Palaeogeography of Late Triassic red-beds in Singapore and the Indosinian Orogeny

G. Oliver, A. Prave

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

A red-bed facies of the Upper Triassic Jurong Formation has been logged on Sentosa Island, Singapore. An overall coarsening and thickening-upward pattern is well developed. The lower part of the section is dominated by purple-red, massive to finely laminated illite-smectite-kaolin-rich mudstones containing thin, discontinuous lenses of fine sandstone marked by low-angle lamination and small ripples. One dinosaur-like foot print has been discovered in a loose block of red mudstone. It is concluded that this is a lacustrine sequence and it is proposed to name the lake, Lake Sentosa. The upper part of the sequence consists of flat-laminated to trough cross-bedded medium-grained sandstone and granule to cobble conglomerates alternating with purple-red mudstone. The mudstone-sandstone packages are arranged in decametre-scale coarsening-upward cycles. The channelling and decimetre-scale cross-bedding characterising the sandstone and conglomeratic beds is evidence for deposition by flashy fluvial flood processes, possibly feeding into the lake as a fresh water delta. One possible dinosaur trackway in granule size conglomerate has been located. Detrital zircon U-Pb ages vary from 2.7. Ba to 209. Ma with significant populations at ~245. Ma and 220. Ma. These ages throw light on the timing of the Indosinian Orogeny. The molasse red-beds of the Jurong Formation were deposited in a half graben formed in the hangingwall of the Bukit Timah Fault when central Peninsular Malaysia went into extension following the climax of the Indosinian Orogeny in the Late Triassic.
Original languageEnglish
Pages (from-to)214-224
Number of pages11
JournalJournal of Asian Earth Sciences
Volume76
DOIs
Publication statusPublished - 25 Oct 2013

Keywords

  • Indosinian Orogeny
  • Late Triassic
  • Red-beds
  • Singapore

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