Skip to main content

Rock Formation

A rock may be defined as a hard compact mass made up of cluster of primary or secondary minerals. The primary minerals are those that are as they were made in nature. Some of them are Quartz, Olivine, Pyroxene, Hornblende, Biotite, Muscovite and feldspar. On the other hand, secondary minerals consists of particles worn out from original minerals which have combined with other elements. They exist in form of:
(i) Oxide such as those of magnesium, Iron and Aluminum.
(ii) Sulphates and carbonates of Iron, Magnesium and Calcium.
(iii) Clay minerals such as the silicate clays and the hydrous Oxide.
  TYPES OF ROCKS
(i) Igneous rock
(ii) sedimentary rock
(iii) Metamorphic rock.
Based on their chemical composition, we have basic and acidic rocks. Granite is a very good example of an acid rock.
PROCESSES OF ROCK FORMATION
IGNEOUS ROCK :This is formed through the process of cooling and hardening of the molten magma. This molten magna is confined deep down below the earth crust under a great pressure. If there is a crack in the earth crust due to earth movement or volcanic eruption, the confined molten magna is pushed out of its base near or on the surface of the earth. At times, the molten magna fails to push out to the surface of the earth before cooling and hardening. Under this condition, the molten magna has enough time to cool and harden into a rock. Big minerals grains develop in form of crystals. These make the rock to be coarse. Gabbro, Granite and Diorite are examples of this type of rock. They are also known as plutonic rocks.

SEDIMENTARY ROCK
These rocks are formed in various ways. However the major process of their formation involves the transportation, deposition and hardening of the deposited material. Natural agents like wind, rain, flood, river or stream and ice help in transporting particles worn out from other rocks. Some sedimentary rock can also result from the deposition and hardening of the skeletons and shells of sea organism such as fishes, snails, corals and oysters. These organisms, when alive, derive calcium carbonate from the sea water and use it to form their skeletons. Sea or Ocean waves causes the remains of these sea animals to accumulate into heaps in cycles. These decompose and get compressed with time to form rocks such as chalk or limestone. 
METAMORPHIC ROCKS
The process involves here is that of Change of already formed rocks due to the action of heat and or pressure. For instance, if igneous or sedimentary rock is exposed to intense heat and, or pressure or to some chemical solution, it changes its nature. 
This change in nature is a type of metamorphosis. As metamorphism takes place, sandstone changes to quartzite, limestone changes to marble, shale is changed to slate. Schist and Gneiss are other examples of metamorphic rocks. 

Comments

Post a Comment

Popular posts from this blog

Why kids run away

Why Kids Run Away Remember how you felt the last time you got in a big fight with your parents or one of your brothers or sisters? That kind of anger and hurt can be what pushes someone to run away from home.These are problems faced by lots of kids and teens — and there are ways to deal with all of these problems besides running away. Kids who think about running away might not know how to solve tough problems or don't have adults to help them. Sometimes a really big problem can make it seem like running away is the only choice. Unfortunately, the problems kids hope to escape by running away are replaced by other — sometimes even bigger — problems of life on the streets. When you think about running away, you probably imagine that there will be no more rules, no parent to tell you what to do, no more fights. Sounds great and exciting, right? In reality, running away is anything but fun. Kids and teens who run away face new problems like not having any money, food to eat, a s
Post a Comment
Read more

Handmade Tiles

Clay can be excavated, moulded and burned without any expensive or elaborate machinery and for centuries clay roofing tiles have been used. There are two qualities of tile: Hand made tiles are moulded from a sandy clay which is pressed into shape by hand pressure so that even if some form of screw press is used the clay will not be heavily compacted. During burning the tiles shrink and there are quite noticeable variations which give a tiled roof attractive appearance. The tiles vary in colour from light brick red to almost black and many of the more expensive tiles are sand faced produce the rough texture which is popular.     Handmade tiles fairly readily absorb water and should not be laid at a pitch of less than 45°to horizontal. If laid at a less pitch these tiles may become saturated in winter and frost will then cause them to disintegrate.      Machine pressed tiles are made from selected pure clays which are thoroughly ground to a fine condition. The clay is mixed with
Post a Comment
Read more

Reading for word pictures

Writers use many devices to enable the reader to follow the main points of a story. One of these devices employed specially in narrative or story writing is the use of word pictures. Descriptions are built up in such a way, with the addition of details, that the active reader is able to visualize in his mind's eye the scenes the writer set out to create. This is why story reading provides so much individual pleasure. Each individual takes from the story something proportional to what he has put into it. If you read with interest and curiosity, then you will find many word pictures to stimulate your imagination. If, on the other hand, you read passively, letting your eyes and mind glide Over the page, then you will overlook many word pictures and consequently, lose some of the meaning. E.g"it was one January morning, very early a pinching, frosty morning (feeling) the cove all grey with hoar-frost(sight), the ripple lapping softly on the stones(sound), the sun still low and tou
Post a Comment
Read more