Publications

Synthesis of geology, paleontology and seismic strati- graphy ina 1200square km areamrrounding Balikpapan Bay, East Kalimantan, has led to the recognition of an eastward prograding delta system, active during Middle Miocene time.Facies interpretation based on well cuttings and side wall cores fiom 9 wells combined with approximately 4000 shothole samples from seismic time equivalent rock units in outcrop, provided the frame-work for this synthesis. Subsurface delineation of the 3 main depostional environments was achieved by means of seismic stratigraphy.It is inferred that this progradationand observed eastward shift of paleoenvironments in thi's delta and shore complex are the result of uplift during Early Middle Miocene times. The source for these fairly pure, well-sorted and rounded quartzose sediments are probably sandstones of an earlier progradational cycle that was derived directly from the highly granitic Sunda shield.