Introduction to Geology

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.

Plate tectonics

What the Earth is made of.

2 basic categories – energy that drives

Internal Processes

Energy within the earth

External Processes

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