Geology Flashcards
What is geomorphology
The study of the shape of the earth/ rocks
When was the Cambrian explosion
550 mya
what is special about the Cambrian explosion?
Sudden appearance of multicellular organisms in fossil records
when were the first land animals and plants?
~450-350 mya
when did O2 levels start to rise?
~2 billion years ago
What was the main cause of rise in O2 levels 2 bya?
cyanobacteria photosynthesising CO2
What ended the Paleozoic era?
The Permian Mass extinction
Which era was the age of the dinosaurs?
Mesozoic era (250-65 mya)
When did Pangea fragmentation occur?
mesozoic era
When was the Permian Mass Extinction?
225 mya
What is the Permian-Triassic extinction event also known as?
The great dying
Which was the age of bacteria?
Archean era
When did the dinosaurs go extinct?
Cretaceous mass extinction ~65 mya
What are the 6 layers of the Earth
inner core (innermost centre of earth) outer core lower mantle upper mantle lithosphere crust (outermost layer)
What mineral is the inner core made most of?
90% iron
What is the innermost layer of the earth
Inner core
Is the Earth’s inner core solid or liquid
solid
Where is the Asthenosphere found?
Upper mantle
Where are tectonic plates found?
lithosphere
Where are volcanoes located
Where tectonic plates meet/ move apart - the boundaries
What kind of current moves plates apart?
Convection current
When does a magma chamber form?
When convection currents move tectonic plates apart
Why do some ecosystems rely on hydrothermal vents (in oceans)
because they release hot sulphur laden gases - contains energy for bacteria to use
When vent closes, bacteria cannot access energy and ecosystem collapses
What are the 3 types of tectonic plate boundaries
Divergent
Convergent
Transform
What happens at divergent plate boundaries
Plates move AWAY - creating a rift where molten rock erupts, cools and forms new plate material
What happens at Convergent tectonic boundaries?
Plates collide
the denser oceanic plate sinks below the less dense continental plate
causes shortening/ folding of lithosphere
produces mountains and volcanoes
Which types of plate boundary causes volcanoes and mountains?
convergent
What are subduction zones?
one plate is forced downwards beneath another plate
Associated with strong Earthquakes, volcanic activity, and mountain range formation
What happens at transform plate boundaries
Two or more plates slide past each other causing earthquakes
What kind of plates are usually divergent?
Oceanic
What kind of plates cause transform boundaries?
Ocean-on-ocean
OR
Continent-on-continent
What are Ratites?
a taxon of flightless bird
Why are Ratites evidence for plate tectonics?
Because they come from the ancestor Gondwana found in south america, africa, australia and new zealand
- suggests all these continents were connected at some point (Pangea) but plates caused them to split
