What is Exploration
What is Exploration
Geochemistry?
Any method of exploration based on the systematic
systematic
y p y
y
measurement of one or more chemical properties of a
naturally occurring material to find abnormal chemical
patterns (anomalies) related to mineralization
patterns (anomalies) related to mineralization

Chemical Properties
• Trace concentration of the element of
interest
• Trace concentration of a related element
(pathfinder)
(pathfinder)
• Concentrations or ratios of groups of
elements
elements
• isotope ratios

Types of Materials
Types of Materials
• Rock (Lithogeochemistry)
Rock (Lithogeochemistry)
• Soil
G
• Gossan
• Glacial debris
• Vegetation (Geobotany, Biogeochemistry)
• Stream sediments
• Drainage water (Hydrochemistry)
• Vapor and aerosols
• Vapor and aerosols

Applied Geochemistry
• Agricultural geochemistry
• Environmental Geochemistry
Environmental Geochemistry
• Public health geochemistry
M i h i
• Marine geochemistry
• Geo-hazards prediction

Exploration

The different
stages in a
stages in a
Geochemical
S r e program:
Survey program:
1. Planning
2. Sampling
3. Analysis
4. Interpretation
5. Follow-up
5. Follow up

Scales of Surveys
Detailed
Reconnaissance

Reconnaissance Surveys
• Detect favorable indicators of ore
– provinces, districts, (ore bodies)
provinces, districts, (ore bodies)
• Large area - X0 to X0,000 km2
Sample densit 0 01 1 0 /km2
• Sample density - 0.01- 1.0 /km2
• Cost $1 to $10 per square mile
• Rapid, minimal samples, low cost

Reconnaissance Media
• Rocks
• Stream water and sediment
Stream water and sediment
• aerosols (airborne dust)
i ( i ll h hi )
• vegetation (especially photographic)
– geobotany and biogeochemistry
• Soils (rarely used because of cost)

Detailed Surveys
• Outline mineralized ground to pinpoint
source
– Locate area for trenching, drilling, etc.
• Small area - X - X0 km2
• Small area - X - X0 km
– Area selected by other methods
S l d it 0 01 1/
• Sample density - 0.01 - 1/m
• Cost $X00 to $X000 per square mile

Detailed Media
• Rocks
• Soils
Soils
• vegetation (biogeochemistry)
V ( il )
• Vapor surveys (soil gases)

Exposed Ore
Mass Transport
Ground Water
Halo

Leeched Ore
Leeched
Zone
Ground Water
Halo

Zoned Ore
Mass Transport
Ground Water
Halo

Blind Ore
Ground Water
Halo

Covered Ore Body
Gravel
Till
Volcanics
Unconformity

Locate the possible
p
source of the
hydrochemical anomaly
hydrochemical anomaly

A soil gas anomaly
over a uranium ore
vein
vein