Month: January 2022

Some important sedimentary rocks

Some important sedimentary rocks are as under; (1). Conglomerate Nature: Consolidated gravels. Colour variable. Mineral Composition: Rounded pebbles are set in a fine-grained matrix. The matrix commonly consists of sand and silt and it is cemented by silica, calcium carbonate, or iron oxide. The individual pebbles may be entirely composed of quartz or maybe rock

Composition of sedimentary rocks

The composition of sedimentary rocks is of two types; chemical composition and mineral composition. The chemical composition of a substance means the aggregate chemicals that constitute that substance, while the presence of different types of minerals illustrates the mineral composition of that substance. Here we will discuss the two types of compositions separately. (1). Chemical

Structural features of sedimentary rocks

Sedimentary rocks constitute about 75% of the total exposed rocks on the earth’s crust. They are found in different forms/structures. The important structural features of sedimentary rocks are stratification, lamination, graded bedding, current bedding, ripple marks. Besides these, there are some minor structures such as mud cracks, rain prints, tracks of terrestrial animals, etc. These

Types and examples of igneous rocks

There are two basic types of igneous rocks i.e. Intrusive Igneous rocks and Extrusive igneous rocks. Intrusive igneous rocks are those, which crystallize below the earth’s surface, and remain buried until the earth’s surface is eroded, while extruded igneous rocks are those, which erupt onto the surface, where they cool quickly to form small crystals.

Origin of the Igneous Rocks

We can find the mineral composition of igneous rocks by means of studying the chemical composition of the magma from which the rock has been crystallized. Because there is a large variety of igneous rocks, thus it was originally thought an equally large variety of magma also existed. But the later research found out that