Geochemistry of glass shards belonging to Youngest Toba Tuff (YTT) ash from eight different localities of Purna alluvial basin, Central India have been carried out to interpret magmatic and postdepositional processes led variations. Inter- and intra-basinal correlations of analytical data have also been made. The ash comprise of abundant glass shards, minor quantity of minerals, and fine-grained admixture. EPMA analysis of the glass shards showing high SiO₂ (76.6–80.3 wt%) along with Al₂O₃ (11.7–13 wt%), K₂O (3.2–4.4 wt%), and Na₂O (1.9–2.7 wt%) reveals their rhyolitic composition. ICP-MS analysis of the same depicts enriched LREE and depleted HREE along with strong negative Eu anomaly; elements like Ba, Sr, Rb, Nb, Y, and Ce are also on higher side. Geochemical variations in major, minor, and trace elements exhibit fractional crystallization and post-depositional processes led heterogeneities in the magma constituents and glass shards, respectively. The same have been interpreted through the ratios of immobile elements i.e., FeO/TiO₂ vs. Al₂O₃/TiO₂, Sr/Nb vs. Ce/Y and mobile elements i.e., SiO₂/Al₂O₃ vs. Na₂O/K₂O, FeO/Al₂O₃ vs. Na₂O/K₂O,Nb vs. Rb. Higher and lower concentrations of LREE and HREE respectively are due to fractional crystallization of magma. Concentrations of major, minor, and rare earth elements including trace are in good agreement with the glass compositions of Toba Caldera and other YTT bearing sites in India and Malaysia.

对来自印度中部 Purna 冲积盆地 8 个不同地点的属于 Youngest Toba Tuff (YTT) 灰烬的玻璃碎片进行了地球化学分析，以解释岩浆和沉积后过程导致的变化。还对分析数据进行了流域间和流域内相关性。灰烬由丰富的玻璃碎片、少量矿物质和细粒混合物组成。玻璃碎片的 EPMA 分析显示高 SiO ₂ (76.6-80.3 wt%) 以及 Al ₂ O ₃ (11.7-13 wt%)、K ₂ O (3.2-4.4 wt%) 和 Na ₂O (1.9-2.7 wt%) 揭示了它们的流纹岩组成。其 ICP-MS 分析描述了富集的 LREE 和耗尽的 HREE 以及强烈的负 Eu 异常；Ba、Sr、Rb、Nb、Y 和 Ce 等元素也偏高。主要、次要和微量元素的地球化学变化分别表现出部分结晶和沉积后过程导致岩浆成分和玻璃碎片的异质性。通过固定元素（即 FeO / TiO ₂与 Al ₂ O ₃ / TiO ₂、Sr / Nb 与 Ce / Y 和移动元素（即 SiO ₂ / Al ₂ O ₃与 Na）的比率来解释相同的情况₂ O / K ₂ O, FeO / Al₂ O ₃与 Na ₂ O / K ₂ O，Nb 与 Rb。高和低浓度的轻稀土和重稀土分别是由于岩浆的分步结晶。主要、次要和稀土元素（包括痕量）的浓度与 Toba Caldera 和印度和马来西亚的其他 YTT 轴承站点的玻璃成分非常一致。