Greg Keller greg'kellergov'mb'ca

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Progress in 3D Geological Mapping in Manitoba and
the eastern Prairies, Canada
Greg Keller (greg.keller_at_gov.mb.ca) Gaywood
Matile (gaywood.matile_at_gov.mb.ca) Manitoba
Geological Survey
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Progress in 3D Geological Mapping in Manitoba and
the eastern Prairies, Canada
Acknowledgements Harvey Thorleifson (thorleif_at_um
n.edu) Minnesota Geological Survey Saskatchewan
Geological Survey
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Manitoba Geological Surveys 3D program
Who?

• Its basically a two man show (Gaywood/Greg)
• Harvey helps keep us on the straight and
  narrow path
• Support from the director of the geological
  survey, both in spirit and financially (to
  purchase and maintain Gocad/3D workshops)
• Total of 10 000/year budget (includes software,
  travel, expenses)

What?

• Province wide 3D geological modeling
• Groundwater modeling is not undertaken by the
  MGS.
• Manitoba Water branch and universities

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Manitoba Geological Surveys 3D program
Where/Why?

• Nearly all of the one million inhabitants of the
  Province of Manitoba live in a 400 km x 700 km
  area of Phanerozoic terrane in the southern
  portion of the province.
• The majority live in the Winnipeg area, a 200 km
  x 230 km area, in the southeastern corner of the
  province.
• The City of Winnipeg obtains water from Shoal
  Lake
• However the 200,000 residents of surrounding
  areas rely on groundwater obtained from bedrock
  aquifers.

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Manitoba Geological Surveys 3D program
Where/Why? Contd

• Models to used to support groundwater studies
• University of Manitoba Thesis (Paula Kennedy
  groundwater flow modeling)
• Water Branch (Manitoba Government) Drill
  targeting (exploration) ie. buried valley aquifer
  delineation
• Educational tool (in house, and for the general
  public)

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3D Geological Mapping in Manitoba
1) Southeast Manitoba (complete)
2) Lake Winnipeg region (complete)
3) TGI Williston Basin (bedrock complete)
4) Southwest MB Quaternary (in progress)
5) Hudson Bay Lowland (future)
6) International Model (future)
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3D Geological Mapping in Manitoba
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Model Inputs
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Digitize existing bathymetric charts
Large Lake Bathymetry
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Lake Winnipeg Seismic

• Seismic surveys 94, 96 (MGS/Feds)
• Echosounding on Lake Winnipeg
• Better understanding of subsurface deposits in
  Lake Winnipeg

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Digital Elevation Data (SRTM)
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Surficial Mapping

• Guide for model interpretation

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Bedrock Model

• Guide for model interpretation

• Provides the termination of each unit below
  surface

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Drillhole Data

• Over 100 000 drillholes

• Waterwells, test holes,
• academic holes, oil and
• gas holes

• Data is sparse in fringe
• areas

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3D Model Requirements Overview

• Geological Maps (surficial and bedrock)
• Drillhole databases
• Process Model
• Paleogeography
• Stratigraphy

Infrastructure
Process
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Modeling Methodology
Southeast Manitoba/Lake Winnipeg
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Cross-sections
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Standardized lithological legend
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Standardized lithological legend
- 5 km grid of PSPs
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Access Database
PSP
Gocad Model
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Southeast Manitoba
Block Model

• Modeled 31 units
• 17 are Quaternary

Section View
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Lake Winnipeg
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Modeling Methodology
TGI Willilston Basin
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Targeted Geoscience Initiative II (TGI) Williston
Basin Architecture and hydrocarbon potential in
southwestern MB and southeastern SK

• Drillhole data is screened by Phanerozoic
  stratigraphers

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TGI Model - Data

• Five to eight deep, stratigraphically
  significant drillholes per township (10 km by 10
  km) were selected and re-picked by geologists
  (9000 wells over the study area).
• The resulting dataset of formation tops, plus a
  dataset of formation edges, form the basis of the
  TGI Williston Basin model.
• Data was available for 60 formations, however
  the key 42 were selected and modeled.

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TGI Model GOCAD Surface Modeling
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TGI Williston Basin 3D model
700 km
3000 m
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TGI Williston Basin 3D model
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Modeling Methodology
Western Canada Sedimentary Basin (WCSB)
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Geological Atlas of the WCSB
Tertiary
Cretaceous
Jurassic
Triassic
Permian
Carboniferous
Devonian
Ordovician/Silurian
Cambrian
Precambrian
Valuable resource, assists in modelling TGI
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Geological Atlas of the WCSB
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Modeling Methodology
Southwest Manitoba
Southeast Manitoba
TGI
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Modeling Methodology
Canada
International
USA
Southeast/Southwest Manitoba
Fargo/ Moorhead
TGI
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Modeling Issues
- In areas with a large number of drillholes, a 5
km n/s width merged onto a single cross-section
trace can make interpretation difficult
- In areas with a small number of drillholes, the
same 5 km cross-section trace can generate data
that aids interpolation
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Data Sharing Issues

• How to get 3D models out to the public?
• Static images of the model on the internet map
  server (IMS)
• Convert to VRML and serve
• Simplified version of the model
• Provide raw data?
• Public has paid for the work
• Manitoba government tries to make all data
  freely available to the public

• We use GOCAD for all of our modeling work
• - Very powerful modeling tool
• Great visualization capabilities
• But

• GOCAD does not have a free data viewer

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Pointset Curve Surface Solid Voxet (block
model) Sgrid
GEOCANDO
http//tu-freiberg.de/fakult3/geo/mageo/projekt_ge
ocando.html
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Questions? GREG.KELLER_at_GOV.MB.CA
More information about Manitobas 3-D Modeling is
available at http//www.gov.mb.ca/itm/mrd/geo/3dm
odel/index.html
More information about the TGI 3-D Model is
available at http//www.willistonTGI.com
More information about the Fargo/Moorhead 3-D
Model is available at http//www.geo.umn.edu/mgs/