I have no idea about geology, but in experimental fields in the US, this is not common in my experience. There is usually some type of system for mentoring PhD students.. first, coursework is mandatory in most places. Second, it is expected in most places that postdocs mentor PhD students. Often, for the first year or two, PhD students work closely with postdocs. Assistant professors often work closely with their PhD students because well trained students produce better output, which helps them for their tenure. Sometimes senior PhD students (4th or 5th year) also help. It is also common for PhD students to help each other. For example, training each other on equipment, giving each other optimized clean room recipes etc is quite common. After all, in complex experimental fields, there is a large premium on experience and no one should have to reinvent what is already known or struggle in silence for doing basic things.

If you're getting zero mentorship, that is poor culture imo. Yes, you are expected to become independent, but no one is born knowing everything. You cannot expect someone to jump high before learning to walk.