Evaluation of the petrogenetic history of continental flood basalt using mineral–chemical data has been sparingly used for several flood basalt provinces of the world. For the Deccan flood basalts, such attempts are still rudimentary. The present contribution highlights several facets of petrogenesis of the Eastern Deccan Volcanic Province using details of constituent phases including glass. The present-study area around Khandwa (21°49′N, 76°21′E) indicates the presence of three distinct lava flows, which were identified on the basis of physical volcanological features based on a three-tier classification. Moreover, the occasional presence of chilled dykes and feeder dykes has been documented. The lava succession rests above (apparent) cumulate gabbro basement. The lava flows, in general, are characterized by dominant pyroxene (mostly augite, locally pigeonite) and plagioclase, opaque (magnetite and ilmenite) and glass, whereas olivine is rare. Both of these principal mineral phases (namely, plagioclase and pyroxene) occur both as phenocrysts and groundmass, while opaque phases occur only as groundmass. Pyroxene and plagioclase are generally zoned due to the changing milieu of crystallization conditions. Pyroxene thermometry data show the equilibration temperature range of 1050–1300 °C. Except for two samples of Flow II and one sample of chilled zone, the pyroxene thermometry data are broadly similar to that obtained from magnetite–ilmenite thermometry. As expected, deduced glass thermometric data reveal a relatively higher temperature. Crystallization history of parental magma was quantitatively modeled using Petrolog 3 software. The results indicate that the parental magma underwent both equilibrium and fractional crystallization (for example initially crystallized olivine reacted with ambient liquid to give rise to pyroxene). Phenocrystal and groundmass plagioclase and pyroxene show distinct patterns of compositional zoning corresponding to fluctuating physical parameters within the magma. Some of the glass [especially from the chilled dyke, feeder dyke, and Upper Colonnade Zone (UCZ) of flow II and flow III] represents ‘higher magnitude pressure ambience’ (fossilized glass) which is distinct from ‘surficial glass’ caused by equilibrium quenching. The glass and pyroxene compositions (using tectonic discrimination diagrams) suggest a non-orogenic continental setting of the parent magma. It is concluded that the studied Deccan volcanism shows a complex interplay of repeated pulses of magma ascent, fluctuation of crystallization condition, effervescence, and local magma mixing.

利用矿物化学数据评估大陆性洪水玄武岩的成因史已很少用于世界上几个洪水玄武岩省。对于Deccan洪水玄武岩，此类尝试仍是基本的。本文稿使用包括玻璃在内的组成相的详细信息，突出了东德肯火山省岩石成因的几个方面。当前研究的Khandwa周围地区（北纬21°49′，东经76°21′）表明存在三种不同的熔岩流，这些熔岩流是根据三层分类的物理火山学特征确定的。此外，已经记录了偶尔出现的冷却堤坝和支线堤坝。熔岩序列位于（明显的）累积辉长岩基底之上。一般来说，熔岩流的特征是主要的辉石（主要是辉石，局部为皂石）和斜长石，不透明（磁铁矿和钛铁矿）和玻璃，而橄榄石很少见。这两种主要的矿物相（即斜长石和辉石）都以隐晶和底质的形式出现，而不透明相仅以地质的形式出现。由于结晶条件的变化，一般将辉石和斜长石划为分区。辉石的测温数据显示平衡温度范围为1050–1300°C。除了两个流动II的样品和一个冷却区的样品，辉石的测温数据与磁铁矿-钛铁矿测温数据大致相似。不出所料，推导的玻璃​​测温数据显示相对较高的温度。父母岩浆的结晶史使用Petrolog 3软件进行了定量建模。结果表明，母岩浆既经历了平衡结晶又经历了部分结晶（例如，最初结晶的橄榄石与环境液体反应生成辉石）。晶状体和基底斜长石和辉石显示出与岩浆内波动的物理参数相对应的组成区带的不同模式。某些玻璃（特别是来自流动II和流动III的冷却堤坝，支线堤坝和上柱廊区域（UCZ））表示“较高压力环境”（化石玻璃），与平衡引起的“表面玻璃”不同淬火。玻璃和辉石的成分（使用构造判别图）表明母岩浆的非造山带。