Major oxide geochemical compositions of glass shards from disseminated tephra...

All iron calculated as FeO. Probe conditions: accelerating voltage 20kV, beam current 15nA, 1µm focused beam, 10 second count times全铁以FeO计。探针测试条件：加速电压20kV，束流15nA，聚焦束斑尺寸1μm，计数时长10秒。