Earth science 9 Flashcards
who proposed the idea of continental drift
alfred wegener
what was pangaea
it means all lands and it was a huge mass of land that had all the continents on it
what book in 1915 did wegner publish for evidence of drift
The origin of continents and oceans
Explain matching fossils
Some fossils like mesosaurus fossils were found in eastern south america and soutern africa. But they are far away so no way a dinosaur could swim that far. so wegener said the continents must have been joined
what were wegeners evidences for continental drift (what animals)
matching fossils(mesosaurus and glossopteris) rock types, and ancient climate.
Explain rock types
when you look at a map you notice that the continents could fit like a puzzle. Then you also notice that the ike mountain ranges in south america and africa lined up almost like they were onced joined
Explain ancient climates
for example, Greenland had warm weathered fossils on it so it was believed that Greenland drifted from the bottom to the top to a colder climate. Wegener also found glacal clues of glacial deposits in southern areas of south America Africa India and australia.
why was wegeners theory laughed at and people did not believe him
because he had no proof. He couldnt explain how when or why these changes happened. Also other scientist couldnt explain it either.
Can we beleive in pangaea and things as christians?
Yes with some modifications and not 200 million years ago.
When was wegeners idea finally accepted
after his death in 1930 scientist began to study his theory and a new theory called plate tectonics was formed.
what gave the best evidence for wegeners hypothesis
sea floor spreading
What helped people in the 1940 and 1950 explore the ocean floor
sonar. It was used to make maps of the ocean floor. and it discoverd underwater mountains and valleys
what are deep ocean trenches
long steep valleys that form in deep parts of oceans. most trenches occure near the edges of the pacific ocean
what is mid ocean ridges
a long chain of mountains extending throughout all oceans. They form the longest feature on earth’s surface.
what are rift valleys
a deep central valley that runs down the center of a ridge called a rift valley. kind of like a canyon
what is the composition of the ocean floor
mostly basaltic or igneous rocks. most of the floor is covered by sediment, thickest near continent and none at ridges.
what is sea floor spreading
a theory made by harry Hess in the 1960s. oldcrust moves out and new crust comes in then the old crust goes down toward mantle.
explain sea floor spreading
As tectonic plates slowly move away from each other, heat from the mantle’s convection currents makes the crust less dense. The less-dense material rises, often forming a mountain or elevated area of the seafloor.
what submarine did ppl use to discover pillow lava?
Alvin. A submerine that could withstand lots of pressure.
How did the life forms that were newly discovered by alvin get their energy if their was no sunlight
Instead of using photosynthesis. They used chemosynthesis. They used chemicals from the vents where the mama reaches the surface.
