Download The Rock Cycle: Exploring the Transformation of Rocks and more Study notes Earth Sciences in PDF only on Docsity!
DESIGNATED TASK 2 DESCANZO, JUAN CARLOS V. SIR RIZCHEL MASONG
PART 1 (WRITTEN WORK)
1. Rock Cycle Sedimentary, igneous, and metamorphic rocks are the three main categories of rocks. Each of these rocks is the result of physical processes that are a part of the rock cycle, such as melting, cooling, eroding, compacting, or deforming. Based from the given illustration, to create sedimentary rocks, organic matter or fragments of already-existing rocks are used. Clastic, organic (biological), and chemical sedimentary rocks are the three different types of sedimentary rocks. Sandstone is a type of clast sedimentary rock, which is formed from fragments of other rocks. Hard, biological elements like plants, shells, and bones that are compacted into rock are what give rise to organic sedimentary rocks like coal. The weathering, or disintegration, of the exposed rock into tiny fragments is the first step in the production of clastic and organic rocks. These fragments are separated from their source through erosion and carried to a different area by wind, water, ice, or biological activity. Once enough sediment has accumulated in one place and settled there, the lowest layers are so firmly packed that solid rock is formed. Chemical precipitation is the process that gives rise to chemical sedimentary rocks including limestone, halite, and flint. A chemical compound that develops when the solution it was dissolved in, typically water, evaporates and leaves the compound behind is known as a chemical precipitate. Examples of such compounds include calcium carbonate, salt, and silica. This happens as water moves through the crust of the Earth, eroding the rock and displacing some of its minerals. When the water evaporates, these dissolved minerals precipitate. When it comes to metamorphic rocks, these are rocks that have undergone extreme heat or pressure changed significantly from their original shape. Foliated and non-foliated metamorphic rocks fall into these two categories. When flat or elongated minerals in a rock are subjected to intense pressure, the minerals stack up to form foliation. Foliation is the alignment of elongated or platy minerals, such as mica or hornblende, perpendicular to the direction of applied pressure. Granite, an igneous rock, is a good illustration of this change. Granite comprises lengthy, platy minerals that are originally out of alignment, but when enough pressure is applied, these particles move to align and become compressed into flat sheets. Non-foliated rocks are created in the same way as foliated rocks, but they lack the minerals that tend to line up under pressure and give foliated rocks their layered look. Given sufficient heat and pressure, sedimentary rocks like bituminous coal, limestone, and sandstone can transform into non-foliated metamorphic rocks like anthracite coal, marble, and quartzite. Metamorphism, which occurs when magma comes into contact with the surrounding rock, is another process that can produce non-foliated rocks.
DESIGNATED TASK 2 DESCANZO, JUAN CARLOS V. SIR RIZCHEL MASONG Going to the process of igneous rocks, when molten, hot material cools and hardens, igneous rocks are created. Additionally, igneous rocks can be created in a few distinct methods. They are referred to be intrusive, or plutonic, igneous rocks when they are generated deep within the earth. They are referred to be extrusive, or volcanic, igneous rocks if they developed outside of or on top of the Earth's crust. Some examples of frequent intrusive rocks include granite and diorite. Since they spent thousands or millions of years cooling down below the earth, a time frame that permitted huge mineral crystals to develop, they have a gritty texture and large mineral grains. As an alternative, rocks with very minute grains and a very fine texture, such basalt and obsidian, exist. Because magma cools more quickly when it erupts into lava than it would if it remained underground, crystals have less time to form. When expelled, obsidian soon cools into volcanic glass, making the grains invisible to the unaided eye. The texture of extrusive igneous rocks can also be vesicular or "holey." This occurs when gases that were present in the ejected lava are now trapped when it cools, giving the rock a bubbly texture. Pumice is a good illustration of this. Questions: Analyze the rocks below. Write the words and phrases to describe the rock's characteristics, and composition. If possible, name the type of this identified rocks. Explain why. A. Characteristics and Composition: Rock 1: Conglomerate ➢ Grain size: coarse-grained ➢ Usual color: brown ➢ Structure: crude bedding, clastic ➢ Shape: sub-angular rounded ➢ Composition: Jasper and Quartz Rock 3 : Limestone ➢ Grain size: fine-grained ➢ Usual color: grey ➢ Structure: crude bedding ➢ Shape: laminate ➢ Composition: calcite Rock 2 : Coquina ➢ Grain Size: fine-grained ➢ Usual color: white, yellow, pink to blue and mauve ➢ Structure: loosely cemented, crossbedding ➢ Shape: wedge-shaped ➢ Composition: mineral calcite. Has shell fragments 0 Rock 4 : Shale ➢ Grain Size: fine-grained ➢ Usual color: Yellow-black (sometimes green) ➢ Structure: lamination, closed fabric ➢ Shape: rounded ➢ Composition: clay minerals, silicates
DESIGNATED TASK 2 DESCANZO, JUAN CARLOS V. SIR RIZCHEL MASONG Rock 3 : Granite ➢ Grain size: coarse-grained ➢ Usual color: light (leucocratic) ➢ Structure: holocrystalline ➢ Texture: inequigranular - equigranular ➢ Composition: feldspar and quartz with minor mica, amphibole, or pyroxene Due to its predominately coarse grain size characteristic, Rock #1 resembles a diorite. The rock's inequigranular/equigranular texture and leucocratic tint make it look like a diorite. The rock's composition includes diorite-like minerals and low-calcium plagioclase. Rock number two, resembling obsidian. The image shows the crystal-like smooth texture and black color. It is made of Rock #3, which is similar to granite. The rock has a pale tint and is large-grained. Minerals such as quartz, feldspar, and mica make up the majority of the composition. Gabbro-like rock # resembles. The rock is black in color and has coarse grains. Feldspar, pyroxene, and occasionally olivine makes up its composition. The fifth rock resembles a pegmatite. It comes in a variety of hues, all of which are light in tone. Peridotite is related to rock number six. The majority of the rock is olivine, and it has a coarse-grained texture. It contains trace amounts of feldspar, quartz, pyroxene, and amphibole. Since the samples were collected from the igneous rock type, all of the rock samples presented above can be categorized as igneous rocks. Rock 4 : Gabbro ➢ Grain Size: coarse-grained ➢ Usual color: melanocratic ➢ Structure: holocrystalline ➢ Texture: equigranular, hypidomorphic ➢ Composition: contains feldspar & one or more dark mineral. The dark minerals are dominant. Rock 5 : Pegmatite ➢ Grain size: very coarse-grained, beautiful crystal outlines ➢ Usual color: leucocratic ➢ Structure: holocrystalline ➢ Texture: inequigranular ➢ Composition: granite with large crystals of quartz, feldspar, and mica. Rock 6 : Peridotite ➢ Grain size: coarse-grained ➢ Usual color: melanocratic ➢ Structure: holocrystalline ➢ Texture: equigranular, hypidomorphic ➢ Composition: olivine with amphibole and/ pyroxene
DESIGNATED TASK 2 DESCANZO, JUAN CARLOS V. SIR RIZCHEL MASONG C. Characteristics and Composition: Rock 1 and 2: Gneiss ➢ Grain size: coarse-grained ➢ Usual color: leucocratic ➢ Structure: gneissos ➢ Texture: granoblastic ➢ Composition: feldspars, mica Rock 4 : Quartzile ➢ Grain size: coarse-grained ➢ Usual color: brown ➢ Shape: Angular ➢ Structure: coarse-grained ➢ Texture: granoblastic ➢ Composition: quartz, feldspar, mica heavy minerals Rock 3 : Marble ➢ Grain Size: coarse-grained ➢ Usual color: white, pink ➢ Structure: coarse - grained ➢ Texture: granoblastic ➢ Composition: calcite Rock 5 : Phyllite ➢ Grain Size: fine-grained ➢ Usual color: shows variety of colors ➢ Structure: schistos ➢ Texture: fine-grained ➢ Composition: quartz, chlorite, mica, alibite, pyrite Rock 6 : Schist ➢ Grain size: fine-grained ➢ Usual color: shows variety of colors ➢ Structure: schistos ➢ Texture: fine-grained ➢ Composition: quartz, chlorite, mica, alibite, pyrite
DESIGNATED TASK 2 DESCANZO, JUAN CARLOS V. SIR RIZCHEL MASONG It is possible to use force to compress the sediments and create rock #5, which I have speculated to be a sedimentary rock. ➢ Sedimentary - Erosion and weathering include the effects of wind and rain, which progressively break large stones into smaller ones. Boulders and even mountains can erode and weather to become sediments like sand or mud. One kind of weathering is chemical weathering, often known as dissolution. This technique progressively removes stone by rinsing it in slightly acidic water. These three processes generate the constituent parts of new sedimentary rocks. ➢ Metamorphic - The preexisting rock must be exposed to extremely high temperatures, intense pressures, or hot, mineral-rich fluids. These three requirements are usually met. These conditions are most frequently seen in the Earth's crust, either there or at plate boundaries where tectonic plates collide. In order to develop metamorphic rock, the existing rock must not melt. ➢ Igneous - Igneous rocks are produced when magma (molten rock), either at volcanoes on the Earth's surface or when the melted rock is still inside the crust, cools and crystallizes. All magma forms underground because of the intense heat in the upper mantle or lower crust. b. Explain the mechanisms involved. ➢ A complex process that requires a lot of power, time, and temperature is required to change a rock from igneous to metamorphic to sedimentary. A rock needs to be heated to the point of melting in order to become an igneous rock. After cooling down, the rock solidifies as igneous rock. A rock needs to be subjected to just the right amount of heat and pressure to mould it into a metamorphic rock in order to undergo metamorphism. A rock must undergo weathering, erosion, compacting, and cementing after it has changed into a sediment in order to become a sedimentary rock. ➢ The rock cycle can be explained from any point; however, it is most convenient to begin with magma. Rock that has melted inside the Earth is known as magma. Depending on the minerals present and the pressure the rock is under, rock can melt at temperatures ranging from 800 °C to 1300 °C. Magma can create intrusive igneous rocks if it cools slowly (over thousands to millions of years) inside the Earth. Lava is the term used for magma that has
DESIGNATED TASK 2 DESCANZO, JUAN CARLOS V. SIR RIZCHEL MASONG erupted onto the surface. On the surface of the Earth, lava cools quickly (from seconds to years) and creates extrusive igneous rocks. Mountain building lifts rocks upward where they are acted upon by weathering. Weathering includes chemical processes that break
rocks apart, as well as physical processes. The results of weathering, which are primarily
tiny pieces of rock and minerals, are eroded, moved, and eventually deposited as sediments. Glaciers, streams, waves, wind, and other forces all contribute to transportation and deposition. In stream channels, lakes, deserts, and the ocean, sediments are deposited. Certain depositional environments produce distinctive sedimentary structures, such as the ripples that appear while moving sand along a river's bottom with flowing water. Sediments will eventually be covered over by more sediments unless they are re-eroded and transferred elsewhere. The sediments become compacted to depths of hundreds of meters or more, squeezing the particles closer together. Mineral crystals form between and around the atoms, fusing them together (cementing them). Rock made of sedimentary materials has been hardened and cemented. c. What are the types (specific example of igneous, sedimentary, and metamorphic) of rocks that can be found there? ➢ Limestone, dolostone, schist, gneiss, and chert are the rock types that can be found in rocks #1 and #4. Diorite, gabbro, basalt, granite, and andesite are the many types of rocks that can be found in rock #2. Rocks #3 and #5 are composed of conglomerate, shale, mudstone, sandstone, and siltstone, respectively. d. What are the possible characteristics that can be observed from the rocks present? ➢ The rocks here may have crystals, ribbon-like layers, a glassy surface, gas bubbles inside the rocks, sand and pebbles, and fossils, among other probable properties.
DESIGNATED TASK 2 DESCANZO, JUAN CARLOS V. SIR RIZCHEL MASONG j. On the other hand, metamorphic rocks can also form in this location because you can easily identify this type of rock by knowing the texture and appearance of the rock; one example of how to identify metamorphic is if the rock has layers compressed together. Possible sedimentary and metamorphic rocks can be seen here in majority due to having the process of weathering and erosion. k. Due to the location's active volcano, igneous rocks can be discovered there. Some igneous rocks are formed when lava flows from the volcano and then begin to cool. l. One of the most popular tourist destinations in the Philippines is Palawan. Here, you can see how gorgeous the rock formations are in each and every site, and you can tell that they are sedimentary because of the area's weathering and erosion. ➢ The size of the continent is the main factor in everything. Geographically speaking, the Philippines is a split country. Particularly in the Zambales region, copper is a prevalent metal. There is a contentious mine called the Dizon Mine, whose open pit mining caused environmental harm. It might be the mountain ranges of Luzon, where minerals are easier to find and more prevalent due to higher altitudes than in central Luzon's flatlands. b. As we can observe, most of the minerals that can be found on each region are non- silicates. Is it possible for us/mining industry to harvest silicate minerals? If yes, where? If no, why? ➢ Yes, in order to prevent catastrophic incidents that could lead to a series of issues, it is critical to first assess the mining area. Yes, the Philippines is a diverse nation, and depending on the region, silicate minerals including feldspar, biotite, and quartz can be found. It is possible to gather silicate minerals with a lot of investigation and mapping. There is yet more to discover and learn about the Philippines because it is a large and diverse country.
