcrustal
This rift valley was formed when the Earth's crust moved downward about a kilometre between two major fault zones known as the Mattawa and Petawawa faults.

Fault (geology)

faultfaultsstrike-slip
This rift valley was formed when the Earth's crust moved downward about a kilometre between two major fault zones known as the Mattawa and Petawawa faults.

Montreal

Montreal, QuebecMontréalMontreal, Canada
The Ottawa-Bonnechere Graben runs from the Montreal area on the east to near Sudbury and Lake Nipissing on the west.

Greater Sudbury

SudburySudbury, OntarioSudbury, Canada
The Ottawa-Bonnechere Graben runs from the Montreal area on the east to near Sudbury and Lake Nipissing on the west.

Half-graben

half grabenhalf grabenshalf-grabens
On the east, it joins the Saint Lawrence rift system, a half-graben which extends more than 1000 km along the Saint Lawrence River valley and links the Ottawa and Saguenay Graben.

Saint Lawrence River

St. Lawrence RiverSt Lawrence RiverSt. Lawrence
On the east, it joins the Saint Lawrence rift system, a half-graben which extends more than 1000 km along the Saint Lawrence River valley and links the Ottawa and Saguenay Graben.

Valley

river valleyhanging valleyvalleys
On the east, it joins the Saint Lawrence rift system, a half-graben which extends more than 1000 km along the Saint Lawrence River valley and links the Ottawa and Saguenay Graben.

Saguenay Graben

Saguenay
On the east, it joins the Saint Lawrence rift system, a half-graben which extends more than 1000 km along the Saint Lawrence River valley and links the Ottawa and Saguenay Graben.

Confluence

confluentconfluxsangam
Since then, it has been traced west to Lake Nipissing, and northwestwards from the confluence of the Mattawa and Ottawa Rivers up the valley of the latter stream to Lake Timiskaming and the Montreal River valley.

Montreal River (Timiskaming District)

Montreal River
Since then, it has been traced west to Lake Nipissing, and northwestwards from the confluence of the Mattawa and Ottawa Rivers up the valley of the latter stream to Lake Timiskaming and the Montreal River valley.

Proterozoic

Proterozoic EonLate ProterozoicProterozoic Era
The graben has been interpreted as a Late Proterozoic to Early Paleozoic failed arm of the Iapetus Ocean, the precursor to the Atlantic Ocean.