that now have very different climates. This suggested that the continents must have been joined together at some point, e.g. South America and Antarctica [2m]. Fold mountains found in northern Europe (Scandinavia) match fold mountains found in eastern US, suggesting that both ranges were created at the same time, on the same plate boundary [2m].
Seafloor Spreading
A chain of underwater volcanoes, known as the Mid-Atlantic Ridge, was discovered on the floor of the Atlantic [2m]. It was suggested that new seafloor was being formed at this point. Lava cooled on the bottom of the ocean as plates separate from each other, causing magma to rise up to fill the cracks in the crust [2m]. Through this process, oceans are widened, as older rock moves away from the ridge and is replaced by younger rock. Ocean sediments are the main proof for seafloor spreading [2m]. The depth of sediment resting on the ocean floor allows scientists to tell which ocean floor is oldest: the thicker the sediment, the older the ocean floor [2m].
Logical order of theories and proofs showing a clear understanding and knowledge of topic
Marks Awarded
Definition of plate tectonics 1 SRP @ 2m Best 14 SRPs @ 2m each Total 30/30
20
EARTH
EXAM FOCUS
Note!
Many of the sample answers will include more SRPs than are needed to answer the question. If you write extra relevant SRPs in the exam, you will be awarded on your best ones.
