Grenville Province

The Grenville Province is a tectonically complex region, in Eastern Canada, that contains many different aged accreted terranes from various origins.

It exists southeast of the Grenville Front[1] and extends from Labrador southwestern to Lake Huron.

The Parautochthonous Belt is made of rocks originally derived from the Superior Craton, which have been metamorphosed and reworked since their emplacement.

[3] The rocks to the southwest of the Parautochthonous Belt are various accreted terranes that have been thrust upon or emplaced during the various tectonic events that have taken place from 2.0 to 0.98 billion years ago.

[3][4] The Central Metasedimentary Belt is bordered to the south by Phanerozoic sedimentary rocks and Lake Ontario.

The origin of this area can be attributed to rifting (which made the accommodation for the sediments) and subsequent thrusting from the collision with Amazonia.

Nd model ages of Quebecia are around 1.55 Ga.[3][7] Mekinac is located northeast of Ottawa, Canada.

Nd model ages of Morin are around 1.3-1.5 Ga.[3] The Adirondacks are located in northeastern New York, United States.

It has a Nd model age ranging from 1.3 to 1.5 Ga.[3] Algonquia is located east of the Georgian Bay in Ontario, Canada.

Its Nd model age is between 1.6 and 1.9 Ga.[3][8] Parry Sound is located east of the Georgian Bay in Ontario, Canada.

The quartzite is evidence that the three terranes were all continuous at one point due to the zircons contained within it matching the Central Metasedimentary Belt and the Adirondack Highlands.

During the beginning stages of the Mesoproterozoic (1.60-1.23 Ga) the Grenville Province was controlled by flat slab subduction.

By the later stages of the Mesoproterozoic (1.23-0.90 Ga), the Grenville Province was controlled by pressure-point orogenesis.

Crustal thickening represented by the accreted arc on preexisting Laurentia caused magmatism.

A passive margin that accumulated sediment formed due to lack of tectonic activity.

Felsic magmatism ceases and accretion of island arcs occurs in the Central Metasedimentary Belt.

This could be related to the Shawinigan orogeny which occurred in the southwestern region of the Grenville Province.

[13] During this time, deformation and metamorphism was widely spread throughout the entire Grenville Province but the level of intensity varied.