Lithosphere
Introduction
The lithosphere is the 70-100 km thick topmost layer of the earth. The lithosphere consists of plates (major and minor) which are moving relative to each other at a very slow rate (2-5 cm/ year) over the aesthonosphere which extends up to a depth of 700km. The surface of the lithosphere is called land. Land, in a broader sense, encompasses all the natural materials present on the earth’s surface composed of rocks and soil. Rock is the natural aggregate of minerals. Variation of rock is due to the different mineralogical combinations. Rocks are of three types: Igneous (formed by solidification of magmai.e. granite, basalt etc); Sedimentary (formed by consolidation of materials carried out by wind, river, glacier etc. e.g. sad stone, lime stone etc) and Metamorphic(formed by transformation of igneous and sedimentary rocks, e.g. gneiss, marble, slate etc.). Physical, chemical and biological processes, by their constant interaction with the different rock types, produce the thin outer skinny layer called soil which contains living and non – living materials. Plants are grown well in the soil containing rich macro and micro (trace elements) nutrients. Macro-nutrients include nitrogen (N), phosphorous (P), potassium (K), calcium (Ca), magnesium (Mg) and sulphur (S). Trace elements include, iron (Fe), manganese (Mn), copper (Cu) and zinc (Zn). Healthy soil is a combination of minerals, rock, water, air, organic matter (plant and animal residue), microorganisms, including bacteria, fungi and protozoa and a variety of insects and worms. This intricate web carries out a process that continually replenishes the soil and maintains long-term soil fertility. A healthy soil should have the mechanism of supplying the nutrients produced by natural weathering processes as well as mediated by organisms to the plants perennially for sustainability. For optimum plant growth, soil must be capable of storing these nutrients and transferring them to the root surface for uptake by plants.
Soil is one of our most precious natural resources, as it integrates all parts of the ecosystem and provides a medium for plant growth, filters water, decomposes waste, stores heat, and exchanges gases. Soil is alive; it is the home to billions of micro- and macroscopic organisms. It is a material used for construction, medicine, and art. It produces a snapshot of the geologic, climatic, biological, and human history at the place that they are found. Unfortunately, there is a limited amount of soil that can actually be used for growing food, and all of the other uses that we require it for. When improperly managed, soil can become eroded, polluted, or destroyed. It can also cause damage to other parts of the ecosystem.
To understand the nature of soil, one has to have knowledge on rocks and their mineral composition. Generally, mineral content of soil is referred to as the elements that are responsible for growth of plants. In fact, rocks are made of minerals (structured atomic arrangement of elements in a crystal form) that in turn disintegrate into different soil components that are easily taken by the plants and used for their better growth. The mobility of nutrients from rock to soil is decided by the geological processes that initiate weathering. To understand the mobility and distribution of micro and macronutrients (calcium, potassium, sodium, nickel, zinc) in the soil system will certainly lead us to manage agricultural practices. The soil system is affected by influences of man intervention as well as natural processes. The removal of topsoil by cutting down the forests and banned agricultural practices would force us to live in environmentally adverse conditions. The environmental degradation of both soil and land makes our planet stressful and initiate us to think over sustainable development. As our interference with natural processes cause many situations unfit for our well being and also for the well being of future generations in stake. In this context we have to look for alternative solutions for enrichment and sustainability of soil as resource mine and in order to sustain for long new management methods are to be adopted.
Collecting data on the past and present land use practices would help us to predict the future pattern of change, which would throw light on our sustainable development. There are diseases caused by the excess presence of certain toxic elements such as fluoride, arsenic and selenium in the biological system introduced through rocks to water and to soil. A Systematic documenting of temporal and spatial distribution of diseases provides a better database for identifying the root cause for their respective diseases.
Project 1
Collection and identification of important economic minerals and the preparation of mineral distribution of topographical map.
Introduction
The use of minerals has been instrumental in raising the standard of living of mankind.
The sophisticated world of today is largely the result of the large use of minerals.Fertilizers, food, and the source of power like coal, petroleum, natural gas, and even atomic energy are derived from minerals. Countless other necessities of life, like automobiles, aero plane, ships, modern communications and chemicals are all in some wayformed out of minerals.
All engineering and structural materials, machinery, plants, equipments and anything from pins to planes are manufactured from the metals and their innumerable alloys. Iron and steel and their special alloys are the most common metals which largely enter in to the fabrication industry. Other metals which are required most commonly are aluminum, copper, lead, zinc and tin. There is not a single industry which can go without minerals or their products. Minerals thus are a part and parcel of our daily life. All this minerals are produce of rocks. It will be a good exercise for the school children to study this minerals in terms of their geologic and geographic distribution, mode of formation,and its uses. Children can very well attempt for making a mineral distribution map.
Objectives
1. To identify host rock and associated ore minerals
2. Demarcate geologic /geographic distribution (occurance)
3. To find out economic importance / uses
Materials required
- Topo-sheet
- Hammer and chisel
- Geological field guide book
Methodology
Procuring the toposheet of the area to be investigated.
Identifying the extent of the area to be sampled and then preparing a plan for making traverses in order to collect the rock. And the mineral samples from the field. Mark the sampling locations on the toposheet. Identify the type of rock and minerals present in them. Plot the minerals in a geographical area to mark their distribution. Evaluate the uses of the studied minerals.
Observations.
- Variation in distribution of rocks and mineral occurrence of the selected area.
- Preparation of rock and mineral distribution map based on the data collected.
Follow up activities
The childrens can further consult the nearby geology department for verification and additional information.
Project 2.
Identification of Structural elements found in the earth crust and their implications
Introduction
The earth surface is expressed in the form of mountains valleys,plateaus and ocean basins. These outer expressions are as a result of the plate ( tortionally rigid part/cover of the earth) movements i.e. the movement of the crust of the earth due to mantle convection. Because of the plate collision earth crust has undergone deformation producing folds, faults and joints etc. The buckling processes of rocks produce mountain and valleys. Himalayan mountain range is a good example of a folded chain of mountains produced by the collision of the Indian and Eurasian plates. The Narmada-son- Damodar graben is a valley produced due to faulting. The processes of folding and faulting may be associated with diastrophic phenomena like earth quakes tsunamis etc. The children can observe the structural features associated with rocks present in their area and investigate the relationship between these structures and the land pump/ landscape of the region. Folds, faults and joints may also serve as good sites for mineralization. For example, faults creates structural traps of petroleum; faults and joints makes the sites for mineralization of gold, copper, lead and zinc etc. when the rocks are well jointed there is high possibility of the formation of an under ground water reservoir (aquifer).
Objectives:
- To identify the structural features, folds, faults and joints in the study area.
- To understand the relationship between these structures and the land forms / landscapes
- To find out mineralization / ground water associated these structures.
Material required
Clinometer compass
Geological field guide
Hammer Pencil etc.
Methodology
The children should carefully make traverses all along the area selected for this purpose. Find out the changes in the rock type, in the courses of river systems, repetitions and omissions of rock strata/ layers, change in attitude of the rock beds etc. The identification of such structures may well be observed in the hill cuts and railway cuts, road cuts and well / trench cuts etc. The type of folds, faults and joints are to be recorded in terms of their orientations, attitudes and size. Such an observation would provide the database for the classification of this structural elements and ultimately to find their importance.
Observation:
Observation of linearity/ parallelism of river patterns, sudden change in rock type could indicate the presence of faults. If there are marked changes in the angle of inclination of dipping strata, then the presence of folds is there. Identification of such deformational structures would help to understand the underlying the structural architecture of the area. Children should observe the shape and geometry of the structure.
Implications
Presence of structures like folds, faults and joints certainly indicate that the rocks having such structures have undergone brittle deformation, that the rock have passed their elastic limits, due to application of natural stresses caused by the movement of the crust of the earth. Further, the occurrence of this structures implies the possibility to find out natural mineral deposit.
Project 3
Collection and identification of fossils
Introduction
Neontology incorporates the study of existing life, while the Paleontology is concerned with the ancient pre-historic life. It is paleontology, the study of fossils (Latin word fosilis meaning “dug-up”), with the help of which the past history of earth since the time from which the life come into existence on this earth could be worked out. Fossils provide much needed information about the history of the earth and evolution of life through out the geologic times. Besides, the fossil collection to many people is most enjoyable, fascinating and rewarding hobby. The presence of fossil plant would suggest a land environment, an assemblageof freshwater snails and leaves indicate the presence of a lake in the past, deltas may be indicated by the mingling of marine and land fauna and floras. Fossilized marine organisms marine organisms would indicate the temperature, depth and salinity of the past marine environment with which the fossils were associated. They are also valuable tools for a stratigrapher and could provide important clues to the age of rocks containing them. Besides, Palynology, the study of spores and pollens is important as the rock formations that contain such micro-fossils would indicate possible reservoirs of petroleum.
In this context, young children will find interesting to collect fossils from the sedimentary rocks that are exposed in the nearby area. This exercise will kindle their interest in becoming an amateur fossil collector as well as to understand the paleo-environment - paleoecology, paleoclimate, paleogeography, etc.
Objective
- To initiate the young minds for scientific method of classifying the fossils.
- To understand and appreciate the importance of fossils with reference to earth’s history and economic importance.
Methodolgy
The first step in studying the fossil is to identify the sedimentary rocks which are promising to contain fossils. The carbonate rocks, sandstones and silt are potential sedimentary rocks for observing the fossil fuel content. Once they have identified the suitable sedimentary rocks for their investigation, they have to make traverse all along the terrain in order to observe the fossils. In the beginning the children may find difficulty in identifying the fossils, but in due course they will be tuned to locate them. River beds, road cut hill slopes are suitable for finding the fossils. If they find any resemblance with the present organisms, they can classify the fossils tentatively, otherwise they should collect enough fossils for further studies. The collected fossils are to be classified, labeled and put into proper order.
Materials required
- Fossil field guide
- Pick Hammer
- Chisel Hammer
- Collecting bag
- Hand lens
- Sample storing bag with label
- Wrapping material
- Adhesive tape
- Stiff-bristles
- Camera
Observations
The fossils that were collected in the field have to be cleaned properly for identification. From proper observation, children can be able to understand whether the fossils are marine, continental or deltaic. Accordingly they can draw conclusion about their paleoecology, paleoclimate, etc.
Interpretation
Environmental conditions responsible for the existence of the animals/plant could be learnt by studying the fossils properly. That could give us valid point to understand how the earth was changing from the past.
Project 4
Energy sources - Fossil
Introduction
The first and the earliest form of energy source used by primitive people was the food they ate. Then woo-fueled fire produced energy for cooking, heat, light and protection from predators. Then it became the fossil fuels that eventually met the energy demand of human being for his well being. The term fossil refers to any remains of ancient life. Energy is stored in the chemical bonds of the organic compounds of living organisms. The fossil fuels are those energy sources that form from the remains of once living organisms. These includes oil, natural gas, coal and fuels derived from oil shale and tar sand. When we burn them, we are using that stored energy. In this context, young children will find interest to learn about the different kinds of fossil fuels, their occurrence and distribution in the earth as well as usefulness they provide to man.
Objective
- To identify sources of fossil fuels
- To correlate the impact of fossil fuel on mankind
Methodology
- Observing oil drilling and coal mining areas so as to understand the rock types and structures which host the fossil fuels.
- Classification of various types of fossil fuels found in their area.
- Analyse the advantage and disadvantage of use of fossil fuels.
From the study children may understand how fossil fuels were formed, with which rocks they are occurring and the positive and the negative impacts given by the use of fossil fuels.
Project 5
Introduction
Soil is defined in different ways for different purposes. Soil scientists define the term soil as materials capable of supporting the plant growth. Conventionally the term soil implies little transportation away from the site at which the soil formed. Soil is the outcome of withering processes which encompasses a variety of chemical, physical and biological processes acting to break down to rock. The relative importance of different kind of weathering processes is largely determined by climate. Climate, topography and the composition of the materials from which the soil is formed, the activity of the organisms, and time govern a soil’s final composition. A vertical section through all the constituent horizons of a soil from the surface to the relatively unaltered parent materials is called the soil profile. The soil profile can be divided into top soil, sub-soil, weathered parent material and bed rock. The soil profile varies in different areas due to the land use variation. Due to the biological activities, the top soil contains more humus. When you go down from top soil to bed rock the content of humus decreases and at certain points you may not find any organic matter except disintegrated original bed rock. These sequences can be well documented in the road cuttings and well cuttings. The kind of study will initiate the children to understand how the soil evolved from the barren rocks.
Objectives
- To identify and delineate the horizon of different physically distinguished part of the soil using parameters such as the size of the grains, colour, etc.
- To mark out the eroded soil horizons
- To understand the physical, chemical and biological activities those are responsible for soil erosion.
Methodology
The children can identify the places where the cuttings were made in the subsurface. Once it is identified children can observe the different soil layering based on physical parameters such as grain size, clay content. Children can measure the thickness of the different layering can be compared with one area profile with another so that they can observe the soil layering is not uniform in all the places. This in turn helps children to understand the land use pattern and soil thickness relationship.