Geology 1: Notes on Earth's geologic forces that shape the crust with video links

This document discusses different types of stresses that cause rock deformation, including confining stress, compression stress, tension stress, and shear stress. It also describes different types of resulting rock features such as folds, fractures, faults, and mountains. Specifically, it compares three types of folds - monoclines, anticlines, and synclines. It also differentiates between three main types of plate boundaries: divergent boundaries which cause tension stress and normal faults, convergent boundaries which cause compression stress and reverse faults, and transform boundaries which cause shear stress and strike-slip faults. Mountains can form at convergent plate boundaries through folding and faulting of rocks.

This document discusses various geological structures including folds, faults, joints, unconformities, and methods to characterize rock mass quality. It describes key terms like dip, strike, anticline, syncline, and classifications of different fold types. Fault types like normal, thrust, and strike-slip faults are outlined. Engineering considerations of these structures are mentioned regarding their suitability for construction projects and impacts. Methods like Rock Quality Designation (RQD) and Rock Structure Rating (RSR) to evaluate rock mass quality are also summarized.

Plate tectonics refers to the theory that the Earth's crust is divided into plates that move around on the mantle. There are 12 major plates that collide, pull apart, or scrape against each other, causing deformation of the crust and creating characteristic geological features. The driving force behind plate tectonics is convection currents in the mantle, where hot material rises and cools, moving the plates in the lithosphere. There are three types of plate boundaries: divergent, where plates move apart; convergent, where they collide; and transform, where they scrape past each other.

The San Andreas Fault is a continental transform fault that extends roughly 1,200 kilometers through California. It forms the boundary between the Pacific Plate and the North American Plate. The fault results in right-lateral strike-slip motion, with the left side moving northward and the right side moving southward. Major earthquakes are caused by the build up of stress from this motion at various segments of the fault. The fault has had a significant impact throughout California's history, causing damage from earthquakes and other natural disasters.

The theory of plate tectonics explains that Earth's outer layer is made up of plates that have moved throughout geological history. These plates float on top of the mantle and move at boundaries where they diverge, converge, or slide past one another. Convection currents in the upper mantle provide the driving force that causes plates to move over time.

This document discusses tectonic plates and transform plate boundaries. It notes that tectonic plates are large pieces of rock that make up Earth's crust, and there are two main types - oceanic and continental plates. At transform boundaries, the plates move horizontally past one another, driven by convection currents in the underlying mantle. When the plates rub together at these boundaries, it causes huge stress that results in earthquakes, faults, and tsunamis.

Plate tectonics is the theory that Earth's outer shell is divided into several plates that glide over the mantle, the rocky inner layer above the core. The plates act like a hard and rigid shell compared to Earth's mantle. This strong outer layer is called the lithosphere.

The document discusses deformation of the Earth's crust through isostatic adjustment and stresses. Isostatic adjustment occurs when crust thickens or thins due to changes in weight, causing the crust to rise or sink into the mantle like a cargo ship. There are three main stresses on the crust - compression at convergent boundaries, tension at divergent boundaries, and shearing at transform faults. The crust is constantly seeking isostatic balance under these stresses.

This document discusses several deep ocean trenches around the world. It provides details on the deepest trenches, including the Mariana Trench in the western Pacific Ocean, which reaches a maximum depth of 11,034 meters. It also describes other extremely deep trenches such as the Tonga Trench in the southwest Pacific Ocean, which reaches 10,882 meters deep, and the Philippine Trench east of the Philippines, with a maximum depth of 10,545 meters. In total it provides location details and maximum depths for 8 different ocean trenches.

Deep-sea trenches are long, deep ocean depressions that form at subduction zones where one tectonic plate slides under another. The deepest is the Mariana Trench near Guam, with the Challenger Deep reaching 10,994 meters below sea level. Trenches form as the leading edge of a heavy plate bends downward due to subduction under a lighter plate. This process also creates volcanic island arcs and causes powerful earthquakes. Life in trenches survives under immense pressure, with microbes like foraminifera the only organisms collected so far from the deepest parts.

The document discusses tectonic plates and their movement. It explains that tectonic plates are large plates that make up the Earth's surface and they are constantly moving against each other. When plates collide, they can form mountain ranges, and when they move apart oceans are formed as the space between fills with water. Examples are given of the formation of the Himalayas from the collision of the Indian and Eurasian plates and the creation of the Atlantic Ocean as plates diverged. Tectonic plate movement can cause natural disasters like earthquakes, volcanic eruptions, and tsunamis.

Divergent plate boundaries occur when tectonic plates pull apart from each other. Rising convection currents in the mantle push up on lithospheric plates, stretching and thinning the crust until it breaks along parallel faults tilted outward. This forms mid-ocean ridges or rift valleys on land. As the plates continue diverging, new crust is formed by magma rising through the cracks from the asthenosphere. Examples of divergent boundaries include the East Africa rift and Rio Grande rift.

This document provides an overview of the internal structure of the Earth. It describes the three main layers - crust, mantle, and core. The crust is the outermost layer and is divided into continental and oceanic crust. Beneath the crust is the mantle, which makes up most of the Earth's volume. The core is at the center and has a solid inner core and liquid outer core. Seismic waves and magnetic reversals provide evidence about the composition and movement of materials in the Earth's interior.

The document summarizes the major ocean basins of the world. It describes the general characteristics of the Pacific, Atlantic, Indian, Arctic, and Southern Oceans, including their average depths, geological features, and freshwater inputs. It also lists marginal seas surrounding each ocean and provides additional details on the largest/smallest oceans, deepest ocean trenches, saltiest seas, and historical definition of "the seven seas".

The document discusses the theory of plate tectonics, including what plates are, how they move, and the three types of plate boundaries. The three types of boundaries are divergent boundaries, where plates move apart; convergent boundaries, where plates move towards each other; and transform boundaries, where plates move past each other laterally. Each boundary type results in different geologic features and events due to the stresses caused by the ways plates are pulled, pushed, or sheared at their edges.

Magma forms deep underground due to decreasing pressure and rising temperature, and volcanoes erupt when this magma reaches the surface. Most volcanoes are located along plate boundaries, where tectonic plates are moving apart or colliding. Scientists can predict volcanic eruptions by monitoring earthquake activity, volcanic gas emissions, changes in slope and surface temperature at volcanoes, all of which indicate rising magma.

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Erosion and weathering shape Earth's surface through mechanical and chemical processes. Mechanical weathering breaks rocks into smaller pieces through freezing and thawing, plant and animal actions, and abrasion by other particles. Chemical weathering alters rocks through reactions with water, oxygen, carbon dioxide, organisms, and acid rain. These weathering processes further break down rocks, which are then transported and eroded by forces like wind, water and glaciers to form landscapes like the Grand Canyon over long periods of time.

Weathering is the process by which rock breaks down into smaller pieces called sediments due to various environmental factors such as water, ice, wind, and plant roots. Rocks can weather through physical processes like freezing and expansion of water in cracks, or chemical processes like acid rain dissolving rocks. The sediments produced by weathering are then eroded and transported by forces like rivers, waves, wind, and glaciers before being deposited in a new location through the process of deposition.

External forces shape the Earth through weathering, erosion, and deposition. Weathering breaks down rock through mechanical and chemical processes. Erosion then transports weathered material through water, wind, and glacial activity. The eroded material is deposited elsewhere, forming landforms like deltas at river mouths or dunes in windy regions, completing the cycle that builds soil in new areas.

1) The document discusses various surface hazards including landslides and tsunamis. It provides context on landslide hazards in eastern Kentucky and West Virginia due to steep slopes, weathering, and mining. 2) It notes the connection between landslides and tsunamis, describing how subaerial and submarine landslides can trigger local tsunamis, such as the 1964 event in Lituya Bay, Alaska. 3) The document emphasizes the destructive power of tsunamis like the 2004 Indian Ocean tsunami that killed 230,000 people, and stresses the importance of tsunami warning systems and public education to help reduce impacts.

Earth's landforms have changed over time due to weathering and erosion. There are two types of weathering - physical and chemical. Physical weathering breaks rocks into smaller pieces without changing their chemical composition, while chemical weathering alters the chemical makeup of rocks. Erosion is the transport of weathered rocks and soil by various agents such as water, wind, ice and gravity. Deposition occurs as the force of these agents decreases, depositing eroded sediments in new locations like bodies of water, alluvial fans and cross-bedded layers. Together, weathering, erosion and deposition are responsible for shaping Earth's constantly evolving surface over geological time.

This chapter discusses the two main types of weathering: mechanical and chemical. Mechanical weathering breaks rock down into smaller pieces with little chemical change, through processes like frost wedging, unloading, and abrasion. Chemical weathering alters the crystalline structure and composition of minerals, forming new minerals or causing dissolution. Key agents of chemical weathering include oxygen and acid. Factors like particle size, rock composition, and climate influence weathering rates.

The document discusses changes to Earth's surface and provides seven examples of landforms with the question "What caused this?". It then briefly introduces two theories for how changes occur on Earth: catastrophism, which involves sudden geological changes, and uniformitarianism, which asserts that changes happen gradually through small, uniform processes over long periods of time.

The document discusses different types of weathering that break down rock into sediment particles. It describes physical weathering processes like abrasion, frost wedging, and exfoliation that crack or break rocks without chemical changes. Chemical weathering involves chemical reactions that alter the rock's composition, such as carbonation, oxidation, hydration, and reactions with plant acids or acid rain. Weathering produces sediments, dissolved minerals, soil, and drives erosion. The rate of weathering depends on climate, rock type, exposure, and particle size.

Weathering is the breakdown of rock in place and includes four main types: freeze-thaw weathering, onion-skin weathering through exfoliation, biological weathering by plant roots, and chemical weathering as water dissolves rock. Weathering breaks up and weakens rock while erosion wears away and removes loosened material, with rivers, ice, sea, and wind causing significant erosion; erosion works together with transportation and deposition to shape landscapes and form environments like coasts.

The document discusses several destructive forces that can cause changes to the Earth's surface: weathering and erosion break down and move rocks and sediment through various means like water, ice, and plant growth; landslides are the mass movement of land down slopes due to gravity; volcanic eruptions expel lava and ash from openings in the Earth's crust and can destroy landscapes; earthquakes are caused by vibrations from sudden movements within the Earth along faults and can trigger landslides and tsunamis; floods occur when large amounts of water cover dry land, causing erosion and depositing new sediments.

Erosion is the transportation of weathered materials by wind, water, ice, or gravity. Water and ice erode rocks by entering cracks and expanding when freezing, weakening the rock over time. Erosion causes mudslides and landslides when materials slide down hills. Deposition occurs when sediment is deposited by slowing winds or water in places like river deltas or banks. Weathering breaks rocks into smaller pieces through extreme heat and cold, water, and ice wearing away at the rocks. There are three types of weathering: mechanical, physical, and chemical.

The document discusses various factors that influence rates of deposition including: particle size and density, with larger and denser particles settling fastest; slope, with lower slopes having higher deposition rates; stream velocity, with slower velocities resulting in more deposition; and stream discharge, with higher discharge carrying more sediment farther. Deposition is greatest inside curves of rivers and at river mouths where velocity is lowest. Particle size decreases in deposited sediments as velocity decreases due to larger particles settling out first. Deltas form at river mouths. Wind deposits sediments in piles called dunes that are oriented with the prevailing wind direction. Glacial deposits like till are unsorted while features like erratics and striations are left by glaciers.

The document discusses the processes of weathering and erosion. Weathering is when rocks break up, while erosion is when rocks wear away. There are 5 main ways rivers erode: 1) abrasion when sand and stones are bashed against banks, 2) corrosion when acidic water dissolves banks, 3) hydraulic action when water forces cracks apart, 4) attrition when stones knock into each other while being washed along, and 5) corrasion when the river scrapes stones along its bed. Mnemonic devices are provided to help remember the terms.

Constructive waves build up the coastline by carrying sediment to shore and depositing it, while destructive waves erode the coastline by removing sediment. Physical processes like weathering, erosion, transportation and deposition are constantly changing the coastline. Erosion wears away rock and sediment by abrasion, attrition and hydraulic action, while weathering breaks rocks through corrosion and wetting/drying. The rate of erosion depends on factors like the rock type, shape of the coastline, and distance waves have traveled.

The document summarizes plate tectonics and its relationship to various geological phenomena. There are three main types of plate boundaries - divergent where plates move apart, convergent where they collide in subduction or collision zones, and transform where they slide past each other. Plate movement is responsible for volcanoes, earthquakes, and mountain building. Earthquakes occur when stress builds up at faults until the plates suddenly slip, releasing energy. Tsunamis are large sea waves generated by earthquakes or landslides that flood coastal areas.

The document discusses various natural processes that shape the Earth's surface over time, including erosion, deposition, and weathering. It provides examples of different types of erosion such as water erosion, glacial erosion, and wind erosion. It also describes related landforms that result from erosion and deposition processes, such as deltas, moraines, and meanders. Various agents that cause weathering and erosion are identified, such as water, wind, ice, and plants.