EAS201 Lecture Notes - Lecture 27: Acasta Gneiss, Archean, Zircon
22 Mar 2020
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Document Summary
Nucleic acids for replication and transfer of its genetic properties. Carbohydrates as the structural backbone of the cell wall. We don"t know how these parts are made** We have not been able to form these in a lab. Inhospitable environment, lots of particles and meteorites bombarding earth. Early earth formed after its collision with a mars-sized planet (theia) Earth"s internal temperature was extremely high 1500c due to kinetic energy of accretion and heat generated by radioactive decay. Temp so high that iron and nickel are melting. Once liquified, the iron and nickel sank by gravity to the core, giving rise to a magnetic field. Silicates began to float outwards from the centre to form the mantle and the crust. Differentiation: iron and nickel melt and sink to the core, silicates float and form mantle and crust. Eventually temperatures began to drop below 1000c and rocks could form. The landmasses that formed at this time were low-lying volcanic islands.
