Accomplishments
Starting from August 1968, the ship embarked on a 15 year-long scientific expedition, the Deep Sea Drilling Program, criss-crossing the Mid-Atlantic Ridge between South America and Africa and drilling core samples at specific locations. When the age of the samples was determined by paleontologic and isotopic dating studies, this provided conclusive evidence for the seafloor spreading hypothesis, and, consequently, for plate tectonics.
In 1970, when doing research in the Mediterranean Sea under the supervision of Kenneth Hsu, geologists aboard the vessel brought up drill cores containing gypsum, anhydrite, rock salt, and various other evaporite minerals that often form from drying of brine or seawater. These were the first solid evidence for the ancient desiccation of the Mediterranean Sea, the Messinian salinity crisis.
Read more about this topic: Glomar Challenger