Original Research Paper

Marine Geophysical Researches

, Volume 30, Issue 4, pp 229-236

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

Drowned carbonate platforms in the Bismarck Sea, Papua New Guinea

  • Gary HoffmannAffiliated withUniversity of California at Santa Cruz Email author 
  • , Eli SilverAffiliated withUniversity of California at Santa Cruz
  • , Simon DayAffiliated withAon Benfield Hazard Research Centre, Department of Earth Sciences, University College London
  • , Neal DriscollAffiliated withScripps Institute of Oceanography
  • , Bruce AppelgateAffiliated withScripps Institute of Oceanography


Extinct volcanic islands in the Bismarck volcanic arc are fringed by well-developed coral reefs. Drowned platforms offshore from these islands provide evidence for subsidence in the central section of the arc, north of the Finisterre Terrane–Australia collision. Bathymetric and backscatter data collected onboard the R/V Kilo Moana in 2004 reveal regularly spaced (~200 m interval) drowned platforms at depths as much as 1,100 m below sea level. However, the adjacent mainland coast has well documented raised terraces indicating long-term uplift. Local subsidence may be due to cessation of magmatic activity and cooling, flexural loading by the uplifting Finisterre Range, loading by nearby active volcanic islands, and/or sediment loading on the seafloor north of the Finisterre Range. We present some simple models in order to test whether flexural loading can account for local subsidence. We find that volcanic and sedimentary loading can explain the inferred relative subsidence.


Drowned carbonate platforms Papua New Guinea Flexural modeling Sidescan sonar