ECE-302: BUILDING MATERIALS & CONSTRUCTION UNIT -1 LECTURE - 4: STONES: ECE-302: BUILDING MATERIALS & CONSTRUCTION UNIT -1 LECTURE - 4: STONES By NAURAS SAIYED Assistant Professor Civil Engineering Department ABES Engineering College PowerPoint Presentation: In this lecture we shall learn about The geological cycle – rock formation Classification of rocks stone as building material: stone as building material In some places like hilly areas, stone is a cheaper option Stones have been used since ancient times as building material. Old roads were paved with stone. Old monuments such as Taj mahal and many temples and palaces were made from stones. Stones are more permanent than most building materials. Stone is good choice for foundations likely to be flooded. Submerged bricks may breakdown but submerged stones remain stable. Today stones form an important source of aggregates and are also used in ornamental work. Interior structure of the earth : Interior structure of the earth The earth is divided into three main layers: Crust Mantle Core PowerPoint Presentation: Crust Continental crust (25-40 km) Oceanic crust (~6 km) Mantle Upper mantle (650 km) Lower mantle (2235 km) Core Outer core: liquid (2270 km) Inner core: solid (1216 km) The crust: The crust The crust is much thinner than any of the other layers, and is composed of the least dense calcium (Ca) and sodium (Na) aluminum-silicate minerals. Being relatively cold, the crust is rocky and brittle , so it can fracture in earthquakes . The shell of the earth, the crust, can be said to have two different thicknesses. Under the oceans, it is relatively thin. It varies in thickness from 5 to 8 km. Under the land masses, it is relatively thick. The thickness of the continental crust varies from 10 to 65 km. The eggshell analogy for the crust is not an exaggeration. It is paper thin compared with the radius of the earth which is approximately 6400 km. Rocks -Definition: Rocks -Definition It is the portion of the earth’s crust having no definite shape and structure Geologist define rock as aggregates or mass composed of one or more minerals. Monomineralic Rocks: having only one mineral Polymineralic Rocks : having several minerals Stones -Definition a natural, hard substance formed from minerals and earth material which are present in rocks. The stone is always obtained from rocks. Minerals : Minerals Minerals are naturally occurring inorganic substances having definite chemical composition and molecular structure. As the basic constituent of rock, minerals control much of rock behavior. Some minerals are very strong and resistant to deterioration and produce rock with similar properties, while others are much softer and produce weaker rock. The Geological Cycle: Rock formation : The Geological Cycle: Rock formation Geological cycle includes many processes acting simultaneously. The most important of these begin with molten magma from within the earth forming into rock, then continue with rocks being broken down into soil, and that soil being converted back into rock. GEOLOGICAL CYLCE: GEOLOGICAL CYLCE The geologic cycle. All rocks begin as igneous, but later can be transformed via weathering into sedimentary rocks, or via heat and pressure, into metamorphic rocks. http://www.thaigem.com/gemopedia/gemstone-formation.asp Classification of rocks: Classification of rocks Geological Classification Igneous Sedimentary Metamorphic Physical Classification Stratified Unstratified Foliated Chemical Classification Silicious Argillaceous Calcareous Physical Classification: Physical Classification Stratified Rocks: These rocks possess planes of stratification or cleavage. They can be easily split up along these planes. Unstratified Rocks: The structure of these rocks may be crystalline granular or compact granular. Foliated Rocks: These rocks have a tendency to be split up in a definite direction only. Examples: Examples Stratified Foliated Unstratified Chemical Classification: Chemical Classification Silicious Silica predomiates Hard and durable Eg . Granites, Quartzites , etc. Argillaceous Clay predomiates Dense, compact and soft Eg . Slates, Laterites , etc. Calcareous Calcium Carbonate predomiates Durability depends upon surrounding atmosphere Eg . Limestone, Marble, etc. Geological Classification: Geological Classification Igneous Sedimentary Metamorphic Igneous rocks: Igneous rocks They are formed by cooling and crystallization of magma (below the Earth’s surface) or Lava (above the Earth’s surface) magma volcano Magma cools and solidifies forming igneous rocks Types of igneous rocks: Types of igneous rocks There are two types of Igneous rocks Intrusive (also called plutonic rocks) : form below the ground surface from magma coming up from the mantle into the crust, where they cool slowly, Extrusive (also called volcanic rocks) arrive at the ground surface in a molten state, such as through volcanic eruption. This type of igneous rock cool very rapidly. Hypabyssal rocks are formed when consolidation of magma takes place very close to the earth’s surface in the form of smaller sheet like bodies (known as sills and dikes) that fill cracks inside other rocks. Examples of Igneous Rocks: Examples of Igneous Rocks Granite is an example of an Intrusive Igneous Rock It forms under the Earths surface from the cooling of magma leaking up from the mantle of Earth Intrusive igneous rocks have noticeably large crystals and are usually rough to the touch unless they are polished Examples: Kitchen Counters The Continental Crust of the Earth is primarily made of Granite Other examples of Intrusive Igneous Rocks:: Other examples of Intrusive Igneous Rocks: Gabbro Andesite Diorite Examples of Extrusive Igneous Rocks: Examples of Extrusive Igneous Rocks Basalt is an example of an E xtrusive I gneous R ock The Oceanic Crust is made primarily of Basalt Basalt is formed from lava on the crust of the Earth. Because it is formed on the surface, the crystals are very fine-grained Other examples of Extrusive Igneous Rocks: Other examples of Extrusive Igneous Rocks Obsidian Rhyolite Scoria Hypabyssal igneous rock: Hypabyssal igneous rock Lamprophyre Rock Dike: Dike A dike is vertical wall-like igneous body that cuts the bedding of the rock. It forms where magma squeezes into fractures in the surrounding rock and cools. The thickness of the dike may vary from a few centimeters to a hundred meter or more. Pegmatite dike cross-cutting basement gneisses sill : sill A sill is a tabular intrusive layer of rock. The sills are parallel to the layered rock beds, whereas the dikes are perpendicular to them. Rising magma follows the path of least resistance. If the magma can no longer rise, then the path of least resistance may take it laterally in between the rock layers. varies in thickness from a few centimeter to several hundred meters. The darker layered diorite sill in the Limestone flanks of Mount Gould in Glacier National Park in Montana (some 1300 million years old.) PowerPoint Presentation: Dolerite sill cutting across sandstone PowerPoint Presentation: Rocks produced by the settling/deposition, compaction and cementation of sediments Limestone Gritstone Conglomerate Shale Sandstone SEDIMENTARY ROCKS PowerPoint Presentation: Sedimentary rocks are rocks formed when particles of sediment build up and are “cemented together” by the effect of pressure and minerals. Sea Fragments washed to the sea Sedimentary rocks Rocks are broken up by weathering Types of Sedimentary Rocks: Types of Sedimentary Rocks Clastic (physical weathering) Chemical Organic Clastic Sedimentary Rocks: Clastic Sedimentary Rocks Breccia Conglomerate Sandstone Shale Clastic Sedimentary Rocks are formed from mechanical weathering debris Mechanical weathering takes place when rocks are broken down without any change in the chemical nature of the rocks breccia, conglomerate, sandstone and shale are some examples Chemical Sedimentary Rocks: Chemical Sedimentary Rocks Chemical Sedimentary Rocks form when dissolved materials precipitate from solution Example : Halite that forms from dried up saltwater lakes Rock salt (Halite) and some limestone are examples of Chemical Sed. Rocks Halite Limestone Organic Sedimentary Rocks: Organic Sedimentary Rocks Organic Sedimentary Rocks form from the dead plants and animals and their debris. Coal and fossiliferous limestone are examples of organic sed. rock An example of fossiliferous limestone has sea shells in it Organic material comes from anything living or has lived before Fossiliferous Limestone Coal Metamorphic Rocks: Metamorphic Rocks Metamorphic rocks are formed by the effect of heat, pressure and chemical process on existing rocks. Exposure to extreme conditions alters the minerals, texture and chemical composition of the rocks. PowerPoint Presentation: Metamorphic rocks are formed by the effect of heat and pressure on existing rocks. metamorphic rock forming here Heat from magma Pressure from surface rocks Metamorphic rocks can form from igneous, sedimentary or other metamorphic rocks.: Metamorphic rocks can form from igneous, sedimentary or other metamorphic rocks. EARTHQUAKES AND VOLCANIC ACTIVITY CAUSE HEAT AND PRESSURE TO ACT ON ROCKS.: EARTHQUAKES AND VOLCANIC ACTIVITY CAUSE HEAT AND PRESSURE TO ACT ON ROCKS. sometimes temperature and pressure are great enough to melt rock, forming magma.: sometimes temperature and pressure are great enough to melt rock, forming magma. sometimes pressure flattens mineral grains in rocks without melting them. : sometimes pressure flattens mineral grains in rocks without melting them. as pressure and temperature continue to increase over time, one type of rock can change into several different metamorphic rocks.: as pressure and temperature continue to increase over time, one type of rock can change into several different metamorphic rocks. Types of metamorphic rocks: Types of metamorphic rocks There are two basic types of metamorphic rocks based on their texture: Non-foliated Foliated Foliated texture: Mineral grains flatten and line up in parallel layers or bands. : Foliated texture: Mineral grains flatten and line up in parallel layers or bands. Nonfoliated texture: mineral grains grow and rearrange but do not form layers. : Nonfoliated texture: mineral grains grow and rearrange but do not form layers. Foliated Rocks: Foliated Rocks Original Rock: shale (sedimentary) Metamorphic Rock: slate Foliated Rock: Foliated Rock Original Rock: granite (igneous) Metamorphic Rock: gneiss Nonfoliated Rock: Nonfoliated Rock Original Rock: limestone (sedimentary) Metamorphic Rock: marble Nonfoliated Rock: Nonfoliated Rock Original Rock: sandstone (sedimentary) Metamorphic Rock: quartzite (melted sand) PowerPoint Presentation: THANKS Reference: Reference The following slides may be referred for further understanding of concepts. PowerPoint Presentation: The Geological Cycle Explanation of geological cycle: Explanation of geological cycle Let's start with the red area at the bottom of the diagram: magma , molten rock. When magma rises through cracks and cools slowly underground, it forms igneous rocks composed of minerals with fairly large crystal sizes, these are known as intrusive igneous rocks. When the magma erupts onto the surface, as through a volcano, it is termed lava , and depending on the rate of cooling, the extrusive igneous rocks which form have medium to very small mineral crystals. Some lava cools so rapidly that it forms an amorphous material without a crystalline structure. Granite and basalt are examples of larger and smaller grained igneous rocks, respectively, and obsidian (volcanic glass) is amorphous. http://www.bwsmigel.info/Lesson10/DE.Gem.Formation.html Explanation of geological cycle – Contd…: Explanation of geological cycle – Contd … Once the igneous rock is on the surface, the forces of erosion and weathering produce smaller particles which accumulate on the surface, and/or are moved by wind and water. As time proceeds, layers of these sediments build up (on land or under water). The pressure from upper layers causes compaction in the lower layers along with various chemical and physical changes ( lithification ), which lead to the creation of sedimentary rock. Evaporation is an alternate factor which also produces sedimentary rocks, as when dripping mineral-laden waters leave behind stalactites or stalagmites. Likewise, surface or subterranean waters carrying dissolved minerals may evaporate or precipitate those minerals within the cracks in other rocks, or between rock layers. Sandstone and limestone are familiar sedimentary rocks formed by lithification . Opal and turquoise illustrate the evaporative mode of formation. Explanation of geological cycle – Contd…: Explanation of geological cycle – Contd … The presence of intrusive magma in a local region (contact metamorphism), or of tectonic plate interactions on a larger scale (regional metamorphism) puts the igneous and sedimentary rocks and minerals under heat and/or pressure which may cause changes in their chemistry and crystal structure. The result is the creation of metamorphic rocks. Thus is limestone turned into marble, sandstone into quartzite, and serpentine into nephrite jade. As with most cycles in Nature there are sub-cycles and cross interactions. So, for example, sedimentary rocks which are subducted through tectonic action may melt and form magma which produces igneous rocks. Or metamorphic rocks, which have been uplifted and exposed at the surface, will erode to form sedimentary deposits.