Abstract

Shell middens are heaps of discarded human refuse, often interspersed with dwelling structures and burials. These deposits are well known features of the archaeological record in northern Chile and span most of the Holocene. Early to mid-Holocene shell middens accumulated from the discarded remains of fish, shell fish and terrestrial remains of local hunter-gatherer populations known as the Chinchorro. Some of the oldest examples of artificial mummification are among the innovations of these social groups, which settled the coastal Atacama desert before 9 ka BP. Abundant terrestrial (especially plants such as Typha) and shellfish remains along with very fast accumulation rates (one midden accumulated 3 m in less than 500 yr) make radiocarbon comparisons of marine and atmospheric ages feasible to estimate local marine reservoir deviations (ΔR). Such deviations result from the influence of mid-depth water masses at the surface of the coastal ocean and thus provide a proxy for the intensity of coastal upwelling. We have estimated ΔR values from and (iii) to reconstruct the pre-eruptive settlements on the island. Our methods include geomorphological and geological surveys on natural outcrops, wells and quarries, coring, inland and near-shore geophysical investigations, as well as exegesis of local written sources. Preliminary results point to a strong increase of the island’s area as a consequence of drastic sedimentation yield since the mid-13th Century. More than half of Mataram city was built on syn-or post-eruption soft sediments (pumice, sand, or clay). The eastern and northern coasts of Lombok also extended seaward up to several kilometers since the 13th century. Some of the present valleys already existed prior to the eruption, whereas others result from a deep incision of the rivers within PDC deposits up to 60 m thick. Although a huge volume of PDC deposits has been well-preserved from natural erosion for centuries, extensive mining activities since the 1980’s have drastically reduced the former extension of these deposits. The drawing of the preeruptive shoreline and paleovalleys will help archaeologists to find the ancient city of Pamatan and other settlements that still lie buried beneath tephra deposits in several places of the island.