GOL-105 Chapter 2

Convergent Plate Boundary

A plate boundary where two plates collide with each other, forming mountains, trenches, earthquakes, and volcanoes

Divergent Plate Boundary

Boundary between tectonic plates in which the two plates move away from each other, and new crust is created between them

Thrust (reverse) faults

Compressional force

Himalayas

Due to continental drift, the collision of India and Asia produced the ____.

Mid-Atlantic Ridge

Early recognition that ____ was site of landmass rupture and Atlantic Ocean formation.

Normal faults

Extensional force

Continental Drift

Idea that continents move horizontally over Earth's surface.

Mid-Ocean Ridge System

Largest geological feature on Earth. A continuous chain of submarine volcanic mountains that encircle the earth and look like seams on a baseball. Earthquakes are clustered at the Ridges. Sea floor rock is young here and gets older as you move away from the ridge. Little or no sediment, but it gets thicker away from the ridge. (explained in Sea Floor Spreading)

Paleomagnetism

Magnetization of ancient rocks at the time of their formation. -Develops in the outer crust -Protects us from solar winds -Weaker at the Equator, stronger at the Poles.

Tectonics

Movement of Earth's crust.

Relative motion

Not all plates move at the same time. Instead they have ____.

Wegener Theory Stalls

Not everyone agrees with Wegener bc he can't provide HOW or WHY and the plausible driving force. Wegener than dies; WWII begins.

glaciers

Orientation of glacial markings on all continents suggests ____ were linked.

Laurasia

Pangaea's Northern landmass.

Gondwana

Pangaea's Southern landmass.

Transform Plate Boundary

Places where crustal plates shear laterally past one another. Crust is neither produced nor destroyed at this type of junction.

Strike-slip faults

Shear force (San Andreas fault)

Hot spot

Small geographic area where heating and igneous activity occur within the crust.

Lithospheric Plates

Tectonic plates consisting of the crust and upper mantle. There are 7 major plates.

Ring of Fire

The ____ is common around the Pacific and has most of the world's trenches.

Fossil evidence

discovered as plots of prehistoric fossils localities shows that Mesozoic land-dwelling organisms occur on multiple continents.

Climate belt

discovered by the distribution of the late rock types plots sensibly in the belts of Pangea.

Continental Rifts

places where continental lithosphere is stretched in the process of breaking apart at a new divergent margin

Pangaea

(plate tectonics) a hypothetical continent including all the landmass of the earth prior to the Triassic period when it split into Laurasia and Gondwanaland

Types of Convergent Plate Boundary

1. Ocean to Ocean Convergent 2. Ocean to Continent Convergent 3. Continent to Continent Convergent

Alfred Wegener

1915-Alfred Wegener proposed that the continents are continually in motion and relative to one another.200 million years ago, there existed one large ocean (Panthalassa) and one large continent (Pangaea) which drifted to form the modern continents (Continental Drift). His theory of continental drift was out of favor with the scientific community until new technology provided evidence to support his ideas.

major plates

African plate, Antartic plate, Eurasian plate, Indo-Australian plate, Nazca plate, North American plate, Pacific plate, South American plate.

mountain belt

Alignment of ____ indicates initial continental fit.

Angles of Declination

Angle that a compass needle makes with the line running to the geographic north pole. 0º at the equator and 90º at the poles.

Plate Boundaries

At plate boundaries, Earth's crust is broken (fault) and rocks slip past each other in one of 3 types of plate boundaries.

plates

The reasons ____ move: 1. Drag on the base of the plate by convection in asthenosphere 2. Elevation at ridge pushes plate ahead of it 3. Plate is pulled into subduction zone by preceding parent plate 4. Broken plate segments create additional suction forces.

Forearc basin

Zone of intensely deformed rocks in belt between island arc and deep-sea trench.

Ridges

____ are the sites of crustal formation where hot rising mantle material rises to top of lithosphere, then cools, and bends away from center to form ridge.

DuToit's evidence

____ expanded Wegener's ideas. Mesosaurus fossils were found on Gondwana continents in freshwater. Without continental drift, this is not possible since mesosaurus could not have swam across Atlantic.

Wegener's Evidence

____ indicates that continents fit together (Pangaea) and have geologic and floral and faunal similarities.

Crust

____ is destroyed at subduction zones.

Transform faults

____ offset Mid Ocean Ridges, have enormous strike-slip faults and are seismically active.

Geologic units (similarities)

____ such as Brazil and South Africa having nearly identical geologic sequences exist due to continental drift.

Plate tectonics

a combination of the seafloor spreading and continental drift.