An iceberg the size of Luxembourg has broken off from a glacier in Antarctica after being rammed by another giant iceberg, scientists said on Friday, in an event that could affect ocean circulation patterns.

The 2,500 sq km (965 sq mile) iceberg broke off earlier this month from the Mertz Glacier’s 160 km (100 miles) floating tongue of ice that sticks out into the Southern Ocean.

The collision has since halved the size of the tongue that drains ice from the vast East Antarctic ice sheet.