Sequence stratigraphy and underlying tectonism of the Northern Richardson Mountains and adjacent Mackenzie Delta related to the formation of the Arctic Ocean

• Author / Creator

  Millar, Ryan

• Jurassic-Cretaceous rifting within Arctic North America that eventually resulted in the formation of the Arctic Ocean greatly affected deposition within nearshore terrestrial basins in surrounding areas, such as the Brooks-Mackenzie Basin and the Sverdrup Basin. In this thesis, measured stratigraphic sections and detrital U-Pb zircon data from outcrops within the Northern Richardson Mountains are integrated with well-log and core data from the adjacent Mackenzie Delta to establish a model-independent sequence stratigraphic framework for the BrooksMackenzie Basin. This framework is then used to elucidate the underlying tectonic forces responsible for the observed stratigraphy, relating patterns of deposition to various phases of rift development. The proposed interpretation classifies the sub-Jurassic unconformity as a first-order sequence boundary, demarcating a change in tectonic setting from pre-rift to rift, meaning it is also classified as the rift onset unconformity for the Arctic Ocean. The overlying Bug Creek Group is largely progradational, representing a first-order lowstand systems tract corresponding to early syn-rift strata. Detrital zircon data from the Bug Creek Group lacks syn-depositional zircons and resemble the underlying Permian, suggesting a recycled source. A change in the detrital zircon signature is observed within the uppermost Aklavik Formation, representing a new source. This also coincides with a rapid transition to the lower offshore deposits of the Husky Formation caused by normal faulting in the Husky Lakes Fault Zone, which is associated with a dramatic basin expansion. Maximum transgression occurs above the arenaceous member of the Husky Formation, likely near the Jurassic-Cretaceous boundary, representing a first-order maximum flooding surface and rift-climax. Above the rift climax, the overall progradational signature represents a first-order HST and post-rift deposits. The sub-Hauterivian basal Kamik unconformity is observed at the base of the subsequent FSST. This first-order sequence boundary is approximately time equivalent to the breakup unconformity for the Arctic Ocean, with the overlying Kamik Formation resembling the Isachsen Formation in the Sverdrup Basin.

• Subjects / Keywords

  • Sequence stratigraphy
  • sedimentology
  • tectonics

• Graduation date

  Spring 2021

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-6h35-q755

• 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.