The resulting tabular iceberg drifts northwest until it runs aground upon a shoal north of the ice shelf.
The floating tongue of the Denman Glacier, fed by ice from the interior of Antarctica, advances until a new large berg is calved about every 40 to 50 years.
The term "island" is technically incorrect, since this geographic feature is in reality a tabular iceberg with nearly vertical sides and a flat top.
At this position, an ice island was first sighted by the United States Exploring Expedition, led by Charles Wilkes, in February 1840.
Douglas Mawson renamed the island Termination Ice Tongue when he encountered it on the 1911-13 Australasian Antarctic Expedition.