NOAA/WDS Paleoclimatology - Stalagmite Oxygen and Carbon Isotope Data from Hoti Cave, Oman Over the Past 333000 Years

The source and seasonality of rainfall in southern Arabia during the early- to mid-Holocene and preceeding humid periods is controversial because fossil lacustrine sediments provide solely indirect information on the amount of rainfall. Hydrogen and oxygen isotope measurements on fluid inclusion water trapped in Holocene and Pleistocene stalagmites from Hoti Cave in Northern Oman are direct indicators of the isotopic composition of paleoprecipitation. Isotope values of fluid inclusions formed during peak interglacial periods plot along monsoonal water lines and are indicative of a southern monsoonal moisture source. The last monsoon dominated period lasting from ~10,100 to 6300 years before present was terminated within a few decades in south-eastern Arabia. The subsequent reduction in rainfall amount and change from predominantly summer to predominantly winter rainfall had a profound impact on human communities living in this area and triggered migration from inland to coastal areas where resources were more abundant.