Sulfur in Tephra of Opala Volcano Eruption ca. 1500 years ago, Kamchatka

Abstract

Sulfur-bearing compounds of Plinian-type volcanic eruptions can be transferred with ash particles of distal tephra over considerable distances. Average sulfur content in tephra of Opala volcano (Kamchatka, eruption ca. 1500 years ago) comprises 310 ppm with maximum concentration up to 800 ppm. Connection detected between sulfur content in bulk samples and the particle size distribution – sulfur is predominantly contained in the fraction 0.25‒0.50 mm represented by elongated ash particles with elongated gas pores 1.0‒10.0 mkm in diameter. The most likely reason for the dependence of sulfur content on the texture of ash particles is preservation of sulfur compounds of the water-soluble complex inside gas pores. Sulfur-containing compounds deposited on the surface of ash particles were removed by precipitation in the process of existing tephra in continental environment. Ingress of ash particles into bottom sediments containing sulfur compounds on the inner surface of gas pores during plinian type eruptions similar to the eruption of Opala volcano ca. 1500 years ago, may influence the geochemistry of lithogenesis and lead to redistribution of elements sensitive to the presence of acid-forming agents in the sediment at the stage of diagenesis.