Final answer:
The technique used in the artwork 'Portrait of Carmelite Monk' by Van Dyck is oil on panel.
Step-by-step explanation:
The technique used in the artwork 'Portrait of Carmelite Monk' by Van Dyck is oil on panel. Oil on panel refers to the use of oil-based paints on a wooden panel as the support for the painting. This technique allows for a greater level of detail, depth, and vibrancy of colors compared to other painting techniques.