The Timiskaming Graben is a long and wide depression straddling the

Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central C ...

–

Quebec Quebec ( ; )According to the Government of Canada, Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is ...

border in

Eastern Canada Eastern Canada (also the Eastern provinces or the East) is generally considered to be the region of Canada south of the Hudson Bay/ Strait and east of Manitoba, consisting of the following provinces (from east to west): Newfoundland and Labrad ...

. It is a northwesterly extension of the

Ottawa-Bonnechere Graben The Ottawa-Bonnechere Graben (also known as the Ottawa Graben) is a geological structure that coincides with a wide topographic depression extending from near Montréal through Ottawa. It is part of the Saint Lawrence rift system that also inclu ...

, a failed arm of the Saint Lawrence rift system which is related to the opening of the

Iapetus Ocean The Iapetus Ocean (; ) was an ocean that existed in the late Neoproterozoic and early Paleozoic eras of the geologic timescale (between 600 and 400 million years ago). The Iapetus Ocean was situated in the southern hemisphere, between the paleoc ...

. Formation of the Timiskaming Graben corresponded with collapse of the regional crust along the Quinze Dam and Cross Lake faults possibly as early as 2.4 billion years ago. It was then reactivated during periods of

crustal extension Extensional tectonics is concerned with the structures formed by, and the tectonic processes associated with, the stretching of a planetary body's crust or lithosphere. Deformation styles The types of structure and the geometries formed depend on ...

related to the breakups of

supercontinent In geology, a supercontinent is the assembly of most or all of Earth's continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, "a grouping of formerly dispersed continents", which lea ...

s Rodinia and

Pangaea Pangaea or Pangea () was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from the earlier continental units of Gondwana, Euramerica and Siberia during the Carboniferous approximately 335 millio ...

and during compression related to the various

orogenies Orogeny is a mountain building process. An orogeny is an event that takes place at a convergent plate margin when plate motion compresses the margin. An ''orogenic belt'' or ''orogen'' develops as the compressed plate crumples and is uplifted t ...

that formed the

Appalachian Mountains The Appalachian Mountains, often called the Appalachians, (french: Appalaches), are a system of mountains in eastern to northeastern North America. The Appalachians first formed roughly 480 million years ago during the Ordovician Period. The ...

. The Timiskaming Graben is now partially filled by Lake Timiskaming, a long successor to the much larger glacial Lake Barlow which drained at the end of the last glacial period about 8,000 years ago. The Timiskaming Graben is a seismically active structure in the Western Quebec Seismic Zone. Reactivation of faults has resulted in

earthquake An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, from ...

s, such as the

1935 Timiskaming earthquake The 1935 Temiskamingue earthquake occurred on November 1 with a moment magnitude of 6.1 and a maximum Mercalli intensity of VII (''Very strong''). The event took place in the Western Quebec Seismic Zone in the Abitibi-Témiscamingue Abitibi-T ...

References

{{coord, format=dms, region:CA, display=title Aulacogens Geology of Ontario Geology of Quebec Seismic faults of Canada Structural geology Natural history of Ontario Natural history of Quebec Valleys of Ontario Valleys of Quebec Landforms of Nipissing District Landforms of Timiskaming District Landforms of Abitibi-Témiscamingue