Question

describe in brief how the formation of coal in earth

Answer 1

Most of the coal we use now wasformed about 300 million years ago, when much of the earth was covered by steamy swamps. As plants and trees died, their remains sank to the bottom of the swampy areas, making layers and layers of plant material and eventually forming a soggy, thick material called PEAT.

Answer 2

Coal formed millions of years ago when the earth was covered with huge swampy forests where plants - giant ferns, reeds and mosses - grew.  As the plants grew, some died and fell into the swamp waters.  New plants grew up to take their places and when these died still more grew.  In time, there was thick layer of dead plants rotting in the swamp.  The surface of the earth changed and water and dirt washed in, stopping to decaying process.  More plants grew up, but they too died and fell, forming separate layers.  After millions of years many layers had formed, one on top of the other.  The weight of the top layers and the water and dirt packed down the lower layers of plant matter.  Heat and pressure produced chemical and physical changes in the plant layers which forced out oxygen and left rich carbon deposits. In time, material that had been plants became coal.