Late Miocene to Pliocene delta-lacustrine to incised-valley fills sedimentation of the Ransiki Area, Bird’s Head Papua, Indonesia: The sedimentary record of Lengguru Fold and Thrust Belt wedge-top depozone

• Published in: Journal of Asian earth sciences Vol. 242; p. 105497
• Main Authors: Fakhruddin, Rakhmat, Sunardi, Edy, Gumelar Adhiperdana, Billy, Heri Hermiyanto Zajuli, Mohammad, Ramli, Taufik, Mersil Saleh, Hanif, Perdana Putra, Andri, Sabra, Eriko, Ghia Arvyalin, Gadis
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.02.2023
• Subjects: Bird’s Head Papua; Delta-lacustrine; Incised-valley fill; Lengguru Fold and Thrust Belt; Lengguru Fold and Thrust Belt; Delta-lacustrine; Incised-valley fill; Bird’s Head Papua
• ISSN: 1367-9120; 1878-5786
• DOI: 10.1016/j.jseaes.2022.105497

[Display omitted] •Lengguru Fold and Thrust Belt (LFTB) and Papua Fold and Thrust Belt (PFTB) orogeny occurred at NN11 zone (∼8.3–5.6) Ma.•Delta-lacustrine sediment was accumulated in the wedge top depozone of LFTB during late Miocene to Pliocene.•Relative sea-level fall during the end of early Pliocene resulted in widespread erosion and the incised valley formed.•The rising of relative sea-level in the late Pliocene resulted in the filling of the incised valley. This study reports new data from sedimentary rocks found at the northern part of the Lengguru Fold and Thrust Belt (LFTB), Bird’s Head of Papua. The studied rock unit, formally named the Mawi Formation, was previously mapped as pre-Tertiary in age. Our palynological result suggested that the age determination for the Mawi Formation is late Miocene to Pliocene. Two sedimentary facies succession was inferred from the studied section: the delta-lacustrine succession (FS1) and the incised-valley fill succession (FS2). The orogeny of LFTB and PFTB (Papua Fold and Thrust Belt) are inferred to be developed simultaneously in the latest Miocene, within the NN11 zone or N17 to lower part of N18 zones, within the range of 8.3 to 5.6 Ma. The studied sediment in the Mawi section is deposited in the wedge-top part of the Lengguru foreland system, while the Bintuni basin is its foredeep depozone and the Berau basin is in the backbulge depozone. FS1 is interpreted to be formed in the lake between the active thrust fault of LFTB during the late Miocene to early Pliocene. Relative sea-level began to fall during the end of early Pliocene, resulting in the widespread erosion of the depositional site, and the incised valley formed. The first deposit during the interval of low sea level was the alluvial deposit, followed by the rising of the local relative sea-level, which resulted in the filling of the incised valley depositing estuarine deposits of FS2.