ESS205H1 Lecture Notes - Lecture 2: Ordovician, Oceanic Crust, Hadean
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Lecture 2: earth system spheres and earth history. Some events take a long geologic time like building mountains whereas some take less than a minute eg. earthquakes. To u(cid:374)de(cid:396)sta(cid:374)d these (cid:272)ha(cid:374)ges, (cid:449)e (cid:374)eed to a(cid:374)alyse the ea(cid:396)th"s syste(cid:373)s a(cid:374)d the i(cid:374)te(cid:396)a(cid:272)tio(cid:374) between these systems. Ea(cid:396)th"s syste(cid:373)s: at(cid:373)osphe(cid:396)e: gas laye(cid:396)s, p(cid:396)ote(cid:272)ts ea(cid:396)th f(cid:396)o(cid:373) su(cid:374)"s (cid:396)ays, hyd(cid:396)osphe(cid:396)e: ea(cid:396)th"s (cid:449)ate(cid:396) (cid:894)li(cid:395)uid, (cid:449)ate(cid:396), i(cid:272)e, gla(cid:272)ie(cid:396)s(cid:895). Types of systems: open systems : exchanges both heat and matter with its surroundings like rivers, closed systems : exchanges only heat (no matter) Equilibrium in systems if input is equal to output, then we can say that this system is in equilibrium. We have knowledge of the hadean era from the proterozoic eon from meteorites and planetary materials. Precambrian times: there was no continental crust, there was a big magma ocean (earth was completely molten, there were asteroid impacts, atmosphere was dense and toxic. Three chemically different layers: crust, mantle and core.
