Biomarker records of terrestrial organic matter input to the Indonesian Seas 0-30 ka BP: Implications for regional climate

The tropical Pacific plays a critical role in modern climate and ocean dynamics, prompting numerous proxy-based reconstructions of its behaviour on geologic timescales. Here, changes in the fluvial delivery of terrestrial matter to the Indonesian Seas are reconstructed for the last glacial-interglacial transition using abundances of n-alkanes in six sediment cores along a N-S transect. At all of the core sites, the flux of n-alkanes is higher during the Last Glacial Maximum than during the current interglacial; a signal postulated to be primarily driven by the deglacial rise in sea level. In contrast, shorter-term variability is discussed in terms of changing precipitation regimes. Other factors possibly influencing the riverine delivery of n-alkanes to the ocean are also considered, including variable discharge associated with changing frequencies of intense storm events, variable rates of erosion and deposition, and variations in local plant biomass.