Why rocks are important

It has also been used for fishing weights, as illustrated here. Its density is so great that it is used as a radiation shield. We most often see it in dentists' offices in the lead apron we wear to protect us from X-rays, but it is also used to shield nuclear reactors because it can capture any stray radiation before it enters the environment.

Lead is, like mercury, poisonous, so it is beginning to fall out of everyday use. Its most common use today is in the lead-acid batteries found in automobiles.

Lead is found in nature most often as galena, a compound with sulfur. The concrete that makes up most of the urban landscape is actually an artificial reconstruction of a naturally occurring rock, conglomerate. To make concrete, we mix sand and gravel, with cement. Cement is created by heating ground limestone with other minerals. When hot enough, the limestone releases carbon dioxide and becomes quicklime, the primary ingredient in cement. When the quicklime in cement reacts with water, it forms a stable crystal: this is what happens when concrete 'dries'.

The process of making cement from limestone releases carbon dioxide, consequently, the cement industry is second only to power production in the release of carbon dioxide gas into the atmosphere. When we describe oil and coal as fossil fuels, we mean it: they are produced by the cooking of decomposed plant and animal matter deep in the earth's crust over many millions of years.

Fossil fuels are a form of solar power: they are energy from the sun trapped by plants millions of years ago. Oil is formed in oil shales, but once it becomes liquid it tends to rise until it is trapped in a porous reservoir rock, like the ones shown here.

Drilling into the reservoirs releases the oil for human use. Finding oil is a tricky proposition, combining the science of geology with the art of imagining where the oil would flow within the crust. Coal is simply the remains of woody plants that died in swampy conditions and was cooked down into a solid mass. Large amounts of wood accumulated on earth during the Carboniferous period, to million years ago, because plants evolved wood and no organisms on earth evolved the ability to digest wood for 50 to 60 million years!

Think of a world where tree trunks never decompose because there are no microbes that know how to break them down. That's the Carboniferous world that left us with a legacy of coal. Graphite is elemental carbon, just like diamond. The difference is that diamond forms at extremely high pressures, which cause the carbon atoms to line up in a strong mineral. Graphite is formed under much lower pressures and has a mineral structure that makes it slippery and easy to break. We use it for the 'lead' in pencils because it makes a good, but erasable, mark.

We also use it as a powder for lubrication. Here we see some of the many products made from petroleum, or crude oil. Oil is used as a machine lubricant, as with the 10W oil. All of the rubber and plastics here are made from oil, including the gas can. The gas can also represents gasoline, the ubiquitous fuel that is refined from crude oil. Many construction- related activities are based on the geotechnic properties of sedimentary rock.

The suspended materials are then deposited and consolidated. Application of rocks to construction.. Often building are made from other materials such as reinforced concrete and are faced with Portland stone. Aberdeen is called the Granite city. Faults, joints, stratigraphy.. Ground Water levels, springs, surface water, or other effects of ground-water regime.

Potential cavities due to mines , tunnels and other caves etc. Potential rock slope instability. Utility service lines e. The preliminary geotechncial reports should be based on obtaining detailed local information using boreholes. Thickness of Bedding. Degree of Fracturing Jointing. Dip of Bed or Fracture. Tanks, reservoirs and buildings, selection of site is important from the viewpoint of stability of foundation and availability of construction materials, geology of area is important and rock-forming region, their physical nature, permeability, faults, joints etc.

Sedimentary rocks are also significant in economic terms, being relatively soft and easy to cut they are often used as construction materials. Total views , On Slideshare 0.

From embeds 0. Number of embeds Downloads 1, Shares 0. What Is the Importance of Rocks? More From Reference. Roe v. What Is Product Orientation? So the basic point is to better understand our world. This helps us to better coexist with nature and reap the benefits that it has to offer. Find Your Rock:. Why Should We Study Rocks? Some types of things that rocks can tell us about our planet as well as other planets are: Was there a lake or a volcano present where the rock was found?