Collision Between Iceberg and Antarctic Glacier

On Feburary 12-13, a collision between a large iceberg named B-9B and the Mertz Glacier tongue caused a large piece of the tongue to break off into the Southern Ocean creating an iceberg that is roughly 78km long and 39km wide [1]. Calving is the term used for the release of ice from a glacier, although it typically involves the breaking off of much smaller pieces. The Mertz glacier is located along the George V Coast in Antarctica and flows along a fjord and then extends out into the ocean. It is this protrusion that is called the Mertz Glacier tongue, which is about 160km long and 40km wide. Previous to the collision the advancing Mertz glacier had horizontal rifts that had been increasing over many years. Once the B-9B iceberg hit the tongue it sheared off along these rifts in a clean break. The surface area of the new iceberg is about 2500 square kilometers. Since its calving from the glacier, the iceberg has rotated approximately 90° about the point of contact and is now residing in a coastal basin called the Adélie Depression. Icebergs are given names by the National Ice Center located in Maryland according to what region of the Antarctic they originate from. The leading letter is assigned based on which quadrant it emerges from (A-D), and the number is given based on how many icebergs have originated from that region since 1976. The new iceberg formed by the recent calving of the Mertz Glacier tongue has been named C-28 since it is the 28th iceberg to come from the region between 90° E and 180° since 1976.