The Military Geology Unit was a unit in the United States military during World War II. It was established on June 24, 1942, six months after Pearl Harbor.^[1] People in the US Geological Survey wanted to get involved in the war effort, either for patriotism or prestige or both, and provided a geological intelligence report for a randomly chosen country, Sierra Leone.

The report described the terrain, locations of water supplies and road-building materials, and other obviously useful facts. The military bought the idea and so the Military Geological Unit was formed, starting out with six people but quickly expanding.

Staff

The entire Military Geology Unit wartime roster was 88 geologists, 11 soil scientists, 6 bibliographers, 5 engineers, 3 editors, 1 forestor and 43 assisting staff.^[1]

"During World War II geology won its spurs as an important tool in both planning and operations in the US Army. This growth of geology was due to the increased appreciation on the part of our military leaders of the importance of scientific techniques and information, and to the increased appreciation on the part of our scientists of the usefullness of their abilities in the solution of a large variety of very practical problems."^[2]

Origin of Balloon Bombs

The Military Geology Unit was key in determining the origin of the Japanese balloon bombs.^[3] Working with Colonel Sidman Poole of US Army Intelligence, the researchers of the Military Geological Unit began microscopic and chemical examination of the sand from the sandbags to determine types and distribution of diatoms and other microscopic sea creatures, and its mineral composition. The sand could not be coming from American beaches, nor from the mid-Pacific. It had to be coming from Japan.

Ultimately the geologists determined the precise beaches in Japan the sand had been taken from. By this time, it was mostly irrelevant, since by early spring the balloon offensive was almost over.