SUG Board Review Module 1 PDF

1  Table of Contents PRINCIPLES OF GEOLOGY........................................................................................................................ 3 GEOMORPHOLOGY.....................................................................

1  Table of Contents PRINCIPLES OF GEOLOGY........................................................................................................................ 3 GEOMORPHOLOGY.................................................................................................................................... 31 GEOLOGY OF THE PHILIPPINES AND SOUTHEAST ASIA............................................................... 62 HISTORICAL GEOLOGY AND PALEONTOLOGY................................................................................. 92 STRUCTURAL GEOLOGY....................................................................................................................... 105 VOLCANOLOGY........................................................................................................................................ 134 STRATIGRAPHY........................................................................................................................................ 152 ANSWER KEYS...................................................................................................................................... 165 2 PRINCIPLES OF GEOLOGY 3  As the solar nebula continued to collapse and PRINCIPLES OF GEOLOGY rotate, the planetesimals in the inner solar system started to gravitationally attract each other and GEOLOGY accrete, or accumulate, into larger and larger bodies. This process of accretion is how the - from the Greek words geo (earth) and logos terrestrial planets - Mercury, Venus, Earth, and (discourse); literally the science of the Mars - gradually formed over millions of years. Earth, dealing with the study of its composition, structure, history, past life The gravity of these growing protoplanets would pull forms and processes responsible for the in and incorporate more planetesimals, heating Earth’s present configuration. them up through the energy of these impacts. This heating led to planetary differentiation, where denser materials like iron and nickel sank to the core, while lighter silicate materials rose to the CHALLENGES IN UNDERSTANDING THE surface, forming the mantle and crust. EARTH Over time, the majority of planetesimals were either incorporated into the growing planets or ejected - The Earth is a dynamic body with many from the solar system entirely. However, some interacting parts and a complex history; remnants of this early planetesimal population still exist today as asteroids, comets, and other small - The Earth has been changing throughout solar system bodies. its long existence and continues to The accumulation of planetesimals into the planets change; and was a crucial step in the formation of our solar system around 4.7 billion years ago, laying the - Changes can be rapid and violent (e.g., foundations for the diverse worlds we see today. landslides, volcanic eruptions) or slow and gradual. TWO MAIN BRANCHES OF GEOLOGY 1. Physical or Dynamic Geology – involved in the study of the material composition, appearance, structure and processes of the Earth. 2. Historical Geology – deals with the history of the Earth. This includes the Earth’s origin, relative and absolute timing of events that have shaped the Earth, as well as the life forms that have appeared in Earth’s history. EARTH ORIGIN PROCESSES Around 4.7 billion years ago, the solar system was in the early stages of its formation (Figure 1.1). At this time, the solar nebula - the cloud of gas and dust that collapsed to form the Sun and planets - was still present. Within this nebula, small solid Figure 1.1. Steps in Forming the Solar System. This illustration particles called planetesimals began to form. shows the steps in the formation of the solar system from the solar nebula. As the nebula shrinks, its rotation causes it to flatten into a Planetesimals were the building blocks of the disk. Much of the material is concentrated in the hot center, which will ultimately become a star. Away from the center, solid particles planets. They were conglomerations of various can condense as the nebula cools, giving rise to planetesimals, the silicate compounds (containing silicon, oxygen, and building blocks of the planets and moons. other elements), iron and magnesium oxides, and smaller amounts of other chemical elements. These planetesimals ranged in size from a few kilometers to tens of kilometers in diameter. 4  PLANETARY DIFFERENTIATION LAYERS BASED ON COMPOSITION − Planetary differentiation is the process by The Crust consists of: which a planet's interior chemically separates into distinct layers due to 1. The continental crust - relatively light differences in density and chemical “granitic” rock that includes the oldest rock properties of its constituent elements. This of the crust; generally richer in Na and K; occurs through partial melting driven by thickness ranges from 30 to 80 km, heat from radioactive decay and planetary sometimes attaining 100 km in some accretion. portions. Differentiation happens through: 2. The oceanic crust - composed of dark, dense volcanic rocks (basalt) with densities ▪ Gravitational separation - Dense iron sinks much greater than that of granite; more Fe- inward, taking siderophile elements with it. rich than the continental crust and thinner, Lighter elements rise. ranging from 3 to 10 km in thickness; young ▪ Collision - Earth's Moon likely formed from and relatively undeformed by folding. material splashed into orbit by a giant impact, removing lighter silicates and leaving dense The Mantle surrounds or covers the core; metal behind. constitutes the great bulk of Earth (82% of its volume and 68% of its mass); composed of iron and magnesium silicate rock. At about 1 billion years after the Earth was formed, the temperature at depths of 400-800 km was The Core is the central mass about 7000 km in enough to melt Fe. diameter; density increases with depth but averages about 10.78 g/cm3 ; constitutes only 16% Large drops of Fe have fallen toward the center, of Earth’s volume but accounts for 32% of Earth’s displacing the lighter minerals. mass; mostly composed of iron. About 1/3 of the material sank to the center, a large part being converted to a molten state. EARTH’S OUTER LAYERS The molten material floated upward to cool and form The outermost layers of Earth are the a primitive crust. atmosphere, hydrosphere, and Such differentiation resulted in the Earth’s internal biosphere. layering (Figure 1.2). The continents and ocean basins are Differentiation probably initiated the escape of Earth’s major surface features. gases from the interior which eventually led to the formation of the atmosphere and oceans, and ultimately, life. THE CONTINENTS AND OCEAN BASINS The transfer of internal heat to the surface was accomplished by convection, even when the mantle The ocean basins occupy about two- solidified. thirds of Earth’s surface; characterized by a spectacular topography. The continents rise above the ocean basins as large platforms. MAJOR FEATURES OF THE CONTINENTS Three basic components: Figure 1.2. The1. MajorShield - large Structural Units ofareas of (1) the Earth. highly Crust:deformed igneous and metamorphic rock (basement complex). Thin, rigid outer shell (continental and oceanic); (2) Mantle: Solid, slowly deformable iron-magnesium silicate layer; and (3) Core: Iron-nickel inner and outer layers. 5  2. Stable platform or craton - extensive flat, stable regions of the continents in which complex crystalline rocks are exposed or buried beneath a relatively thin sedimentary cover. 3. Folded mountain belts – uplifted mountain ranges that are sites of tectonic convergence. The relative sizes and ratios of these three Figuew 1.3. Major Provinces of the Ocean Floor. components vary from continent to continent. For example, Africa has the largest shield areas, while Asia has more fold mountains and volcanic belts. MAJOR FEATURES OF THE OCEAN FLOOR 1. Mostly basalt, a dense volcanic rock, and its major topographic features are somehow related to volcanic activity. Figure 1.4. Oceanic Ridge 2. The rocks are young in a geologic time frame; most are less than 150 million years old. 3. The rocks have not been deformed by Tectonics – study of the origin and compression. arrangement of the broad structural features of the earth’s surface (e.g., 4. The major provinces (Figure 1.3) of the ocean continents, mountain belts, island arcs, floor are: earthquake belts, faults, folds, etc.). a. Oceanic ridge - most striking and important feature on the ocean floor; a Plate – a large, mobile slab of rock that is huge, crack-like valley, called the rift part of the earth’s surface. It may be made valley, runs along the axis of the ridge up entirely of sea floor (e.g., Nazca plate) throughout most of its length (Figure 1.4). or both continental and seafloor (e.g., North b. Abyssal Plain - vast areas of broad, American plate). relatively smooth, deep- ocean basins on both sides of the ridge; lies at depths of Plate tectonics – the principle that the about 4000 m; consists of: earth’s surface is divided into large, thick plates that move slowly and change size Seamounts - isolated peaks of relative to one another. submarine volcanoes. Plate boundary – narrow areas of intense c. Trenches - the lowest areas on Earth’s geologic activity where plates move away surface; adjacent to island arcs or coastal from one another, past one another or mountain ranges of the continents. toward one another. d. Continental margins - zone of transition 3 PLATE BOUNDARIES between a continental mass and an ocean basin consisting of continental shelf and 1. Diverging plate boundaries (Figure continen 1.5) ▪ Where plates move away from e. tal slope. each other, either within the ocean or continent. Types: ▪ Continental extension ▪ Continental rifting ▪ Ocean spreading. 6  ROCKS AND MINERALS Rock - the material or substance, consisting of a mineral or aggregate of minerals, the Earth is made of. Mineral 1. It occurs naturally as an inorganic Figure 1.5. Divergent Boundary and its Landform Created. solid; 2. It has a specific internal structure; that is, its constituent atoms are 2. Converging plate boundaries (Figure precisely arranged into a crystalline 1.6) solid; ▪ where two plates move toward each other. 3. It has a chemical composition that Types: varies within definite limits and can be ▪ Ocean-Ocean Convergence expressed by a chemical formula; and ▪ Ocean-Continent Convergence 4. It has definite physical properties ▪ Continent-Continent (hardness, cleavage, crystal form, etc.) Convergence that result from its crystalline structure and composition. THE STRUCTURE OF MINERALS Law of Constancy of Interfacial Angles - each mineral has a characteristic crystal form. Although the size and shape of a mineral crystal form may Figure 1.6. Convergent Boundary and its Landform Created. vary, similar pairs of crystal face always meet at the same angle. Polymorphism - ability of a specific chemical 3. Transform boundaries (Figure 1.7) substance to crystallize with more than one type of ▪ where one plate slides structure. Example: Diamond and graphite, pyrite, horizontally past another plate and marcasite, etc. along a fault or a group of parallel faults. ▪ the displacement along the fault abruptly ends or PHYSICAL PROPERTIES OF MINERALS transforms into another kind of displacement 1. Crystal Form - natural crystal faces that assume a specific geometric form. Figure 1.7. Transform Boundary. At 2. Cleavage - tendency of a crystalline transform boundaries, substance to split or break along smooth tectonic plates slide planes parallel to zones of weak bonding in past each other the crystal structure. horizontally, creating a fault line between them. This motion does 3. Hardness - measure of a mineral’s not generate or destroy resistance to abrasion (Review Moh’s crust, but it does cause earthquakes. Transform Scale). boundaries are not sites of volcanic 4. Specific Gravity - the ratio of the weight of activity (Estrada, a given volume of a substance to the weight of an equal volume of water. 7  5. Color – the external identity of a mineral characteristic of deep intrusive rocks that that can occur as one or as many colors slowly cooled. due to impurities. Aphanitic – fine grained; the mineral 6. Streak - It is the color of a mineral in components are not visible to the naked powder form. eye (i.e., microscopic); formed by relatively fast cooling of some volcanic rocks (e.g., basalt). IGNEOUS ACTIVITY Glassy – texture of igneous rock with a high glass content; formed by very rapid An igneous rock is one that is formed from cooling, such that minerals had no time to the solidification of magma. form crystals. Magma - is the hot-liquid molten material, generated within the Earth, that forms Porphyritic – igneous texture in which igneous rocks when solidified. crystals visible to the naked eye are embedded in a matrix of aphanitic texture; Magmas may be: it represents a solidifying magma that has suddenly erupted to the surface. 1. Intrusive (plutons) - magmas stored within the crust. HOW MAGMA FORMS 2. Extrusive – magma erupted on the Magma originates principally by partial melting of surface either as lava or as fragments pre-existing rock. sent into the air (pyroclastic material). Plutons may be emplaced as concordant or Sources of heat: discordant bodies in relation to the layering of the intruded rock or host rock. 1. Geothermal gradient a. Sills are concordant plutons; they are flat, 2. The hotter mantle – geothermal gradients tabular bodies intruded parallel to the are higher in hot spots, where mantle layering of the host rock. plumes, which are narrow upwellings of hot material within the mantle occur. b. Dikes are discordant plutons that cut across the layering of the host rock. When no layering in the host rock is evident, the Factors affecting melting temperatures: pluton is called a dike. 1. Pressure – In general, the melting point of c. A volcanic neck is an intrusive structure a mineral increases with increasing apparently formed within the throat of a pressure (P). Upwelling mantle material volcano. originating from deeper high- pressure portions would melt at shallower portions d. Laccoliths are mushroom-shaped bodies where there is lower P. that rise near the surface and domes the overlying layers while it spreads laterally. 2. Water – water vapor under high pressure can lower the melting temperature (T) of e. Batholiths are enormous, complex rock rocks. bodies that cover at least 100 km2. EVOLUTION OF MAGMA f. Stocks are plutons like batholiths but smaller in size ( 256 mm, cobble 5. Lithification – The 256-64 mm and pebble 64-2 mm). conversion of sediment into rock trough such processes 2. Sand – grains from 1/16-2 mm. as compaction, cementation, 10  and recrystallization. temperatures and chemical conditions that prevail deep within the earth. 6. Recrystallization – the It alters the mineralogy, texture and formation of new crystalline structure of the rocks, to give rise to mineral grains in a rock. metamorphic rocks. CLASSIFICATION OF SEDIMENTARY ROCKS FACTORS CONTROLLING THE CHARACTERISTICS OF METAMORPHIC ROCKS Sedimentary rock – rock that has formed from: (i) lithification of sediment; (ii) precipitation from 1) Composition of the parent rock. solution; consolidation from the remains of plants and animals. 2) Temperature Types of sedimentary rock: 3) Pressure and stress - buried rocks 1. Clastic (or detrital) – are subjected to confining pressure formed from cemented (or geostatic pressure), or the sediment grains that are pressure applied equally on all surfaces of a body because of fragments of preexisting burial. rocks (e.g., conglomerate, 4) Fluids sandstone, shale) 2. Chemical – deposited by 5) Time precipitation of minerals from solution (e.g., rock salt, limestone). DIFFERENTIAL STRESS 3. Organic or biochemical – rocks formed by the The stronger or weaker stress acting on a body accumulation of the remains of in different directions; often caused by tectonic organisms. forces. There are 2 types: a) Compressive stress SEDIMENTARY STRUCTURES b) Shearing stress Bed (or stratum) – The smallest division Foliation – planar texture that develops as a of stratified (or bedded) sedimentary rock, result of differential stress. consisting of a single distinct sheet-like layer of sedimentary material, separated from the beds above and below by CLASSIFICATION OF METAMORPHIC relatively well-defined planar surfaces ROCKS called bedding planes which mark a break in sedimentation. Stratification – the condition shown by sedimentary rocks of being disposed in 1. Non-Foliated Rocks (Figure 1.10) horizontal layers of beds. (name based on mineral content) Lamina – the thinnest or smallest recognizable unit layer of original deposition in a sediment or sedimentary rock