Geophysical and geochemical methods can be used to obtain information about areas with poor outcrop or mature exploration areas. Magnetic, gravity, electromagnetic, electric, and radiometric methods are common geophysical techniques that investigate physical parameters like magnetic susceptibility, density, electrical conductivity, apparent resistivity, and natural radioactivity. Magnetic and gravity methods study magnetic and density anomalies caused by rocks containing magnetic minerals or differences in density. Electrical surveys introduce electric currents into the ground to measure resistance. Geochemical methods involve analyzing chemical properties of materials like sediments, soils, rocks, water, and plants to detect ore bodies, with stream sediment sampling being a common technique.

1. Geophysical and
Geochemical Methods
Prepared by Edoson
Ernesto

2. Outline

3. Introduction
In prospective areas where outcrop is poor, or
mature exploration areas, the use of
geophysical and geochemical techniques are
necessary to get information about of that
areas where the observation/studies cannot
be performed directly.
Based on the aim of the survey (study of the
regional geology or to locate ore), one
specific geophysical or geochemical technic
might be used.

4. Geophysical methods
Method Physical parameter
Magnetic Magnetic susceptibility
Gravity Density
Electromagnetic Electrical conductivity
Electric Apparent resistivity
Radiometry Natural radioactivity

5. Magnetic and Gravity Methods
known as the “Potential Fields” methods, are used in natural-resource exploration to help locate
mineral, petroleum and groundwater resources.
Magnetic Methods
The magnetic methods investigate magnetic anomalies caused by the earths magnetic field. And
this magnetic anomalies are caused by the rocks which contain enough magnetic minerals such
magnetite, hematite or ilmenite.
The instrument used for magnetic surveys is called a magnetometer, which record disturbances in
the earth’s magnetic field caused by magnetically susceptible rocks.

6. Gravity Methods

7. Electrical methods
Electrical surveys are all ground based. In their
simplest form, they put an electric current directly
into the ground and measure, by means of arrays
of receivers, the resistance of the rocks through
which the current passes.
They are mostly useful for ore bodies exploration

8. Geochemical Methods
The geochemical exploration methods consist of carrying out chemical analyzes of different geological
and biological materials (sediments of streams, soils, rocks, waters and plants) in a systematic way.
1. Stream Sediment Sampling
It consists in measure semimobile and mobile sediments from river or stream sediments.
In so many case, this technique is used to detect ore bodies;
The following conditions should be met for the effectiveness of this technique:
 The area should be one of active erosion with an incised drainage pattern.
 Only the active sediment on the stream bed should be sampled.
 As much detail as possible about the sample site should be recorded.

9. Geochemical methods

10. Conclusion

11. References

12. Thank You