Fluxgate magnetometers in archaeological prospection can detect depths ranging from a few meters to tens of meters. Specifically, the depth of detection is influenced by factors such as the magnetic properties of the archaeological targets and the geological conditions. According to a study conducted at the site of Qasr ʿAllam in the Western Desert of Egypt, fluxgate magnetometers were able to reveal magnetic anomalies at different depths from 0.15 to 2.4 meters, which corresponded to different occupations from at least the 8th or 7th century B.C. to the 2nd century A.D. This indicates that fluxgate magnetometers are capable of detecting magnetic anomalies at varying depths within this range. It's important to note that the actual depth of detection can vary based on the specific conditions of the site and the sensitivity of the magnetometer used.