Midterm Exam File Questions Flashcards
The largest of the “rocky” or terrestrial planets is…
Earth
The most abundant three elements within Earth are
iron, oxygen, and magnesium
Bodies in our solar system grew by the colliding of millions of bits of matter, this process is called
accretion
As one result of accretion, bodies larger than about 500 km in diameter became very hot, perhaps molten, resulting in a gravity driven separation of material with different dentition. This is called…
differentiation
The portion of Earth that is broken into tectonic plates is the
lithosphere
Orogenic mountains form at or near
colliding plates
The very first stars in the history of our universe would have differed from our sun (Sol) in that
they were larger and contained little except hydrogen and helium
Small bodies of rock or metal that orbit Sol are called
asteroids
Objects made of a mixture of ice and rock that orbit Sol are called
comets
EArth’s lithosphere is composed of the
all of the crus and uppermost 100-150 km of mantle
The Moho is the base of EArth’s
crust
the age of oceanic crust___with increasing distance from the mid ocean ridges
increases
The oldest lava (basalt) on the sea floor is about___
200 Ma
Continental coastlines that occur within the interior of a tectonic plate are called
passive margins
When rock is melted within the earth, resulting in volcanic activity, which statement is true about the melting
a) all material is melted
b) only a portion of the rock is melted–partial melting
b
Melting at divergent plate boundaries is partly the result of
reduction of pressure
Volcanic arcs have a direct geological relationship to
1) subduction
b) plate collision
c) oceanic trenches
d) all 3 of the above
e) none of the above
d
A massive continental-scale glacier covered southern India and much of the land now south of the equator during the later part of the___Era
Palaeozoic Era
Which is the oldest unit of the Geological Time Scale
Hadean
Which is the youngest unit of the Geological Time scale
Cenozoic
The oldest life forms on planet Earth lived during which time unit?
Archean
Th last of the 3 major extinction events on Earth occurred at about
65 Ma
The most significant of the 3 major mass extinction events on Earth occurred at about
245 Ma
The process of plate tectonics results from___in EArth’s mantle
convection
Which of the following is true about EArth’s mantle
It is solid except for small liquid patches
Evidence indicates that Earth is about___old
4.5 Ga
Modern astronomy indicates that the Big-Bang occurred at about
14 Ga
One of the most important processes to take place after the Big-Bang and before the formation of our solar system was
the fusion of atoms inside large suns
The condition of floating equilibrium of the lithosphere in the rest of the mantle is called
isostasy
Although high variable, the average rate of movement of Earth’s tectonic plates is approximately
2 cm/year
The deepest parts of the oceans occur
at convergent plate countries
An isotope is
an atom with a specific number of protons plus a specific number of neutrons in its nucleus
What is the depth of the base of oceanic crust
8 km
What is the mantle/core boundary depth
2900 Km
what is the centre of Earth depth
6400 km
Earth’s asthenosphere is
a zone of weak roc in the lower part of the upper mantle
the rate of 15O to 16 O in the shell of a marine planktonic organism can be used to determine
the temperature of the water in which the organism lived
the most common type of meteorite (by far) is what is called ‘an ordinary chondrite’ One reason why their study is important to us is that
they seem to have the same chemical composition as Earth overall
Regarding eArth’s atmospheric temperature (climate): in the geological past it has
fluctuated numbers times between ice ages and much water periods
In the chemical classification of igneous rocks, which material is the most important
the silica content
Imagine the following geological situation,a s determined fro a groups of rock strata in a tectonic mountain belt. A sequence of horizontal beds of clay and sandstone overlie a series of folded lava flows, displaying a number of anticlines an disinclines. The lava beds are all approximately 100 to 90 Ma, and the oldest of the sedimentary layers of 50 Ma, the youngest 35 Ma. The boundary between the lava and the sedimentary beds is called a (an)
angular unconformity
