Abstract The Elan Bank microcontinent was separated from East India during the Early Cretaceous break-up. The crustal architecture and rifting geometry of East India and the Elan Bank margins document that the early break-up between India and Antarctica was initiated in the eastern portions of the Cauvery and Krishna–Godavari rift zones, and in the southern portion of Elan Bank. However, the westwards break-up propagation along the Krishna–Godavari Rift Zone continued even after the break-up in the overstepping portion of the Cauvery Rift Zone. Eventually, the western propagating end of the Krishna–Godavari Rift Zone became hard-linked with the failed western portion of the Cauvery Rift Zone by the dextral Coromandel transfer fault zone. Consequently, the break-up location between India and Antarctica shifted from its initial to its final location along the northern portion of the Elan Bank formed by the western Krishna–Godavari Rift Zone. The competition between the two rift zones to capture continental break-up and asymmetric ridge propagation resulted in a ridge jump and the Elan Bank microcontinent release.

Abstract The intracratonic, supra-subduction zone setting of the Thailand rift basins caused the rifts to evolve in several ways differently from other intracratonic rifts. Key differences include: widespread occurrence of low-angle normal faults; basin inversion alternating with rifting; diachronous initiation and cessation of rifting; rapid post-rift subsidence; and extensive, low-displacement post-rift faults. These characteristics are related to hot, weak continental lithosphere, rapid evolution of the plate boundaries and stresses during the Cenozoic, and the history of subduction and accretion. Low-angle normal faults impacted the Sirikit Field by controlling the location of fluvio-deltaic reservoirs interfingering lacustrine shales (source and seal). Basin inversion alternating with syn-rift section is detrimental to prospectivity of the southern half of the Phitsanulok Basin by destroying syn-rift structure, and halting hydrocarbon maturation early in the basin history. The diachronous timing of basin development resulted in large, gas-dominated hydrocarbon accumulations in the eastern Gulf of Thailand basins, but was detrimental for younger basins that lack the post-rift section, and the greater variety of petroleum systems and traps that post-rift basins offer. The extensive low displacement–length ratio post-rift faults form significant hydrocarbon traps in the Pattani and North Malay basins. They represent a structural style not usually found in post-rift basins.