Geochemistry

The difference between precious and semi-precious comes down purely to human definitions that have been imposed.

There is nothing in and of itself about the nature of a stone, which makes it precious or semi-precious.

Rather it is down to human desirability of an element or mineral or form or a stone that decides.

Generally, the rarer and more sought after a mineral is, the more likely it is to be defined as precious.

Desired, but more common and less valuable items may be, in contrast, semi-precious.

This is to do with light and the atmosphere.

The way the rays of light strike the mountains at a greater height than us, then reflect and reach our eyes below the height of mountains, coupled with the air in-between, leads to them looking purple, in a similar way to the process with different wavelength light makes the sky look blue on a sunny day.

The lower section of the Earth’s crust has been reached. The possibility of the mantle is not far away. Depths of over 4,500 feet have been reached.

This is because of the way that it is formed. When you have a rock that is formed through metamorphosis then it has been created through heat and pressure acting on other rocks.

Fossils are inherently delicate things and therefore precious little would withstand the conditions that are required to create marble – and therefore marble hardly ever contains fossils as a direct result of this.

The overall composition of the Earth, in terms of elemental composition is as follows:

☛ Iron 34.6%

☛ Oxygen 29.5%

☛ Silicon 15.2%

☛ Magnesium 12.7%

☛ Nickel 2.4%

☛ Sulphur 1.9%

☛ All others: 3.7%

The three types of rocks are as follows:

1) Igneous (from volcanoes etc)

2) Sedimentary (Dead Sea creatures, time and pressure)

3) Metamorphic (other rock types compressed, squished, heated and geologically stressed in massive temperatures and pressure fairly deep in the earth)

Give an example of a resource formed by a sedimentary process

Limestone is formed from pressure applied over time to dead creatures in the sea. Oil is formed because of sedimentary processes and which is one of the most important resources.

Over time it developed an atmosphere that changed in time as liquid water gathered on the surface of the earth and created an atmosphere with clouds of water and levels of certain gases that protected the planet below and made it the temperature that it is, which is obviously fit for life as we can tell by looking around us.

Things as if climate and food availability will make a big difference if it is too cold, too dry then people will need to move.

In addition, the amount of food is important too. Other factors might be human and political ones – such as a tough regime in charge of a country or if there is a war and so on then people will want to move too.

The largest volcano in the world over ground is called Mauna Loa.

Mauna Loa is to be found in Hawaii, now a US State.

This is due to the heat generated from the earth’s interior and earthquakes – the convection currents deep within the earth because the movement of the material that sits on top.

This refers to the Cambrian period, a geological time, at around 570 – 510 million years ago. It is when invertebrate life first appeared.

During the period comes what is known as the Cambrian Explosion – where the fossil record suddenly seems to radiate with an array of multi-celled creatures.

Fossils are created amongst periods of rock formation, and caused by the gradual accumulation of sediment over millions of years at the bottom, most commonly, of the seabed.

Factors such as the volume and surface area of the lake together with average wind speed and temperature at the surface are the factors that can be used to work out how much evaporation there is at the surface.

It is a type of clay first used by the Chinese for making chinaware and porcelain.

Igneous rocks – got to that stage of your geography or chemistry class already?

Well here is a little information for you on the ways in which igneous rocks can form.

Igneous rocks are created when melted material crystallizes, e.g. from magma.

There are two formation methods, the first is that they form on the surface and these are called extrusive igneous rocks, or they can form inside the crust, and these ones are called intrusive igneous rocks.

The rock is being subjected to intense heat and pressure at the time – this is what causes the dramatic stresses that are indeed what happens during the metamorphic process and what triggers the profound change in the chemical make up or constitution of the rocks.

Well each type of volcano can be very destructive and if you are talking in human loss of life terms than the answer is any type of volcano that is near dense population.

The most destructive type of volcano though that is generally acknowledged; as such, independent of people is that which is called the stratovolcano.

Specifically gases that are found in the magma correspond to having been formed at pressures many times greater than those in the outer core have, and rather therefore indicate that it was formed elsewhere.

Radon is a radioactive gas that is associated with certain rocks, so perhaps this is a measure of the geology of the area, as in the rocks that are present in that location?