Introduction to Earth Science

• Includes all the sciences that collectively seek to understand Earth and its neighbor in space.
• Earth is at the perfect location (Goldilocks Zone)

4 Major Branches of Earth Science

• Geology studies the Earth: physical and historical
• Physical Geology studies the Earth's materials and processes on and below its surface
  • Minerals of the Earth include lava (after eruption) and magma (before eruption)
• Historial Geology aims to understand the origin of Earth and its development through history
• Oceanography studies the ocean's physical properties, sea floor topography, chemical composition, ecosystems, and coastal processes
  • It has aspects from chemistry, biology, physics, and geology
• Meteorology studies the atmosphere and the processes that produce weather and climate
  • The conditions that we experience are due to the atmosphere
• Astronomy studies the universe, including celestial objects, their origins, movements, compositions, and the physical laws that govern them

Why Study the Universe?

• Relates to the Big Bang Theory
• Earth and its processes are part of the universe.

Earth's Spheres

• Atmosphere: The layer of gases surrounding Earth, including oxygen, nitrogen, and other gases
  • It protects the planet, regulates temperature, and enables weather and climate
  • The stratosphere is one of the layers in the atmosphere
• Hydrosphere: All the water on Earth, including oceans, lakes, rivers, groundwater, and ice.
  • It supports life, shapes the land, and regulates climate
  • Other planets (ex. Mars) are not habitable because the water is frozen
  • Early life forms were found in water (bacteria, etc.)
• Geosphere: solid part of Earth, consisting of rocks, minerals, and the land itself, including the Earth's crust, mantle, and core
  • A part of the Geopshere is the lithosphere
  • Physical composition of the Earth (out to in): Crust, Mantle, Core
• Biosphere: Living organisms on Earth, including plants, animals, and humans, as well as the ecosystems they form
  • It interacts with the other spheres to support life and maintain ecological balance

Nature of Science

• Facts collected to seek an answer to a well-defined question
• A hypothesis is constructed as a tentative explanation, based on the gathered facts
• A hypothesis is elevated as a theory, which is well tested and widely accepted

Origin and Fate of the Universe

• The Big Bang Theory is the most accepted theory of the Origin of the Universe
• Suggests that the universe began as a single, extremely hot, and dense point around 13.8 billion years ago.
• The Big Bang was an expansion rather an explosion, of space itself
• Big Bang proponent: George Lemaître
• Hypothesis of the primeval atom or cosmic egg
• Evidence for the Big Bang Theory: Cosmological Redshift and Cosmic Microwave Background Radiation
• Cosmological Redshift. Atmosphere of stars absorbs specific wavelengths of light, this tells us the chemical comp and relative distance
• Galaxies moving away from us shifted to longer (redder) wavelengths
• Edwin Hubble discovered that most galaxies are moving away from us and that their speed is proportional to their distance
• Cosmic Microwave Background Radiation: Discovered by Arno Penzias and Robert Wilson by accident; they received a Nobel Prize in 1978.
• It is leftover radiation from the Big Bang, very cold 2.725 K
• Timeline of the Big Bang: Planck Epoch (Singularity Epoch) 0 to 10^-43 seconds
• All matter was condensed into a single point, all fundamental forces unified
• Inflationary Epoch lasts from 10^-36 to 10^32 seconds and included rapid exponential expansion and extremely high temperatures.
• Following Inflationary Epoch, Quark Soup lasted from 10^-32 to 1 second
• Liquid-like material formed out of quarks and gluons, the most basic known building blocks of matter
• Nucleosynthesis takes 3 to 20 seconds. Temperature cools down.
• Nucleus contains protons and neutrons (positive charge); protons and neutrons combine through nuclear fusion to form hydrogen, helium, and lithium.
• Recombination takes 240,000 to 300,000 years, and allows formation of neutral atoms (using electron)
• The universe cold enough for hydrogen and helium to form neutral atoms, allowing light to travel freely and creating the CMBR
• The Dark Age takes 300,000 to 150 million years. It was a lightness period before stare formation.
• Dominated by diffuse matter, low energy, and "dark matter"
• Reionization takes 150 million to 1 billion years. Quasars were formed which emitted intense radiation
• The universe is composed of ionized plasma
• Star and Galaxy Formation took 300-500 million years. Solar System Formation: 300,000 to 150 million years
• Steady State Theory: The universe is in a steady state
  • Is already been debunked because of the law of conservation of matter: matter is neither created nor destroyed
• Big Crunch Theory: The expansion of the universe reverses, and the universe collapses. The universe will stop expanding
• The result would be gravitational contraction, causing all matter to collide and coalesce into high-energy, high-density state from which the universe began
• Open Universe: The universe expands forever
  • If the density of the universe is less than the critical value, aout one atom for every cubic meter, it will continue to expand forever
• Multiverse Theory: the universe will expand but within the universe, there are other universes
• Universe: vast, all-encompassing system of matter, energy, space, and time; believed to have begun 13.8 billion of years ago and is constantly expanding ever since
• Cosmology is the study of the universe; its origin, structure, and behavior.

Stellar Evolution

• Begins with stellar birth in nebulae: interstellar clouds rich in dust and gases
• Triggered by shockwave from a catastrophic explosion or supernova (death of a nearby star)
• Mechanism: gravitational attraction of particles causes the cloud to contract, pulling particles to the center
• Protostar Stage: not hot enough to engage in nuclear fusion; not yet a star
  • As contraction continues, the core of the developing star heats up to 10 million K
  • Radiates energy in the red wavelength
• (Stable) Main Sequence Star: outward pressure balances the inward gravitational force
  • Nuclear fusion occurs
  • Stars spend 90% of their life as a hydrogen-burning main sequence star
  • The sun is expected to remain a stable main sequence star for another 5 billion years
• Red Giant Stage: usable hydrogen in the star's inferior is consumed, leaving a helium rich core
  • Core contracts since it no longer has gas pressure necessary to support against inward force of gravity
  • The core's collapse causes its temperature to rise, expanding the star's outer gaseous shell. -This gaseous shell is also known as a Planetary Nebula
  • White dwarf is also formed at this stage
• Variable Stage: Eventually the star's gravitational force stops outward expansion and the two opposing forces, gravity and gas pressure, again achieve balance
• Variable stars alternately expand and contract, and never reach equilibrium
• Burnout and Death: Stars exhaust their usable nuclear fuel and collapse in response to their immense gravity
  • Low-mass stars become white dwarfs
  • Medium-mass stars (such as the red giant) become planetary nebulae
  • Massive stars become supernovas
• Stellar Remnants include black holes and neutron stars
  • All stars consume their nuclear fuel and collapse into one of three celestial objects-white dwarfs, neutron stars, or black holes
• White Dwarf: after low- and medium-mass stars consume their remaining fuel, gravity causes them to collapse into white dwarfs
  • Contains degenerate matter
• Neutron Stars: remnants of explosive supernova events
  • Electrons are forced to combine with protons in the nucleus to produce neutrons
• Black Holes: densest objectives in the universe
  • Immense surface gravity, even light cannot escape it
  • Formed after a supernova event

H-R Diagrams

• Herzsprung-Russel diagram where stars are plotted according to temperature and luminosity (absolute magnitude)
  • Values on the left are higher so hotter ang white dwarfs
• Nebular Hypothesis/Theory: Bodies of our solar system evolved from an enormous rotating cloud called the solar nebula.
  • Remnants of red giants become gravitationally attracted forming a planetary nebula
  • Solar nebula contains microscopic dust grains and the ejected matter of long-dead stars
  • Began as a cloud of dust and gas called a nebula, started to gravitationally collapse
  • Outside materials formed a flat rotating accretion disk which cooled down and condensed to grains.
  • The nebula contracted into a rotating disk that was heated by the conversion of gravitational energy into thermal energy
  • The stellar material contracted to the center forming the protosun
  • Cooling of the nebular cloud caused rocky and metallic material to condense into tiny solid particles.
  • Repeated collisions caused the dust-size particles to gradually coalesce into asteroid-size bodies called planetesimals.
  • MVEM is the acronym to remember: Composition: soil (rocks), Relatively rocky materials, TERRESTRIAL PLANETS. JSUN is the acronym for Jovian Planets: Composition: ammonia, methane, cooler, GASEOUS PLANETS
• Solar nebula gravitational collapse/contraction: includes not hot enough for fission, condensation, rotating matter, etc.
• Collection of outside materials (continue to collect matter
• Denser materials condense closer to the sun (terrestrial) - rocks lighter condense far away (jovian) - air Solar system Planets: proximity to the protosun determines its composition

How is Life Possible on Earth?

• Prokaryote - ocean
• Asteroid bombardment carried water
• Water became liquid (water vapor) through precipitation of atmospheric gases
• Water vapor came from volcanic eruptions
• Volcanic eruptions caused by asteroid bombardment
• Formation of the Earth's Layers and the Atmosphere: Through collisions and gravitational attraction, larger planetesimals merged to form the proto-Earth
• Due to intense heating, Earth became hot enough that iron and nickel began to melt
• Heavy metals sank, forming the dense iron-rich core
• Produced a magma ocean
• Buoyant masses of molten rock rose about the magma ocean which solidified to form a primitive crust
• A Mars-sized body (Theia) collided with the proto-Earth, and the debris from this collision coalesced into the Moon
• Volcanic eruptions released gases, forming an early atmosphere consisting of water vapor, carbon dioxide, and sulfur dioxide (NO FREE OXYGEN)
• Earth cooled, water vapor condensed to form clouds, and torrential rains began to fill low-lying areas, which became the oceans

Earth's Material

• Minerals: building blocks of rocks.
  • In the mining industry, it refers to anything taken out of the ground (coal, iron ore, sand, gravel)
  • Minerals are naturally occurring inorganic solids that possess an orderly crystalline structure and can be represented by a chemical formula -Characteristics of Minerals: Naturally occurring only, Solid substance, orderly composition, and generally inorganic
• Orderly crystalline structure refers to Orderly, repetitive packing of atoms (crystals)
• Nonorganic refers to substances that are not derived from living organisms and typically lack C-H bonds
• Minerals also need to be represented by a chemical formula
• Luster: Appearance/quality of light reflected from the surface of a mineral
  • Metallic luster - minerals with appearance of metals
  • Submetallic luster- Look somewhat dull or tarnished, as if they have a metallic surface that has been weathered
  • Nonmetallic - generally not shiny or reflective
• Opaque - Ability to transmit light
• Cleavage: Tendency of a mineral to break (cleave) along planes of weak bonding Melting: Rocks melt due to intense heat beneath Earth's surface, forming magma

Rock Cycle and Types

• Magma → (cool & crystallize) → igneous rock → (weathering, erosion, deposition) → sediments → (lithification) → sedimentary rocks → (metamorphism) → metamorphic rock → (melting)
• Magma or lava cools and solidifies to form igneous rocks. Can happen underground or on the surface
  • Extrusive igneous rock is pushed outside & quickly solidify ; iIntrusive igneous rock - cools slowly underneath the earth Weathering, Erosion, Deposition: Rocks are broken down into sediments
  • Lithification (Compaction, Cementation): Over time, layers of sediments are compressed and bind together, forming sedimentary rocks
• Metamorphism: Rocks buried deep within the Earth are subjected to high heat and pressure, transforming them into metamorphic rocks, causing them to change their mineral structure
• Uplift: Geological processes bring rocks to the Earth's surface, exposing them to weathering and erosion, restarting the cycle
• Igneous rocks are formed from magma or lava sediment solidifications and have no layers
• Sedimentary rocks are formed from sediment composition and are crumbly and layered
• Metamorphic rocks are formed by transformation of other rocks and are relatively hard and layers may or may not be present Textures of Igneous Rocks: coarse grained (diorite) (intrusive), Fine Grained (rhyolite) (extrusive), Porphyritic (granite) (intrusive), Glassy (obsidian) (extrusive), Vesicular (pumice) (extrusive)
• Igneous Rocks are formed as magma cools and crystallizes.
• Magma: molten rock generated by partial melting of rocks in Earth's mantle and in the lower crust.
• Lava: molten rock (magma) that reaches the surface.
• Intrusive/Plutonic: Form when molten rock solidifies beneath the Earth's surface -Has large or coarse-grained crystals due to slow cooling.
  • Contains granite, coarse grained texture or gabbro, coarse-grained texture
• Extrusive/Volcanic: Form when molten rock solidifies at the surface. -Has small/fine-grained crystals due to rapid cooling; Contains presence of bubbles Composition of Igneous Rocks:
  • Felsic: Rich in feldspar and silica and that is light in color; Ex: granite.
  • Mafic: Rich in magnesium/iron that is dark in color; Ex. gabbro.
  • Intermediate: med-silica rocks with a mix of light and dark minerals; Ex: diorite. (60% of the Earth's crust is composed of Felsic rocks)
  • Intrusions: Igneous rocks masses that form underground (intrusive).
  • Batholiths: "Deep rock", largest intrusion, Spread over at least 100 km2, Ex: Slerra Nevada Batholith, Palawan Batholith
  • Laccoliths are a “Lake of rock”; Occurs when magma intrudes between layers of sedimentary rock; Ex: Montana, US.
  • Sills: Horizontal or parallel intrusions of magma between rock layers, forming sheets, and are concordant with the layers; Ex: PalisadePalisades Sill, NY.
  • Dikes: vertical/steeply inclined intrusions that cut across rock layers, and are discordant with the layers; Ex: Great Dike, Zimbabwe.
  • Sedimentary Rocks Formed from pre-existing/living origin that includes weathering and erosion, deposition, and lithification.
  • Sedimentary rocks at the Earth's surface are broken down into smaller particles (sediments) through physical/chemical weathering.
• Erosion: Sediments are carried away from their source by natural agents such as water, wind, ice, or gravity.
  • Deposition: Sediments are deposited in layers in environments, such as riverbeds/oceans. -Lithification (“turning into rock”): Layers of sediments accumulate and the weight of the overlying layers compresses the deeper layers, reducing pore space and expelling water/Minerals dissolved in water (silica, calcite) precipitate and bind the sediments togehter, turning them into solid rock. Categories if Sedimentary Rocks:Detrital (detrius), Chemical, Organic
• Features of Sedimentary Rocks: Stratification is layering of the sedimentary rock Organic rock is material, such as plant debris/shells/remains of living organisms

Types of Rocks

• Sedimentary Rocks: Formed from pre-existing rocks or remains of once living organisms. Weathering and erosion, deposition, Lithification (compaction and cementation)
• Metamorphic rock transformation-protolith form, elevated temperature vs high pressure, two major types is foliated and non-foliated
• Protolith= parent Materials:
  • Metamirphism leads to change in mineralogy, texture, and/or chemical composition. Happens in elevated temperatures & pressures, below Earth's surface to the upper mantle. -Low-grade meta: slight change, High grad meta is subsatantional rock can't be determined.
  • Two types is Foliated or non-foliated: Must be solid;
  • Agent of Heat: trigger chemical, results in recrystalization of existing minerals and formation of new minerals
• Stress -Confining pressure: equal force in all direction; causes spaces between mineral grains to produce dense rocks.
• Differential Stress: some forces are greater in one direction than others, to deformation and devopment of metamorphic
• Metamorphic rocks: from the uplift of the soil Foliated is layering/banded;
• Nonfalited: cannot have layering

Surface Processes and Landforms

• Exogenic versus Endogenic Processes: endogenic: Internal Earth forces from geothermal ,mantle convection, and plate tectonics
• exogenic is driven by external forces water earth, energy of weather uplift
• • endogenic versus exogenic processes weather
• weathering processes -plant roots grow into cracks (biological) -chemical (alter minerals )
• water saturation increases soil (weather) erosion (one place to another)
• slope mass mvt- movement if material down slope to rock solid, earth deposition: -sediment: process which sediment carried by which water win snow gravel
• • 2 major landforms -plateus vlaules**
• Mountains: uplitted portion from earth from at least 1000 feet forms over millions of years Orogenes (procss mountain) * types folder volcanic forms are not through soil they are dome.
• Plateaus is flat elevted w/sleep sides: -3 plains (structural (2,3)