 Part of a several part series on plate tectonics This is a series of lectures done for my introduction to geology classes, but I figure I put on YouTube To share to everyone out there. So the first thing we're going to talk about is Introducing this concept of plate tectonics and lay some of the foundation of the early science behind it. So I think Since the beginning of our understanding of basic geology There have been people asking questions like why are there earthquakes and why are there volcanoes and How did mountains form? Why do we have mountains and why do the continents fit together so well at you know as we begin to map the world through through these various travels people start to ask about the Shape and geometry of the various continents and why they look like they fit together like pieces of the puzzle you know and short of it using a deity to explain earthquakes and volcanoes and mountains and things like that Geologists started to formulate some hypothesis and one of the most notable was in 1912 Which is fairly recent for science. I think Alfred Wagner came up with this idea of Pangea, which was a supercontinent Where all of the other continents on the planet were combined into one large landmass and He explained that we don't have Pangea anymore because something he called continental drift Wagner's experience was primarily in meteorology and he spent a lot of time in the North Pole area Examining icebergs and their movements and other weather features up there He actually died up on the ice he was in Greenland and He hypothesized that continents skidded through the oceans very much like icebergs and And his evidence that he provided to support this was the fit how the continents fit together as you saw in the last maps and How there are matching fossils Between the continents which will show in an upcoming slide and there's also geology that matched across the across the Atlantic Ocean and You know ancient climate Inferred from that geology interpreted from that geology Also matched across the oceans. So all good piece of evidence. However a big area where his His evidence was lacking was What was driving these motions of these very large landmasses is really hard for people to Imagine that something as large as a continent could move Right and be dynamic even over a geologic time scale. So Here is the distribution of fossils Over the different continents and you can see when you kind of fit them together here you could see things like this Cyanog Mathis And then Mesasaurus and the glossopterus is usually the the key species or Gene is mentioned when when a lot of these people talk about this as hypothesis You know, there's not many other ways to explain how you get this kind of distribution of species Without the continents being connected. No, there's obviously some other hypotheses flying around like these Fossil plants or these plants Travel across the ocean on a log to get to these other continents and that's why they're dispersed like they are so obviously Easiest explanation is that the landmasses were once connected or maybe it's the easiest explanation now So the the whole paradigm at the time was a continent's or stationary, right? They're enormous Nobody has ever observed a continent moving. So it must be a lot of malarkey and Like I mentioned earlier The weakness in and Begner's hypothesis was that he did not have a mechanism He couldn't explain how these comments were moving. So That is it for this lecture and we'll continue on with the next one Picking up from there