Draft:Sulu-Zamboanga Arc

The Sulu-Zamboanga Arc is a geological feature in the Philippines, which includes the Sulu Sea and the Zamboanga Peninsula. This arc is a complex system with significant geological and tectonic features.

Sulu Sea
The Sulu Sea, situated amidst the major Pacific, Indo-Australia, and Eurasia/Sundaland plates, is a vast marginal sea. The historical trajectory of the Philippine Sea plate's movements, dating back to approximately 52 million years ago, remains contentious and unclear, largely due to the absence of lithospheric records around the circum-Philippine Sea plate subduction zones and other convergent plate boundaries in East Asia. Notably, the Sulu Sea has experienced significant tectonic events, including the proposed south-dipping subduction during the Miocene era, which resulted in the disappearance of the southern portion of the SE Sulu Sea basin. This event likely led to back-arc extension southeast of the Sulu arc and the emergence of major transform faults along the northeastern and southwestern margins of the Sulu Sea to accommodate the subduction tectonics.

Zamboanga Peninsula
The Zamboanga Peninsula, situated within Mindanao Island in the southern Philippines, comprises numerous ophiolitic bodies and mélanges. This region constitutes a continental block alongside the eastern-central Mindanao block, which is associated with island arc formations. The Middle Miocene Siayan–Sindangan Suture Zone demarcates the tectonic interface between these island arcs and continental blocks.

Future Research
The Philippine archipelago comprises a multifaceted island arc system, with numerous areas yet to be studied in terms of geopotential fields. Ongoing investigations into the Philippine Sea plate stem from its significance in the tectonics of northeast Asia, encompassing regions such as Taiwan, the Philippines, SW Japan-Ryukyus, the South China Sea, the Izu-Bonin-Marianas arcs, and other marginal seas in southeast Asia.