Rocks Study Outline PDF

ROCKS STUDY OUTLINE ROCKS- are solid mass of mineral or mineral-like ma:er that occurs naturally as part of our planet. Igneous- Ignis = fire magma/lava – cooling *Magma consists mainly of Silicon and Oxygen plus...

ROCKS STUDY OUTLINE ROCKS- are solid mass of mineral or mineral-like ma:er that occurs naturally as part of our planet. Igneous- Ignis = fire magma/lava – cooling *Magma consists mainly of Silicon and Oxygen plus Aluminum, iron, calcium, sodium, potassium, and magnesium, gases, water vapor. These gases are kept within the magma by the pressure of surrounding rocks. Magma is less dense than surrounding rocks so it slowly works its way towards the surface. AS Magma rises, it cools, elements combine forming minerals, which eventually grow in size, forming solid mass of interlocking crystals How do we classify Igneous rocks? Texture and composiTon Texture- appearance based on size, shape, arrangement of interlocking crystals ComposiTon- proporTon of light and dark minerals Intrusive= magma hardens beneath Earth’s surface - intrude ○ Slow cooling -> coarse-grained texture (phaneriTc)  GRANITE: This mineral composiTon usually gives granite a red, pink, gray, or white color with dark mineral grains visible throughout the rock. it is the most common igneous rock found at Earth's surface and because granite is used to make many objects that we encounter in daily life. These include counter tops, floor 9les, paving stone, curbing, stair treads, building veneer, and cemetery monuments. Stone Mountain, Georgia; Yosemite Valley, California; Mount Rushmore, South Dakota, etc. Diorite: This specimen clearly shows the familiar "salt and pepper" appearance of diorite, produced by white plagioclase contrasTng with black hornblende and bioTte. it is someTmes mined for use as a crushed stone. It has a durability that compares favorably to granite and trap rock. It is used as a base material in the construcTon of roads, buildings, and parking areas. It is also used as a drainage stone and for erosion control. The most famous diorite sculpture is the Code of Hammurabi, a black diorite pillar about seven feet tall, inscribed with Babylonian laws in about 1750 BC. Gabbro: is usually black or dark green in color and composed mainly of the minerals plagioclase and augite. It is the most abundant rock in the deep oceanic crust. Gabbro has a variety of uses in the construcTon industry. It is used for everything from crushed stone base materials at construcTon sites to polished stone counter tops and floor Tles. Extrusive= lava hardens- extruded at the surface rapid cooling -> fine-grained texture (aphaniTc)  Basalt-It is most commonly crushed for use as an aggregate in construcTon projects. Crushed basalt is used for road base, concrete aggregate, asphalt pavement aggregate, railroad ballast, filter stone in drain fields, and may other purposes. Basalt is also cut into dimension stone. Thin slabs of basalt are cut and someTmes polished for use as floor Tles, building veneer, monuments, and other stone objects. Rhyolite is an extrusive igneous rock with a very high silica content. It is usually pink or gray in color with grains so small that they are difficult to observe without a hand lens. rarely used in construc9on or manufacturing. It is oeen vuggy or highly fractured. Its composiTon is variable. When be:er materials are not locally available, rhyolite is someTmes used to produce crushed stone. People have also used rhyolite to manufacture stone tools Andesite is usually light to dark gray in color. Intermediate composiTon – silica poor basalt, silca rich rhyolite. Sodium rich plagioclase plus pyroxede. Or hornblade. Pyroclas9c rocks= explosive volcanic acTvity rapid cooling -> very small or very large  ❖ Igneous Rocks with Glassy texture-llava spews onto Earth’s surface -> no enough Tme- ions-> network of crystals = randomly distributed ❖ spews onto Earth’s surface -> ❖ Obsidian is an igneous rock that forms when molten rock material cools so rapidly that atoms are unable to arrange themselves into a crystalline structure. It is an amorphous material known as a "mineraloid." The result is a volcanic glass with a smooth uniform texture that breaks with a conchoidal fracture. CUMng tool during the stone age, modern surgery scalpels Pumice is a light-colored, extremely porous igneous rock that forms during explosive volcanic erup9ons. It is used as aggregate in lightweight concrete, as landscaping aggregate, and as an abrasive in a variety of industrial and consumer products. an abrasive in condiToning "stone washed" denim an abrasive in bar and liquid soaps such as "Lava Soap" PorphyriTc granite or andesite Porphyri9c ❖ different size minerals -> different rates of cooling ❖ phenocryst = large crystals surrounded by fine-grained minerals Sedimentary- sedimentum = se:ling sediments Many different minerals are found in clasTc rocks. The most common are the clay minerals and quartz. This is because clay minerals like those that make up much of the shale are the most abundant products of chemical weathering. Quartz which is major mineral in the breccia is a common sedimentary mineral because its durable and resistant to chemical weathering. Conglomerate has very few commercial uses. Its inability to break cleanly makes it a poor candidate for dimension stone, and its variable composi9on makes it a rock of unreliable physical strength and durability. Conglomerate can be crushed to make a fine aggregate that can be used where a low-performance material is suitable. The rock, breccia, has very few uses. It can be used as fill or road base where the technical requirements are minimal. It is rarely used in important projects because its composiTon, degree of cementaTon and competence are highly variable. Sandstone is one of the most common types of sedimentary rock and is found in sedimentary basins throughout the world. It is oeen mined for use as a construcTon material or as a raw material used in manufacturing like in mortar(Mortar is a workable paste which hardens to bind building blocks such as stones, bricks, and concrete masonry units,). In the subsurface, sandstone oeen serves as an aquifer for groundwater or as a reservoir for oil and natural gas. Black shales contain organic material that someTmes breaks down to form natural gas or oil. Other shales can be crushed and mixed with water to produce clays that can be made into a variety of useful objects. Limestones: It most commonly forms in clear, warm, shallow marine waters. It is usually an organic sedimentary rock that forms from the accumulaTon of shell, coral, algal, and fecal debris. It can also be a chemical sedimentary rock formed by the precipitaTon of calcium carbonate from lake or ocean water. Most limestone is made into crushed stone and used as a construcTon material. It is used as a crushed stone for road base and railroad ballast. It is used as an aggregate in concrete. It is fired in a kiln with crushed shale to make cement.Limestone is oeen cut into blocks and slabs of specific dimensions for use in construcTon and in architecture. It is used for facing stone, floor 9les, stair treads, window sills, and many other purposes. When crushed to sand-size or smaller parTcles, limestone becomes an effec9ve material for trea9ng acidic soils. It is widely used on farms throughout the world. Rock Salt is a chemical sedimentary rock that forms from the evaporaTon of ocean or saline lake waters. It is also known by the mineral name "halite". It is rarely found at Earth's surface, except in areas of very arid climate. It is oeen mined for use in the chemical industry or for use as a winter highway treatment. Some halite is processed for use as a seasoning for food. Chert is a sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert has very few uses today; however, it was a very important tool-making material in the past. Thousands of years ago people discovered these properTes of chert and learned how to intenTonally break it to produce culng tools such as knife blades, arrowheads, scrapers, and ax heads. CHALK- carbonate rock Metamorphic Rocks -form from heat and pressure changing the original or parent rock into a completely new rock. metamorphism = to change form ❖ occurs at elevated temperature and pressure = few km below Earth’s surface Slate-The pressure on the shale causes the microscopic clay minerals to become more compact. The increase in pressure also causes the clay minerals to align in similar direcTons. Phyllite-It is composed mainly of flake-shaped mica minerals in parallel alignment. The strong parallel alignment of the mica grains allows the rock to be easily split into sheets or slabs. Schist-This texture allows the rock to be broken into thin slabs along the alignment direcTon of the platy mineral grains. This type of breakage is known as schistosity. Its abundant mica grains and its schistosity make it a rock of low physical strength, usually unsuitable for use as a construcTon aggregate, building stone, or decoraTve stone. Gneiss- It does not split along planes of weakness like most other metamorphic rocks. This allows contractors to use gneiss as a crushed stone in road construcTon, building site preparaTon, and landscaping projects Most marble is made into either crushed stone or dimension stone. Crushed stone is used as an aggregate in highways, railroad beds, building foundaTons, and other types of construcTon. Dimension stone is produced by sawing marble into pieces of specific dimensions. These are used in monuments, buildings, sculptures, paving and other projects.Being composed of calcium carbonate, marble will react in contact with many acids, neutralizing the acid. It is one of the most effecTve acid neutralizaTon materials. Marble is oeen crushed and used for acid neutralizaTon in streams, lakes, and soils. Quartzite- Its extreme toughness made it a favorite rock for use as an impact tool by early people. Its conchoidal fracture allowed it to be shaped into large culng tools such as ax heads and scrapers. Quartzite is an extremely durable crushed stone that is suitable for use in the most demanding applicaTons. Its soundness and abrasion resistance are superior to most other materials. Unfortunately, the same durability that makes quartzite a superior construcTon material also limits its use. Its hardness and toughness cause heavy wear on crushers, screens, truck beds, culng tools, loaders, Tres, tracks, drill bits, and other equipment.