Testing the feasability of sea-level reconstructions using SEALEX, a spreadsheet based reef growth model

SEALEX, a simple reef growth model (Koelling et al. 2009) has been used to test the feasability of different sea-level reconstructions. The forward model is driven by a user definable sea-level curve. Other adjustable model parameters include maximum coral growth rate, coral growth rate depth dependence and light attenuation, subaerial erosion and subsidence. A time lag for the establishment of significant reef accretion may also be set. During the model run, both, the external shape and the internal chronologic structure of the growing reef as well as the paleo-water-depths are continuously displayed and recorded. The effects of driving the reef growth model with different sea-level reconstructions such as those of Lambeck & Chappell (Science, 2001), Waelbroeck et al (QSR,2002), Siddall et al (nature,2003) and Bintanja et al (nature,2005) for different tectonic settings such as both on slowly subsiding islands like Tahiti (subsidence rates of 0.25 m ka-1) and rapidly subsiding islands like Hawaii (subsidence rate of 2.5 mka-1) as well as rapidly uplifting coastal settings like Huon Peninsula (uplift rates of 0.5 to 4 m ka-1). The model runs show the sensitivity of the resulting overall morphology and internal age structure to the sea level reconstruction used to drive the model.These results can then be compared to observed data allowing different hypothesis concerning reef development to be tested. The model may also be used to assist in finding sampling locations in reef bodies that are likely to contain critical information for sea level studies. Model run of a Huon Peninsula-type reef driven by a spliced sea level curve (200 ka-120 ka:Waelbroeck et al., 2002,120 ka to present: Lambeck and Chappell, 2001 as shown in the inset) and an uplift rate of 2.8 mka-1. For comparison the idealized Huon Peninsula profile is inset together with terrace ages compiled from a Esat et al., 1999, Stein et al., 1993, b Potter et al. (2004), c Chappell et al. (1996) and d Yokoyama et al. (2001). From Koelling et al., GPC 2009