"The Sulu Archipelago (Tausug: Sūg, Malay: Kepulauan Sulu, Filipino: Kapuluan ng Sulu) is a chain of islands in the Pacific Ocean, in the southwestern Philippines. The ...
archipelago forms the northern limit of the Celebes Sea and southern limit of the Sulu Sea. The Sulu Archipelago islands are within the Mindanao island group, consisting of the provinces of Basilan, Sulu, and Tawi-Tawi.
The archipelago is not, as is often supposed, the remains of a land bridge between Borneo and the Philippines. Rather, it is the exposed edge of small submarine ridges produced by tectonic tilting of the sea bottom. Basilan, Jolo, Tawitawi and other islands in the group are extinct volcanic cones rising from the southernmost ridge. Tawi-Tawi, the southernmost island of the group, has a serpentine basement-complex core with a limestone covering. This island chain is an important migration route for birds." - (en.wikipedia.org 23.09.2020)
