Geology 1313 Introduction to present notes
Geology 1313 Introduction to present notes GEOL 1313 - 001
Popular in Intro to physical geology (c)
Popular in Geology
This 7 page Study Guide was uploaded by Alejandra Juarez on Tuesday February 16, 2016. The Study Guide belongs to GEOL 1313 - 001 at University of Texas at El Paso taught by Musa Jad Abdel-Wahab Hussein in Winter 2016. Since its upload, it has received 181 views. For similar materials see Intro to physical geology (c) in Geology at University of Texas at El Paso.
Reviews for Geology 1313 Introduction to present notes
Can you just teach this course please? lol :)
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 02/16/16
• GEOLOGY: is the science that pursues an understanding of planet Earth • Physical geology examines Earth materials and seeks to understand the many processes that operate on our planet • Historical geology seeks an understanding of the origin of Earth and its development through time Geology, people, and the environment • More people now live in cities than in rural areas • Populations are affected by geologic hazards and rely on natural resources • Geologic hazards are natural processes that adversely affect people • Natural resources addressed by geology include: Water, soil, metallic and nonmetallic minerals, and energy • The nature of Earth has been a focus of study for centuries • Catastrophism – Earth’s landscapes were shaped primarily by catastrophes. • Uniformitarianism – the physical, chemical, and biologic laws that operate today have operated throughout the geologic past. • The present is the key to the past. • The magnitude of geologic time involves millions and billions of years. • Earth is 4.6 billion years old • • An appreciation for the magnitude of geologic time is important because many processes are very gradual. • Science assumes the natural world is consistent and predictable • The goal of science is to discover patterns in nature and use the knowledge to make predictions • Scientists collect data through observation and measurements • How or Why things happen are explained using: • Hypothesis – a tentative (or untested) explanation • Theory – a well-tested and widely accepted view that the scientific community agrees best explains certain observable facts Experiments are developed to test the hypotheses • Hypotheses are accepted, modified, or rejected • Data and results are shared with the scientific community • Earth is a small, self-contained planet • Earth’s four spheres are: • Hydrosphere – the water portion • Atmosphere – the gaseous envelope • Geosphere – the solid Earth • Biosphere – all plant and animal life Earth system science: • Aims to study Earth as a system composed of numerous interacting parts. • Employs an interdisciplinary approach to solve global environmental problems • The universe began with the Big Bang. • Earth and the other planets formed at essentially the same time out of the same material as the Sun. The Nebular Theory proposes that the bodies of our solar system evolved from an enormous rotating cloud called the solar nebula • Nebular Theory • The solar nebula consisted of hydrogen and helium, in addition to microscopic dust grains • A disturbance caused the solar nebula to slowly contract and rotate • The solar nebula assumed a flat, disk shape with the protosun (pre- Sun) at the center • Inner planets began to form from metallic and rocky substances • Larger outer planets began forming from fragments of ices (H O, CO , 2 2 and others) • Formation of Earth’s layered structure • Metals sank to the center, Why? • Molten rock rose to produce a primitive crust • Chemical segregation established the three basic divisions of Earth’s interior • A primitive atmosphere evolved from volcanic gases • The earliest primitive crust was lost to erosion and geologic processes • Earth is divided into three major layers by composition: • Crust – Earth’s thin, rocky outer skin, divided into the continental and oceanic crust • Oceanic crust is approximately 7 kilometers thick and composed of basalt • Continental crust is 35 – 70 kilometers and composed primarily of granodiorite • Mantle – is approximately 2900 kilometers thick and composed of peridotite • Core – is composed of an iron-nickel alloy • Additionally, Earth is divided into different zones based on physical properties: • Lithosphere – the rigid outer layer of Earth that consists of the crust and the upper mantle • Asthenosphere – the soft, weak layer below the lithosphere Transition zone – a zone marked by a sharp increase in density below the asthenosphere • Additionally, Earth is divided into different zones based on physical properties: • Lower Mantle – a zone of strong, very hot rocks subjected to gradual flow below the transition zone • Outer core – liquid outer layer of the core • Inner core – solid inner layer of the core • Rocks are divided into three major groups: • Igneous rocks • Cooling and solidification of magma (molten rock) • Sedimentary rocks • Sediments are derived from weathering of preexisting rocks • Sediments will lithify into sedimentary rocks • Accumulate in layers at Earth’s surface • Metamorphic rocks • Formed by “changing” preexisting igneous, sedimentary, or other metamorphic rocks • Driving forces are heat and pressure • The rock cycle allows us to visualize the interrelationships among different parts of the Earth system • Earth’s surface is divided into continents and ocean basins. The difference between these two areas is relative levels • The elevation difference is a result of differences between density and thickness • Continents are relatively flat plateaus approximately 0.8 kilometers above sea level composed of granitic rocks • The average depth of ocean basins, composed of basaltic rocks, is 3.8 kilometers below sea level • Features of continents include mountain belts, cratons, shields, and stable platforms • Mountain belts are the most prominent features of continents • Cratons are the stable interior of the continents • Shields are expansive, flat regions of deformed crystalline rocks in the cratons • Stable platforms are the flat portions of cratons covered with a thin veneer of sedimentary rocks • Features of the ocean floor include continental margins, deep-ocean basins, and oceanic ridges • Continental margins are the portion of the sea-floor adjacent to major landmasses • The continental shelf is a gently sloping region • The continental slope is a relatively steep dropoff • The continental rise consists of a • thick wedge of sediment • Deep ocean basins are the portions of the sea- floor between the continental margins and the oceanic ridges • The abyssal plain is a flat feature of the deep ocean basin • Deep-ocean trenches are deep and relatively narrow depressions that make up only a small portion of the ocean floor • Seamounts are small volcanic structures that dot the ocean floor • Oceanic ridges are the most prominent feature on the ocean floor and are composed of igneous rock that has been fractured and uplifted • Prior to the late 1960s, many geologists believed that the positions of the continents and ocean basins were fixed. • Continental drift, a hypothesis designed to explain continental movement, was first proposed in the twentieth century, but initially rejected by North American geologists • Alfred Wegener • First proposed continental drift hypothesis in 1915 • Published The Origin of Continents and Oceans • Continental drift hypothesis • A supercontinent, consisting of all of Earth’s landmasses, once existed • This supercontinent was called Pangaea and began breaking apart about 200 million years ago • Evidence used in support of continental drift hypothesis: • The Continental Jigsaw puzzle • Fossil evidence —identical fossil organisms are found on continents now separated by vast oceans • Objections to the continental drift hypothesis: • Wegener incorrectly suggested that the gravitational forces of the Moon and Sun were capable of moving the continents • Wegener also incorrectly suggested that continents broke through the ocean crust • There was strong opposition to this hypothesis from all areas of the scientific community. • Following World War II, oceanographers learned much about the seafloor • The oceanic ridge system winds through all of the major oceans • There is no oceanic crust older than 180 million years old • Sediment accumulation in the deep oceans was relatively minor • These developments led to the theory of plate tectonics • Rigid Lithosphere Overlies Weak Asthenosphere • The lithosphere is Earth’s strong, outer layer • The asthenosphere is a hotter, weaker region of the mantle under the lithosphere Because of the differences in physical properties, the lithosphere is effectively detached from the asthenosphere • Earth’s Major Plates – The lithosphere is broken into approximately two dozen smaller sections called lithospheric plates – These plates are in constant motion • Plate Boundaries – Most interactions among individual plates occur along their boundaries – Types of plate boundaries: • Divergent plate boundaries (constructive margins)—plates move apart (Mid Oceanic Ridges) • Convergent plate boundaries (destructive margins)—plates move together (subduction zone) • Transform plate boundaries (conservative margins)—plates grind past each other without the production or destruction of lithosphere (also called a transform fault) (San Andreas Fault) • New ocean floor is generated as two plates move apart. • Most divergent plate boundaries are located along the crests of oceanic ridges • Oceanic ridges and seafloor spreading Along well-developed divergent plate boundaries, the seafloor is elevated, forming oceanic ridges • Oceanic Ridges and Seafloor Spreading – Along the crest of the ridge is a canyon-like feature called a rift valley – Seafloor spreading is the mechanism that operates along the ridge to create new ocean floor – Spreading Rates – The average spreading rate is 5 cm/year – The Mid-Atlantic Ridge has a spreading rate of 2 cm/year – The East Pacific Rise has a spreading rate of 15 cm/year • Continental Rifting – Occurs when a divergent plate boundary occurs within a continent – A landmass will split into two or more smaller segments – A continental rift, an elongated depression, will develop within the region of the divergence – Examples include: East African Rift, Rio Grande Rift • Two plates move toward each other at these destructive plate margins, • where the older portions of oceanic plates are returned to the mantle – The leading edge of one plate is bent downward, as it slides beneath the other at subduction zones – Deep-ocean trenches are the surface manifestations produced at subduction zones – Examples include: • Peru-Chili Trench • Mariana Trench • Tonga Trench
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'