Sedimentary rocks, which are formed from the sediments of other rocks and materials, form via different methods. These processes include clastic sedimentation, chemical sedimentation and biochemical sedimentation.

Sedimentary rocks are formed on or near the Earth’s surface, in contrast to metamorphic and igneous rocks, which are formed deep within the Earth. The most important geological processes that lead to the creation of sedimentary rocks are erosion, weathering, dissolution, precipitation, and lithification.

Also, sedimentary rocks are generally less hard than igneous or metamorphic rocks – this is because the lithification process (how a sedimentary rock becomes a rock) does not involve heat or pressure, and sedimentary rocks are kind of just “smooshed” together.

The age of the sedimentary layer is defined as the time elapsed since the material was deposited. In the Park we have many sedimentary rock units that are only a few million years old, or less, but that nevertheless contain particles (small rock fragments or mineral grains) that are over 100 million years old.

Sedimentary rocks are largely found on the Earth’s surface. They cover 75% area of the Earth. These rocks are generally not crystalline in nature. They are soft and have many layers as they are formed due to the deposition of sediments.

Bedding is often the most obvious feature of a sedimentary rock and consists of lines called bedding planes, which mark the boundaries of different layers of sediment. Most sediments were deposited along a flat surface that was roughly parallel with the depositional surface.

Ripple marks and mud cracks are the common features of sedimentary rocks. Also, most of sedimentary rocks contains fossils.

Fun Facts about Sedimentary Rocks for Kids

• Sandstone is made from grains of sand that have melded together over time, or lithified.
• Sedimentary rock often contains fossils of plants and animals millions of years old.
• Limestone is often made from the fossilized remains of ocean life that died millions of years ago.

Sedimentary Rocks. Sedimentary rocks are formed from broken down bits of other rocks or even from the remains of plants or animals. The little pieces collect in low-lying areas by lakes, oceans, and deserts. They are then compressed back into rock by the weight of the materials around them and on top of them.

Shale

Rock salt is a chemical sedimentary rock formed by the evaporation of seawater and the precipitation of halite.

Sedimentary rocks Petroleum may occur in any porous rock, but it is usually found in sedimentary rocks such as sandstone or limestone. Sandstones, because of the inherent porosity between their grains, often become excellent reservoirs for oil or natural gas. …

Granite is the oldest igneous rock in the world, believed to have been formed as long as 300 million years ago.

Hardness and Durability: Granite is harder than marble, so it is more resistant to chips and scratches. Both marble and granite countertops are quite durable, but ONLY if they are properly sealed every one or two years.

Granite, coarse- or medium-grained intrusive igneous rock that is rich in quartz and feldspar; it is the most common plutonic rock of the Earth’s crust, forming by the cooling of magma (silicate melt) at depth. …