Detrital Zircon Studies in Silurian Basins of Southern New Brunswick

• Author / Creator

  Dokken, Robert J.

• The Appalachian orogen in eastern Canada resulted from the Paleozoic convergence of the continents Laurentia and Gondwana during the closure of the intervening Iapetus Ocean. In New Brunswick, the Fredericton Trough and Mascarene Basin were filled in the Silurian within the peri-Gondwanan domain of Ganderia during associated convergence and ocean closure. Detrital zircon geochronological studies demonstrate that the northern formations of the Fredericton Trough were juxtaposed with Laurentia in the early Silurian; however, southern portions of the trough were still separated from Laurentia at this time, indicating the persistence of the Iapetus Ocean. These southern formations record the arrival of Laurentian detritus by the mid-Wenlock, indicating that components of Ganderia were juxtaposed with Laurentia by this time, coinciding with ocean closure. The location of the terminal Iapetan suture, marking the closure of the last portion of Iapetus Ocean, is approximated by the Fredericton Fault, which bisects the trough. Analogous studies in the Mascarene back-arc basin, to the south of the Fredericton Trough, show that it was separated from Laurentia until at least the late Llandovery, and may suggest juxtaposition with a composite Laurentia by 423 ± 1 Ma. These combined results suggest a scenario where Ganderian terranes were successively accreted to Laurentia in the Silurian, as recorded by the progressively increasing extent of Laurentian detritus in juxtaposed terranes.

• Subjects / Keywords

  • Ganderia
  • Fredericton Trough
  • Appalachian
  • Iapetus
  • Detrital zircon
  • Mascarene
  • Geochronology

• Graduation date

  Fall 2017

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R33N20T6R

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.