Explaining Spreading Centers: Mid-Atlanic Ridge & Iceland скачать в хорошем качестве

Explaining Spreading Centers: Mid-Atlanic Ridge & Iceland

The mid-Atlantic ridge is a spreading center that runs along the entire ocean and passes across the Raykjane Peninsula of Iceland. Most of the time we don't see what happens on this spreading center because it is deep below the ocean surface. In Iceland we are witnessing part of the spreading activities at thw moment, which includes volcanic eruptions and faulting of the crust. When the crust spreads apart, a graben can form and the associated faults can be used as conduits for magma flow towards the surface. In this video I try to use a sandbox to help explain the spreading center and illustrate what it looks. Each new extrusion of lava captures a moment in time and once the lava hardens into rock it locks in the current magnetic North pole orientation. This orientation changes with time and so older rocks record variations in this magnetic orientation. This means we can see the sequence of extrusions moving away from the Mid-Atlantic ridge. Hope the video helps to explain what is happening in Iceland at present. For a detailed explanation on paleomagnitism see this lecture -    • Paleomagnetism in the Pacific Northwest