Derrick Midwinter Supervisors Martin Gibling - Dalhousie University Thomas Hadlari - GSC
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Transcript of Derrick Midwinter Supervisors Martin Gibling - Dalhousie University Thomas Hadlari - GSC
R esso urces n atu rellesC ana da
N atu ral Re sou rce sC ana da C anada
Depositional Regime of Early Triassic Sedimentation in the Bjorne
Formation on the Eastern Margin of the Sverdrup Basin
Ellesmere Island, Nunavut, Canada
Depositional Regime of Early Triassic Sedimentation in the Bjorne
Formation on the Eastern Margin of the Sverdrup Basin
Ellesmere Island, Nunavut, Canada
Derrick Midwinter
SupervisorsMartin Gibling - Dalhousie University
Thomas Hadlari - GSC
Derrick Midwinter
SupervisorsMartin Gibling - Dalhousie University
Thomas Hadlari - GSC
R esso urces n atu rellesC ana da
N atu ral Re sou rce sC ana da C anada
Interest/ObjectivesInterest/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
• 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
R esso urces n atu rellesC ana da
N atu ral Re sou rce sC ana da C anada
STUDYAREA
RegionalMap
Study AreaStudy Area
Sverdrup Basin
Embry and Beauchamp, 2008
R esso urces n atu rellesC ana da
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MethodsMethods
• Conducted field work to create detailed section
• Collected samples
for thin sections/
petrographic
analysisN
1000m
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Bjorne FormationBjorne Formation
• Early Triassic sandstone unit deposited in Sverdrup Basin
• Tongues of shaly Blind Fiord Fm
• Dominantly fluvial
• Early Triassic sandstone unit deposited in Sverdrup Basin
• Tongues of shaly Blind Fiord Fm
• Dominantly fluvial
Bjorne Blind Fiord
Near Study Area
Embry, 2009
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3rd M
em
ber2
nd M
em
ber1
st Mem
ber
Creating a Depositional ModelCreating a Depositional Model
1,05
0m
250m
Total Measured Section
First Member
Outcrop Quality
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Facies AssemblageFacies Assemblage
Se: Erosional Scours and Mud Clasts
Sh, St: Horizontally Stratified, Trough Cross Stratification
Sr: Sand with ripples
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Facies AssemblageFacies Assemblage
Sl: Low angle to sinusoidal cross stratification Fl: Silt to sand, fine lamination, very small ripples
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Facies AssemblageFacies Assemblage
Multistorey Fluvial Channels (Sl, Sh, Se, St, Sr)
Sandstone unit with lineated low angle to horizontally stratified sandstone with primary current lineation or trough cross stratification sandstone, shallow elongate scours overlain by mudstone intraclasts
Overbank Fines(Fl,Sr)
Red bed dominantly siltstone with minor amounts of sandstone with climbing ripples, wavy laminations, desiccation cracks
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Interpretation – Multistorey Fluvial Channels
Interpretation – Multistorey Fluvial Channels
Shallow, elongate erosional scours
Primary Current Lineation
Sharp contact, preserved paleosurface
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Interpretation – Overbank FinesInterpretation – Overbank Fines
Bioturbation, Ripple Lamination, Climbing Ripples
Dessication Cracks
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Depositional Environment: Ephemeral Sheet Flow
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
• 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
R esso urces n atu rellesC ana da
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Evidence for Waning FlowEvidence for Waning Flow
Aggradation > Migration = Waning flow with high suspended and bed load
Type B Climbing Ripples (Depositional Stoss)
Silty veneer /Well-Preserved paleosurface - reflect fluctuating conditions during episodic flow
Ashley et al., 1982
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Evidence for Rapid FlowEvidence for Rapid Flow
Transitional Dune or Antidune
Upper Flow Regime Sedimentary Structures, (Fielding, 2006)
OR
Plane BedChute and Pool Bedform
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TheoryTheory
• 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
• 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
R esso urces n atu rellesC ana da
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Basin Evolution – Early TriassicBasin Evolution – Early Triassic
Sediment SupplyEmbry and Beauchamp, 2008
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Economic PotentialEconomic 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
• 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
R esso urces n atu rellesC ana da
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Further WorkFurther 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
• Analyse facies for the remaining two members – create depositional model for entire Bjorne
• Study petrography for burial history and diagenetic information
• Overview hydrocarbon potential
R esso urces n atu rellesC ana da
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Thanks for your attentionThanks for your attention
Questions?Questions?
R esso urces n atu rellesC ana da
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Selected ReferencesSelected 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.
• 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.