Week 18 Flashcards
(25 cards)
What is the Lithosphere?
Top-most layer of the earth, made up of the crust and lithospheric mantle
Made up of:
Oceanic lithosphere
Continental Lithosphere
Subducted Lithosphere
Oceanic Lithosphere
Made by the injection of molten mantle material through mid-ocean ridges
Ejected molten rock rapidly cools and pushes the plates apart allowing for more mantle to be pushed through mid-ocean ridge
How is Sima created?
When magma released from the oceanic ridge cools rapidly and reacts with seawater to produce Sima.
Due to rapid cooling, oceanic crust is denser than continental crust
What is continental lithosphere?
The layer of rocky surface which forms the geological continental shelves and their low-lying seabed.
What are the 2 types of continental crust?
Igneous rocks: Formed by cooling and recrystallisation of magma
CAN BE EITHER:
Intrusive: When liquid magma cools slowly within the crust, surrounded by pre-existing rock
Extrusive: Magma cools on surface of the earth, brought to the surface via fissures in the Earth or volcanic eruptions
TYPE OF CONTINENTAL CRUST
How are Sedimentary rocks formed?
Through the accumulation and deposition of different sediments which can be inorganic or organic
Erosion of existing igneous and metamorphic rocks result in particulates being produced, slowly settles in layers called Strata
TYPE OF CONTINENTAL CRUST
How are Metamorphic rock formed?
Cycles of elevated temperatures and high pressures that alter the physical and chemical properties of the rock
Process doesn’t melt the rock but allows for minerals within the rock to dissolve and be replaced by other minerals
Cannot be formed from igneous or sedimentary rock
TYPE OF CONTINENTAL CRUST
Plate tectonics?
Earth’s Lithospheric crust is split into many tectonic plates, these are rigid crusts of continental and oceanic plates that float on the mantle
These plates are moved by the convection currents of the mantle due to the differences of density and temperature.
What are Divergent boundaries?
Formed as two tectonic plates move away from each other
As plates move apart, lava erupts from the gap produced, rapidly cools to fill spaces forming a new plate
How is the Mid-Atlantic ridge formed?
Formed by the separation of the North American, Eurasian and African plates.
How is the East African Rift formed?
African plate begun to split apart into 2 new plates (Nubian and Somalian plates)
Has formed many of the African Great Lakes within this valley.
What are Convergent Boundaries
Formed by the collision of two plates.
Can form a Subduction zone or a Continental collision zone
Subduction zone occurs when one plate is denser than another plate. Denser plate forced underneath and less dense plate is forced upwards
What is the difference between Convergent Boundaries and Divergent Boundaries?
Differences in densities of the two plates colliding
Equal Densities: Divergent
Different Densities: Convergent
Andes Mountains?
Example of a mountain formed by the subduction of the oceanic Nazca Plate
Andes were uplifted in irregular pulses, form a chain of volcanos and mountains along the ridge of Nazca/South American Plate
What are Transform Boundaries?
Neither create nor destroy tectonic plates, two plates grind against each other. Site of the grinding is called the transform fault.
What is Palaeontology?
Scientific study of life which existed prior to the Holocene epoch
Using different technologies palaeontology can evaluate almost 4 billion years of evolutionary history
What is Palaeozoology, Palaeobotany and Micropalaeontology
Palaeozoology:
Study of historical animal species
Split into invertebrate and vertebrate Palaeozoology
Palaeobotany:
Study of the evolution and development of photosynthetic organism
Micropalaeontology:
Study of historical microbial species
Palaeozoology in detail?
Discovery and research of macroscopic fossilised remains
Hard organic structures, like teeth and shells survive due to resisting decay whilst the soft structures decay.
RHUL and Leicester Uni discovering tooth from extinct species of hippo
Near Complete iguanodon discovered in surrey
Palaeobotany in detail?
Discovery and research of the origins of photoautotrophs and their evolution
Important to reconstruct and understand connection between photosynthesis and climate
Petrification of plant tissues
Mineralisation of crossotheca hughesiana pollen organs
Palaeoclimatology in detail?
Study of historical climates, using chemical composition of rocks, ice sheets or tree rings.
Ice sheets build up as layers, we can drill down to find old ice and analyse them.
What is Molecular Palaeontology
Study of Fossils and sub-fossils for presence of biological molecules using DNA sequencing and GC/LC-MS.
DNA/RNA, carbohydrates and lipids can be discovered.
By evaluating changes in mtDNA, relation and age can be evaluated.
Different forms of Fossil formation (Permineralisation, casts and moulds)
Require fossilised organism is quickly buried by sedimentation post-death
Soft tissues quickly decompose leaving behind hard tissue in sediment
Fossil casts and moulds encase the hard tissue, making an impression on the hardening rock, impression remains forming a mould.
Reversing Extinction?
Use of artificial semination and cloning, we can bring back extinct species to life.
Pros of Reversing Extinction?
Pros:
Can be used to prevent the extinction of other endangered species by advancing techniques for cloning/ artificial insemination
Reviving extinct species could reintroduce functioning ecological systems –> solves overpopulation and ecological damage
reviving plant and animal species can allow for new biomolecules to be discovered –> Can cure human diseases
Tourism
