From Tectonic Influence to Sea-Level Dominance: Cenozoic Stratigraphic Evolution of the Tropical Eastern Sunda Shelf

The Sunda Shelf is the most extensive tropical epicontinental shelf and is the second largest drowned continental shelf on Earth. Unlike much of the Sunda Shelf, where stratigraphic successions have been disrupted or removed by tectonic deformation, the eastern Sunda Shelf preserves a complete Cenozoic stratigraphic archive that records the evolution of regional tectonics, sea level change, and paleoenvironmental histories. However, the basin‐scale stratigraphic architecture and their links to tectonic and sea-level fluctuation are poorly constrained in the eastern Sunda Shelf. These gaps limit our ability to evaluate the role of the Sunda Shelf in global climate and carbon-cycle regulation. In this work, we integrate extensive 2D (~8,000 km) and 3D (~4,000 km²) high resolution seismic reflection data with lithologic and age information from wells to reconstruct the tectonic and sedimentary evolution of the eastern Sunda Shelf. We identified four basin‐scale stratigraphic evolution stages: (1) tectonically controlled syn-rift stage (Late Oligocene, ~28-23 Ma), dominated by alluvial-fan and lacustrine systems that developed under rapid fault-controlled subsidence and relatively arid climatic conditions. (2) Post-rift subsidence-dominated stage (latest Oligocene to Early Miocene, ~23-17 Ma), characterized by thermal sagging and a major transition from terrestrial to shallow-marine environments. (3) Mixed tectonic-eustatic stage (Middle to Late Miocene, ~17-11.6 Ma), during which mild basin-margin uplift, inversion, and rising and falling sea level jointly influenced accommodation, sediment supply, and depositional patterns. (4) Sea-level dominated stage (Late Miocene to Quaternary, ~11.6 Ma to present), when tectonic activity waned and sedimentation became primarily governed by glacial-interglacial sea-level fluctuations, resulting in widespread shelf-edge clinoform development, channel complexes, and incised-valley systems. Our results demonstrate that the eastern Sunda Shelf underwent terrestrial-lacustrine-marine transitions with cyclical climate change, revealing how the long-term effects of Indian-Eurasian plate interactions were progressively overprinted by ice-age sea-level fluctuations. The early rift-related structural confinement, mild Middle Miocene inversion, long-term tectonic stability since the Late Miocene, and the high-frequency sea-level fluctuations since the Pliocene collectively enabled the eastern Sunda Shelf to preserve a complete tropical stratigraphic archive. This framework provides a critical geological foundation for future International Ocean Discovery Program (IODP) drilling aimed at resolving low-latitude sea-level change, tropical carbon-cycle dynamics, and hydroclimate evolution across the Sunda Shelf region.