Banfield was educated at the Australian National University where she completed her bachelor's and master's degrees (1978–1985) both examining granite weathering.
She attributes her initial interest in geomicrobiology to Dr Tony Eggleton who drew her attention to processes at the earth's surface, mineral weathering and the regolith.

Banfield graduated with a PhD in Earth and Planetary Sciences from Johns Hopkins University for high-resolution transmission electron microscopy (HRTEM) studies of metamorphic reactions supervised by David R. Veblen.
Banfield was educated at the Australian National University where she completed her bachelor's and master's degrees (1978–1985) both examining granite weathering. She attributes her initial interest in geomicrobiology to Dr Tony Eggleton who drew her attention to processes at the earth's surface, mineral weathering and the regolith.
Banfield graduated with a PhD in Earth and Planetary Sciences from Johns Hopkins University for high-resolution transmission electron microscopy (HRTEM) studies of metamorphic reactions supervised by David R. Veblen.
Jillian Banfield