Unit 2 Earth Science Study Guide

What are the criteria for a fossil to be considered an index fossil

1) widespread geographically

2) limited to a short lifespan in geologic time
3) occurred in large numbers

half life number

5,730

what is a source of heat within earths interior

radioactive isotopes in earths interior decay, cycling materials in convection currents formed in the mantles and asthenosphere

Metamorphism

continental convergence/subduction of one plate under another

magma

seafloor spreading/diverging/rising magma above a hot spot

solid, stable iron:

found in a layer where compressional wave velocity is approximately 11.2km/sec

the ocean floor is

younger at the mid ocean ridge

seafloor spreading occurs at the

mid ocean ridge, allowing new molten material to rise

past & current movements of continental crust & the theory plate tectonics to determine the pattern in ages in ages of crustal rock

evidence: continents look like puzzle pieces that fit together

past & current movements of continental crust & the theory plate tectonics to determine the pattern in ages in ages of crustal rock

pattern: there are rocks that formed during the formation of mountain ranges that are the same type and age found on continental separated by large oceans

past and current movements of oceanic crust and the theory of plate tectonics to determine the pattern in ages of the ocean floor surrounding the mid atlantic ridge

evidence: magnetization of the ocean floor

past and current movements of oceanic crust and the theory of plate tectonics to determine the pattern in ages of the ocean floor surrounding the mid atlantic ridge

pattern: there is a pattern of normal of normal magnetic polarity and reversed magnetic polarity and reversed magnetic polarity that mirror each other on each side of the ciage

evidence of the movement of oceanic crust

earthquakes and volcanic islands

evidence of the theory of plate tectonics

magnetism of the ocean floor

explanation of the age of the mid-atlantic ridge

lava is seen oozing out of the crust of the ridges that shows new/younger rocks are present and other rocks are present and older rocks are further

evidence of movements of continental crust

trenches/volacnoes/mountains

evidence of the theory of plate tectonics

subduction zones

explanation of the age of the canadian shield

that is the old /stable precambrian rock that has survived the merging and splitting over 500 million years

order of events

formation → first oceans form → iron enters → bonded iron → oxidation

Sudden change in velocity:

change in density

presence of certain types of seismic waves

state of matter

which of the following statements locations of juan de fuca ridge model

the greater amount of outward flow of energy from earths interior occurs at location A than at location B

describe how the pattern magnetic firled reversal ocean floor basalt shown in the rocks on either side of the juan de fuca ridge is evidence of convection currents in the mantle

convection cells cause magma to rise at the top so it solidates at the surface with a certain magnetic polarity, then it moves away from the ridge forming the same pattern on both sides

identify the relative age of the north american craton located in the midwest and easyern part of north american and the accetion belt located on the west coast of North America

the north american craton has remained stable over the past 500 million years, making it older than the accretion belt which elded to the North American continent within the last 500 million years

evidence for how huronian ice occur

radioactive dating of elements in rocks was used to determine ages of rocks in the huronian super group

what is the driving force for the theory of plate tectonics

heat from the core is causing convection in the mantle leading to the movement of plate tectonics

how did the central pangean montains seperate into the appalachian mountains and the caldeonian mountains

over 300 million years ago continents seperated by diverging plates creating 2 seperate mountain ranges

what is 1 characteristic of zicron crystals that makes them ideal for determining absolute age

small amounts of uranium are present in these crystals, which will decay into a stable material

which of the following groups of living organisms survived all 5 major mass extinctions

brachiopods

how would the hydrosphere most likely change and how does this effect global sea level

less water goes into the mantle, this would lead to an increase of sea level