GEOL 240Lg 1st Edition Lecture 11 Outline Current Lecture Overview Where s all that Lava Plate moment over hot spots Hink of the hot spot like the direction What happened 42 43 million years ago It was moving north plates move direction Current Lecture There are lots of hot spots in the world but Hawaii is the most renown Yellowstones it s a hotspot Mostly nest the ocean continental hot spot Snake river plane a long hole in the ap lava flow hot spot hyper geothermal activity When any magma is coming up to a continental lithosphere Lava gets sticky boom Why does this matter Cant 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 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 Eurosean plate But it is also a hot spot above sea level Hot spots do not only occur in mid Atlantic ridges Alfred Wegener Extremely important Continental drift Father of plate tectonics Key figure German meteorologist Interested in glaciers died in a Greenland expedition studying glaciers 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 cohent way that continents were moving around well another and assembled as the super continent he called it PANGEA all lands He was ridiculed 20 years after he proposed this people thought it was ridiculous 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 especially Africa and south America this idea had been around He assembled all the data into a cohent argument Why did people make fun of this Gondwanaland the idea was 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 distribution of 300 Ma glaciers Makes no sense in current configuration Probable palo S asia in 3 distribution of ancient deserts and swamps 4 distribution of ancient plates and animals from palcotology ex glosopherisifn mammal like reptiles the ideas that you don t 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 plaustic 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 o Why did they move Proposed they had as a result of Lunar gravitational day Sir Harold Jeffries ancient geophysics Quickly should that if lunar forces were that earth would stop rotating within a few years How much hotter does the earth get as you go down 4k For every K you go down temperature increases by 30 degrees subduction zone slab pull the plate tectonics paradigm shift 1960s the most convincing evidence came from the study earth s interior diploe magnetic field formed by dynamo in liquid outer core lines of minclinations angle when o at equatos agnetic flux