Earth's Materials and Processes PDF

Lord of light and wisdom, grant us bright intellect, a sound judgement and retentive memory. Help us to study patiently, orderly and diligently to develop our gifts and make good use of them according to you will, as we commit ourselves to Veritas et Fortitudo, Pro Deo et Pat...

Lord of light and wisdom, grant us bright intellect, a sound judgement and retentive memory. Help us to study patiently, orderly and diligently to develop our gifts and make good use of them according to you will, as we commit ourselves to Veritas et Fortitudo, Pro Deo et Patria. AMEN. UNIT 5 Earth's Materials and Processes UNIT 5 Earth Science Topics: A. Exogenic Process B. Endogenic Process C. Earth's History  LESSON PROPER Endogenic Process Exogenic Process Exogenic processes include geological phenomena and processes that originate externally to the Earth's surface. Weathering (Physical Biotic Weathering Mass Wasting Soil Erosion and Chemical) Biotic Weathering Caused by living organisms Examples: Plant roots growing in rock cracks Burrowing animals Lichens secreting acids Role in ecosystem development and soil formation Physical Weathering Mechanical breakdown without changing rock composition Processes: o Freeze-thaw cycling o Thermal expansion and contraction o Salt crystallization o Abrasion o Common in areas with extreme temperature changes o Frost Weathering o Block Disintegration o Exfoliation Chemical Weathering Changes rock composition through chemical reactions Key processes: o Dissolution (e.g., limestone in acidic water) o Oxidation (e.g., rusting of iron-bearing minerals) o Hydrolysis (e.g., feldspar to clay) o Carbonization More prevalent in warm, humid climates  Mass Wasting Definition: Downslope movement of rock and soil due to gravity Types: o Slow: Creep, solifluction o Rapid: Landslides, mudflows, rockfalls o Factors influencing mass wasting: o Slope angle o Water content o Vegetation cover o Rock/soil type  Soil Erosion Definition: Removal of topsoil by wind, water, or ice Types of erosion: o Water erosion (sheet, rill, gully) o Wind erosion (Wind Erosion) o Glacial erosion o Sheet Erosion o Impacts: Loss of fertile soil, sedimentation in water bodies Endogenic Process Endogenic processes are those that occur or are created under the Earth's surface. Volcanism Tectonic Forces Plate Motion Seafloor Spreading  Volcanism Volcanoes are openings, or vents where lava, tephra (small rocks), and steam erupt onto the Earth's surface. Volcanic eruptions can last days, months, or even years. Volcanism is the eruption of molten rock from inside the Earth to the surface. Volcanism occurs because of Earth's internal heat and is associated with tectonic processes and a part of the rock cycle.  Subduction Zone Subduction zones are where Earth's tectonic plates dive back into the mantle, at rates of a few to several centimeters per year.  Tectonic Forces Folding: Process where rock layers bend due to compressional forces Types: anticlines (upward fold) and synclines (downward fold) Can occur on various scales, from microscopic to mountain-sized Faulting: Fracturing of rock layers due to stress Occurs when rocks break and move relative to each other Results in discontinuities in rock layers  Joints Joint, in geology, a brittle-fracture surface in rocks along which little or no displacement has occurred. Present in nearly all surface rocks, joints extend in various directions, generally more toward the vertical than to the horizontal. Plate Motion Definition: Plate motion refers to the movement of Earth's lithospheric plates Lithosphere: Rigid outer layer of Earth, including crust and uppermost mantle Plates move at rates of 1-15 cm per year Driven by convection currents in the mantle Fundamental to understanding earthquakes, volcanoes, and mountain formation  Continental Drift Theory The continental drift theory states the movement of tectonic plates, which drift apart from the land which sits on top, is the cause for this shift. When the land spread apart, it formed individual smaller landmasses known as continents. Continental drifts are caused by the spreading of the seafloor.  Continental Drift Theory https://www.youtube.com/wat ch?v=AqrInJ8_Nes  Major and Minor Plates Plates are rigid bodies of rock that essentially float atop a region of partial melt called the asthenosphere. The plates comprise the lithosphere, composed of the crust (which is the rigid, outermost layer of the Earth) and the solid portion of the upper mantle. Major and Minor Plates  Plate Boundaries (a) Divergent boundaries, where plates separate and move in opposite directions, allowing new lithosphere to form from upwelling magma. This either occurs at mid- ocean ridges (the so-called seafloor spreading) or at rifted continental margins;  Plate Boundaries (b) Convergent boundaries, where plates move towards each other. One plate either sinks beneath the other along a subduction zone or plates collide because neither can be subducted; and  Plate Boundaries (c) Transform fault boundaries, where plates move horizontally past each other.  Earth's History The earth's history is being proved through different laws, methodologies and processes. Some of these processes were: o Relative Dating o Absolute Dating o Index Fossils o Geologic Time Scale  Relative Dating Relative dating is the science of determining the relative order of past events (i.e., the age of an object in comparison to another), without necessarily determining their absolute age (i.e., estimated age). Absolute Dating Absolute dating is the process of determining an age on a specified chronology in archaeology and geology using radiometric dating. Some scientists prefer the terms chronometric or calendar dating, as use of the word "absolute" implies an unwarranted certainty of accuracy. Radiometric Dating The process of examining the ratio of one isotope to another in a rock to determine its age. Isotopes having different number of Neutrons. Radiometric Dating Most Isotopes are stable and some are not and these are what we called as “radioactive”. Since radioactive decay occurs at a steady state, we can use the relative amounts of stable and unstable isotopes present in an object to determine its age.  Radiometric Dating The rate of radioactive material is constant, that is why comparing the amount of parent material with the amount of daughter material is important in dating rocks. Therefore, more daughter material there is, the older the rock. Half-life is the time needed for half of a sample radioactive substance to undergo radioactive decay. After every half life, the amount of parent material decreases by one-half. Radiometric Dating Radiometric Dating The potassium-argon method uses potassium-40 as the parent isotope, which has a half life of 1.25 billion years as it decays, it leaves its daughter material, argon. This method is used mainly to date rocks, which are older than 100 000 years old. The uranium-lead method uses uranium-238 as the parent isotope, which has a half life of 4.8 billion years, Uranium-238 decays in series of steps, which becomes lead-206. This method is used mainly to date rocks, which are older than 10 million years old. Geologic Time Scale A fossil is a remnant of any ancient animal or plant that has been preserved in crystalized rocks. Age of fossils is equal to the age f the rock from where it is found. Index fossils will serve as a guide or indicators of similar geologic periods. For instance, two rocks where found in different areas and contains same index fossil then it can be noted that the rocks were forms from the same period. Index Fossils Geologic Time Scale The system used to relate stratigraphy and time to any geologic events is called the Geologic Time Scale. Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Paleontology the study of life prior and at the start if Holocene Epoch as well as the study of fossils to determine how organisms evolved and how they interact with the environment. Paleoecology is the study that deals with relationship between fossil organisms and their inferred environments. Geologic Time Scale Hadean Eon (4.6-4.0 billion years ago) Earth's earliest eon, named after Hades (Greek god of the underworld) Formation of Earth from cosmic dust and gas Constant meteorite bombardment and volcanic activity Formation of Earth's core, mantle, and crust Early atmosphere: mainly hydrogen and helium No solid surface, oceans of molten rock End marked by formation of first rocks and possible water oceans Archean Eon (4.0-2.5 billion years ago) Name means "ancient" in Greek Cooling of Earth's surface and formation of first continents Development of primitive atmosphere (no free oxygen) Emergence of first life forms (single-celled organisms) Evolution of photosynthetic cyanobacteria Beginning of oxygen production Formation of banded iron formations due to oxygen reaction with iron Proterozoic Eon (2.5 billion-541 million years ago) Name means "earlier life" in Greek Significant rise in atmospheric oxygen (Great Oxygenation Event) Formation of ozone layer First multicellular organisms Evolution of sexual reproduction Appearance of first eukaryotic cells Development of first plant and animal life Several major ice ages (Snowball Earth events) Early Paleozoic Era (541-419 million years ago) Name means "ancient life" in Greek Cambrian Explosion: rapid diversification of complex life forms Development of hard body parts (shells, exoskeletons) First vertebrates appear Colonization of land by plants Formation of Gondwana supercontinent Major extinction event at the end of Ordovician period Late Paleozoic Era (419-252 million years ago) Formation of Pangaea supercontinent Evolution of amphibians and early reptiles Development of seed-bearing plants Carboniferous period: vast swamp forests (source of coal deposits) Permian period: diversification of reptiles End-Permian extinction: largest known mass extinction (95% of marine species) Mesozoic Era (252-66 million years ago) Name means "middle life" in Greek Age of reptiles, particularly dinosaurs Evolution of mammals and birds Diversification of flowering plants Breakup of Pangaea Generally warm climate with no polar ice caps Ended with Cretaceous-Paleogene extinction event (dinosaur extinction) Cenozoic Era (66 million years ago- present) Name means "recent life" in Greek Age of mammals Evolution of primates and humans Diversification of birds and insects Development of grasslands and deciduous forests Formation of modern continents and mountain ranges Ice ages and climate fluctuations Current era we live in Thank you!