Estimates of sulfur and chlorine yield to the atmosphere from volcanic eruptions and potential climatic effects

摘要: We report analytical methods based on electron microprobe analysis of volcanic tephra which allow estimation minimum masses sulfur and chlorine released to the atmosphere by eruptions. Differences between contents glassy melt inclusions (trapped phenocrysts) matrix glasses, respectively, scaled estimated eruption volumes, provide estimates yield atmosphere. Declines in mean northern hemisphere surface temperatures associated with several Recent eruptions (Laki 1783, Tambora 1815, Krakatau 1883, Agung 1963, Mount St. Helens 1980) are positively correlated our rnimimum mass atmosphere, reinforcing idea that sulfate aerosols have a greater climatic impact than “dust.” Injection emissions into stratosphere increases optical thickness may result cooling earth's surface. Our results indicate decreases listed above appear vary linearly cube root This apparent geometric relationship suggests be completely related particulates stratospheric aerosol layer-Correlations observed temperature other eruption-related parameters (estimated yield, total volume dense rock equivalent) poor compared correlation yield. Application 1982 El Chichon volcano underestimation judging from independent airborne sampling satellite observations plume. The presence anhydrite phenocrysts decomposition contributed this eruption. Potential contributions volatile species basaltic magma generally about an order magnitude higher equal volumes silicic magma, spite fact magmas inject more fine ash volatiles (H2O, CO2) upper In view significant Laki 1783 fissure we suggest flood or basalt should taken account along explosive volcanism paleoclimatic reconstructions.