Description of Project Mohole, which was an attempt to drill to the mantle of the Earth. Information on the idea and story.
What is it exactly that you see when you look at the ground? Most of us see meaningless dirt and rocks. To an experienced geologist, these are clues to the origin of our planet. The layers of the Earth are equivalent in importance to that of our DNA and dental records. They provide essential information regarding the Earth's evolution and development.
Originally the idea for Project Mohole was expressed by Walter Munk in 1957. It had been described as the "earth sciences' answer to the space program". If successful the project was to provide scientists with answers about the age and internal mechanisms of our planet. Continental drift theories were highly debated during this period, and it was hoped that the Mohole Project would offer evidence proving and/or disproving such an idea.
The Earth's "mantle" is known as the Mohorovicic Discontinuity. According to the Columbia Electronic Encyclopedia, this area is situated between "7 to 70km below the Earth's surface". Andrija Mohorovicic who was a Croatian geologist discovered that there was this area, which is also known as the "moho". His find was discovered in 1909 while he was researching information from seismogram recordings.
The entire project was to entail three phases. The first phase began in 1961, and it was to offer evidence of what materials made up the Earth. This undertaking was the deepest offshore drilling that had ever been attempted. The experimental drilling was implemented in the Pacific and was sponsored by the National Science Foundation and directed by the National Academy of Science. The work was done jointly by the Russians and the Americans, covering both land and the sea.
The barge used for the Mohole Project was named the Cuss I. It was literally converted from a naval barge for the project and was equipped with heavy drilling equipment. During this time the petroleum industry used a drilling method referred to as "a standard rotary method". This same method was enlisted to drill through the ocean floor. Attempting to drill through the ocean floor was more feasible than on land, which would be virtually impossible for the drills to manage. The crust under the ocean is much thinner and is less affected by other elements both natural and man-inflicted. The drill was passed through the ocean floor and before it went through to the basalt, both siliceous and calcareous micro fossils were found. This indicated to the geologist's that materials here were from a Miocene to Pliocene time period.
One major issue that arose with this project was how to maintain a stable position with the barge while drilling. Bendix-Pacific was a company who at the time was involved with sonar, aviation and space research. They provided the project with a navigation system which constantly monitored the barge's position. A "marine underwater scanner" picked up signals transmitted by "transponders" which were attached to the underside of the barge. Floating on the ocean with the barge were "reflectors" which also transmitted signals to the operators. These signals were then used by the operators to adjust the position of the vessel and prevent the possible cracking of the drilling pipe.
The Mohole Project was cancelled in 1966 and approximately $50 million had already been committed, without even beginning phase two. Congress came to the conclusion that it wasn't economically feasible to continue with the research. Possibly had technology been more advanced, the project may have been able to continue for a longer period.
Even though the project was halted, vast knowledge was gained as a result. It provided insight into the value of deep sea drilling and has resulted in the emergence of other similar ventures. It has also provided an avenue in which to research and create technological sonar equipment. As well it can make available oil and mineral resources for research and possible economic gain. Sediments provide valuable clues to functions occurring deep in our planet and may in the future provide for a safer and more sustainable Earth.
