Detecting entry into and drilling through a magma/rock transition zone

A system, comprising:

• drilling equipment comprising a drill bit attached to a drill string, wherein the drilling equipment is configured to drill a borehole from a surface towards an underground magma reservoir;
• and
• a drilling controller coupled to the drilling equipment and configured to:
• monitor drilling characteristics associated with the drilling equipment during drilling the borehole;
• monitor borehole characteristics associated with the borehole during drilling the borehole;
• determine, based at least in part on the monitored drilling characteristics and the monitored borehole characteristics, that the drill bit has entered a transition zone between a solid rock layer and the underground magma reservoir;
• and
• in response to determining that the drill bit has entered the transition zone, cause the drilling equipment to operate in a transition zone mode, different than a prior mode of operation, associated with drilling in an at least partially molten rock;
• and
• in response to determining that the drill bit has not entered the transition zone, continuing operating the drilling equipment in the prior mode of operation.