Decoupling post-glacial tectonism and eustasy at Huon Peninsula, Papua New Guinea

Abstract

Abstract Late Quaternary uplift of coral terraces varies along the coast at northeast Huon Peninsula, Papua New Guinea, but the uplift rate has been assumed to be constant at any given locality in previous studies. Measurements indicate that rates for the last 7000 and 120 000 years were similar but this may be coincidence, because uplift at Huon Peninsula is dominated by isolated, metre-scale events with recurrence intervals around 1000 years. Using age-height data from 54 corals from the post-glacial reef, we examine the uplift rate over the last 13 000 years near Kwambu, where facies changes in a drill core indicate several uplift events before 7 ka bp . To separate uplift from sea level, a eustatic curve for Kwambu was generated by the global sea-level model described by Lambeck, recalibrated to new, Late Pleistocene sea-level data. With Barbados as a test case, predictions compare well with observations reported earlier, but predicted sea levels for Kwambu cannot be reconciled with the coral data unless the water depth of coral growth at the site was greater than estimated previously.