Climate-Volcanism Feedback and the Toba Eruption of ∼74,000 Years Ago

摘要: A general feedback between volcanism and climate at times of transition in the Quaternary record is suggested, exemplified by events accompanying Toba eruption (∼74,000 yr ago), largest known late explosive volcanic eruption. The paroxysm occurred during δ18O stage 5a-4 transition, a period rapid ice growth falling global sea level, which may have been factor creating stresses that triggered event. estimated to produced 1015 1016 g fine ash sulfur gases lofted co-ignimbrite clouds heights least 32 ± 5 km, led dense stratospheric dust sulfuric acid aerosol clouds. These conditions could created brief, dramatic cooling or "volcanic winter," followed annual Northern Hemisphere surface-temperature decreases ∼3° 5°C caused longer-lived aerosols. Summer temperature ⩾10°C high northern latitudes, adjacent regions already covered snow ice, might increased cover sea-ice extent, accelerating progress. Evidence for such climate-volcanic feedback, following Milankovitch periodicities, found several climatic transitions.