Depositional Regime of Early Triassic Sedimentation in the Bjorne Formation on the Eastern Margin of the Sverdrup Basin Ellesmere Island, Nunavut, Canada

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



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



STUDYAREA

RegionalMap

Study AreaStudy Area

Sverdrup Basin

Embry and Beauchamp, 2008



MethodsMethods

• Conducted field work to create detailed section

• Collected samples

for thin sections/

petrographic

analysisN

1000m



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



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



Facies AssemblageFacies Assemblage

Se: Erosional Scours and Mud Clasts

Sh, St: Horizontally Stratified, Trough Cross Stratification

Sr: Sand with ripples




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




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



Interpretation – Multistorey Fluvial Channels

Interpretation – Multistorey Fluvial Channels

Shallow, elongate erosional scours

Primary Current Lineation

Sharp contact, preserved paleosurface



Interpretation – Overbank FinesInterpretation – Overbank Fines

Bioturbation, Ripple Lamination, Climbing Ripples

Dessication Cracks



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



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



Evidence for Rapid FlowEvidence for Rapid Flow

Transitional Dune or Antidune

Upper Flow Regime Sedimentary Structures, (Fielding, 2006)

OR

Plane BedChute and Pool Bedform



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



Basin Evolution – Early TriassicBasin Evolution – Early Triassic

Sediment SupplyEmbry and Beauchamp, 2008



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



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



Thanks for your attentionThanks for your attention

Questions?Questions?



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.

Documents

Depositional Regime of Early Triassic Sedimentation in the Bjorne Formation on the Eastern Margin of the Sverdrup Basin Ellesmere Island, Nunavut, Canada