Word: moho
(lookup in dictionary)
(lookup stats)
Dates: all
Sort By: most recent first
(reverse)
Target Mohole. This effort is part of Project Mohole, which will cost more than $20 million. It is backed by the National Science Foundation, and its goal is to drill clear through the earth's crust to the "Moho,"* the boundary between the comparatively light rocks of the crust and the much denser mantle, which extends downward for i ,800 miles and whose properties are largely unknown. Geophysicists are sure that even one hole drilled to the Moho will tell invaluable volumes about the history, structure, content and behavior of the earth...
Never had any drilling been done in such deep water. The new tests that will start soon off Guadalupe will show what modifications of ship and drilling apparatus will be needed to drill through miles of rock down to the Moho itself...
...drilling cannot be done on the continents because they are great rafts of granite "floating" in deeper plastic material. The granite is too thick (20 miles) to drill through. Oceanic islands are also ruled out as drilling sites; their weight has pressed the Moho to an impossible depth. The best place to drill is the floor of the great ocean basins. The floor may be three miles beneath the ocean's surface, but the Moho lies only three or four miles deeper, under a thin skin of sedimentary deposits and a layer of basalt...
First step toward the Moho would be to drill a cone-shaped hole in the sea bottom. The hole would be filled with cement poured down the drill stem and a steel platform fixed in the cement. The rock drill would be passed through this steel collar and turned from the barge. The long drill stem would be flexible enough to allow for the ship's motions...
...sample wells off California in water 1,500 ft. deep. Drilling in three miles of water would be harder, but Geologist Bascom thinks it can be done. So do the Russians, who claim to have drilling equipment just as good, and are apparently trying to beat AMSOC to the Moho...