Geologic Flashcards
In ____, who proposed the idea of continental drift?
Alfred Wegener, a german scientist, in 1912
Why did the other scientists reject/accept Alfred’s ideas at the time?
Alfred could not provide credible mechanism for the process of continental drift
When was Pangaea formed?
250 million years ago
What were Alfred’s 4 pieces of evidence?
- Jigsaw fit
- Glaciation
- Fossils
- Mountain chains
How is glaciation support the evidence of continental drift?
South America, South Africa, India, and Australia indicate they experienced glaciation at about the same time (glacial striations are left when boulders are dragged beneath glaciers; scratch surface, creating grooves). In their current positions, the striation point to continental glaciers originating in different locations. However, by aligning the continents, the striations point to 1 continental glacier at the pole
What is the Earth’s thickest layer?
Mantle
What is the Earth’s thinnest layer?
Crust
What elements are in the crust?
Granite + basalt
What elements are in the core?
Nickel + iron
Which layer of the Earth is liquid?
Outer layer
What is the lithosphere?
Crust + upper mantle, divided into tectonic plates that are solid
What is the asthenosphere?
Tectonic plates float on this hot, semi-liquid upper mantle, beneath lithosphere
What are the convection currents in the Earth caused by?
Hot material of lower mantle rising, cooling dropping, heating, etc.
When was the Precambrian era? What organisms were there?
4600 - 570 million years ago
Fossils + bacteria
When was the Paleozoic era? What organisms were there?
50 - 245 million years ago
Reptiles, fish, shells, amphilbians
When was the Mesozoic era? What organisms were there?
245 - 66 million years ago
Dinosaurs, ammonites
When was the Cenozoic era? What organisms were there?
66 - 0 million years ago
Neanderthals, mammals
What can happen at convergent boundaries?
Subduction zones = volcanoes, tsunamis, earthquakes
Collision zones = mountains
What can happen at divergent boundaries?
Seafloor spreading = mid-ocean ridge, new ocean floor
Rifts = New sea/ocean, new tectonic plate
What can happen at transform boundaries?
Strike-slip fault = Earthquakes
What are volcanoes?
Openings to Earth’s core
What is pyroclastic flow?
Dense mass of hot ash, lava, gas from volcano @ high speeds
What is lahar?
Flows of hot ash and mud
What is a volcano bomb?
Large rocks hurled out as far as 5 miles from crator
