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Alfred Wegener 1880-1930 How Wegener Proved His theory • • • • Continental Fit Matching Fossils Matching Mountains Sea Floor Age Mesosaurus Describe what is happening in this photograph. Time Two countries Plate movements Everest What causes plates to move Caused by thermal convection currents • 1. Hot rock moves like tar • 2. Hot interior of the earth Types of plate margins • Divergent – constructive • • • • Plates pull apart Hot magma released to the surface New oceans can form – mid atlantic ridge Continents pull apart at 2.5 cm per year. Types of plate margins • Convergent - Destruction of Crust When two plates collide, one plate travels beneath another. This is known as subduction Types of Convergent Plates • Oceanic – Cceanic Convergence • Oceanic - Continental Convergence • Continental – Continental Convergence Oceanic – Oceanic Plates • The smaller plate slips below the thicker plate • A Trench forms where the plate subducts • Example – The Mariana Trench where the Pacific and Phillipines plates collide Oceanic – Continental Plates • The oceanic crust is heavier and sinks beneath the continental crust • The continental plate deforms forming a mountain range • Exampe Nazca Plate and South American Plate converge to form the Andes Andes Mountains Oceanic – Continental Plate Convergence Continental - Continental • The two plates are very light • Neither plate subducts • They fold upwards to form a mountain range • Example the Indian Plate and the Eurasian Plate began to form the Himalayas 50 million years ago Red Sea Africa Pulling Apart. Separating Plates form the Agen and the Red Seas