His innovative excavation techniques were partly adopted by the University of Chicago Field School, one of the few training programs in archaeological field techniques in the United States in the first half of the 20th century.
22.
Due to the size required to create a far-field range for large antennas, near-field techniques were developed, which allow the measurement of the field on a surface close to the antenna ( typically 3 to 10 times its wavelength ).
23.
The second and perhaps the most important influence was that of Wheeler, who then was excavating at the famous site of Maiden Castle, Dorset, and by then had already perfected his field techniques, experiments on which he had started since 1921.
24.
This impact extinction hypothesis is still in debate due to the exacting field techniques required to extract minuscule particles of extra terrestrial impact markers such as Iridium at a high resolution from very thin strata in a repeatable fashion, as is necessary to conclusively distinguish the event peak from the local background level of the marker.
