Comparing Lignin-Derived Phenols, δ ~(13)C Values, OC/N Ratio and ~(14)C Age Between Sediments in the Kaoping (Taiwan) and the Kapuas (Kalimantan, Indonesia) Rivers

摘要

The Kaoping (Taiwan) and Kapuas (Indonesia) Rivers differ in hydrological cycle, topography and landscape. These differences strengthen the use of ~(14)C dating, ligninderived phenols, δ ~(13)C values and C/N ratios to determine the sources and diagenesis of surface sedimentary organic carbon (OC) in both rivers. The Kapuas River is surrounded by forest, resulting in sedimentary OC with a ~(14)C age between 600 and 740 years, Λ (total lignin expressed as mg/100 mg OC) values from 0.94 to 3.70, δ ~(13)C values from -27. 87 to -30.00‰, C/N ratios from 6.7 to 30.8, %OC from 0.63 to 9.24% and vanillic acid to vanillin ratio, (Ad/Al)v, values from 0.73 to 2.09, all of which indicate the presence of recent plant-derived organic matter. The tributaries and three locations upstream of the Kaoping River are also surrounded by forests, resulting in Λ values (0. 51-4. 80), δ ~(13)C values (-23.85 to -27.08‰), C/N ratios (14.1-28.7), %OC (1.01-7.86%) and (Ad/Al)v values (0.86-1.88), which are indicative of a terrestrial signal. No lignin oxidation products were detected in the mainstream of the Kaoping River or its coastal zone, hence the surface sediments OC with a ~(14)C age between 4,915 and 15,870 years, enriched δ ~(13)C values (-23.30 and -26.54‰), lower C/N ratios (6.0-17.5) and lower %OC (0.15-2.24%) likely represent old rock and soil material. Massive floods during typhoons most probably cause plant materials from the Kaoping River and its coastal zone to be transported into the deep sea.