Sedimentary GeologySedimentary GeologyGeos 240 – Chapter 2Geos 240 – Chapter 2Collecting the DataCollecting the Data

Part 2 – Regional Geophysical Part 2 – Regional Geophysical DataData

Dr. Tark HamiltonDr. Tark HamiltonCamosun CollegeCamosun College

Collecting the DataCollecting the Data Stratigraphic Sections from Surface Stratigraphic Sections from Surface

OutcropsOutcrops Petrophysical logging of boreholesPetrophysical logging of boreholes Well cuttings and coresWell cuttings and cores Regional Geophysics (Seismic, Gravity, Regional Geophysics (Seismic, Gravity,

Magnetics, Electro-Magnetics, Ground Magnetics, Electro-Magnetics, Ground Penetrating Radar)Penetrating Radar)

Labwork on sediments, rocks, fossils, fluidsLabwork on sediments, rocks, fossils, fluids Computer/Office: Mapping, Interpretation Computer/Office: Mapping, Interpretation

& Modelling& Modelling

Multi-Channel Reflection Multi-Channel Reflection SeismicSeismic

Sound source: explosive, vibroseisSound source: explosive, vibroseis Geophone arrays ~21 per group to enhance S/nGeophone arrays ~21 per group to enhance S/n

Vibroseis Crews: Source Vibroseis Crews: Source TrucksTrucks

Seismic Sections need Seismic Sections need Well TiesWell Ties

Time Time Depth conversion & marker beds Depth conversion & marker beds

Contrasts between Contrasts between Seismic FaciesSeismic Facies

Deep Marine Basin River Channels

Seismic versus Log Seismic versus Log Scales!Scales!

Seismic = Regional, Logs = Local featuresSeismic = Regional, Logs = Local features

Seismic Section NW Africa Seismic Section NW Africa (Morocco)(Morocco)

Rifting of Pangea ~205 Ma Triassic/Lower Jurassic through CretaceousRifting of Pangea ~205 Ma Triassic/Lower Jurassic through Cretaceous Drift phase Tertiary, draping of older inactive structuresDrift phase Tertiary, draping of older inactive structures

3D-Seismic for detailed 3D-Seismic for detailed areasareas

Generate structure volumes, cross sections & Generate structure volumes, cross sections & subsurface mapssubsurface maps

GPR – Ground GPR – Ground Penetrating RadarPenetrating Radar

Radar Frequency electromagnetic pulsesRadar Frequency electromagnetic pulses Reflect off of Water TableReflect off of Water Table Density contrasts, buried walls, graves, channels, vaults, Density contrasts, buried walls, graves, channels, vaults,

subways!subways!

Core Strip Log & GPR Section: Core Strip Log & GPR Section: AlaskaAlaska

Nested channels, migrating barsNested channels, migrating bars Gas sands on North Slope, also for placers, aquifersGas sands on North Slope, also for placers, aquifers

Offshore Rigs & DrillingOffshore Rigs & Drilling

THIS COVERS MOST THIS COVERS MOST CONVENTIONAL CONVENTIONAL

SEDIMENTARY GEOLOGY SEDIMENTARY GEOLOGY FOR RESOURCE FOR RESOURCE EXPLORATIONEXPLORATION

Mining Exploration, Environmental, Mining Exploration, Environmental, Geotechnical, Aquifer, Academic & Geotechnical, Aquifer, Academic & Archeological studies all do similar things but Archeological studies all do similar things but with smaller tools, areas of interest and way with smaller tools, areas of interest and way smaller budgets!smaller budgets!