Week-8 Assignment-8 Solution PDF

Week-8_Assignment-8_Solution 1. A river is consisting of a network of_______ in the headwater region, collects and funnels water and sediment and deposited its load to basin area through_______. a) Distributaries, Tributaries b) Tributaries, Distributaries c)...

Week-8_Assignment-8_Solution 1. A river is consisting of a network of_______ in the headwater region, collects and funnels water and sediment and deposited its load to basin area through_______. a) Distributaries, Tributaries b) Tributaries, Distributaries c) Trunk stream, Tributaries d) Distributaries, Trunk stream Answer: b) Tributaries, Distributaries Explanation: Tributaries collect water and sediment from various sources and flow into the main river. The river may have distributaries that branch off and distribute the water to various smaller channels or bodies of water. 2. A stream flowing through steep valleys in upland area debouches suddenly onto a nearly flat valley floor, decrease in slope, drop in velocity, and a decrease in its ability to carry sediment with forming_______. a) Delta b) Gorge c) Alluvial fan d) Flood plain Answer: c) Alluvial fan Explanation: When a stream flows from steep upland valleys onto a flat valley floor, it experiences a decrease in slope and velocity. This causes a reduction in its ability to carry sediment, leading to the formation of an alluvial fan - a fan-shaped deposit of sediment. 3. The Ganges-Brahmaputra delta in India and Bangladesh is an example of a) Wave dominated delta b) Gilbert delta c) Estuarine delta d) Tide dominated delta Answer: d) Tide dominated delta Explanation: The Ganges-Brahmaputra delta, located in India and Bangladesh, is an example of a tide-dominated delta. In such deltas, tidal action plays a significant role in shaping the landform. The interplay of river sediment and tidal currents results in a distinct deltaic landscape. This type of delta is characterized by numerous distributaries, tidal flats, and mudflats. 4. _______________ is an area of maximum slope and energy in the river, which generally lies on the erosional side of the meandering channel. a) Strath terraces b) Floodplain c) Thalweg d) Point bar Answer: c) Thalweg Explanation: The thalweg refers to the line connecting the lowest points along the length of a riverbed or stream channel. It represents the path of maximum flow velocity and energy, often found on the erosional side of a meandering channel. This is where the river typically has the steepest gradient, making it an important feature for understanding the dynamics of river systems. 5. ____________ is a very rapid type of downslope mass movement that involving mudflows from volcanic ash. a) Soil Creep b) Solifuction c) Debris slide d) None of these Answer: d) None of these Explanation: Lahar flow is a very rapid type of downslope mass movement that involves mudflows from volcanic ash. Therefore, “None of these” will be the correct option. 6. When ________ are saturated with water under pressure they are likely to produce a slippery foundation for any structure therefore not suitable for civil engineering structures. a) Granite b) Gneiss c) Limestone d) Shale Answer: d) Shale Explanation: When shale is saturated with water under pressure, it can become highly plastic and prone to slippage. This makes it an unsuitable foundation material for civil engineering structures, as it lacks the stability required to support the weight and forces exerted by buildings or other infrastructure. 7. Which of these is not a contributing factor to landslides? a) Water saturation b) Unstable subsurface c) Gravity d) Cohesive soil Answer: d) Cohesive soil Explanation: Cohesive soil has the high internal molecular attraction, giving it a sticky quality. Thus, Cohesive soil is not a contributing factor to landslides. 8. Koyna tunnel was excavated through which rock type that has caused rock falls and heavy leakage of water. a) Sandstone b) Granite c) Basalt d) Gniess Answer: c) Basalt Explanation: The Koyna Tunnel, located in the state of Maharashtra, India, was excavated through basalt rock. The presence of basalt rock in this region has led to challenges such as rock falls and significant water leakage issues within the tunnel. This is a common concern when tunneling through certain types of rock formations, as they can have varying degrees of structural stability and permeability. 9. The RQD is a modified percentage of the core recovery that incorporates only intact pieces of core that are __________ or greater in length along the core axis. a) 2 cm b) 5 cm c) 7 cm d) 10 cm Answer: d) 10 cm Explanation: The Rock Quality Designation (RQD) is a measure used in geology and engineering to assess the quality of rock core samples obtained from drilling. It represents the percentage of intact pieces of core that are 10 cm or greater in length along the core axis. RQD provides valuable information about the degree of rock mass fracturing and can be used to evaluate the suitability of a rock formation for construction or other engineering purposes. 10. Bieniawski (1973) published the details of a rock-mass classification called the Geomechanics Classification or the Rock Mass Rating (RMR) system which includes ______________parameters. a) Uniaxial Compressive Strength (UCS) of rock material b) Rock Quality Designation (RQD) c) Spacing of discontinuities d) All of these Answer: d) All of these Explanation: The Geomechanics Classification, also known as the Rock Mass Rating (RMR) system, was introduced by Bieniawski in 1973. It incorporates parameters such as Uniaxial Compressive Strength (UCS) of rock material, Rock Quality Designation (RQD), and spacing of discontinuities to assess the mechanical behavior and stability of rock masses. Thus, “All of these” is the correct option.  Assignment-7 Solution Earth Sciences for Civil Engineering (Hindi) 1. 2005 Muzaffarabad Earthquake in which more than 80,000 people died occurred along the________________. a) Tanda fault b) Kangra Valley fault c) Kashmir Valley fault d) Hajipur fault Answer: a) Tanda fault Explanation: The 8 October 2005 Mw 7.6 Kashmir, Pakistan, earthquake struck the westernmost part of the Indian-Eurasian collision zone, providing a rare opportunity to study a fresh thrust surface rupture, but at a sacrifice of more than 80,000 fatalities. The epicenter was located in the mountainous area ∼100 km northeast of Islamabad, and the damage was particularly concentrated in the Pakistan-controlled Jammu-Kashmir. Although no historical large earthquake along the frontal Himalaya is reported to have produced primary surface rupture, prompt analyses of satellite images after the 2005 earthquake suggested coseismic surface faulting for a distance of ∼80 km. Most of the surface rupture follows the preexisting traces of several active faults or fault segments, collectively called the Balakot–Bagh fault, the main part of which had been mapped before the earthquake as the active Tanda fault based on aerial photograph interpretation. 2. A fault is known as active fault if it moved in last _________ years. a) 10,000 b) 100,000 c) 1,000,000 d) 2,000,000 Answer: a) 10,000 Explanation: Active faults are those weak zones along which movements occurred during last 10,000 years and likely to be occur in near future. The crustal deformation is manifested on the earth's surface by displaced landforms. Active faults are considered to be source for large magnitude earthquakes in near future and are vital for seismic hazard assessment. 3. Surface expression in form of elevated cliff exposed at the surface due to faulting is known as______________. a) Terraces b) Outlier c) Inlier d) Scarp Answer: d) Scarp Explanation: A "Scarp" is a visible and often abrupt surface feature that results from the displacement along a geological fault. It is a type of topographic expression of faulting and is typically characterized by a steep, linear cliff or slope. Fault scarps form when one side of the fault has moved vertically relative to the other side, causing a noticeable offset in the landscape. 4. __________ are the features form on the fault plane indicating the direction of movement of block. a) Slickensides b) Fractures c) Lineation d) Joints Answer: a) Slickensides Explanation: Slickensides are polished, smooth, often striated surfaces found on rocks that have been subjected to frictional movement along a fault line or a fracture. They are a result of the grinding and polishing action that occurs as rocks slide past each other due to tectonic forces. Slickensides can provide important information to geologists about the direction and amount of movement along a fault, as well as the type of stress that caused the movement. They are commonly used in structural geology to analyse and interpret the history of rock deformation and faulting in a given area. 5. The earthquake on the blind fault will result in no _________ manifestation on the surface. However, those earthquakes can be studied by considering the _____________ features. a) Fault, Primary b) Rupture, Liquefaction c) Deformation, Fault plane d) Rupture, Primary Answer: b) Rupture, Liquefaction Explanation: Earthquakes on blind faults don't rupture the Earth's surface. Despite this, they can be studied by examining liquefaction features. Liquefaction happens when saturated soil temporarily loses its strength due to shaking during an earthquake, causing it to behave like a liquid. Analysing these features helps geologists understand how blind faults behave during seismic events, providing valuable information for assessing earthquake risks, particularly in regions where blind faults are present. 6. The rupture (displacement) in the subsurface often reaches the surface, when the magnitude is generally over Mw____________. a) 5.0 b) 6.0 c) 6.5 d) >7.8 Answer: d) >7.8 Explanation: In larger magnitude earthquakes, typically those with a moment magnitude (Mw) greater than 7.8, the rupture or displacement along a fault in the subsurface can extend all the way to the Earth's surface. This means that the movement of the fault is powerful enough to rupture through the ground, causing visible surface rupture. 7. Which of the geomorphic feature would be form in a strike slip fault system? a) Linear valley b) Sag Ponds c) Drainage offset  d) All of the these Answer: d) All of the these Explanation: Geomorphological features associated with strike-slip faults include offset streams, fault scarps, sag pond, transform faults, pressure ridges, pull-apart basins, linear topographic features, and fault-related mountains. These features are shaped by horizontal movement along the fault, providing valuable insights for geologists studying tectonic activity. 8. The deformation manifested on the surface due to ongoing convergence or collision between the Indian plate and Eurasian plate can be monitored from ________________. a) Total station b) Ground penetrating radar c) Elastic rebound theory d) Global positioning system Answer: d) Global positioning system Explanation: The deformation resulting from the ongoing convergence or collision between the Indian Plate and the Eurasian Plate can be tracked using the Global Positioning System (GPS). GPS technology allows scientists to precisely measure the movement of tectonic plates over time. By placing GPS stations across regions experiencing tectonic activity, scientists can monitor the displacement and deformation of the Earth's surface. This provides crucial data for understanding the dynamics of plate interactions and helps in assessing earthquake hazards in areas prone to tectonic stress. 9. There are different types of faults, which can produce scarps, although some are more likely than others, so which type of fault produce a proper fault scarp? a) Dip-slip fault b) Strike slip fault c) Oblique slip fault d) All of the above Answer: a) Dip-slip fault Explanation: Proper fault scarps are typically associated with dip-slip faults. They have a steep, linear shape and result from vertical displacement, with the hanging wall moving downward relative to the footwall or vice versa. Dip-slip fault scarps are characteristic features of regions undergoing extensional or compressional tectonic forces. Strike-slip faults, can cause surface deformation but have different characteristic features. 10. The slip direction of the hanging wall block measured in the fault plane and from the dip vector is known as ___________. a) Heave b) Throw c) Rake d) None of these Answer: c) Rake Explanation: The rake of a fault refers to the direction of slip along the fault plane. It is measured by determining the angle between the slip direction of the hanging wall block, as observed in the fault plane, and the dip vector, which is a line perpendicular to the fault plane. This measurement is crucial in understanding the mechanics and movement associated with faulting in geological contexts. Rake is typically expressed in degrees.  Assignment-5 Solution Earth Science for Civil Engineering (Hindi) 1) The reason for the __________ temperature gradient in oceanic lithosphere is because the thickness of oceanic lithosphere is ____________, whereas the temperature gradient is __________ in continental lithosphere because the thickness of continental lithosphere is __________. a) Lower, thin, higher, thick b) Higher, thick, lower, thin c) Higher, thin, lower, thick d) Lower, thick, higher, thin Answer: c) Higher, thin, lower, thick Explanation: The reason for the higher temperature in oceanic lithosphere (OL) is because the thickness of the oceanic lithosphere is ~100 km and the average geothermal gradient in oceanic lithosphere is ~1300 C/100 km or 13 C/km. Whereas, the Continental lithosphere (CL) is ~200 km thick, so the average geothermal gradient in Continental lithosphere is ~1350 C/200 km or 6.7 C/km. 2) Which type of seismic wave travels the fastest? a) P-wave (Primary wave) b) S-wave (Secondary wave) c) Love wave d) Rayleigh wave Answer: a) P-wave (Primary wave) Explanation: P-waves travel at speeds ranging from about 5 to 8 kilometers per second (km/s) through the Earth's crust, which is primarily composed of rock. The actual velocity depends on factors such as the type of rock and the physical conditions present. In comparison, S-waves (secondary waves) and surface waves propagate more slowly due to their different modes of motion and the nature of the materials they encounter. 3) The shadow zone for S-waves occurs because they cannot ___________. a) Pass through the Earth's crust b) Travel through the Earth's liquid outer core c) Be detected by seismographs d) Transmit energy efficiently Answer: b) Travel through the Earth’s liquid outer core Explanation: The outer core of the Earth is primarily composed of molten iron and nickel, which are in a liquid state due to high temperatures and pressures. Since liquids do not exhibit the necessary rigidity to transmit shear deformations, S-waves are unable to propagate through the liquid outer core. This phenomenon is a crucial piece of evidence that helped scientists infer the liquid state of the Earth's outer core and led to the development of the concept of Earth's layered interior structure. 4) Under a differential stress, major as well as minor grains will be oriented __________ to one another and ___________ to the maximum stress direction, giving the rock a distinct foliation. a) Perpendicular, parallel b) Parallel, inclined c) Perpendicular, inclined d) Parallel, perpendicular Answer: d) Parallel, perpendicular Explanation: Differential stress occurs when a rock is subjected to unequal forces in different directions. This can lead to deformation within the rock, causing minerals to change shape or reorient themselves. Under a differential stress, rocks can undergo a process called foliation, where mineral grains align themselves in a preferred orientation. This alignment creates distinct layers or bands of minerals within the rock. The orientation of these mineral layers is typically parallel to each other and perpendicular to the direction of the maximum stress. This phenomenon can be explained by the concept of stress and strain within the rock. 5) What is the focus of an earthquake? a) The point on the Earth's surface directly above the earthquake's origin b) The point deep within the Earth where the earthquake begins c) The point where two tectonic plates meet d) The point where seismic waves are the strongest Answer: b) The point deep within the Earth where the earthquake begins Explanation: The focus of an earthquake, also known as the hypocenter, refers to the point within the Earth's crust where the rupture or initial break occurs along a fault plane, resulting in the release of seismic energy. It is the actual location beneath the Earth's surface where the seismic waves originate. The focus is often described in terms of its depth below the Earth's surface. 6) How is the epicenter of an earthquake typically determined? a) By measuring the depth of the focus b) By analyzing the types of seismic waves generated c) By triangulating the arrival times of seismic waves at multiple recording stations d) By calculating the energy released by the earthquake Answer: c) By triangulating the arrival times of seismic waves at multiple recording stations. Explanation: The epicenter of an earthquake is determined by analyzing arrival times of seismic waves from the earthquake at multiple seismographic stations. The intersection of circles drawn around these stations reveals the likely epicenter location through triangulation. 7) The curb in California, has been offset by creep along the __________ fault. a) Hayward fault b) San Andreas c) San Gregorio d) Rodgers Creek Answer: a) Hayward fault. Explanation: The Hayward Fault in California is well known for experiencing fault creep. This movement is observable through features such as offset sidewalks, curbs, fences, and other structures that are gradually displaced over time. Fault creep occurs due to the ongoing accumulation of tectonic stress in the Earth's crust. As stress builds up along the fault, it is released through steady movement rather than in the form of sudden, jarring earthquakes. 8) The elastic rebound theory explains the release of accumulated strain energy during: a) Volcanic eruptions b) Earthquakes c) Tsunamis d) Landslides Answer: b) Earthquakes. Explanation: The elastic rebound theory explains how faults store and release energy through earthquakes. As the tectonic forces continue to push and deform the Earth's crust, stress accumulates along faults until it reaches a critical point, leading to sudden fault movement and the release of seismic energy. 9) Which type of stress is responsible for the elongation and stretching of rock? a) Tensional stress b) Compressional stress c) Shear stress d) Uniform stress Answer: a) Tensional stress. Explanation: Tensional stress is a type of stress that acts to pull apart or stretch a material. It is responsible for the elongation and stretching of rocks and other materials. When tensional stress is applied to a rock, the material experiences a strain that causes it to become longer in the direction of the applied force. This is known as "extensional" or "stretching" deformation. 10) Differential stress involves: a) Equal forces acting in all directions b) A single force acting in one direction c) Rock deformation due to unequal forces in different directions d) The absence of any forces acting on a rock Answer: c) Rock deformation due to unequal forces in different directions Explanation: Differential stress refers to the unequal forces or stresses acting on different planes within a material. It is a type of stress that causes deformation or changes in shape within the material. When differential stress is applied to a substance, the material can experience different types of strain and deformation depending on its response to the varying stress magnitudes on different planes.  Assignment-6 Solution Earth Science for Civil Engineering (Hindi) 1. Vibration in the shorter buildings are by the Hz range of frequency near to the epicenter. a) 0.01-0.3 b) 0.3-0.5 c) 0.5-20 d) 20-100 Answer: c) 0.5-20 Explanation: Vibrations in shorter buildings near the epicenter of an earthquake can indeed span a wide range of frequencies, typically between 0.5 to 20 Hz. This broad frequency range occurs due to the complex nature of seismic waves generated by an earthquake. This variability in frequency content can make it challenging to design structures to withstand the full spectrum of earthquake-induced vibrations. Engineers use various techniques to account for this complexity when designing buildings in seismically active regions. 2. represents the effects (ground shaking and damage) of an earthquake at a particular place based on the observations of the affected areas. a) Magnitude b) Shaking c) Frequency d) Intensity Answer: d) Intensity Explanation: The intensity of an earthquake refers to the measure of its effects at a specific location on the Earth's surface. It quantifies the impact of the earthquake in terms of damage to buildings, infrastructure, and the environment, as well as its potential to cause harm to people and animals. 3. are the waves which primarily travel along the uppermost layers of the Earth and are responsible for major destruction to the locations near the epicentre. a) P wave b) S wave c) Rayleigh wave d) None of these Answer: c) Rayleigh wave Explanation: Surface waves are a type of seismic wave that travel along the Earth's surface, causing the ground to move in a rolling or swaying motion during an earthquake. Unlike body waves, which propagate through the Earth's interior, surface waves travel along the outermost layer of the Earth. There are two primary types of surface waves: Love waves and Rayleigh waves. 4. Which of the following magnitude scales is now used worldwide for measuring moderate and large magnitude earthquakes?  a) Richter scale (ML) b) Surface wave magnitude (Ms) c) Body-wave magnitude d) Moment magnitude (Mw or M) Answer: d) Moment magnitude (Mw or M) Explanation: The moment magnitude scale (Mw), often denoted as simply "magnitude," is now the scale that is widely used worldwide for measuring moderate and large magnitude earthquakes. The moment magnitude scale is considered the most accurate and consistent scale for quantifying the size of earthquakes, especially for events of magnitude 3.0 and above. It replaced the older Richter scale and other magnitude scales because it provides a more comprehensive and consistent measure of earthquake size across a wide range of magnitudes. 5. Deep focus earthquakes occur 300-700 km deep within the subduction zones and are also called as. a) Trenches b) Wadati-Beniof f zones c) Transform Fault Margins d) Seismic shadow zones Answer: b) Wadati-Benioff zones Explanation: Wadati-Benioff zone is a region in the Earth's crust and upper mantle where a series of earthquakes occur along a dipping plane. These earthquakes are typically deep-focus earthquakes, meaning that they originate at depths ranging from about 70 kilometers (43 miles) to several hundred kilometers (over 600 miles) below the Earth's surface. This distinguishes them from shallow-focus earthquakes that occur in other tectonic settings. 6. The moment magnitude (Mw) of the earthquake on the Kangra Valley Fault was of around from the computed seismic moment in the previous studies. a) 5 Mw b) 6.5 Mw c) 7.5 Mw d) 9 Mw Answer: c) 7.5 Mw Explanation: The moment magnitude (Mw) of the Kangra Valley earthquake of 1905 has been estimated at around 7.5 in previous studies. These estimates are based on historical data and seismic observations, and they provide a range rather than a precise value for the earthquake's magnitude. Different studies may produce slightly different magnitude estimates, but they generally fall within this range. 7. Stereographic projections display geometries and orientations of lines and planes i.e. the strike and dip of the planes, which is used for solving. a) Apparent dip b) trend and plunge of the intersection of two planes c) Angle between planes  d) All of these Answer: d) All of these Explanation: Stereographic projections are used in geology to analyze and visualize the orientation of geological features such as rock layers, fault surfaces, and linear structures. They help geologists solve problems related to structural analysis, strain analysis, fault analysis, geological mapping, and geotechnical engineering. Stereographic projections provide a two-dimensional representation of three-dimensional geological orientations such as Apparent dip, trend and plunge of the intersection of two planes and angles between planes, aiding in the interpretation of rock structures and tectonic processes. 8. If both the limb angles are similar concerning the vertical axial plane, then they are known as. a) Symmetrical fold b) Asymmetrical fold c) Recumbent fold d) Overturned fold Answer: a) Symmetrical fold Explanation: A symmetrical fold is a type of geological fold in which the two limbs of the fold are essentially mirror images of each other, and the fold axis (the line connecting the hinge points of the fold) is horizontal. In other words, the two limbs of a symmetrical fold dip at the same angle in opposite directions, and the axial plane (the imaginary plane that divides the fold into two symmetrical halves) is vertical. 9. A is a type of fold with the successive older beds to its core and a concave upward form. a) Syncline b) Anticline c) Monocline d) Recumbent Answer: a) Syncline Explanation: A syncline is a type of fold with the successive older beds to its core and a concave upward side. 10. is a line of the maximum curvature in the folded bed. a) Axial Plane b) Hinge c) Fold Axis d) Dip Answer: b) Hinge Explanation: The "hinge" is the term used to describe the line of maximum curvature in a folded bed or geological fold. The hinge line runs along the axis of the fold and represents the point where the curvature of the rock layers is most pronounced.  Assignment 3 1) ___________ forms during fast cooling process of magma containing gas. (a) Bombs (b) Lapilli (c) Pumice (d) Obsidian Answer: (C) Explanation: Pumice is a type of extrusive volcanic rock, produced when lava with a very high content of water and gases is discharged from a volcano. As the gas bubbles escape, the lava becomes frothy. When this lava cools and hardens, the result is a very light rock material filled with tiny bubbles of gas. 2) The volcanic province in India is termed as (a) Gondwanaland (b) Deccan (c) Eastern Ghat Mobile Belt (d) Vindhyan Answer: (b) Explanation: The Deccan Volcanic Province has been considered as one of the largest magmatic regions, involving an aerial coverage of ca. 500,000 km2. 3) Igneous plutonic rock forms at the later stage of crystallization (a) Pumice (b) Pegmatite (c) Vesicular (d) Pyroclastic Answer: (b) Explanation: Pegmatites form from waters that separate from a magma in the late stages of crystallization; this activity often occurs in small pockets along the margins of a batholith. 4) Which silicate groups of rocks, such as micas, have platy, lamellar or flaky characteristics, i.e. occurring in rock orient themselves parallel to one another? (a) Inosilicate (b) Sorosilicate (c) Sheet silicate (d) Single chain silicate Answer: (c) Explanation: Sheet silicate groups of rocks, such as micas, have platy, lamellar or flaky characteristics, i.e., occurring in rock orient themselves parallel to one another. 5) Cleavage is said to be _________ when it occurs perpendicular to the major axis of the  mineral. (a) Prismatic (b) Cubic (c) Basal (d) Rhombohedral Answer: (c) Explanation: Cleavage is said to be basal when it occurs perpendicular to the major axis of the mineral, and prismatic when it occurs parallel to the major axis. 6) _________ is the last mineral to crystallize according to Bowen’s reaction series. (a) Quartz (b) Muscovite (c) Pyroxene (d) Na-Plagioclase Answer: (a) Explanation: Bowen's reaction series is a means of ranking common igneous silicate minerals by the temperature at which they crystallize. Minerals at the top have a relatively high crystallization temperature, which means that they will be the first minerals to crystallize from a magma that is cooling. If they are chemically compatible with the magma as it continues to cool, they will grow larger by addition of external layers of additional material. If they are chemically incompatible, they will react with the melt. What ultimately determines this chemical compatibility is in large part the total silica content of the melt. 7) The characteristic symmetry of cubic system is: (a) a ≠ b ≠c; alpha = gamma = 900; beta > 900. (b) a = b =c; alpha = gamma = beta= 900. (c) a ≠ b ≠c ≠ d; alpha = beta = 1200 and gamma= 900. (d) a = b ≠ c; alpha = beta= 1200 and gamma= 900. Answer: (b) Explanation: The cubic lattice is the most symmetrical of the systems. All the angles are equal to 90°, and all the sides are of the same length (a = b = c). Only the length of one of the sides (a) is required to describe this system completely. 8) __________ has zero cleavage because it has equally strong bonds Si-O bonds in all directions. (a) Biotite (b) Fluorite (c) Sphalerite (d) Quartz Answer: (d) Explanation: Quartz has zero cleavage because it has equally strong bonds Si-O bonds in all directions. 9) ___________ minerals having same chemical composition but different crystal structure. (a) Polymorph (b) Isomorph (c) Pseudomorph (d) Pegmatitic Answer: (a) Explanation: A polymorph is a mineral with the same chemical composition but a different internal structure. Aragonite and calcite are polymorphs – both contain calcium carbonate (CaCO3) but have different internal structures. 10) ______________ form when magma erupts at the surface, rapidly cooling to fine ash or lava and developing glassy texture. (a) Intrusive igneous rocks (b) Sedimentary rocks (c) Extrusive igneous rocks (d) Metamorphic rocks Answer: (c) Explanation: Extrusive igneous rocks form when magma erupts at the surface, rapidly cooling to fine ash or lava and developing glassy texture.  Assignment 4 Solution 1) 75% of land surface on the earth is covered by thin veneer of ___________. (a) Igneous rocks (b) Metamorphic rocks (c) Sedimentary rocks (d) Alluvium Answer: c) Sedimentary rocks Explanation: The process of weathering, erosion, and deposition takes place on the land surface which led to conversion of igneous, sedimentary, and metamorphic rocks to sedimentary rocks. Thus, 75% of land surface on the earth comprises of thin veneer of sedimentary rocks. 2) Which of the following criteria is essential for the cementing material to have a firm grip in sedimentary rock? (a) Size of grains (b) Composition of grains (c) Shape of grains (d) All of them Answer: d) All of them Explanation: In sedimentary rock formation, cementing materials, often minerals that precipitate from pore waters, fill the spaces between individual sediment grains. As these materials solidify, they create a binding matrix that holds the sediment grains together, forming a cohesive rock. For this cementing process to be successful and result in a durable rock structure, the three criteria mentioned—size, composition, and shape of grains—need to be taken into consideration. These criteria collectively determine how well the cementing material can establish a firm grip, thus contributing to the overall integrity and strength of the sedimentary rock. 3) ___________ forms basically from calcium carbonate- both by chemical leaching and by organic source. (a) Limestone (b) Gypsum (c) Coal (d) Shale Answer: a) Limestone Explanation: Limestone can form through a chemical process involving the dissolution and precipitation of calcium carbonate. Limestone can also originate from organic sources. In marine environments, various organisms such as corals, mollusks, and microorganisms build their skeletons and shells using calcium carbonate extracted from the surrounding water. Over time, as these organisms die and accumulate on the ocean floor, their calcium carbonate-rich remains can compact and lithify (turn into solid rock) to form limestone. 4) Metamorphic changes that occur as temperature and pressure are declining (with less inter- granular fluid) are called __________ metamorphic effects. (a) Retrograde (b) Regional  (c) Contact (d) Prograde Answer: a) Retrograde Explanation: When the pressure and temperature decrease due to geological processes such as uplift and erosion, the rock may undergo retrograde metamorphism. 5) Sediments size between 2-64 mm termed as: (a) Cobble (b) Boulder (c) Pebble (d) Granule Answer: c) Pebble Explanation: Clay: Particles smaller than 0.002 mm in diameter, Silt: Particles ranging from 0.002 mm to 0.063 mm in diameter, Sand: Particles ranging from 0.063 mm to 2 mm in diameter, Pebble: Particles ranging from 2 mm to 64 mm in diameter, Cobble: Particles ranging from 64 mm to 256 mm in diameter, Boulder: Particles larger than 256 mm in diameter. 6) Which of the following sequence having from lowest to highest grade of metamorphic rock? (a) Gneiss, schist, phyllite, slate (b) Slate, phyllite, schist, gneiss (c) Schist, phyllite, gneiss, slate (d) Phyllite, schist, gneiss, slate Answer: b) Slate, phyllite, schist, gneiss Explanation: The sequence from slate to phyllite to schist to gneiss reflects an increase in metamorphic grade, which is associated with higher temperatures, pressures, and more intense geological conditions. Slate is formed at lowest grade of metamorphism and gneiss is formed at highest grade of metamorphism. As the metamorphism progresses, the rocks undergo changes in mineral composition and texture, leading to distinct visual characteristics in each rock type. 7) In a provenance, the majority of sediments are ___________, which can be interpreted as less distance transport. (a) Rounded (b) Angular (c) Highly sorted (d) Very fine Answer: b) Angular Explanation: When sediments are angular, it suggests that they haven't travelled over long distances. Angularity is an indicator that the sediments haven't been exposed to extended transportation, which would have caused them to become rounded through abrasion and attrition. In environments where sediments are quickly eroded and deposited near their source areas, they may not have enough time to be rounded, resulting in an angular appearance. 8) Which silicate groups of rocks, such as micas, have platy, lamellar or flaky characteristics, i.e. occurring in rock orient themselves parallel to one another? (a) Inosilicate (b) Sorosilicate (c) Sheet silicate (d) Single chain silicate Answer: c) Sheet silicate Explanation: The sheet-like structure of Sheet silicates gives them unique properties, including excellent cleavage along the plane of the sheets. This cleavage allows these minerals to be easily split into thin, flexible layers or flakes. Sheet silicates often have important roles in geology, as they can influence the properties of rocks, such as their strength, stability, and weathering behavior. Micas, for example, are commonly found in igneous, metamorphic, and sedimentary rocks and can have significant implications for the properties of these rocks. 9) Argillaceous rocks predominantly consist of (a) Sand (b) Shale (c) Silt (d) Clay Answer: d) Clay Explanation: Argillaceous rock is a type of sedimentary rock that is primarily composed of clay minerals and other fine-grained particles. The term "argillaceous" comes from the word "argill," which is an old term for clay. These rocks are often characterized by their fine-grained nature, which is a result of the small size of the clay particles they contain. 10) Cross-bedding observed in sand dunes can be used to determine: (a) Speed of the wind (b) Height of the sand dune (c) Direction of the wind (d) All the above Answer: c) Direction of the wind Explanation: Cross-bedding occurs as sand grains are transported by the wind and accumulate on the downwind side of the dune. The inclined layers, or cross-beds, are formed as the sand is deposited in the lee side (the side sheltered from the wind) of the dune. These inclined layers are characteristic of the way sediment accumulates in dune environments. By analyzing the direction of the cross-bedding, geologists can determine the direction in which the wind was blowing when the dunes were forming.  Assignment 2 1) The principle of ___________ governs the rise or subsidence of the crust until the mass is buoyantly balanced so that all parts of the lithosphere are in a floating equilibrium. a) Plate Tectonics b) Sea floor spreading c) Isostasy d) Uniformitarianism Answer: C) Isostasy Explanation: Isostasy is the rising or settling of a portion of the Earth's lithosphere that occurs when weight is removed or added in order to maintain equilibrium between buoyancy forces that push the lithosphere upward, and gravity forces that pull the lithosphere downward. 2) The lithosphere of the earth is the __________. a) Rigid part b) Partially melted part c) Completely melted part d) Oceanic part Answer: a) Rigid Part Explanation: The upper part of the earth Mantle and crust, together known as the Lithosphere and it is a rigid part. 3) The principle of ___________ given by Alfred Lothar Wegener deals with the supercontinent named Pangea and due to its breakup and movement of landmasses away or towards each other gave us the continents lying at their present position. a) Plate Tectonics b) Continental Drift c) Earth Dynamics d) Isostasy Answer: b) Continental Drift Explanation: The continental drift theory was proposed by the Alfred Wegner which deals with the supercontinent named Pangea and due to its breakup and movement of landmasses away or towards each other gave us the continents lying at their present position. 4) The ________________, are characterized by shallow focus earthquake zones and chains of submerged mountains are densely distributed. a) Island arcs b) Subduction zones c) Transform faults d) Mid-oceanic ridges Answer: d) Mid Oceanic Ridges Explanation: The shallow submerged ridge in the Atlantic Ocean is known as the mid oceanic ridges. This is the region of shallow focus earthquake because of the divergent plate boundary. 5) Hawaiian Island chain is the result of ___________. a) Collision of two oceanic plates b) Intraplate hot spot activity c) Divergence of two oceanic palates d) Interplate hot spot activity Answer: b) Intraplate hot spot activity Explanation: The Hawaiian volcanic island chain is a result of the intraplate hot spot activity. When a lithospheric plate moves over the Hot spot plume such type of volcanic chains are forming. 6) The highest point (8850 m) and the lowest point (11035 m) on the earth are the result of two plates ____________ against each other. a) Diverging b) Converging c) Transverse d) Both a &b Answer: b) Converging Explanation: The highest and the lowest point on the earth is a result of the convergent-convergent plate boundary collision. The mount Everest and the Mariana trench is the highest and lowest point on the earth respectively. 7) Majorly crust is composed of _________ elements that constitute most of the rock- forming minerals. a) Iron, Magnesium b) Silicon, Oxygen c) Silicon, Iron d) Aluminium, oxygen Answer: b) Silicon, Oxygen Explanation: The earth crust is composed with 47% of Oxygen and 28% of silicon. 8) At _______________, a new lithospheric layer is produced as the new molten magma rises up due to the convection cells from the asthenosphere or from core-mantle boundary. a) Convergent boundaries b) Divergent boundaries c) Transform boundaries d) Mid-oceanic ridges Answer: b) Divergent Boundaries Explanation: At divergent boundary, a new lithospheric layer is produced as the new molten magma rises up due to the convection cells from the asthenosphere or from core-mantle boundary. 9) The ________________ discontinuity that demarcates between crust and mantle, marks  the density and leading to P and S wave velocity differences. a) Conrad b) Lehmann c) Mohorovicic d) Gutenberg Answer: c) Mohorovicic Explanation: The crust and Mantle is demarcated with Mohorovic discontinuity where we can see the gradual change of the P and S waves. 10) The type of plate boundary existed between Indian and Eurasian plate is: a) Convergent plate boundary b) Transform plate boundary c) Divergent plate boundary d) Transcurrent plate boundary Answer: a) Convergent plate boundary Explanation: The Indian and Eurasian plates are the continental plate so the boundary between them is the continental plate boundary.  Assignment – 1_Solution (Earth Sciences for Civil Engineering (Hindi)) 1. _________ and _________ epochs belongs to the Quaternary period. (a) Holocene and Pleistocene (b) Pliocene and Miocene (c) Holocene and Miocene (d) Pliocene and Pleistocene Answer: (a) Holocene and Pleistocene. Explanation: The Quaternary period is divided into two epochs, from youngest to oldest i.e., the Holocene and Pleistocene. 2. The “Supernova” explosion took place at around _________ years ago. (a) 7 billion (b) 7 million (c) 12 billion (d) 12 million Answer: (a) 7 billion. Explanation: At around 7 billion years ago an explosion occurred which was called as “Supernova”. 3. When magma rises from deep in the mantle, it fprms new oceanic crust at _________ (a) Collision zone (b) Subduction zone (c) Transform plate boundary (d) Mid-oceanic ridges Answer: (d) Mid-oceanic ridges. Explanation: The production of new seafloor and oceanic lithosphere results from mantle upwelling in response to plate separation. The melt rises as magma at the linear weakness between the separating plates, and emerges as lava, creating new oceanic crust and lithosphere upon cooling also called Mid-oceanic ridges. 4. Ocean ridge system is a continuous belt of _________ km and it is a prominent feature in ocean (a) 6500 km (b) 65 km (c) 65,000 km (d) 650 km Answer: (c) 65,000 km. Explanation: The first discovered mid-ocean ridge was the Mid-Atlantic Ridge, which is a spreading center that bisects the North and South Atlantic basins; hence the origin of the name 'mid-ocean ridge'. The mid-ocean ridge system thus is the longest mountain range on Earth, reaching about 65,000 km (40,000 mi). 5. Seismic waves characterize the internal structure of the earth and nature of its layers, which suggest that the outer core and the inner core are ______________respectively. (a) liquid and solid (b) solid and liquid (c) plastic and liquid (d) liquid and plastic Answer: (a) liquid and solid. Explanation: Inner core is the centre and the hottest layer of the Earth. The inner core is solid and made up of iron and nickel with temperatures up to 5,500oC. The outer core of the Earth is similar to a very hot ball of metals, whose temperature is around 4000oF to 9000oF. The outer core is so hot that the metals inside are all liquid. 6. Low-density rocks float _________ and have _________ roots, whereas high-density rocks float _________ and have _________ roots. (a) high, deep, low, shallow (b) low, deep, high, shallow (c) high, shallow, low, deep (d) low, shallow, high, deep Answer: (a) high, deep, low, shallow. Explanation: Because of isostasy, all parts of the lithosphere are in a floating equilibrium. Low-density wood blocks float high and have deep roots, whereas high-density blocks float low and have shallow roots. 7. The principle of isostasy governs the rise or subsidence of the _________ until the mass is buoyantly balanced. (a) Outer Core (b) Lower Mantle (c) Mantle (d) Crust Answer: (d) Crust. Explanation: The principle of isostasy governs the rise or subsidence of the crust until the mass is buoyantly balanced. Because of isostasy, all parts of the lithosphere are in a floating equilibrium. 8. The Geodynamo system involves interactions between the _________ and _________. (a) Crust and Mantle (b) Upper Mantle and Lower Mantle (c) Inner and outer core (d) Continental and oceanic crust Answer: (c) Inner and outer core. Explanation: The dynamo mechanism that generates the Earth's magnetic field: Convection currents of fluid metal in the Earth's outer core, driven by heat flow from the inner core, organized into rolls by the Coriolis force, generate circulating electric currents, which supports the magnetic field. 9. The heat flowing out of the Earth’s _________ causes convection that generates and maintains the magnetic field. (a) Inner Core (b) Upper Mantle (c) Lowe Mantle (d) Outer Core Answer: (d) Outer core. Explanation: The dynamo mechanism that generates the Earth's magnetic field: Convection currents of fluid metal in the Earth's outer core, organized into rolls by the Coriolis force, generate circulating electric currents, which supports the magnetic field. 10. The _________ discontinuity marks the boundary between Outer and Inner core. (a) Mohorovicic (b) Repetti (c) Lehmann (d) Gutenberg Answer: (c) Lehmann. Explanation: It is the transition zone between outer and inner core. The Lehmann discontinuity is an abrupt increase of P-wave and S-wave velocities at the depth of 220 km.