Igneous rocks form when magma cools and solidifies. This happens both above and below the surface of Earth. Magma is made up of the atoms and molecules of melted minerals that rearrange themselves into mineral grains. When magma cools, rocks are formed. Magma can be forced into adjacent rocks, forced to the surface as lava, and also be blown out in volcanic explosions.
Over 700 different types of igneous rocks exist. Some of these types include granite, pumice, obsidian, tuff, and basalt.
Types of Igneous Rocks
Granite is a very common rock that contains 25% quartz and is commonly used in construction due to its strength and abundance.
Pumice is a very lightweight rock that forms when molten rock is quickly blown out of a volcano. As pressure is lost and the rock cools quickly, tiny bubbles (vesicles) are formed.
Obsidian is a volcanic glass that forms very rapidly without any crystal growth. Its edges are sharp and smooth making it a great choice for cutting tools or arrowheads.
Tuff is a rock formed from volcanic ash. During volcanic eruptions, rock, ash, and magma falls back onto Earth and is compacted and cemented into a rock, becoming a lens-shaped deposit called tuff.
Basalt is extremely common rock found all over our solar system. It is used in building materials and thermal insulators. When subjected to extreme heat and pressure over time it will metamorphosize into granulate.
Metamorphic rocks are rocks that have been changed over a long period of time by extreme pressure and heat. These types of rocks can be made by pressure deep under the Earth’s surface, from extreme heat caused by magma, or by intense collisions and friction of tectonic plates. Metamorphic rocks are brought up to the Earth’s surface by erosion and uplift. Types of metamorphic rock include marble, slate, quartzite, and gneiss.
Types of metamorphic rock
Marble is formed from the sedimentary rock limestone. Marble is usually white with streaks of color. It can take polish very well which makes it a commonly used rock in architecture and sculpture.
Slate is a fine grained rock derived from the sedimentary rock mudstone. When cut on a parallel to its foliations, slate will form smooth flat sheets that have long been used for roofing, floor tiles, as well as for writing on.
Quartzite is formed from quartz-rich sandstone that has been altered by heat, pressure, and chemical activity. It is very durable and heat resistant, with a similar look to marble but much more sturdy.
Gneiss is a coarse grained rock that can metamorphosize from either igneous or sedimentary rock. Its name comes from the Middle German word gneist, to spark, due to its glittery appearance.
135 years ago a meteor struck land in Australia. Hidden inside the chondritic meteorite, lies a previously undiscovered form of garnet which belongs to the majorite group. The microscopic particles of this dense mineral make up a large portion of the Earth’s crust and upper mantle. In 1985, this mineral was artificially created and given the nickname of tetragonal garnet.
The ones to discover the mineral naturally were a group of mineralogists at the Kochi Institute for Core Sample Research in Japan led by Naotaka Tomioka. The scientists had the honor of naming the mineral which they discovered in a slice of the 19th century meteorite. The new mineral formed in space when two asteroids collided at a speed of 2 kilometers per second.
Each component of this new mineral contains 32 magnesium atoms, 32 silicon atoms and 96 oxygen atoms which is identical to the previously artificially created tetragonal garnet. The researchers identified the undiscovered mineral by bouncing electrons off of the mineral’s crystal structure. It’s unique structure and shape let the mineralogists identify it. Other minerals discovered in the same meteorite include akimotoite and bridgmanite.
How do you calculate your age? You simply go take out the difference between your birth year and current year, isn’t it? But when it comes to taking out the age of the sprawling sphere which we call home, Earth, it becomes a bit trickier. Let’s explore what science has to say about the age of the Earth.
The age of the Earth couldn’t be guessed by anyone before the process of radiometric dating came into play. In 1898, the pioneer of radiology, Marie Curie discovered the phenomenon of radioactivity. The atoms either decay or lose energy by emitting radiation in the form of electromagnetic waves or particles. Later, in the year 1904, Ernest Rutherford, the famous physicist determined how this decay could let them explore the age of old rocks.
With this exploration, Arthur Holmes, who was completing his geology degree in London, acted as a helping hand by developing a new technique of dating rocks using the uranium lead method. He applied this technique to the oldest rock and got to know its age. Applying the similar technique to calculate the age of the Earth made him reach the conclusion that the Earth was at least 1.6 billion years old.
But wait, this is not the actual age of the Earth! The Earth’s age has always been hotly debated among the scientists over the years. That is why several revisions have been made. Later, in 1920’s, an unknown scientist declared that Earth’s age was approximately 3 billion years. This suggested that the Earth was even older than the universe, which itself is 1.8 billion years old.
Later, the scientists declared that radiometric dating of the fragments from Canyon Diablo iron meteorite was the best estimate for calculating the age of the Earth. From those fragments, they got to know that the true age of Earth was 4.56 billion years.
Since then, scientists have been using radiometric dating to determine the age of extraterrestrial objects such as Earth, meteorites, space rocks and moon rocks. For many years, scientists have tried to determine the exact age and now that they have discovered its age using the radiometric dating, they are using it for several other space objects as well.
If you want to explore some more interesting information from the world of geology, come back and join us for more interesting information on other fascinating topics.
The term ‘mining’ means extraction. The process of mining entails the extraction of valuable resources from the earth by using various methods and techniques.
Discovery of Mining Techniques – A Revolutionary Development
The discovery of the methods and techniques to extract the treasures that lie beneath the surface of the earth and the development of various machines to carry out the processes was a revolutionary development in the history of mankind.
It not only makes our daily lives a lot easier by allowing us to utilize the vast reserves of oil, coal and gas for daily purposes, but it also led to the invention of various instruments, gadgets and items of everyday use which are made with the help of various metals, like copper, iron, aluminum etc. In addition to these, we were also able get our hands on some of the most precious metals and stones just because of the development of various mining techniques and methods. Had geologists not invented these techniques, we would not have been able to use gold, silver, diamond, emerald and other precious stones to make beautiful ornaments to adorn ourselves with.
Countries prospered and civilizations developed as they started extracting the natural wealth lying beneath the surface of the earth and used it to further their economic activities and industrial growth.
Types of Mining
The process of mining can be broadly divided into 2 categories:
These types are further divided into various sub-categories.
Surface mining is a broad category that is comprised of various methods used by geologists to extract the mineral deposits, metals and ores lying near the surface of the earth. Different kinds of surface mining are:
Open pit or Opencast mining
The most common element extracted through surface mining is ‘coal’.
Underground mining includes techniques and methods used to extract metals, ores and minerals that lie deep within the earth and cannot be taken out with surface mining techniques. In these types of mining techniques, an entrance point is made from the earth’s surface, which is in the form of a mine shaft, an adit or a tunnel. Major types of underground mining are:
Room and pillar mining
Cut and fill stoping
Negative Effects of Mining
In addition to the numerous benefits provided to human beings due to the extraction of valuable natural resources, the processes used to carry out mining produces have some negative effects as well, particularly on the environment. Some of the major negative impacts are as follows:
Mining causes the emission of various gases, dust and trace elements that lead to the contamination of air and surface water.
The quality of the soil and its fertility is compromised because of mining. Also, it makes the soil toxic.
It causes deforestation, destruction of landscapes and wildlife habitats.
The water table gets lowered due to mining which in turn affects the flow of groundwater.
Geology is an interesting subject as it involves studying different features of the earth including the oceans, mountains, rocks, earthquakes, and volcanoes.
Basically, a geologist studies all solid and liquid matter that forms the earth in addition to the history and processes that have fashioned it. A basic and important part of geology is the earth’s interior. This part of geology is what we’re going to discuss here.
Just like the interior of your car, the earth’s interior is made up of a variety of elements and a number of layers are present in the earth’s interior. The earth’s crust, mantle, and the core are its major layers. The mantle is further divided into the upper and lower mantle while a liquid outer core and a solid inner core constitute the earth’s core.
The earth’s crust
The first layer of the earth consisting of about 16 kilometers of rock as well as unattached materials is known as the crust. Compared to its thickness under the oceans, the crust’s thickness underneath the continents is almost three times more.
The Earth’s Mantle
Mantle is the layer beneath the crust and accounts for a large majority of the Earth’s volume. Movements, know as convection in geology circles, is responsible for earthquakes and volcanic activity. Almost 1,800 miles deep, the mantle consists of substances that are rocky, solid and thick. Of the earth’s total weight and mass, 85 percent is made up of this substance. Very hard, rigid rocks make up the mantle’s first few miles. Super heated solid rock makes up the next 100 or so. Solid and sturdy rock materials make up the next hundred miles of the earth’s mantle.
The Earth’s Core
Two layers that are mostly iron make up the earth’s core. Iron is estimated to make up about 90% of the earth’s core with oxygen, sulfur, or nickel combining to form the remaining 10 %. The earth’s core consists of mostly iron and nickel. Solid, the earth’s inner core measures about 1500 miles in diameter.
The earth’s outer core also consists of mostly nickel and iron. The earth’s inner and outer cores combine to become as big as the planet Mars. Superheated liquid molten lava is what most people believe earth’s outer core is made of. A solid ball comprising mainly of nickel and iron is believed to make up the earth’s inner core.
There you have it—the earth’s interior and its components. The next time you start digging holes in your garden, you will know exactly what lies underneath it.
Collecting minerals is a very interesting hobby with collectors passionate about saving minerals from all over the world. In fact, they have taken mineral collecting to a whole new level. But, if you are a beginner and new to this fascinating specialty, you should consider a few things before treading on this path. Let’s explore them below.
Know Your Interest
If you are also a passionate mineral hunter, then you must first know about your interest in detail. Out of the many types of minerals, you may feel like collecting the multi-colored tourmaline and the beautiful red rhodochrosite. On the other hand, your friend may like to get the one they have seen plentiful in their childhood, that is the beautiful little quartz.
Whatever your motivation is, it is always good to know of your interest in detail before starting mineral collection. Interest will be the ultimate element which will make you focus and thus, you must know what types of minerals interest you.
Make a Budget
When you get to know of your interest, you will get an idea and realize how much budget you will require to pursue it. If you are fond of collecting rhodium (one of the most expensive minerals in the world), then need to know that you must have a handsome budget to purchase it. While the best quality minerals can eat up your budget very quickly, you must ensure that you purchase a few that are less costly.
Buy a Book
A novice mineral collector must buy a book. Veteran mineral collectors suggest buying a book so that they are able to know the ins and outs of each mineral. Furthermore, books help develop your interest even more. Also, with good reference books, new mineral collectors will be able to get all the answers to their queries. Veteran mineral collectors suggest investing in publications like Rocks and Minerals, Rocks and Gems and the book titled Mineralogical Record.
Understand its Uniqueness
While there are many people who love collecting other items, mineral collectors must understand and realize the importance of collecting fine minerals that are natural instead of being man-made. As they are formed naturally, they are more valuable. The value of mineral may vary with beauty, rarity, quality, origin, form, shape and size but they are truly the richest resources among all collectibles.
Are you a mineral collector? If you are, then you have come to the right place. Veteran mineral collectors learn lessons in their quest to collect minerals from around the world. Here are some tips that can help you in collecting minerals:
Tip # 1: Label the Minerals
Labels helps keep your mineral collection organized. If you do not keep your minerals labelled, then how will you ascertain that a rare tourmaline is from Connecticut and the ordinary green tourmaline is from Brazil? Labeling them with information such as their source of origination will keep you informed as we all tend to forget things. Also, if you have a large number of minerals, then it is most likely that you will forget where you bought them from. By giving them identification, a label helps mineral collectors remember and recall everything about it.
Tip # 2: Buy and Use a Book
If you are new to mineral collecting, you may have many questions to ask. With a good reference book on minerals or mineral collection, you will be able to get the answer to all your queries. Veteran mineral collectors suggest that a mineral collector who is new to the fray must invest in a good reference book on minerals to start with. By resolving every kind of technicality to understanding the types of minerals, a single reference book is enough to guide them.
Tip # 3: Join Nearest Mineral Club
Among all the tips, joining a mineral club can be one of the most attractive and advantageous options. Joining a local mineral club will help you go on trips with groups. Also, these clubs share their experiences, allowing you to learn about the ins and outs of minerals too. You must always choose a mineral club that suits your requirements. These clubs will be fun for you because they arrange field trips, give lectures and arrange social events for you to meet other collectors.
Tip # 4: Catalog Your Collection
Several mineral collectors have passed away but they have left behind their collection of minerals to serve as a source of reference and inspiration for others. For example, Joe Cilen died a long time ago but left 23,000 minerals specimens for other mineral lovers and collectors to see. You can also make a catalog out of your mineral collection with proper references and labels. This can be impressive and also encourage you to collect more. So, do not just box your collection; start cataloging them or else, you will just ending up finding the rare tourmaline you bought from Brazil.
The best way to catalog your collection is to use a spreadsheet. Microsoft Excel and Google Sheets are two of the most popular sheets to use. You can organize and sort them anyway you desire, so it is definitely worthwhile the time to invest in organizing your minerals this way.
Though much of these tips are common, some beginners may not know about it. If you are also fond of collecting minerals, then you should follow these tips for a better mineral collecting experience.