In geology , a depression is a landform sunken or depressed below the surrounding area. Depressions form by various mechanisms.
2-757: The Timiskaming Graben is a 400 km (250 mi) long and 50 km (31 mi) wide depression straddling the Ontario – Quebec border in Eastern Canada . 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 . Formation of the Timiskaming Graben corresponded with collapse of
4-530: 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 related to the breakups of supercontinents Rodinia and Pangaea and during compression related to the various orogenies that formed the Appalachian Mountains . The Timiskaming Graben is now partially filled by Lake Timiskaming ,
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