GEOL 240Lg 1st Edition Lecture 4 Outline of Last Lecture I II III IV V VI VII VIII IX Sea Floor Spreading Drawing w explanation Rifting of a Continent What is Decompression melting East African Rift Mount Kilimanjaro Aulacogens Diagram of the Subduction Zone Convergent Plate Boundaries Volcanoes Outline Current Lecture I II III IV V VI Where s all that Lava Plate movement over hot spots Alfred Wegener Continental Drift PANGEA Distribution of Ancient Glaciers Current Lecture I Plate moment over hot spots Think of the hot spot like the compass What happened 42 43 million years ago to the hot spot It was moving north plates move direction There are lots of hot spots in the world but Hawaii is the most renown Yellowstone it s a hotspot Mostly nest the ocean continental hot spot Snake river plane a long hole lava flow hot spot Hyper geothermal activity When any magma is coming up to a continental lithosphere Lava gets Sticky and then it goes boom the explosion Why does this matter Can t get out and hits 0 pressure so it explodes Yellowstone is so big people never imagine it was a volcano about 75 kilometers prox Iceland and Mid Atlantic ridge coincidence of a hot spot and oceanic spreading ridge What is Iceland Basically a mega shield volcano a strange spot Being split in half Eurasian plate But it is also a hot spot above sea level Hot spots do not only occur in mid Atlantic ridges Alfred Wegener o Extremely important Continental drift o Father of plate tectonics Key figure o German meteorologist o Interested in glaciers He died in a Greenland expedition studying glaciers o The reason he is known as the father is because he collected all the data available that bored on this issue known as the continental drift 1915 synthesize all the available data and composed in a very cogent way that continents were moving around well another and assembled as the super continent he called it PANGEA all lands o He was ridiculed 20 years after he proposed this people thought it was ridiculous o He proposed that the continents were once assembled and once together as PANGEA and gradually drifted idea was continental drift Kind of data he assembled 1915 in support of continental drift 1 Fit of the coast lines of continents Esp Africa and South America This idea had been around He assembled all the data into a cogent argument Gondwanaland Older than PANGEA Distribution of ancient glaciers 300 ma By starting these glaciers in this detail you can tell what direction it is going 2 Distributing of 300 Million year old glaciers o Makes no sense in current configuration o Probable Palo S Asian 3 Distribution of ancient deserts and swamps 4 Distribution of ancient plates and animals from paleontology Ex glosopherisifin Mammal like reptiles The ideas that you do not think inside the box continents don t move 5 Distribution of Ancient Mountain belts on opposite sides of oceans Appalachians caladonides e n America Scotland Ireland Fatal flaws of Wegener s continental drift Proposed mechanisms for moving continents Continents don t really fit the way Wegener reconstructed them In plastic he had to bend them to get the continents to fit In 1965 early computer models matched continental shelf Wegener proposed a driving mechanism how did continents move o He proposed they placed through oceanic crust like a plow o Quickly disproved widely ridiculed Why did they move o Proposed they had as a result of Lunar gravitational day Sir Harold Jeffries Ancient geophysicist Quickly should that if lunar forces were that earth would stop rotating within a few years Quickly should that if lunar forces were that earth would stop rotating within a few years