EAR 105 1st EditionExam # 1 Study Guide Lectures: 1 - 8Lecture 1 (January 12)Introduction to Earth ScienceWhat is the main reason to care about earth science?Understanding the mechanics of the Earth systems allows us to detect and react to ways in which human activity, as especially as it relates to the dependency on fossil fuels, has contributed to global climate change.Lecture 2 (January 14) Origin and Composition of the EarthDescribe the four spheres of the Earth system.- Biosphere: Relates to all living organisms; exists almost entirely at or near the Earth’s surface- Hydrosphere: Earth’s largest sphere, water; 71% of Earth’s surface- Atmosphere: The Earth’s very thin layer of surrounding gas. 50% of the atmosphere lies below 5 kilometers (3.5 miles)- Geosphere: Earth’s mass from surface to center; rock, magma, lava, minerals, soil, regolithWhat are the Earth’s layers as categorized by composition?The Earth’s three layers are the crust, the mantle, and the core. The crust is the Earth’s rocky outer shell which encompasses the mantle, an internal shell that makes up 82% of the Earth’s volume. As it strengthens with depth, the mantle exerts pressure on the underlying core, which is the Earth’s very center.What is the most popular theory of the Earth’s origin?The solar nebula (big cloud of hydrogen and helium) set in rotating motion sometime after the Milky Way originated 13.7 billion years ago. 5 billion years ago, this solar nebula began to contract, forming a flat, disk-like shape with the protosun (pre-sun) at the center (aka. Early formation of solar system.) Heavier elements settled on the inner planets, whereas lighter elements were able to travel farther and thus accumulated to form the gaseous planets of Jupiter, Saturn, Uranus, and Neptune.Lecture 3 (January 21)Earth’s Internal Composition and TopographyWhat are the Earth’s layers as categorized by behavior (rheology)?The earth’s layers are the lithosphere, asthenosphere, mesosphere, outer core, and the inner core. The lithosphere consists of the Earth’s crust and a part of its upper mantle. It is rigid, and divided into lithospheric slabs aka tectonic plates. The lithospheric slabs are set in motion by theunderlying asthenosphere, which is made out of molten rock that flows like taffy. It is located in the mantle. Under the asthenosphere is the mesosphere which is a solid layer in the lower mantle which encapsulates the outer core. The outer core is an extremely hot and pressurized liquid layer in the Earth’s composition—this liquid consistency generates the Earth’s magnetic field. The inner core is the solid innermost center of the Earth’s structure.What are the different types of crust, and what are their respective characteristics?The two types of crust are continental and oceanic.Continental Crust Oceanic CrustThickness: 30-40 km; max 70 km 5 km (very thin!)Composition: Silica-rich less dense Iron-rich more denseRock: Granite BasaltLecture 4 (January 28)Matter & MineralsDescribe elements’ and minerals’ atomic structure and the types of bonds they eventually form.An atom is the most basic particle that makes up molecules. Atoms are made of positively charged protons and neutral neutrons in the nucleus. The nucleus is surrounded by small, high energy negatively charged electrons that hover around the center in an electron cloud. The electrons are separated into electron shells, which have a set limit capacity of electrons. It is the outermost electron shell, that of the valence electrons that reacts to form atomic bonds with other atoms. The valence electron shell has a maximum or ideal capacity of 8 electrons, and on the whole, atoms aim to fill their valence layers through exchanges in essentially 3 types of bonds.- An ionic bond occurs when the valence electrons are transferred between positively and negatively charged atoms, aka ions.- A covalent bond occurs when the valence electrons are shared between two atoms. This is the strongest type of bond covered in great length in EAR 105.- A metallic bond occurs when the valence electrons are free to move throughout the newly formed joint structure.Elements are made out of one more of a single type of atom bonded together. Elements then join to form minerals, or they can exist as minerals in their own right given they fit the requirements. Ex: gold. Lecture 5 (February 2)Igneous Rocks & Introduction to VolcanoesList and describe the three main types of volcanoes.- Cindercone volcanoes are formed of steep layers of crystallized lava fragments. They are relatively small in size and frequently occur in groups- Composite volcanoes (stratovolcanoes) are the most explosive of the volcano types. Theyare formed of interbedded (or composite) layers of fragmented lava and pyroclastic materials. Composite volcanoes are relatively large.- Shield volcanoes are massive, shield-shaped domes formed of fluid, basaltic lava. They have generally quiescent eruptions and make up a famous topographical feature of the islands of HawaiiWhat are the key determining factors related to the explosiveness of a given eruptionKey diagnostics include the melt’s include silica content—the higher the silica content, the more explosive the eruption. Another important factor is the melt’s viscosity, wherein the thicker the melt, the more pressure is harnessed since gaseous materials are less likely to escape the compression. To that end, the presence of gases is an equally important factor, as is the melt’s temperature, being that the higher the temperature of the melt, the less explosive it will be.Recall: Boren’s Reaction Series- in a melt, mafic minerals tend to settle out first, since they may crystallize at higher temperatures. As the magma cools, felsic minerals remain which contributes to the potential explosive nature of the eruption.Lecture 6 (February 4)Introduction to Sedimentary RocksWhat is the process by which sedimentary rocks are formed?Sedimentary rocks form as a result of weathering, erosion, transportation, deposition, and finally lithification (compaction & cementation).Essentially, sedimentary rocks are formed by the physical and chemical breakdown of other types of rocks, followed by the transportation of those rocks by moving energy forces as water, wind, glaciers, and living organisms, and are finally deposited where they can become lithified.There are two types of weathering, which constitutes the initial