Publications

A succession of middle Miocene rocks is exposed in section near Samarinda, East Kalimantan. The succession is characterized by massive sandstone rich in carbonaceous materials at the bottom of the section. The middle part of the section is dominated by mass flows as well as thin bedded sandstones showing Bouma divisions. The abundant coal and organic materials within turbidite sandstones are important for generating hydrocarbons. Bioturbated thin-bedded sandstones occupy the upper part of the section. The sandstones and shales in the lower part of the succession are interpreted as deposited by turbidity currents in slope to basin floor setting. The whole section is then capped by the carbonate Air Putih in the form of patch reefs interpreted here as to have been grown at the shelf-edge.Above the carbonate Air Putih three shallow marine Para sequences are observed. These parasequences show a coarsening-upward trend with very fine sandstones and shales in the bottom grading to coarser-grained sandstone with low angle planar cross-stratification in the upper section. The uppermost part of the section is highly bioturbated and capped by reefal carbonates.The geometrical disposition of different sand layers shows a wedge-like prism, i.e. they are thinner on the west side of the outcrops and thicker to the east. The wedge geometry can be attributed to the increase of accommodation space towards the slope. Sands deposited at the shelf-edge filled the space available at the head of the slope forcing the shelfedge to prograde eastward.These shallow marine parasequences and reefal carbonates are interpreted as representing a prograding shelf and shelf-edge setting respectively.