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Abstract: Hydrocarbons extracted from the Tertiary age coals from the Lower Suban seam, South Sumatra Basin, Indonesia have been investigated using gas chromatography (GC) and combined gas chromatography/mass spectrometry (GC/MS). Low rank (vitrinite–huminite reflectance ∼0.41–0.45%) coals from the Tambang Air Laya mine represent different maceral assemblages of an ideal succession of ombrogenous palaeo-peat development in a vertical section. High rank coals (vitrinite reflectance ∼1.42–5.18%) from the Suban mine have been thermally metamorphosed by an andesitic intrusion. Variations in the distributions of n-alkanes, isoprenoids and saturated and aromatic biomarkers in the low rank coals reflect variations in local source input and palaeomire conditions. Terpenoid biomarkers, such as cadinane- and eudesmane-type sesquiterpenoids and oleanane- and ursane-type triterpenoids, indicate the predominance of angiosperm plants in the palaeomire, particularly Dipterocarpaceae. The distribution of hopanoids is affected by the organic facies of the coal and their maturity, and correlates with the palaeomire evolution as derived from petrological studies. Close to the igneous intrusion, rapid thermal stress has destroyed most of the biomarkers, but variations in n-alkane distributions, attributable to palaeomire conditions, remain. Reversals in the trends for molecular parameters based on aliphatic hydrocarbons (n-alkane distribution and pristane/phytane ratio) and aromatic hydrocarbons (methyl phenanthrenes) with coal rank are observed. [Copyright &y& Elsevier]

Abstract: Flow depth and speed are crucial but sensitive parameters describing a tsunami''s overland flow. Both parameters can be measured in post-tsunami field surveys for recent events, but are difficult to infer for ancient ones. TsuSedMod, an inverse model produced by Jaffe and Gelfenbaum (2007), can be applied to estimate both the minimum flow depth and speed by using the thickness and grain size distribution of a tsunami deposit. For given estimates of flow speeds or flow depths, the application of this code can help to evaluate the magnitude of a tsunami. In this study, we compare flow depths and flow speeds calculated with TsuSedMod to field data obtained in the aftermath of the 2004 Sumatra and 2006 Java tsunami. This study shows that the model gives a reasonable estimation of local tsunami flow depths and speeds for the analyzed tsunami runup sections. These data give information on the tsunami''s onshore flow characteristics, such as the number of waves and flow deceleration due to obstacles. Sediment layers from different locations within the runup section can be correlated and assigned to the same wave. The testing of TsuSedMod on recent examples shows it to be a valuable tool for calculating flow depths and speeds of ancient tsunami. Together with the dating of respective tsunami deposits, information on magnitude and frequency of events along a particular coastline can be gained. [Copyright &y& Elsevier]