Preliminary identification of palaeofloods with the alkane ratio C(31)/C(17) and their potential link to global climate changes

A major challenge in palaeohydrology is the extraction of continuous palaeoflood information from geophysical records. A high-resolution sediment core off the Minjiang estuary area in the Taiwan Strait, SE China, records the sedimentation history from approximately 1660 to the present. The alkane ratio C(31)/C(17), a classic organic geochemical indicator of terrestrial/aquatic matter, peaks in the layers dating as 1876-1878 and 1968-1970, suggesting the large terrestrial input to the Minjiang estuary area by huge flood transporting during the each peak interval. Historical archives are consistent with this interpretations and record catastrophic floods in the Minjiang River during both intervals. Furthermore between 1876-1878 there were floods in southern China and droughts in northern China, as well as throughout Asia, Africa, Australia, and the Americas. The 1876-1878 catastrophic flood of the Minjiang River may therefore has been the local response to global climate anomalies during that time interval.