Ians ogs slides
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The document discusses the Ontario Geological Survey's (OGS) work conducting 3D mapping of surficial aquifers in Ontario. The OGS is mapping regional aquifers to address issues like contaminated municipal water, inform legislation around source water protection, and characterize aquifer vulnerability. Mapping involves developing a conceptual geological framework, fieldwork, geophysics, drilling, and building 3D models of sediment packages. Final products include reports, datasets, maps, cross-sections and interactive tools to aid groundwater management, resource development, and scientific studies.
Ians ogs slides
- 1. 3D Sediment Aquifer Mapping Ontario, Canada Abigail Burt Ontario Geological Survey
- 2. Today’s Talk • Introduction • Why is the OGS doing 3-D mapping? • Where are we working? • What are the goals? • How do we go about 3-D mapping • What do we produce?
- 3. Why is the OGS doing 3-D mapping? • Contaminated municipal water • Walkerton Inquiry • Provincial legislation!!!!!
- 4. Legislation Source Water Protection Plans • Watershed characterization • Water budget • Aquifer recharge • Aquifer vulnerability • Well head protection areas • Threats to drinking water Greenbelt Act Places to Grow Act
- 5. Where are we working?
- 6. Build a 3D model of Quaternary deposits that form regional-scale aquifers and aquitards • Reconstruct the regional Quaternary history and develop a conceptual geological framework • Construct a 3D model of key sediment packages • Characterize the properties of modelled sediment packages
- 7. How do we go about 3-D mapping?
- 8. Build a Conceptual Framework
- 9. Fieldwork • Auger and probe holes • Pits and quarries • River and lake bluffs
- 12. Glaciolacustrine sediments Till Peat Shallow water glaciolacustrine Glaciolacustrine Outwash Peat Shallow water Beverly Swamp
- 14. Southern Wetlands Dune Reactivation Glaciolacustrine Sediments Peat Till Dune Reactivation Glaciolacustrine Sediments Peat 4440 BP 8235 BP
- 16. Till Deformed deep water glaciolacustrine sediments Shallow water glaciolacustrine sediments Shore Till Deformed deep water glaciolacustrine sediments Deep water glaciolacustrine sediments Shore
- 17. Ground-based gravity surveys • Show the least sensitivity to cultural interference. • Not affected by stratigraphy (velocity contrasts of stratigraphic units) and depth to water table. • Simple and cheap
- 20. Drilling!!!
- 22. Detailed Logs
- 23. Legacy Data
- 24. Reduce and translate Sand Sandy Quicksand Medium sand Coarse sand Sand New Term Original Term 1 Original Term 2 Original Term 3 Gravel Gravel Packed Water-bearing Sand Sand Sand Silt Sand Sand Soft Clean Clay Clay Sticky Soft Diamicton Clay Sand Gravel Diamicton Hardpan NA NA
- 25. Building a 3-D Model Plot borehole traces Digitize 3-D points (picks)
- 26. Building a 3-D Model Fill spaces with blocks Create 3-D wireframe surfaces
- 27. What really goes on…. Tales from the Orangeville Moraine
- 28. DEM
- 29. Drift Thickness
- 31. Surficial Geology We are a long way from Niagara… • Lots of till (green) • Lots of sand and gravel (orange and beige) • LANDFORMS!!!!
- 32. What about those tills? • Tiny windows into older glaciations • Some tills look different, some don’t • PSA, Chittick, HM, Pebbles, fabrics • LANDFORMS
- 33. Outwash! • Paleoflows (sediment source) • Flow velocity • Ice margins
- 34. Bars (no, not that kind of bar) Bar Front Bar core Waning Flow
- 37. Coarse
- 38. And fine
- 39. Stratigraphy!
- 40. Drilling!
- 42. Bedrock Surface
- 43. Older Sediments • Weathered bedrock and contact aquifer • Older tills (aquitards) • Stratified sediments overlying the tills (aquifers) SE 5 cm 5 cm 5 cm 5 cm
- 44. The magic of sub-till organics! 5 cm >52 200 54 500 +2 900 • Radiocarbon dating • Pollen / macrofossils
- 45. Late Wisconsin Glaciation • Early lobate flow • Main glaciation characterized by regional flow NW SE 5 cm 5 cm 5 cm
- 46. Breakup of Catfish Creek Ice • Ice thins and begins to break up • Glaciolacustrine sediments and fine- textured diamicton deposited • Rare coarse-textured glaciofluvial sediments NW SE 5 cm 5 cm 5 cm
- 47. Orangeville Moraine • Paleoflow directions to the southwest • Coarse-textured proximal sediments • Fine-textured distal sediments dominant NW SE
- 48. Ice from all directions • Port Bruce advance of Ontario, Huron and Simcoe lobe ice • Advanced over the flanks of the Orangeville moraine • Drumlins, streamlined landforms, till fabrics NW SE 5 cm 5 cm 5 cm
- 49. Final Advance • Advance of Ontario lobe ice • Paris moraine (end moraine) NW SE
- 50. What our clients want to know • Aquifer or aquitard? • Location / continuity? • Thickness / volume? • Surface elevation? • Pathways? • Characteristics? • Reliability?
- 51. The subsurface revealed! • Stratigraphy • Pathways?
- 53. Don’t over do it!
- 54. Are buried valleys important?
- 55. YES!!!
- 57. Monitor!
- 58. Products: guiding principles • Standardized from one project area to the next • Terminology and geologic conceptualizations need to be standardized to allow for merging of models • Products need to be useable by a wide range of clients • Need to release products that eliminate the need for high-end computers or software to use the data.
- 59. Products Groundwater Resource Studies Datamine exports of volumes and grids for hydrogeologists and geoscience specialists Interactive drillhole data
- 60. Maps and Cross-Sections Prepared cross-sections Aquifer recharge and vulnerability maps Structural contour and isopach maps
- 61. Cross-Section Viewer and Google Earth
- 62. Groundwater Applications • Source water protection • Search for new water supplies • Groundwater flow models • Tier 2 and 3 water budgets • Monitoring wells (PGMN) • Sanitary landfill planning • Remediation of Ontario’s brownfields • Nutrient management plans
- 63. Resource Applications • Protection of sensitive ecosystems • Environmental Bill of Rights • Geotechnical studies • Bridges and overpasses • Building foundations • Resource development • Search for buried aggregate
- 64. Scientific Applications • Stratigraphic studies • Improved regional framework • New radiocarbon dates • Climate Change • The past is the key to the future Measured sections, borehole logs and geophysical profiles are excellent primary data sources
- 65. Summary • Rural and urban Ontarians rely on overburden aquifers for their water supply. • The OGS is engaged in the effort to find, assess and protect Ontario’s groundwater resource through regional scale and targeted 3-D surficial aquifer mapping projects. • Each 3-D project addresses • Quaternary history • Conceptual framework • 3-D mapping • Interpretation • Groundwater resource reports, digital datasets, maps, cross-sections and Google Earth applications are key products.