Question

Describe in brief the formation of coal in the earth

Answer 1

Like oil and natural gas, coal is a fossil fuel. It started forming over 350 million years ago, through the transformation of organic plant matter. It all starts with a swamp on the edge of a sedimentary basin, such as a lagoon or a lake. Tectonic activity raises sea levels, covering and killing vegetation. Plant debris accumulates and is buried under layers of mud and sand in a process known as sedimentation. This protects the debris from the air and slows down the decomposition process. The vegetation grows back, until the next flooding. The sedimentary basin gradually sinks under the weight of the sediments, and the layers of dead plants are subjected to rising temperatures that gradually “cook” them, leading to their transformation. The different stages of sedimentation turn cellulose, the main component of wood, from peat to lignite (brown coal), then sub-bituminous coal, followed by bituminous coal and, finally, anthracite. Anthracite has the highest carbon content Geological Time For The Formation of Coal The most favorable conditions for the formation of coal occurred 360 million to 290 million years ago, during the Carboniferous (“coal-bearing”) Period. However, lesser amounts continued to form in some parts of the Earth during all subsequent periods, in particular the Permian (290 million to 250 million years ago), and throughout the Mesozoic Era (250 million to 65 million years ago). The accumulated plant matter buried during the Tertiary Era — less than 65 million years ago — is generally less mature. It is often in the form of lignite, which still contains a high content of volatile matter (bitumen and decayed wood) and has a lower carbon content. However, there is also some higher rank coal from the Tertiary Era, coal that matured early, heated by plate tectonics. Examples of this include Paleocene coal (65 to 55 million years ago), found in Columbia and Venezuela, and Miocene coal (20 million years ago), found in Indonesia. In Indonesia, where the geothermal gradient is very high, anthracite lies close to the surface. However, the deposits in the Moscow Basin have never gone beyond the lignite stage. It’s too cold! Finally, recent accumulations (from 10,000 years ago to today) are very rich in fibrous debris known as peat, in which the shapes of branches and roots can still be discerned. This material was not buried deep enough to contain elemental carbon.

Answer 2

Coal was formed from plants and animal got buried deep under the earth crust over a large period of time the chemical and physical properties of this plants remains were changed throw geographical actions that leads to the certain of these soil material, the process of conversion of the plants material into coal . The formation of coal depend on the quality of the coal , As you know that there are four variety of coal depending upon the occurrence of coal and formation of coal, the types of coal depend on the temperature and pressure condition and the time period of formation there are four different varieties of coal, they are as follows ------»

★ PEAT :------ It is imperia quality of the coal it is soft brown substance having 30% of carbon it is earliest stage during the formation of coal.

★ LIGNITE :----- It contains 38% of carbon it is used for making on other types of fuels as well as used for electricity production, Example as :----- used for electric power generation, (NTPC)......

★ BITUMINOUS :----- It has 68% of carbon it is used for making another types of fuel as well as used for electricity production example as fuel and coke.

★ ANTHRACITE :----- It has a hard coal and it contains 90% of carbon it is quite hard, it is best quality of coal.

The variety of coal depend upon the formation of coal from each other in terms of their -----›

• Content a volatile material
• Percentage of carbon
• Moisture
• Other (Impurities) element