Abstract:

To study the relationships of differential stresses and temperature to the melting degree of rocks, we use hornblende granulite to do some high-T and high-p experiments. Firstly, we carried out the dynamic melting experiment by imposing differential stresses from 0 to 25 MPa with step at 5 MPa on natural bulk rock samples under confining p and T at 100 MPa and 700 ℃, respectively. Then, we did the static experiment under the same confining pressure but without differential stresses by increasing the T from 700 to 900 ℃ with the step at 50 ℃. Our experimental results indicate that the melting degree of rocks increases with the increase of differential stresses. Through comparing the slopes of the experiments, we found that if taking 700 ℃ as the starting point, the increase of 5 MPa differential stress is equal to the effect of increasing 40 ℃, suggesting that the intermediate rocks are more sensitive to differential stress then felsic rocks.

Key words: differential stress, degree of melting, temperature, metamorphic rocks