Geology 101 Exam 1

Define “Geology”

The Science of the Earth, understanding planet earth

Earth Subsystems

Hydrosphere, Atmosphere, Biosphere, Geosphere

Hydrosphere

Water, 96% of water is Ocean, and 4% is freshwater from lakes, streams, and glaciers

Atmosphere

Earth’s gas layer, made of mostly Nitrogen and Oxygen, protects us from the sun. Climate and Weather

Biosphere

Life on Earth, cells, plants, animals.

Geosphere

Solid Earth; rocks, minerals, and Earth’s Interior.

Core of Geology; mountains, volcanoes, and rocks

Origin of Earth

Dense material like Iron and Nickel sank to the center

Lighter material like Silicon, Oxygen, Aluminum, rose to the surface

Earth’s Internal Structure

Crust, Mantle, Core

Crust

Thin, rocky outer skin

Oceanic and Continental Plates

Silicon and Oxygen

Mantle

Solid, rocky shell

carries heat from core to crust

Iron and Magnesium

Core

Outer Core: liquid, flowing iron 0 → magnetic field

Inner Core; Solid, mostly Nickel

Continental Drift Hypothesis

The continents drift around the Earth, and were once united as one big super

continent

Wegener’s Evidence

Fossils Matching Across Seas, Similar Rock Types and Geologic Features across seas, Ancient Climates

Tectonic Plates

Seven Major Plates, Seven Minor

Plate Boundaries: Divergent, Convergent, and Transform

Divergent Plate Boundary

Plates move away from each other

Magma rises up and produces new crust

Mid-Ocean Ridges, Seafloor Spreading

Convergent Plate Boundary

Plates move towards each other

Subduction Zones: denser crust sinks, melts, and produces a volcanoe

Oceanic-Continental Convergence

Oceanic Crust subucts

Continental volcanic arcs

Oceanic-Oceanic Convergence

older, denser crust subducts

volcanic island arcs

Continental-Continental Convergence

mountain belts

Transform Plate Boundary

Plates move past each other

Creates Valleys

Three Types of Atomic Bonds

Ionic Bonds: Atoms transfer electrons to each other, weak bond

Covalent Bonds: atoms share electrons, very strong bond

Metallic Bonds: Atoms share electrons in a group

Elements in Earth’s Crust

Feldspars make up 51% of the crust

Quartz: second most abundany mineral in crust

Mineral Def

naturally occuring

inorganic

solid

w/ crystalline structure

definite composite

Identifying a Mineral

Luster: how light reflects off

Color:

Streak: color of powdered mineral

Transmission: Opaque, Translucent, Transparent

Mineral Strength

Hardness: resistance to abracsion, scratcehs mohs hardness scale

Cleavage: breakage along planes

Fracture: how it looks broken

Tenacity: how it responds under stress, bend, crack…

Igneous Rocks Classification

Texture and Composition

Composition of Igneous Rocks

Mafic (Dark), Intermediate (Oreo), Felsic (Light)

Texture of Igneous Rocks

Aphanitic,

Phaneritic

Poryphyritic

Vesicular

Glassy

Pyroclastic

Aphanitic

microscopic minerals

rock cooled quickly, volcanism

Phaneritic

100% visible minerals

rock cooled slowly, plutonism

Poryphyritic

Mix of large crystals with lard microscopic mass

Vesicular

Many holes/ pores, made from frothy lava

Evolution Of Magmas

Magmatic Differentiation - formation of different magmas from an original magma

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Assimilation - Rising magmas melt + absorb host rock

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Magma Mixing - magmas combine

Viscosity

Resistance to flow of lava

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More silica = Higher Vis.

More Temp = Higer Vis.

Gases = More Gas = Lower Vis.

Types of Volcanoes

Shield Volcanoes

Strato Volcanoes

Pyroclastic Volcanoes

Claderas

Lava Domes and Plugs

Shield Volcano

Largest volcano

effusive eruptions and low viscosity

Strato/Composite Volcano

Classic “Volcano” shape

Alternating layers of mafic and felsic materials, dominated by intermediate

Pyroclastic Cones

Smallest Volcano

Mafic Lava

Lava Domes and Plugs

Bulbous accumulation of lava within vents

Too thick to flow and clogs vent

Calderas

Volcano collapses into the void of the emptied magma chamber

Summit is blown off by the extremely violent eruption

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Volcanic Derpressions with a diameter larger than 1km