SiO2 48.21 TiO2 1.70 Al2O3 15.23 FeO(T) 10.00 MgO 8.72 CaO 11.51 Na2O 2.29 K2O 0.20 H2O 0.10This is done by clicking in the white box to the right of SiO2 (use the left mouse button to select the box) and typing the weight % value: . The delete key, arrow keys and mouse may be used to edit the ty ped value.
Typing a return advances the text entry cursor to the next oxide. Continue entering the composition until the liquid composition display panel looks like:
The starting temperature is a guess for the liquidus temperature of this olivine tholeiite bulk composition. The stopping temperature is the final temperature of the model. The temperature increment is the model increment. Results will be displayed and output to disk every increment from start to finish. The starting and stopping pressures are set equal to each other so that the model evolution path is isobaric. The pressure increment may be left blank. In this example the dP/dT gradient is zero and needn't be input.
To impose an oxygen fugacity equivalent to the Quartz-Fayalite-Magnetite buffer at the starting temperature and pressure, select the f O2 Constraint entry of the Intensive Variables menu and while depressing the left mouse button, slide the mouse to the right and down and release on the Q-Fa-Mt constraint buffer entry.
Next, go to the Composition menu and select the Compute Redox State entry. The Fe2O3 and FeO quantities displayed in the liquid composition panel should change to reflect a ferric/ferrous ratio appropriate to the QFM buffer for a hypothetical liquid of the bulk composition displayed at the starting T and P entered above.
The f O2 constraint will be left set to QFM which will keep the ferric/ferrous ratio displayed in the liquid composition panel consistent with the QFM buffer as the system crystallizes.
The model may be halted at any time by invoking the Execute/Halt entry of the Commands menu. The user may change bulk composition or model constraints and restart the calculation using the same menu entry.
A manual page describes many common numerical problems that may occur when the program is running.