What is the age of lithosphere at Tonga trench?

The age of the lithosphere at the Tonga trench varies depending on the location along the trench. The Tonga trench is a convergent boundary where the Pacific Plate is subducting beneath the Indo-Australian Plate. The Pacific Plate is moving westward and is being subducted beneath the Indo-Australian Plate at a rate of about 15 centimeters per year. The age of the Pacific Plate at the Tonga trench ranges from about 50 million years near the northern end of the trench to about 120 million years near the southern end of the trench.