Describe the modern methods employed for the exploration of natural resources.

Describe the modern methods employed for the exploration of natural resources.

Answer:

In olden days discovery of minerals and oil was purely accidental. People use to come across the hidden treasures of the earth while tilling land for agriculture or construction. These days much of the exploration is done by the analysis of photographs taken from aircraft or spacecraft and other data supplied by the sensors mounted on these vehicles by a method called ‘remote sensing’.  Remote sensing is a method of collecting information about ground objects like soil, water, vegetation, and minerals, from a remote place, such as an aircraft or a satellite. This technique not only enables us to locate various resources but also helps us to know about their quantity and quality and monitoring deforestation.

 The simplest device could be a camera carried by an airplane to photograph large areas of land systematically. Television cameras could be mounted on satellites and they could take pictures showing details of clouds, water, forests or buildings on the earth. Both these are optical methods of remote sensing because visible light is used by the cameras. But one could send out radio waves from the satellite and observe how they are reflected or absorbed on the surface of the earth. Similarly, infra-red signals can be sent from the satellite and reflections studied to reveal the nature of the reflecting surface.

Remote sensing device is used in the exploration of various natural resources.

Remote sensing of water resources

Radio waves of the shortest wavelengths are called ‘gamma rays’. These are given off by atoms of several elements. As a result, the ground soil sends out gamma rays which can be picked up by detectors in airplanes or satellites. This emission is affected by the presence of moisture or water in the soil and hence it can be easily detected if the soil holds water. Moreover, in the pictures taken from space, the wet soil will have an altogether different appearance compared to dry or waterless soil. Due to the presence of moisture, the water-rich soil will not only show day time variation in temperature on its surface but will also have a cover of vegetation.

Survey of the vegetation cover

Vegetation cover can be surveyed by measuring and analyzing infra-red reflection, or with the help of photographs. The density of vegetation, shape, and size of the plants and even the size, orientation and health of the leaves can be studied from afar. The pattern of seasonal growth of deciduous trees is different from that of coniferous trees like pine and deodar and thus the difference can be detected in the photos taken by the spacecraft. By measuring ground temperature from a distance, the presence or absence of vegetation can be detected.

Search for mineral deposits

Aerial photos and satellite pictures show very clearly if there is a break in the continuity of layers of rock or other unusual features on the surface of the earth. The distinctive linear features are found to be very common centres where mineral deposits and groundwater accumulated. Radio waves and magnetic measurements also provide information about minerals and oil under the surface.