Question

1) What effect does water have on the melting temperature of a material? 2) why would the effect of water on the melting temperature of a rock be important at subduction zones

2) Why would the effect of water on the melting temperature of a rock be important at subduction zones?

3) Where in the world can you find an island arc system?

Answer 1

Hello Student

1. Water is a very special kind of liquid  and can change a materials melting point . Suppose water is incorporated into a mineral crystal. It will  act as an impurity causing the melting point to decrease, The decrease in melting point will  allow the mineral to melt at lower temperatures. this is how water effect the melting temperature of a material.

2. The effect of water on melting temperature of a rock be important at subduction zones is very important. Water lowers the melting point of mantle rock, initiating melting at a subduction zone .In the region of the earth's crust where one tectonic plate moves under another tectonic plate.This is where oceanic crust gets recycled back into the mantle and continental crust gets created by the formation of arc magmas. Subduction zones host a unique variety of rock types created by the high-pressure, low-temperature conditions a subducting slab encounters during its descent. The metamorphic conditions the slab passes through in this process creates and destroys water bearing (hydrous) mineral phases, releasing water into the mantle. This water lowers the melting point of mantle rock, initiating melting. The timing and conditions in which these dehydration reactions occuris important for mantle melting, volcanic arc magmatism, and the formation of continental crust.

3.In the world we can find an island arc system in a region roughly encircling the Pacific Ocean. In this region,there is a lot of tectonic activity that causes numerous volcanoes, earthquakes, and island arcs. Aleutian Islands of Alaska is one such region.

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