Question 1 chapter 3.1.2. box 3.1. true/false. an increase in temperature is the main cause of melting in earth's upper mantle ○true o false question 2 chapter 3.1.2. box 3.1. what is decompression melting? when crust melts as a result of high compressive stresses in subduction zones o b when hot mantle rises to shallow depths where lower pressures induce melting when rocks on planets with no atmosphere come in contact with the vacuum of space od when ices at the base of glaciers melt because of the weight of the glacier above

1- TRUE

2- Option (B)

Explanation:

The upper mantle is comprised of the layer of the asthenosphere over which the lithospheric plates float. The rocks of the upper melting undergo melting when they come in contact with water. As a result of which the temperature increases and pressure relatively decreases. This melt then forms magma that becomes less dense due to the extreme temperature and eventually comes out to the surface along the mid-oceanic ridge or through volcanoes. The decompression melting refers to the melting of the mantle rocks that produce magma. This magma then moves to a region of low pressure. It generally occurs in the region that is comprised of mantle plumes and in the divergent plate boundaries where the crust undergoes stretching and thinning.