Carbonate seismic stratigraphy of the Gulf of Papua mixed depositional system: Neogene stratigraphic signature and eustatic control

Abstract

The Eocene–Miocene carbonate deposition in the Gulf of Papua (GoP) corresponds to the carbonate evolution phase of this continental margin mixed depositional system. Global sea‐level (eustatic) fluctuations appear to have been the most important factor influencing the mixed depositional system development during its carbonate phase. Development of the major carbonate system in the Gulf was initiated during the Eocene. Subsequent to an early Oligocene hiatus, the carbonate system expanded its surface area, vertically aggraded, then systematically backstepped, and finally partially drowned during the late Oligocene–early part of the early Miocene. During the late early Miocene–early middle Miocene, the carbonate system continued its vertical growth in most platform areas, where it was able to keep up with sea‐level rise. At the early middle/late middle Miocene (Langhian/Serravallian) boundary, carbonate deposition shifted downward during a long‐term sea‐level regression, exposing most of the early middle Miocene platform tops. Following this downward shift, active carbonate production became restricted during the late middle Miocene to only the northeastern part of the study area, and carbonate accumulation was characterized by four systematically prograding units. At the very beginning of the late Miocene, the platform tops were re‐flooded. The carbonate system was partially drowned, systematically backstepped, and locally aggraded during part of the late Miocene, the early Pliocene, and the Quaternary. The overall organization of the carbonate sequence geometries, observed in the GoP, display a clear pattern, often referred to as the Oligocene–Neogene stratigraphic signature. This pattern is identical to contemporaneous sedimentary patterns observed in pure carbonate systems such as in the Maldives and in the Bahamas, and also in some siliciclastic systems. Because this pattern is observed in several globally distributed locations, the recognition of the Oligocene–Neogene stratigraphic signature in the GoP demonstrates that the depositional evolution during the late Oligocene–Miocene and the early Pliocene must have been dominantly controlled by eustatic fluctuations.

Seismic geomorphology and growth architecture of a Miocene barrier reef, Browse Basin, NW-Australia

“…Particularly because there are many examples of reef growth in mixed carbonate-siliclastic environments with much higher siliciclastic input. For example Tcherepanov et al (2008) report on a carbonate/ siliciclastic mixed system from the Gulf of Papua, which shows a coherent evolution to Browse Basin during the Miocene, beginning with an aggradational phase in the early Miocene, a significant downward shift and an exposure event in the second half of the Middle Miocene (Serravallien), followed by reflooding, reestablishment of reef growth and progradation, aggradation and at least partial drowning in the late Miocene.…”

The global Middle and Late Miocene and the deep earth: Model for earlier orogenies

“…Bartek et al (1991). See widely separated examples both in clastics (Greenlee and More, 1988) and carbonates (Betzler et al, 2000 andTcherepanov et al, 2008). Sea level fall at the base of the Tortonian is notably widespread and is inferred to result from a large advance of East Antarctic ice (Flower and Kennett, 1994.…”

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

“…The late Oligocene-early middle Miocene periods in the GoP mixed system were characterized by the most extensive development of the carbonate system (Tcherepanov et al, 2008b). Since the onset of the arc-continent collision in the early Oligocene, the fold and thrust belt has been progressively uplifted and eroded, supplying siliciclastic sediments into the GoP where they intermixed with carbonate sediments produced and accumulated in-situ.…”

“…Active neritic carbonate accumulation characterized the second phase (Eocenemiddle Miocene). During this phase, mostly eustatic fluctuations controlled the large-scale sedimentary geometries of the carbonate system (Tcherepanov et al, 2008b). The third stage (late Miocene-early Pliocene), influenced by a combination of several factors, was characterized by the partial or complete drowning of the carbonate platforms.…”

“…Prior to the late Miocene, the depositional environments of the carbonate system were deepening towards the east and northeast due to overall pre-existing depositional system configuration (Tcherepanov et al, 2008b), which represented shallower conditions in the western part (e.g. Mesozoic siliciclastic shelf and later Miocene carbonate shelf -Borabi Platform) and deeper conditions to the east and northeast (e.g.…”