J.T. (Han) van Gorsel
Houston, Texas

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Introduction to Cenozoic Biostratigraphy of Indonesia-SE Asia J.T. (Han) van Gorsel; Peter Lunt; Robert Morley
Berita Sedimentologi Vol 29, No 1 (2014)
Publisher : Ikatan Ahli Geologi Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (4492.323 KB) | DOI: 10.51835/bsed.2014.29.1.140

Abstract

An overview is presented of the current 'tools' of biostratigraphy and biofacies interpretation, as applied in the Cenozoic basins of Indonesia and Southeast Asia. We discuss previous work and historic developments of the biozonations and biofacies significance of the principal microfossil groups used in the region (foraminifera, calcareous nannofossils, palynology) and present the latest zonation charts and tables of key references. Brief reviews of work done on ostracodes, diatoms and radiolaria are also included.
A Late Oligocene Drowned Pinnacle Reef in Deepwater Makassar Straits J.T. (Han) van Gorsel; C.E. Helsing
Berita Sedimentologi Vol 29, No 1 (2014)
Publisher : Ikatan Ahli Geologi Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1966.226 KB) | DOI: 10.51835/bsed.2014.29.1.147

Abstract

A steep seamount with 320-350m of relief was recently discovered in about 2050m deep water of the South Makassar Straits. It was informally named Snorkel by ExxonMobil interpreters, but remains unnamed. Drop core samples collected from different levels of the buildup by ExxonMobil in 2008 show the Snorkel feature to be an Oligocene pinnacle reef, which drowned in latest Oligocene time.The carbonate buildup is covered in a thin coating of ferro-manganese cement, representing over 20 Million years of exposure and non-deposition in a deep water environment.The Snorkel feature is one of the many carbonate buildups that formed on Sundaland and around its margins after a Middle-Late Eocene regional rifting/subsidence event (e.g. 'Berai Limestone' of East Kalimantan), but until now is the only known example of an Oligocene reefal buildup that was never buried under younger sediments.
The Life and Scientific Legacy of Indonesian Paleontologist Dr. Tan Sin Hok (1902-1945) Munasri Munasri; J.T. (Han) van Gorsel
Berita Sedimentologi Vol 31, No 1 (2014)
Publisher : Ikatan Ahli Geologi Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (7120.26 KB) | DOI: 10.51835/bsed.2014.31.1.129

Abstract

Tan Sin Hok was probably Indonesia's most influential paleontologist. He was born and raised in West Java and was the only Indonesian with an academic earth science education from The Netherlands before World War II. His Ph.D thesis in 1927 was a pioneering study on little-known Cretaceous radiolaria and Tertiary calcareous nannofossils from Roti and Timor. Subsequent work during his professional career as paleontologist of the Geological Survey in Bandung mainly focused on evolution of Cenozoic larger foraminifera. Tan's scientific legacy was accomplished before he was 40 years old, when the Japanese occupation terminated his research and the turmoil immediately thereafter took his life.Although Tan Sin Hok made significant original contributions to taxonomy and evolution of several microfossil groups, he initially failed to recognize the potential biostratigraphic value of radiolaria and nannofossils; important high-resolution zonations of these groups were developed by other workers in the 1950's and later. Tan's novel approach to evolution and systematics of larger foraminifera of Indonesia appeared to resonate only with 'schools' in The Netherlands, probably largely because his publications were mainly written in Dutch and German and published in Dutch and 'Netherlands Indies' journals with limited distributions.