--> Pliocene to Quaternary Submarine Channel Systems in Rahkine Basin: Implication for Sediment Routing to Offshore Myanmar

AAPG Asia Pacific Region, The 4th AAPG/EAGE/MGS Myanmar Oil and Gas Conference:
Myanmar: A Global Oil and Gas Hotspot: Unleashing the Petroleum Systems Potential

Datapages, Inc.Print this page

Pliocene to Quaternary Submarine Channel Systems in Rahkine Basin: Implication for Sediment Routing to Offshore Myanmar


Submarine channels represent an important component of deep-water depositional systems and contain information on sediment dispersal to deep-water basins. Although the Bengal fan (i.e., the world’s largest submarine fans) has attracted great attention from the oil industry, architecture and evolution of Bengal deep-water depositional systems and their implication for source-to-sink sediment partitioning into the deepwater area are still understudied. The present study uses the integrated two- and three-dimensional seismic-reflection data (~30 Hz) from the western offshore of Myanmar to characterize Pliocene to Quaternary submarine channel systems, and to address their implication for sediment routing to offshore Myanmar. Two main types of submarine channel complex of Pliocene to Quaternary age are recognized, including erosional channels characterized by V-shaped or U-shaped channel cross-sections and low-relief overbank levees and depositional channels characterized by mounded channel cross-sections and high-relief levees. Erosional channel complexes are mainly early and late Pliocene in age, and appear to be comprised of a series of meandering channels. The early Pliocene erosional channel complexes with NE-SW trending are observed at the southeast of the study area, and reach a depth of about 240 ms (TWT) and a width of < 7 km. However, the late Pliocene erosional channel complexes with NW-SE trending occur at the northwest of the study area, with a maximum depth of about 300 ms (TWT) and a width of < 14 km. They appear to undergo a change of strike and a largening-upward variation in scale from early Pliocene to late Pliocene. Depositional channels, with a width of 2-30 km and a thickness of 100-320 ms (TWT), which occur mainly in the Quaternary, appear to create topographic lows between levee-over bank deposits. The early Quaternary depositional channels with NW-SE trending usually exist in isolation. The height is up to 320 ms (TWT) and the width is around 30km. In contrast, the mid-late Quaternary depositional channels with NNE-SSW and NNW-SSE trending are smaller in scale and appear in a group due to frequently lateral migration. They reach a height of 100ms (TWT) and a width of <10km. It seems that there is a diminishing-upward trend in dimensions. Submarine channel pathways into the Rakhine basin seem to respond to sediment routing transition. The submarine channels with approximately NS and NE trending reflects two provenances of northern Himalayan and eastern Indo-Burman Ranges documented by the previous studies. However, the NW trending submarine channels indicate that the detritus from northwestern India were likely to deliver into the deep-water areas of offshore Myanmar via erosive channel complexes during the upper Pliocene. Furthermore, terrigenous sediment supply and paleo-seafloor depositional topography created by active tectonism result in the variation of submarine channel type from Pliocene erosive channels to Quaternary depositional channels and appear to have created unique submarine channel patterns compared to other deep-water basins. This study has implications for the regional understanding of post-Miocene sedimentary routing to offshore Myanmar. Further study opportunity in the Pliocene-Quaternary Rakhine basin will focus on the provenance of deep-water sediment based on more available seismic data, heavy mineral, and Zircon data to investigate if a predictable relationship between the source area and sediment routing, deep-water depositional elements and dimensions.