A global cataclysm is portrayed in black and white in the sediments off the southeastern coast of the United States. Deep below the seafloor, chalky muds evince an ancient ocean flourishing with life. But a stark black layer cuts through the pale grains, marking the moment 66 million years ago when a six-mile wide asteroid slammed into Earth and our planet was never the same. The impact, known as the Chicxulub event, set off dramatic climate swings that sent 75 percent of Earth’s species — including all non-avian dinosaurs — spiraling toward extinction.

Many details of the devastation come from cores — long tubes of sediment or rock that result from drilling into the seafloor — that were hauled onboard the JOIDES Resolution. The ship, known to those who sailed on it as the J.R., was the only dedicated American scientific drill ship. Drill cores from the ship and its predecessor also helped confirm the theory of plate tectonics, which shapes our planet’s surface. They provide records of climate change throughout Earth’s history. They unveiled microbes thriving far deeper beneath Earth’s surface than ever thought possible.

Yet the J.R. returned from its last expedition earlier this month, and crews removed its crucial scientific equipment.

There’s no concrete plans for its replacement. The ship’s fate was announced last year by the federally funded National Science Foundation, which financed most of the J.R.’s operations. The foundation cited rising costs and a lack of international support to meet the funding gap.

“It was a punch in the gut,” said Beth Christensen, a marine geologist at Rowan University in New Jersey.