Geoarchaeology of the Burmarrad ria and early Holocene human impacts in western Malta

Abstract

Holocene sediments from the ria of Burmarrad (western Malta) provide a record of changing geomorphology, relative sea-level rise and human impacts. Chronostratigraphic evidence attests to a fluvial-dominated upper estuarine environment between -7500 cal. BP and -7000 cal. BP. with increasing salinity linked to rising post-glacial sea level. The shift to a marine setting is dated to -7000 cal. BP. characterized by a wave-dominated coastline that accreted up until -4000 cal. BP. During the maximum marine ingression, the Burmarrad floodplain formed a vast 1.8 km2 marine bay, -3000 m long by -650 m wide, whose environmental potentiality presented western Malta's early societies with a multiplicity of coastal, terrestrial, and fluvial resources. in addition to a low energy context favourable to the anchoring of boats. New palynological data show intensified human impact on the landscape beginning - 7300 cal. BP. which is broadly consistent with the earliest archaeological traces. Western Malta was already void of a significant vegetation cover by the mid-Holocene. Rapid human-induced sedimentation means that by the Bronze Age, the palaeobay had been reduced by -40% compared to its mid-Holocene maximum. The final morphogenetic phase constitutes fluvial silts and sands that began accreting after 2700 cal. BP. During Punic/Roman times. the ria bay was -1 km2• and was flanked to the south by a well developed deltaic plain providing fertile land for agriculture. Today. the ria is -60% smaller than it was 7000 years ago.