H3 REPORT #1 PDF - Geology for Civil Engineers - Mindanao State University

Republic of The Philippines Mindanao State University– Iligan Institute of Technology Andres Bonifacio Avenue, Tibanga, Iligan City College of Engineering WRITTEN REPORT CVE 104 (H3) Geology for Civil Engineers...

Republic of The Philippines Mindanao State University– Iligan Institute of Technology Andres Bonifacio Avenue, Tibanga, Iligan City College of Engineering WRITTEN REPORT CVE 104 (H3) Geology for Civil Engineers Bachelor of Science in Civil Engineering Submitted to : ENGR. RENGIE P. BAGARES Department of Civil Engineering and Technology Submitted by : Amer Shakil S. Bacaro Nur Rhyan M. Mangorac Abdul Raffy D. Sigayan August 29, 2024  I. History of Geology The history of geology traces the development of our understanding of Earth’s structure, materials, and processes over time. From ancient civilizations observing rocks and minerals to the emergence of modern scientific theories, geology has evolved through centuries of inquiry and discovery. Key breakthroughs, such as the concept of deep time, the study of fossils, and the revolutionary theory of plate tectonics, have shaped geology into a comprehensive science that explains how Earth’s landscapes formed and continue to change. Today, geology plays a crucial role in addressing environmental challenges and exploring the planet’s future. Ancient Observations and Early Theories (Pre-17th Century) Aristotle (384–322 BCE) made critical observations of the slow rate of geological change. He observed the composition of the land and formulated a theory where the Earth changes at a slow rate and that these changes cannot be observed during one person's lifetime. Aristotle developed one of the first evidence-based concepts connected to the geological realm regarding the rate at which the Earth physically changes. Theophrastus (371–287 BCE), a student of Aristotle, wrote On Stones, one of the earliest treatises on minerals and fossils. He described many minerals and ores both from local mines such as those at Laurium near Athens, and further afield. He also quite naturally discussed types of marble and building materials like limestones, and attempted a primitive classification of the properties of minerals by their properties such as hardness. Much later in the Roman period, Pliny the Elder (Gaius Plinius Secundus) produced a very extensive discussion of many more minerals and metals then widely used for practical ends. He also laid the basis of crystallography by recognizing the octahedral habit of diamond.  During the Islamic Golden Age, scholars like Avicenna (Ibn Sina) (980–1037 CE) made significant contributions. Avicenna proposed that mountains and rock layers were formed through natural processes like erosion and sedimentation, and he recognized the role of time in geological change. Ibn Sina wrote an encyclopedic work entitled "Kitab al-Shifa" (the Book of Cure, Healing or Remedy from ignorance), in which Part 2, Section 5, contains his commentary on Aristotle's Mineralogy and Meteorology, in six chapters: Formation of mountains, The advantages of mountains in the formation of clouds; Sources of water; Origin of earthquakes; Formation of minerals; The diversity of the Earth's terrain. Renaissance and the Dawn of Modern Geology (16th–18th Century) The Renaissance saw a revival of scientific inquiry, including the study of Earth’s materials. Georgius Agricola (1494–1555), a German scholar, published De Natura Fossilium (1546), a foundational text in mineralogy, and De Re Metallica (1556), which detailed mining techniques and the classification of minerals. Agricola’s work was critical in moving geology from speculation to systematic observation. During the 17th and 18th centuries, major debates emerged regarding Earth’s formation. One such debate was between the Neptunists, led by Abraham Werner, who believed all rocks precipitated from a primordial ocean, and the Plutonists, led by James Hutton, who argued that rocks formed from volcanic activity and deep-earth processes. Hutton’s Theory of the Earth (1785) introduced the concept of uniformitarianism, which states that Earth’s features were shaped by continuous, gradual processes over vast timescales—an idea summarized as "the present is the key to the past." These contrasting theories offered differing explanations of how the rock layers of the Earth's surface had formed. One suggested that a liquid inundation, perhaps like the biblical deluge, had created all geological strata. Werner's views become internationally influential around 1800. He argued that the Earth's layers, including basalt and granite, had formed as a precipitate from an ocean that covered the entire Earth. The Neptunist thesis was the most popular during the late eighteenth century, especially for those who were chemically trained. However, another thesis slowly gained currency from the 1780s forward. Instead of water, some mid-eighteenth-century naturalists such as Buffon had suggested that strata had been formed through heat (or fire). The thesis was modified and expanded by the Scottish naturalist James Hutton during the 1780s. He argued against the theory of Neptunism, proposing instead the theory of based on heat. Those who followed this thesis during the early nineteenth century referred to this view as Plutonism: the formation of the Earth through the gradual solidification of a molten mass at a slow rate by the same processes that had occurred throughout history and continued in the present day. This led him to the conclusion that the Earth was immeasurably old and could not possibly be explained within the limits of the chronology inferred from the Bible. Plutonists believed that volcanic processes were the chief agent in rock formation, not water from a Great Flood. The Birth of Modern Geology (Late 18th–19th Century) In 1785, Hutton presented his Theory of the Earth, proposing the principle of uniformitarianism—the idea that Earth’s features were shaped by continuous, slow processes, not sudden catastrophes. This concept introduced the notion of "deep time," the vast timescales over which geological processes operate. The 19th century was a turning point in the development of geology as a science. William Smith, a British surveyor, developed the principle of faunal succession. By observing the order of fossils in rock layers, he created the first geological map of England in 1815, which helped establish stratigraphy—the study of layered rock formations. Charles Lyell (1797–1875) built on Hutton’s ideas and popularized them through his influential book Principles of Geology (1830–1833). Lyell’s work emphasized uniformitarianism and deep time, arguing that slow, consistent processes—like erosion and sedimentation—were responsible for shaping Earth’s features over millions of years. His ideas influenced many scientists, including Charles Darwin, whose theory of evolution was partly based on the concept of gradual geological change. Advancements in Paleontology and the Geological Time Scale The study of fossils and stratigraphy in the 19th century led to the creation of the geological time scale, dividing Earth’s history into eras, periods, and epochs based on rock formations and fossil records. Key contributors included Georges Cuvier (1769–1832), who developed the concept of extinction and used fossil evidence to argue that catastrophic events shaped Earth’s history, contrasting with Lyell’s uniformitarianism. By the mid-19th century, geologists divided Earth’s history into eras, periods, and epochs based on fossil records and stratigraphy. Key divisions include the Paleozoic, Mesozoic, and Cenozoic eras. The 20th Century and the Revolution of Plate Tectonics The 20th century brought a revolutionary understanding of Earth’s dynamics with the development of plate tectonics. Alfred Wegener (1880–1930) proposed the theory of continental drift in 1912, suggesting that continents were once part of a supercontinent called Pangaea before drifting apart. Although his ideas were initially rejected due to the lack of a mechanism, further evidence of seafloor spreading and the discovery of mid-ocean ridges in the 1950s and 1960s confirmed the theory. The theory of plate tectonics, which explains that Earth’s lithosphere is divided into tectonic plates that move over the asthenosphere, became the unifying framework for geology. It explained the origins of earthquakes, volcanoes, mountain ranges, and the distribution of continents, transforming geology into a more coherent and predictive science. Modern Geology (Late 20th Century to Present) In the late 20th and early 21st centuries, geology has expanded to include environmental and applied studies. Fields like environmental geology address issues such as resource management, climate change, and natural hazards. Advances in radiometric dating have refined the geological time scale, and planetary geology has provided new insights into Earth’s processes by studying other celestial bodies. The study of other planets and moons (such as Mars and the Moon) has expanded our knowledge of geological processes and offered insights into Earth’s history. Geology today is an interdisciplinary science, incorporating principles from chemistry, physics, biology, and environmental science to explore everything from Earth’s deep history to future planetary changes. Conclusion The history of geology is a journey from ancient philosophical speculation to a sophisticated scientific discipline. From the debates between Neptunists and Plutonists to the revolutionary concept of plate tectonics, geology has evolved through discoveries that have reshaped our understanding of Earth’s past, present, and future. As the study of Earth continues to expand, geology remains central to understanding the planet and addressing the challenges of sustainability and environmental change. Sources: 1. Principles of Geology by Charles Lyell (1830–1833). 2. Rudwick, M. J. S. Bursting the Limits of Time: The Reconstruction of Geohistory in the Age of Revolution. University of Chicago Press, 2005. 3. Winchester, Simon. The Map That Changed the World: William Smith and the Birth of Modern Geology. HarperCollins, 2001. 4. Allègre, Claude J. From Stone to Star: A View of Modern Geology. Harvard University Press, 1994. 5. Engineer’s Circle. IMPORTANCE OF CIVIL ENGINEERING IN GEOLOGY. 2022. https://www.valuerworld.com/2022/01/10/importance-of-geology-in-civil-engineering/ 6. Wikipedia. History of Geology. 2024. https://en.wikipedia.org/wiki/History_of_geology 7. Nicholas F. Kauffman. Geotechnical Failures. https://www.capitalgeotechnical.com/geotechnical-failures.html  II. History of Geology Several branches of geology are closely related to civil engineering, providing critical insights into the Earth's materials and processes that affect construction and infrastructure projects. Here are the key branches of geology relevant to civil engineering. Petrology Petrology is a branch of geology that focuses on the study of rocks, their origin, composition, structure, and the processes that have formed and altered them over time. It provides crucial insights into understanding the Earth's crust and mantle and plays a significant role in various geological and engineering applications. Structural Geology Structural Geology is the branch of geology that focuses on the study of the deformation of rocks and the structures formed as a result. It investigates the processes that cause rocks to fold, fault, and fracture, as well as the stress and strain associated with these deformations. Structural geology is essential for understanding the tectonic processes that shape the Earth's crust and for applications in natural resource exploration, engineering, and geohazard assessment. Geochemistry Geochemistry is the study of the Earth's chemical composition and the processes that govern the distribution and cycling of chemical elements and their isotopes. It integrates principles from chemistry, physics, biology, and geology to understand the Earth's systems, from the deep interior to its surface, and extends to studying the chemical characteristics of other planets. Environmental Geology Environmental Geology is the branch of geology that focuses on the interactions between humans and the geological environment. It involves studying how geological processes and materials impact human activities and how human actions affect the Earth. Environmental geology plays a critical role in managing natural resources, assessing geological hazards, mitigating environmental impacts, and planning sustainable land use. Geophysics Geophysics is the branch of geology that applies principles of physics to study the Earth's interior and its physical properties. It involves investigating the Earth's subsurface, atmosphere, oceans, and magnetic and gravitational fields using various methods such as seismic waves, gravity, magnetism, electrical conductivity, and electromagnetism. Geophysics is essential for understanding geological processes, exploring natural resources, and assessing geohazards. Paleontology Paleontology is the scientific study of the history of life on Earth through the examination of plant and animal fossils. It integrates knowledge from geology, biology, chemistry, and ecology to reconstruct the evolution of life and the interactions between organisms and their environments over geological time. Paleontologists analyze fossilized remains, such as bones, shells, leaf impressions, and footprints, to understand extinct species, evolutionary processes, and past ecosystems. Mineralogy Mineralogy is the branch of geology that focuses on the study of minerals, their properties, structure, composition, classification, and the processes that lead to their formation. Minerals are naturally occurring, inorganic solids with a definite chemical composition and a crystalline structure. Mineralogy is fundamental to understanding the composition of the Earth's crust and mantle, as well as the processes that shape the planet's geology. Geomorphology Geomorphology is the scientific study of landforms and the processes that shape them. It involves understanding the formation, evolution, and classification of Earth's surface features, from mountains and valleys to deserts and coastlines. Geomorphologists examine the physical landscape to interpret past environmental conditions, understand current processes, and predict future changes. Hydrogeology Hydrogeology is the branch of geology that focuses on the distribution, movement, and quality of groundwater. It combines principles from geology, hydrology, and environmental science to study how water interacts with geological materials beneath the Earth's surface. Hydrogeologists investigate groundwater resources, assess water quality, and evaluate the impacts of human activities on aquifers and water supplies. Conclusion These branches of geology provide essential data and insights that help civil engineers make informed decisions about site selection, design, construction methods, and hazard mitigation for safe and sustainable infrastructure development. III. Earth Structure and Composition Introduction Around 4.6 billion years ago, the Earth was believed to have started to form. It all began with a disk-shaped cloud of dust and gas rotating around the early sun, made up of material left behind after the sun’s formation. Gas and dust particles of different sizes within the said disk, orbited the sun at slightly different speeds, which allowed them to bump into each other and stick together. Eventually, they grew from tiny dust grains into boulders, then into larger “planetesimals” that ranged from miles to hundreds of miles in diameter. It is believed that about 20 million years after the formation of the Earth, about 30 to 65 percent of the Earth melted due to the build up of heat throughout those years. The heat was caused by the violent and giant impact of planetesimals and other large bodies amongst each other. Consequently, the lighter materials floated to the outer layers of the Earth, and gasses from the interior initiated to escape. This eventually led to the formation of the atmosphere and oceans. The outer layers of the Earth formed were called the Magma Ocean. Additionally, the interior of the Earth has heated to a soft state allowing movement of its contents. This was believed to have resulted in the sinking of heavier materials to the interior and the rising of lighter materials towards the surface. Along with this phenomenon, the heat that was brought to the surface of the Earth is believed to have radiated to space. Eventually, the Earth’s temperature decreased due to the said event, and the Earth solidified and was transformed into a differentiated (zoned) planet. The shape of the Earth is commonly described as a spheroid. It has an equatorial diameter of 12757.776 km and a polar diameter of 12,713.824 km having a difference of 43.952km. The Earth shows an equatorial bulge and a slight flattening at the poles. The planet Earth is generally differentiated into three parts – the atmosphere, the lithosphere/geosphere, and the hydrosphere. However, the biosphere has also been described in the subsection to follow since it explains life on the planet Earth. Atmosphere Atmos means “air.” The atmosphere includes all the gases surrounding the Earth making it the outermost portion that encloses the earth. We often call the atmosphere “air.” All planets have an atmosphere, but Earth is the only planet with the correct combination of gases to support life. The atmosphere consists of five layers and is responsible for Earth’s weather. Even though it seems like air is made of nothing, it consists of particles too small to be seen. All these particles have weight that pushes down on Earth. The weight of air above us is called air pressure. Five Layers of the Atmosphere 1. Troposphere - The troposphere is the lowest layer of Earth's atmosphere, extending from the Earth's surface up to an average altitude of about 13 kilometers. It is the layer where weather occurs, and it is where we live and breathe. Hot air balloons and airplanes fly within the troposphere because it provides the necessary conditions for safe and efficient air travel. 2. Stratosphere - The stratosphere is the layer of Earth's atmosphere located above the troposphere. It extends roughly from an altitude of about 12 kilometers to 50 kilometers above the Earth's surface. The stratosphere is also home to the ozone layer, which shields the Earth from harmful UV radiation. Radiosondes can collect data and travel up to the lower part of the stratosphere. 3. Mesosphere - The mesosphere is the third layer of Earth's atmosphere. It extends approximately from an altitude of about 50 kilometers to 85 kilometers above the Earth's surface. The mesosphere is characterized by thin air and low atmospheric pressure. It is also the layer where meteors burn up upon entry into the Earth's atmosphere, creating the visual phenomenon known as shooting stars. 4. Thermosphere - The thermosphere is the fourth layer of Earth's atmosphere. It begins approximately at an altitude of 85 kilometers and has no clearly defined upper boundary. The thermosphere is primarily composed of individual gas molecules, such as oxygen and nitrogen, rather than molecular combinations. The thermosphere is also where the auroras, such as the Northern Lights and Southern Lights, occur. 5. Exosphere - The exosphere is the outermost layer of Earth's atmosphere, located above the thermosphere. It is the uppermost region of the atmosphere and gradually transitions into the vacuum of space. The exosphere is where satellites and other human-made objects in  Earth's orbit are found. Satellites are strategically placed in orbit within the exosphere to perform their various functions. Geosphere Geo means “earth.” The Earth’s geosphere (sometimes called the lithosphere) is the portion of the earth that includes rocks and minerals. It starts at the ground and extends all the way down to Earth’s core. We rely on the geosphere to provide natural resources and a place to grow food. Volcanos, mountain ranges, and deserts are all part of the geosphere. Put simply, without the geosphere, there would be no Earth! Hydrosphere The Hydrosphere contains all the solid, liquid and gaseous water of the planet. The hydrosphere has a thickness that ranges from 10 to 20 kilometers. It extends from the Earth’s surface downward several kilometers into the lithosphere and upward about 12 km into the atmosphere. Ninety-seven percent of the Earth’s water is covered by the ocean which is salty water. While the remaining portion comes from the forms of rivers, streams, and groundwater, which provides fresh water. However, most of the Earth’s freshwater is frozen. Water near the poles has a very low temperature while water near the equator has a relatively high temperature compared to that near the poles. Biosphere Bio means “life.” The biosphere is made up of all the living things on Earth and it includes fish, birds, plants, and even people. The living portion of the Earth interacts with all the other spheres. Living things need water (hydrosphere), chemicals from the atmosphere, and nutrients gained by eating things in the biosphere. The Biosphere also includes organic matter that has not yet decayed. The sphere hugely depends on the other three spheres as follows: The hydrosphere replenishes plants and animals with water and moisture. The geosphere renders a solid surface for the plants and animals to inhabit. It also provides heat from beneath the earth. The atmosphere screens the sun’s UV radiation and helps us receive just enough of the sun’s heat. A theory known as the ecosystem better explains the interaction of the biosphere with the other spheres. The Inner Structure of Earth Crust The Earth's Crust is like the skin of an orange. Compared to the other layers, the crust is significantly small. The crust can be categorized into two. The first classification is the oceanic crust which is only about 3-5 miles thick under the oceans. The second classification is the continental crust which is about 25 miles thick under the continents. The temperatures of the crust vary from air temperature on top to about 1600 degrees Fahrenheit (870 degrees Celcius) in the deepest parts of the crust. The crust is composed of two basic rock types: granite and basalt. The continental crust is composed mostly of granite. The oceanic crust consists of a volcanic lava rock called basalt. Basaltic rocks of the ocean plates are much denser and heavier than the granitic rock of the continental plates. This results in the continents riding on the denser oceanic plates. The crust and the upper layer of the mantle together make up a zone of rigid, brittle rock called the Lithosphere. The layer below the rigid lithosphere is a zone of asphalt-like consistency called the Asthenosphere. The asthenosphere is the part of the mantle that flows and moves the plates of the Earth. The crust of Earth is broken into many pieces called plates. The plates “float” on the soft, plastic mantle which is located below the crust. These plates usually move along smoothly but sometimes they stick and build up pressure. The pressure builds and the rock bends until it snaps. When this occurs an Earthquake is the result. Mantle The mantle is the layer located directly under the sima. It is the largest layer of the Earth, 1800 miles thick. The mantle is composed of very hot, dense rock. This layer of rock even flows like asphalt under a heavy weight. This flow is due to great temperature differences from the bottom to the top of the mantle. The movement of the mantle is the reason that the plates of the Earth move! The temperature of the mantle varies from 1600 degrees Fahrenheit at the top to about 4000 degrees Fahrenheit near the bottom. Convection Currents The mantle is made of much denser, thicker material, because of this the plates "float" on it like oil floats on water. Many geologists believe that the mantle "flows" because of convection currents. Convection currents are caused by the very hot material at the deepest part of the mantle rising, then cooling, sinking again and then heating, rising and repeating the cycle over and over. When the convection currents flow in the mantle they also move the crust. The crust gets a free ride with these currents. Core The core is divided into two parts: Outer Core and Inner Core. The core of the Earth is like a ball of very hot metals. (4000 degrees F. to 9000 degrees F.) The outer core is so hot that the metals in it are all in the liquid state. The outer core is located about 2900 kilometers beneath the crust and is about 2300 km thick. The outer core is a liquid layer composed mainly of molten iron and nickel. The inner core of the Earth has temperatures and pressures so great that the metals are squeezed together and are not able to move about like a liquid, but are forced to vibrate in place as a solid. The inner core begins about 6500 kilometers beneath the crust and is about 1300 kilometers thick. The temperatures may reach 9000 degrees F. and the pressures are 45,000,000 pounds per square inch. This is 3,000,000 times the air pressure on you at sea level. IV. Continental Drift Theory Introduction Plate Tectonics is a scientific revolution that has guided humanity to understand the geological phenomena around it, challenging the notion of a world completely still and giving birth to the knowledge of how earthquakes, oceans, islands, and mountain ranges are formed. Yet, a scientific revolution is not an event wherein a complete turnover happened instantaneously; it is a process by which many people contributed in lighting the notion along the passage of time. Every scientific revolution in human history was born out of the desire to challenge the status quo, the “common sense”. Such desire comes from a faithful person — not to a deity but to a vision — who is determined to uncover the mysteries that nature and society intentionally conceal. Often, that type of people were ridiculed or disregarded during their times but their work would bear fruit, even long after their death. Among the most significant revolutions was heliocentrism which would forever change how mankind would view its place in the universe. Some of the pioneers of the revolution were Aristarchus of Samos, who was heavily outmatched by the prevailing geocentric beliefs of his time which had been led by Aristotle and Plotemy. Nearly 1800 years later, a priest by the name of Nicholas Coppernicus continued the pursuit, and would face the might of the Catholic Church. Following the motion was Galileo Galilei, who was also faced by the resistance of the devotees. Then came Johannes Keppler, who furthered the intricacies of the universe. Then finally, Isaac Newton, who put the nail in the coffin for the geocentric belief. Many scientists from different fields experienced similar dramatic comedy, to name a few were Gregor Mendel (genetics), Ignaz Semmelweis (hygiene), and Alfred Wegener (plate tectonics). Some decades after his death, Wegener would be hailed as the forefather of the theory of plate tectonics, built from his Continental Drift Theory. “All Earth” Pangaea — a greek word for “all earth” — was the most far-ranging and most criticized idea during its time. Just like the revolutionary concept of heliocentrism, the idea of moving continents was bizarre for most people. Behind such a radical idea was a brilliant meteorologist with a doctorate degree in astronomy, an interdisciplinary scientist, Alfred Lothar Wegener (1880-1930). During his lifetime, Wegener was primarily known for his contributions in meteorology and polar research. He led four greenland expeditions to study the climate of the polar regions using weather balloons. In 1911, during his professorship in Marburg, Wegener was studying in the university library when he found a paper that listed identical animal and plant fossils found on the continents of South America and Africa. He contemplated such a puzzle. The mainstream explanation was that land bridges connecting the two continents had existed, which allowed the distribution of the animal and plant population. Wegener would also study the similarity of the mountain ranges in Canada and in Scotland. One thing that had clicked in Wegener’s mind was the apparent fit of the coastlines of Southern America and Western Africa, which gave him the conviction to postulate the existence of Pangaea, a supercontinent that had connected all of the present continents today. Jigsaw Puzzle One of the most intuitive hints to the continental drift is the apparent fit of the east coastline of South America and the west coastline of Africa, like a puzzle. However, many people have known this for many centuries, way before Wegener, but no one bothered looking deeper into it. Wegener postulated that the continents were once connected in the form of Pangaea and were constantly moving apart which resulted in their eventual state that we observe today. Wegener would need more evidence to prove the existence of such a supercontinent, and so he looked into the other data, such as the correlation in the distribution of fossils in Southern America and in Africa. Fossil Distribution Wegener studied an article that listed some fossils that are distributed around the world. He found that some fossils are distributed on different continents that are divided by ocean, such as the Atlantic ocean. A particular animal was the mesosaurus, a freshwater reptile that had lived around South America and South Africa million years ago. Wegener thought that this fossil distribution can be strong evidence to support his theory. He posited that mesosaurus were able to roam the lands of South America and South Africa because they were once connected, therefore leaving some fossils on those two areas that we now can observe. Some geologists and paleontologists supported Wegener’s reasoning, but the majority of the scientific community believed in the existence of land bridges which presumably connected the continents, allowing land animals to cross. There are also other fossils that can be found in different continents, such as the cynognathus in South America and Central Africa; the lystrosaurus in South Africa, India, and Antarctica; and the glossopteris, a type of fern that is found in South America, Africa, India, Antarctica, and Australia. If the fossil distributions were to be mapped according to their location, all of them lineup appropriately. This evidence served as a strong support for the existence of pangaea. Geological Correlations Determined to collect every bit of evidence in different fields, Wegener was constantly roaming around North America and North Europe when he noticed similarities in the rock types and stratas in both regions. Also, he found out a strong correlation in the mountain ranges found in Canada, Arkansas, Morocco, and Scotland. Those mountains are so closely related that if the two continents were to be connected, the mountains would perfectly match. Wegener was fascinated with this discovery but he did not stop there as he marched on to find other similar evidence, particularly in the Atlantic region. He found that the rock strata of the Karoo system in Africa were identical to that of the Santa Catarina system in Brazil. At this point, Wegener was more eager in advocating for his theory, although the consensus remains the same. So he decided to proceed with one of his expertise to find more evidence, which was paleoclimatology. Paleoclimate Data One of the primary reasons why most polar researches were done was to study climate change, but Wegener wanted to look deeper into the matter. He wanted to study how the drifting of the continents affected their own climate. Most tropical regions found around the Atlantic ocean show signs of different past climates. Wegener investigated past climate data in South America and Africa and he noticed signs that the tropical rainforests in these two continents were once cold regions. Some glacial striations can be seen on the rock formations found in such tropical regions. These scratches can only be produced in cold regions where glacial, ice formations can exist. When this river of ice slides past mountains and rocks, it leaves noticeable patterns of scratches. With this evidence, Wegener was determined to conclude that these tropical regions have not always had warm climates and were once located near the polar regions. Intrigued by such discovery, Wegener continued to embark on finding more evidence until he discovered that bituminous coals can be found in many cold regions. Bituminous coals are typically made of compacted remains of trees. These fossil fuels are primarily extracted from regions near and on the Arctic and Antarctic regions. If those cold regions were always in the same place, the distribution of such fossil fuels would be irrational as plants can never flourish in cold climates, it would not be possible for them to exist in such regions in the first place. This rationale suggests that those cold regions were once found near the equator having tropical climates where plants can thrive. Conclusion Having gathered substantial evidence to support his theory, Wegener would compile all of his discoveries into a book titled The Origin of Continents and Oceans. He presented his findings in many symposiums, lectures, and seminars only for him to face the criticisms of many scientists. One fatal gap in Wegener’s theory is the lack of mechanism of how the continents were actually moving; Wegener failed to convince the community. To add fuel to the matter, Wegener would rationalize that the continents were able to plow over the oceans by the centrifugal force produced by the Earth’s rotations. It might seem plausible, but when the mechanisms were calculated, it was determined that the magnitude of force needed to move the continents would actually stop the Earth’s rotation, which means Wegener’s mechanism was impossible. In his fourth Greenland expedition, Wegener faced his final moments when he had heart failure during his exploration. He died without seeing his lifelong work come to fruition. Only after some decades would humanity open up to Wegener’s revelation, coming in the form of the Theory of Plate Tectonics. This later discovery would provide the clear basis and mechanism for the continents movement. All this time, Wegener was wrong about his emphasis that only the continents were moving, because Plate Tectonics would explain that even the oceanic crusts are also moving alongside the continental crusts.  V. Plate Tectonics Theory Introduction During World War II, warfare was dictated by which country could invent new technologies before their oppositions could. When massive battleships and aircraft carriers became the staple of naval warfare, the countries that did not possess such power were doomed to be defeated. Luckily, they could use naval mines to stall the advances of such massive fleets. With effective countermeasures, countries like the UK and the USA were forced to implement new technology to neutralize the naval mines; so, military submarines were developed. Submarines were used to locate naval mines under the sea. SONAR devices were also used to map the geography of the ocean floor to establish strategic parameters during the war. Such devices would have allowed the accurate mapping of the geological features of the ocean floor and eventually led mankind back to Alfred Wegener’s Continental Drift Theory. Since then, mankind became able to understand the underlying mechanism of how mountains, volcanoes, islands, earthquakes, and the location of each continent came to be, and it all started with the discovery of a vast mid-oceanic ridge in the Atlantic ocean. Mid-Atlantic Ridge During the early 20th century, the outside space was easier to visualize than the seafloor. Wegener gave emphasis only to the geography of the continents and disregarded the seafloor as a vast, flat surface. Decades after his death, a scientist would study the features of the crust under the sea and show that it is more than just a desolate flat surface, rather, it can show the actual origin of how the continents have formed.  Amidst World War II, Marie Tharp, an oceanographic cartographer and a geologist, would help on the Theory of Continental Drift to completion. She studied Bathymetric data that were compiled since the first World War. By carefully dotting each sounding, the depths of the seafloor were mapped. Tharp discovered that in the middle of the Atlantic ocean, spanning from the north to south, a giant, great ridge exists. This oceanic ridge would become known to contain trenches, mountain ranges, and active volcanoes, where magmas spew out, forming new layers of rock that push the entire oceanic crust laterally. This revolutionary discovery would prove that the Theory of Continental Drift was correct. With that, the scientific community all around the world would praise Wegener’s revelation through the works of Marie Tharp. This would mark the beginning of the Plate Tectonics Theory. Spreading Seafloor The discovery of the mid-Atlantic ridge opens Earth Science up to the underlying mechanisms for the Continental Drift Theory to make sense. It was concluded that both oceanic and continental crusts are parts of moving, fragmented plates of lithosphere called tectonic plates. These plates are able to move by the convection currents that occur in the asthenosphere, a layer of earth beneath the lithosphere. Asthenosphere is a viscous body of molten rocks that allows the lithosphere to float over it and move around. These two layers of earth interact with each other and simulate a conveyor belt. Magma from the asthenosphere pushes up through the volcanic vents and the preexisting layer of crust is pushed laterally by the convection currents. Once a slab of crust collides with another crust, an interaction between them occurs called subduction and the point of collision is called the subduction zone. During the collision, the denser crust will sink beneath while the other creates folds as the denser crust slides under. The sunken layers of crust will then melt into the asthenosphere to continue the cycle, just like a conveyor belt. Due to the immense size of the plates, the crusts can only move about 10 cm per year. That is why the motion of the crust is never felt, unless an earthquake causes it to shake. Paleomagnetism Following the concept of seafloor spreading was the existence of an alternating pattern that can be observed on seafloors. It is known that the earth’s magnetism changes once in a while. During this alteration, the magnetic minerals and rocks record the direction and intensity of the magnetic field. As the seafloor drifts apart, the new layers of seafloor would be able to record the changes in the magnetic field. When the magnetization of the minerals and rocks of the seafloors were studied, recurring patterns were observed. This evidence proves that the seafloors are actually spreading apart. Plate Boundaries Each plate comes in different sizes and shapes, and they interact with one another in many ways. These interactions are what causes some geological features such as mountain ranges, volcanoes, and trenches to form. The locations where every plate interacts with another are called plate boundaries. Alongside these interactions is the production of earthquakes caused by the friction between the colliding plates. All of the earthquakes, and many geological formations are found around plate boundaries, where actions take place. When every earthquake and volcano are to be mapped, the majority is found around what’s called the Pacific Ring of Fire, or the Circum-Pacific belt. There are three common types of plate boundaries. They are the convergent, divergent, and transform boundaries. Each type of plate boundary interacts differently and produces different formations. Transform boundary is a type of plate boundary where two tectonic plates slide past each other horizontally. In the context of geological faults, the transform boundary is also called the strike-slip fault. This boundary can neither create nor destroy land features, they can only cause earthquakes around them by the energy accumulated from the friction of the two plates. This characteristic is called conservative. Another type of boundary is called the convergent boundary. This is where two plates collide. Their interaction is typically destructive as it interferes and brings changes to the geological features of the earth, that is why it is also called destructive boundary. The effects of the convergent boundary differ depending on which types of crusts are involved and there are three of them. When a continental crust and oceanic crust collide, they form a oceanic-continental convergent boundary and between them is a subduction zone. As the two crusts collide, the oceanic crust will slide beneath the continental crust and sink into the asthenosphere while the continental crust crumbles due to friction. This interaction happens because the oceanic crust is denser than the continental crust and buoyancy plays a significant role. The oceanic-continental convergent boundary forms geological features on either side of the subduction zone. On the oceanic side, trenches are formed as the crust sinks, while on the continental side, volcanic arcs and mountain ranges are formed. Volcanoes are formed primarily by the help of buoyancy. First, magma from the asthenosphere becomes less dense as they gain more heat. The cooler, denser rocks will sink beneath the magma, causing it to be pushed upwards until it reaches the surface of the earth where it escapes through the volcanic vents. The permanent change caused by the escape of the magma is the formation of a volcano. When both continental crusts collide, they form a series of crumples and folds in the form of mountain ranges. This boundary is called continental-continental convergent boundary. In such a boundary, subduction does not take place, instead, the  two crusts will keep on pushing against each other so much so that geological crumples become apparent, which eventually causes the formation of mountains. When both oceanic crusts collide, they form an oceanic-oceanic convergent boundary. Either crust may subduct, but the denser, cooler, and older crust will be the one to sink. Such interaction forms many volcanic islands around the convergent boundary similar to the oceanic-continental collision. The side of the oceanic crust that sinks is where trenches are formed. The third type of plate boundary is the divergent boundary. It is where two plates are moving away from each other, and where new layers of rocks are being created. This is why it is also called the constructive boundary. Divergent boundaries occur both on continental and oceanic crusts. If it is located on land, it forms a rift zone. On the other hand, it forms a mid-oceanic ridge if it is beneath the ocean. Although plate boundaries can form volcanoes around them, not all volcanoes are created by plate boundaries. Volcanic islands such as the Hawaii are anomalies and they did not emerge from any types of plate boundaries, rather, they are formed from the hotspots that are randomly located on some tectonic plates. Geologists had been observing the existence of island chains. In these chains, there is always one island that contains active volcanoes, and the rest of the islands are dormant. The explanation for this phenomenon is that certain mantle plumes beneath the lithosphere where magmas emerge cause the formation of volcanoes. The volcanic hotspot would keep on spitting magmas which eventually formed the entirety of the volcanic island. But, the tectonic plates are constantly moving, which means that the affected crust where the volcano is situated only sits on the hotspots temporarily. As the crust continues to shift, newer volcanic islands are formed above the hotspot, while the older volcanoes start to become inactive. Conclusion The Plate Tectonics Theory completed what the Continental Drift Theory of Alfred Wegener could not do. Although Wegener’s theory provided a solid description of how all the continents were actually once connected as a single supercontinent, it failed to account for the underlying mechanism for how such a supercontinent was able to drift apart into the fragmented continents that we can observe today. The Continental Drift and Plate Tectonics are both a revolutionary breakthrough in the field of Earth Science as they paved the way in our understanding of the dynamics of the Earth’s geology. Both theories helped us in many different ways, most particularly in the field of disaster management. Now that we know where and how earthquakes are formed, we are able to devise strategies in mitigating their effects and even try to predict their occurrence. We are also able to study past data regarding the climate and geology around the globe. The result of these discoveries enabled us to develop new and advanced knowledge and technology that furthered our engineering practices around the areas prone to earthquakes. The constant dynamics of the lithosphere compelled us to accept that change is ever constant and that we must catch up to the changes that nature brings to us. Yet, such scientific revolution is not just credited only to the founding father, Alfred Wegener himself, but also to the many great scientists around the world that had decided to open up their minds to collectively form and contribute to a great unifying theory that would forever change how we view the earth. VI. References Admin. (2023, February 14). Fundamentals of Earth’s Sphere - Interaction Between Spheres. BYJUS. https://byjus.com/physics/four-spheres-of-earth/ Alfred Wegener. (n.d.). https://ucmp.berkeley.edu/history/wegener.html CrashCourse. (2021, July 12). The Plate Tectonics Revolution: Crash Course Geography #19 [Video]. YouTube. https://www.youtube.com/watch?v=7CPv0NSIG2M Continental drift. (n.d.). https://education.nationalgeographic.org/resource/continental-drift/ Dastrup, A. (n.d.). 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