Geology Exam 2 Review Flashcards | Quizlet

Physical weathering examples

Frost wedging, roots, fracturing

Chemical weathering examples

Dissolution, oxidation, hydrolysis

What happens to sediment with farther transport?

Becomes rounder and smaller

Well-sorted sediment

Sediment with similar grain sizes

Poorly sorted sediment

Sediment with mixed grain sizes

Grain size order

Boulder → Cobble → Pebble → Sand → Silt → Clay

Breccia

Clastic sedimentary rock with angular clasts

Conglomerate

Clastic sedimentary rock with rounded clasts

Sandstone

Sedimentary rock made of sand-sized particles

Siltstone

Sedimentary rock made of silt-sized particles

Shale/Mudstone

Sedimentary rock made of clay-sized particles

Lithification

Compaction + cementation

Cross-bedding

Indicates dunes or current flow

Graded bedding

Coarse grains at bottom, fine grains at top

Ripple marks

Indicate movement of water or wind

Mud cracks

Indicate a drying environment

Transgression sequence

Sandstone → Mudstone → Limestone

Regression sequence

Limestone → Mudstone → Sandstone

Compression stress

Causes folds and reverse faults

Tension stress

Causes normal faults

Shear stress

Causes strike-slip faults

Normal fault

Hanging wall moves down

Reverse fault

Hanging wall moves up

Thrust fault

Low-angle reverse fault

Strike-slip fault

Horizontal motion along the fault

Anticline

Arch-shaped fold; oldest rocks in center

Syncline

Trough-shaped fold; youngest rocks in center

Dome

Circular anticline

Basin

Circular syncline

Contact metamorphism

Heat from magma

Regional metamorphism

Heat and pressure over large areas

Shale metamorphic sequence

Shale → Slate → Schist → Gneiss

Sandstone metamorphoses into

Quartzite

Limestone metamorphoses into

Marble

Brittle deformation

Shallow crust; rocks break

Ductile deformation

Deep crust; rocks flow

Original Horizontality

Sediments are deposited in horizontal layers

Law of Superposition

Oldest layers at bottom; youngest at top

Cross-Cutting Relationships

A feature that cuts another rock is younger

Inclusions

Inclusions are older than the surrounding rock

Angular unconformity

Tilted layers overlain by horizontal layers

Disconformity

Gap in time between parallel sedimentary layers

Nonconformity

Sedimentary rock deposited on igneous or metamorphic rock

Half-life

Time required for half of the parent atoms to decay

Example of radioactive decay

1000 → 500 → 250

Index fossil

Widespread, abundant, and short-lived fossil used for correlation

Major geologic divisions

Precambrian, Paleozoic, Mesozoic, Cenozoic

Paleozoic life

Fish and amphibians

Mesozoic life

Dinosaurs

Cenozoic life

Mammals and humans

Continental Shelf

Shallow submerged edge of a continent

Continental Slope

Steep drop-off beyond the shelf

Continental Rise

Gentle incline at base of continental slope

Abyssal Plain

Flat, deep-ocean floor

Mid-Ocean Ridge

Underwater mountain chain where new crust forms

Ocean Trench

Deep depression where crust is subducted

Island Arc

Chain of volcanic islands near subduction zones

Seamount

Underwater volcanic mountain

Guyot

Flat-topped seamount

Youngest ocean crust location

Mid-ocean ridge

Oldest ocean crust location

Farthest from mid-ocean ridge

Where ocean crust is destroyed

Trenches

What happens to ocean crust as it ages?

It becomes deeper

Fringing Reef

Reef attached directly to shore

Barrier Reef

Reef separated from shore by a lagoon

Atoll

Ring-shaped coral reef surrounding a lagoon

Turbidity currents create

Submarine canyons, submarine fans, graded beds

Evaporite examples

Rock salt and gypsum

Black smokers

Hydrothermal vents

Black smokers produce

Ore deposits and unique ecosystems

Isostasy

Crust floats on the mantle

Why mountains are high

They have deep crustal roots

How elevation increases

Crustal thickening, magma intrusion, heating, volcanism

How elevation decreases

Erosion, cooling, normal faulting

Subduction mountain example

Andes Mountains

Continental collision example

Himalayas

Mountain-building processes

Folding and thrust faulting

Basin formation processes

Rifting, normal faulting, subsidence, strike-slip movement

Continental hot spot example

Yellowstone

Continental hot spot/rift example

Afar Rift

Hypocenter (Focus)

Source of an earthquake below ground

Epicenter

Point on the surface directly above the focus

Elastic rebound theory

Stress builds, strain accumulates, fault slips, earthquake occurs

P-wave

Fastest seismic wave; travels through solids and liquids

S-wave

Slower than P-wave; cannot travel through liquids

Surface wave

Slowest seismic wave; travels along Earth's surface

How are earthquakes located?

Measure P-S arrival times and triangulate

How many stations are needed to locate an epicenter?

Three stations

Major earthquake settings

Mid-ocean ridges, transform boundaries, subduction zones, continental collisions

Earthquake hazards

Ground shaking, surface rupture, landslides, liquefaction, tsunamis, aftershocks, fires

How a tsunami forms

Seafloor movement displaces water

What happens to tsunami waves near shore?

They grow higher and cause flooding

Breccia vs. Conglomerate

Breccia = angular; Conglomerate = rounded

Compression associated fault

Reverse fault

Tension associated fault

Normal fault

Shear associated fault

Strike-slip fault

Anticline center

Oldest rocks

Syncline center

Youngest rocks

Quartzite parent rock

Sandstone

Marble parent rock

Limestone