Lecture 2- Evolution of ocean basins

Question 1

What are continents placed on?

Answer 1

• continetal float on a semi liquid substrate

Question 2

How did liquid water form on Earth?

Answer 2

-volcanoes spewed water and gases into the outside, eventually clouds= rain, cooling, started forming oceans -comets= water so also extraterrestrial origin of water

Question 3

What is the origin of salt?

Answer 3

-some area above water= lot of minerals, soluble in water,; rains the water flows over a continets gets to the sea and collects mineral on the way and these accumulate in seas.

Question 4

Where did the minerals for salt in oceans come from?

Answer 4

-whole range of ions that get to the sea, have long residence time= million to billion years -also some input of minerals from underwater volcanic activity -originally oceans were freshwater

Question 5

What is continental drift and what does it cause?

Answer 5

-Oceans are born when continents break apart (e.g., deconstruction of Pangea and formation of Atlantic and Indian Oceans)

Question 6

Where do continents break apart?

Answer 6

-Continents break apart at a continental rift—a region of crustal extension