Scientists some 900 kilometers (about 560 miles) west of Costa Rica in the Pacific Ocean have spent 16 days cleaning and stabilizing a drill hole left by a previous expedition.
The work is being done on a 143-meter (469-foot) vessel specially designed to remain stationary in the ocean while its drill penetrates the sea floor.
The drill met and spent considerable time surmounting an obstacle about 980 meters (3,215 feet) below the sea floor. The team, which left from Puntarenas in mid-April, has been making frequent reports online. The team seeks to drill perhaps 2 kilometers (6,560 feet) into the Coco tectonic plate beneath the sea. The first step was to locate and insert the drill into a hole drilled in 2005. That hole was 1,500 meters (about 4,900 feet) deep.
A report Tuesday said that the drill was advancing and reached the bottom of the hole. Drilling to a new depth has begun and already the science team reports that the crew has a core from the enlarged hole on deck for study.
The professional drillers on the ship, the JOIDES Resolution, pumped 60 barrels of cement into the drill hole and then drilled through the hardened cement. This had the effect of hardening the walls of the drill hole that had been eroding.
The team will dock in Panamá June 3.
The crust of the Cocos plate, formed 15 million years ago, is expanding at 20 centimeters a year, which is faster than any existing active ridge, scientists have said.
That is why the area is of such interest.