Nd isotope mapping of Grenvillian crustal terranes in the vicinity of the Manicouagan Impact Structure

作者：Thomson Stephanie D; Dickin Alan P^*; Spray John G

来源：Precambrian Research, 2011, 191(3-4): 184-193.

DOI：10.1016/j.precamres.2011.08.006

• Manicouagan
• Grenville
• Nd isotope
• Crustal formation

Over 70 new Nd isotope analyses are presented for the Manicouagan area of the Grenville Province to estimate the crustal age of target rocks involved in the 214 Ma Manicouagan Impact Structure, and to reconstruct the Precambrian geological evolution of this crustal segment. The rocks fall into two main groups: Samples from the Archean-aged Gagnon Terrane to the north and west of the impact give T-DM ages averaging 2.70 Ga. Samples from the Manicouagan Imbricate Zone (MIZ) and other allochthonous lithotectonic domains to the south of the impact yield Paleoproterozoic T-DM ages averaging 2.01 Ga for the MIZ and 1.86 Ga for the southern domains. These Paleoproterozoic terranes are correlated with Makkovikage crust in Labrador that was heavily reworked by Labradorian magmatism that increased in intensity southwards. The target rocks involved in the impact event would have consisted almost entirely of the MIZ, which formed a layer several kilometres thick, overlying Archean crust at depth.

• 出版日期2011-12