Posted on Leave a comment

Sedimentary Rocks.

What Is Sedimentary Rock , Sedimentary Rocks Formation, Sedimentary Rocks  are about 80% of rocks on the Surface.

What is/are Sedimentary Rocks.

When Rocks are weathered and eroded, they break down into smaller pieces of rock or Mineral.

This  Mineral rock is called Sediment, it is transported to a new site in many different ways like by Sea- River Beds, Wind, Water. and more.

Water Transport. Swift moving water , erosion and the prime means of transporting sediment to be deposited elsewhere.

Sediment are deposited into layers which become buried and compacted.

Sedimentary Rocks Formation

Over Time the particles are cemented together to form a solid new rock. Known as a sedimentary Rocks.

In some rocks you can see the different layers .

Examples Sedimentary Rocks Are.

Sandstone Rock.

The individual mineral grains that make up sandstone can be seen.  Grains are partially rounded as a result of abrasion during transport.

Sandstone Rocks are made by Cementing Together of grains of sand, their texture varies. The red Sandstone is formed in the desert . The Quartz grains are rounded and polished by the wind .  The Grains in grit are more angular as they were buried quickly, before they could be smoothed by rubbing.


Limestone Rock

Some Limestone are very compact, while others are grainy or friable.  Many Have sedimentary structures such as cross bedding and ripple marks. Properties are Rock Type-Marine, chemical, sedimentary. Fossils– Marine and freshwater invertebrates.  Major Minerals– Calcite.  Minor Minerals– Aragonite, Dolomite, Siderite, Quarts, Pyrite.  Colour– White, Grey, Pink. Texture– Fine to medium, angular to round.

Conglomerate Sedimentary Rock

Conglomerate Sedimentary Rock

The Pebbles in this Rock were rounded by water as they were rolled about at the bottom of the river or sea. After they were buried, they gradually became cemented together to form a rock known as conglomerate.

Clay Dirt/Rock.

red clay.

Formed of very fine grains that cannot be seen by the naked eye, clay feels sticky when wet. Colours grey, black, white, yellowish, and red. When it is compacted and all the water forced out of it, it forms hard rocks called mudstones or shale.  Red Dirt Is clay . You have to take top layer of dirt off, mix with water to get clay.

Clay being used to make a bowl



Halite Sedimentary Rock

Evaporites . Some Sedimentary rocks are formed from the evaporation of saline waters. Example of these include Gypsum and Halite, the latter being more commonly known as rock salt, from which we get table salt. Gypsum is used to make Plaster of Paris, and in its massive form is called alabaster. Both Halite and Gypsum are minerals that can be found in large deposits worldwide at sites where evaporation of sea water has occurred.


Shale is one of the most abundant Sedimentary Rocks, Shale consists of silt- and clay size particles deposited by gentle transporting currents, and laid down on deep-ocean floors, basins of shallow seas, and river floodplains.

Shale Differ from mudstones in that they are easy to splitinto layers. Most shale occurs in widespread sheets up to several metres thick, they are also found thinly interbedded with layers of sandstone or limestone. Shale consist of a high percentage of clay minerals, substantial amounts of Quartz, and smaller quantities of feldspars, iron oxides, carbonates, fossils, and organic matter. Reddish and purple shales result from presence of hematite and goethite, blue, green, and black from ferrous iron, grey or yellowish from calcite.

Bedded Volcanic Ash.

Stripes layers of Volcanic Ash.

In many Sedimentary Rocks it is possible to Distinguish the individual layers od sediments as they visible bands. Stripes layers of Volcanic Ash.





Leave a Reply

Your email address will not be published.