FORAMINIFERA TAPHONOMY AS PROXY FOR LARGE WAVE EVENTS: A CASE STUDY IN THE MARSHALL ISLANDS

摘要

Observational records of tropical cyclones can be extended over the past few thousand years using sediment proxies of transport and overwash by large waves. However, in high-energy carbonate environments, conventional methods of identifying large wave events in sediment proxy records can fail due to homogeneous, coarse grain size and homogeneous chemical makeup. We investigated the relative weathering of foraminifera tests as an alternative proxy for large wave events in a blue hole sediment core retrieved from Jaluit Atoll, Republic of the Marshall Islands. We found clear evidence of gradients in weathering under ambient hydrodynamic conditions across the fringing and back reef flats bracketing the blue hole. However, despite the existence of these gradients, event layers in the sediment core were not clearly distinguishable from non-event layers using weathering as a proxy.