If Earth’s history were a calendar year:
Formation of Earth: 1 January
First indirect evidence of life: 4 March
First direct evidence of multicellular life: 15 november
Multicellular animals with hard skeletons: 18 November
Dinosaurs appear: 10 December
Dinosaur go extinct: 25 December
HomoSapiens appear in Africa: 31 December, 11:43pm
Christopher columbus sails to the Americas: 31 December, 11:59:57
Geology happens in time and space.
Paradigm: A way of looking at the world
Paradigm shift: entrenched way of looking at the world somehow
People started learning about evolution
Late 60s, 70s, theory of plate tectonics.
What the Earth is made of.
2 basic categories – energy that drives
Energy within the earth
Energy from the sun
Observation and interpretation are two different things.
Depth of river systems
Elevation of north and south poles
Geochronology: Study of Earth over time
Age of Earth: 4.5 Billion years
Mountains on seafloor appear to be youngest.
Easier to collect seafloor data than it is age data, not much data near N/S poles.
Atlantic – mountain range down the middle, towards edge of continents, old seafloor there.
Volcanology: Most of the volcanos follow mountain ranges
“Ring of Fire” – active volcanoes surrounding pacific ocean on coastline of N. America and Asia
Seismology: Earthquake activity
Epicenter of earthquake – area on earth’s surface directly on top of quake.
Different colors on map – different depths of quake.
Focus: Where the plates slip next to each other (epicenter is area directly above focus)
red – close to surface
blue – deep
Lots of earthquakes under mountain ranges
usgs.gov – US geological survey
Mostly red, patches of red and green together
might be more sensors / detectors than in other areas
Seems to be a pattern
old seafloor – deep earthquakes