1 / 20

Derrick Midwinter Supervisors Martin Gibling - Dalhousie University Thomas Hadlari - GSC

Depositional Regime of Early Triassic Sedimentation in the Bjorne Formation on the Eastern Margin of the Sverdrup Basin Ellesmere Island, Nunavut, Canada. Derrick Midwinter Supervisors Martin Gibling - Dalhousie University Thomas Hadlari - GSC. Interest/Objectives.

ianthe
Download Presentation

Derrick Midwinter Supervisors Martin Gibling - Dalhousie University Thomas Hadlari - GSC

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Depositional Regime of Early Triassic Sedimentation in the Bjorne Formation on the Eastern Margin of the Sverdrup Basin Ellesmere Island, Nunavut, Canada Derrick Midwinter Supervisors Martin Gibling - Dalhousie University Thomas Hadlari - GSC

  2. Interest/Objectives • Poorly studied unit in the Canadian Arctic • Create Deposition Model • Understand Burial History • Use results for Economic Potential and link back to Sverdrup Basin evolution • Part of Geo-Mapping for Energy & Minerals for GSC – stratigraphy and economics • Large scale fluvial system worth knowing

  3. Study Area Sverdrup Basin STUDY AREA Regional Map Embry and Beauchamp, 2008

  4. Methods • Conducted field work to create detailed section • Collected samples • for thin sections/ • petrographic • analysis N 1000m

  5. Bjorne Formation Near Study Area • Early Triassic sandstone unit deposited in Sverdrup Basin • Tongues of shaly Blind Fiord Fm • Dominantly fluvial Embry, 2009 Bjorne Blind Fiord

  6. Outcrop Quality Creating a Depositional Model First Member Total Measured Section 3rd Member 250m 1,050m 2nd Member 1st Member

  7. Facies Assemblage Sr: Sand with ripples Se: Erosional Scours and Mud Clasts Sh, St: Horizontally Stratified, Trough Cross Stratification

  8. Facies Assemblage Fl: Silt to sand, fine lamination, very small ripples Sl: Low angle to sinusoidal cross stratification

  9. Facies Assemblage

  10. Interpretation – Multistorey Fluvial Channels Primary Current Lineation Shallow, elongate erosional scours Sharp contact, preserved paleosurface

  11. Interpretation – Overbank Fines Bioturbation, Ripple Lamination, Climbing Ripples Dessication Cracks

  12. Depositional Environment: Ephemeral Sheet Flow • Pulsatory deposition • Rapid influx of sediment mainly as sheet flow • Repeated events create multistorey sand sequences with high regime deposits dominating • Red silt beds represent waning flood stages

  13. Evidence for Waning Flow Type B Climbing Ripples (Depositional Stoss) Ashley et al., 1982 Silty veneer /Well-Preserved paleosurface - reflect fluctuating conditions during episodic flow Aggradation > Migration = Waning flow with high suspended and bed load

  14. Evidence for Rapid Flow OR Transitional Dune or Antidune Plane Bed Chute and Pool Bedform Upper Flow Regime Sedimentary Structures, (Fielding, 2006)

  15. Theory • Why the fine grained sandy ephemeral braidplain? • Provenance of Devonian siliciclastic material • Paleoclimate – semi-arid – variable discharge • Overlies Permo/Triassic boundary – influenced by extinction of vegetation – no meandering deposits

  16. Basin Evolution – Early Triassic Sediment Supply Embry and Beauchamp, 2008

  17. Economic Potential • Age equivalent to super giant oil field, Prudhoe Bay, Alaska • Oil Sands on Melville Island • Minimal organics in Bjorne, but present in Blind Fiord tongues and unit above • 20% Porosity • Potential stratigraphic-structural and flanks of salt dome traps Embry, 2009

  18. Further Work • Analyse facies for the remaining two members – create depositional model for entire Bjorne • Study petrography for burial history and diagenetic information • Overview hydrocarbon potential

  19. Thanks for your attention Questions?

  20. Selected References • Embry, A.F., 2009, Lower Triassic Stratigraphy and Petroleum Potential, Sverdrup Basin, Arctic Canada, Oral Presentation, AAPG Convention, Denver, Colorado, June 7-10, 2009 • Embry, A.F. and Beauchamp, B., 2008, Sverdrup Basin. In: K.J. Hs ü , series editor: Sedimentary Basins of the World, Vol 5, The Sedimentary Basins of the United States and Canada, Andrew D. Miall. The Netherlands: Elsevier, 2008, pp. 451 – 471 • Fielding, C.R., 2006, Upper flow regime sheets, lenses and scour fills: Extending the range of architectural elements for fluvial sediment bodies: Sedimentary Geology, v. 190, p. 227-240. • Stear, W.M., 1985, Comparison of the bedform distribution and dynamics of modern and ancient sandy ephemeral flood deposits in the southwestern Karoo region, South Africa: Sedimentary Geology, v. 45, p. 209-230.

More Related