Habitat and C-14 ages of lignitic terrace deposits along the northern Sarawak Coastline

Author : Franz L. Kessler & John Jong
Publication : Bulletin of the Geological Society of Malaysia
Page : 27 - 34
Volume Number : 60
Year : 2014
DOI : https://doi.org/10.7186/bgsm60201403

Bulletin of the Geological Society of Malaysia, Volume 60, December 2014, pp. 27 – 34

Habitat and C-14 ages of lignitic terrace deposits along the northern Sarawak Coastline

Franz L. Kessler1 & John Jong2

1Curtin University of Technology, Department of Applied Geology, CDT 250, 98009 Miri, Sarawak
Currently at Lundin Malaysia BV, Lot 13A-01, Level 13A, Menara HLA,
No. 3 Jalan Kia Peng, 50450, Kuala Lumpur, Malaysia
Email address: Franz-Luitpold.Kessler@lundinmalaysia.com
2 JX Nippon Oil and Gas Exploration (Deepwater Sabah) Limited
Level 51, Menara 3 PETRONAS, Persiaran KLCC, Kuala Lumpur City Centre, 50088 Kuala Lumpur

The young terraces fringing the Miri coastline from Miri to Bekenu are formed by lignitic sands, fossil wood, and conglomeratic beds that contain reworked quartz pebbles derived from the older Tukau Formation. The sequence can be subdivided into four sub-units: I. Basal Conglomerate, II. Sandstone with fossil wood and Ophiomorpha, III. Cross-bedded lignitic sandstone, and IV. Bleached and weathered palaeosol. These sediments are indicative of a transgressive near-shore, fluvial to marginal marine depositional environment, as water energy peaked in cross-bedded sandstone of Sub-unit III. Radiometric C-14 based age determination in ten coastal locations indicates an age range from Late Pleistocene to Early Holocene (28,570 + 230 to 8,170 + 50 years BP). Given the terraces were formed in the same environment, but are now located at different elevations and appear to be block-faulted, it might imply significant tectonic movements in the Holocene.

Keywords: terraces, Quarternary, Pleistocene, Holocene, Borneo, tectonics, Ophiomorpha, C-14 dating