Neogene evolution of the mixed carbonate‐siliciclastic system in the Gulf of Papua, Papua New Guinea

Abstract

This paper outlines the evolution of the late Cenozoic mixed carbonate‐siliciclastic depositional system in the Gulf of Papua (GoP), using seismic, gravity, multibeam bathymetry, well data sets, and Landsat imagery. The deposition of the mixed sedimentary sequences was influenced by dynamic interplay of tectonics, eustasy, in situ carbonate production, and siliciclastic sediment supply. The roles of these major factors are estimated during different periods of the GoP margin evolution. The Cenozoic mixed system in the GoP formed in distinct phases. The first phase (Late Cretaceous–Paleocene) was mostly driven by tectonics. Rifting created grabens and uplifted structural blocks which served later as pedestals for carbonate edifices. Active neritic carbonate accumulation characterized the second phase (Eocene–middle Miocene). During this phase, mostly eustatic fluctuations controlled the large‐scale sedimentary geometries of the carbonate system. The third phase (late Miocene–early Pliocene) was characterized by extensive demise of the carbonate platforms in the central part of the study area, which can be triggered by one or combination of several factors, such as eustatic sea level fluctuations, increased tectonic subsidence, uplift, sudden influx of siliciclastics, or dramatic changes in environmental conditions and climate. The fourth phase (late Pliocene‐Holocene) was dominated by siliciclastics, which resulted in the burial of drowned and/or active carbonate platforms, although some platforms still remain alive until present‐day.

Siliciclastic influx and burial of the Cenozoic carbonate system in the Gulf of Papua

“…4; B) Gravity map of the study area with superimposed structural features, black dots are industrial wells; C) Main structural features in the GoP. Tcherepanov et al, 2008a;Francis et al, 2008;Jorry et al, 2008;Carson et al, 2008;Febo et al, 2008;Muhammad et al, 2008).…”

“…During the early part of the last sea level transgression, subsequent to the interval of Last Glacial Maximum (LGM, 25-20 ka), coralgal reef edifices grew on top of lowstand costal deposits when the siliciclastics were restricted to the inner shelf (Fig. 2, Droxler et al, 2006;Tcherepanov et al, 2008a). The early transgressive reefs are often drowned during the late transgression and buried under prograding siliciclastics during subsequent late sea level highstands.…”

“…8). This can be interpreted as a large submarine fan, similar to the fan present in the modern Moresby Trough (Tcherepanov et al, 2008a;Francis et al, 2008), composed of a number of smaller fans (Figs. 8 and 9).…”

“…The mixed system formed in distinct phases (Tcherepanov et al, 2008a). The first phase (Late CretaceousPaleocene) was mostly driven by tectonics.…”

“…The Cenozoic mixed carbonate-siliciclastic depositional system in the GoP represents an excellent example of a transition from an almost pure carbonate to a mixed carbonate-siliciclastic system Pigram et al, 1989;Tcherepanov et al, 2008a). The GoP neritic carbonate system thrived in the late Oligocene-middle Miocene, and partially drowned first in the early Miocene, and then with a major transgressive phase in the early late Miocene.…”