The widespread records of mafic intrusives (both sills and dykes) are reported from the Proterozoic sedimentary basins of the Indian Shield. Amongst them, the Bijawar basin is also intruded by Paleoproterozoic (ca. 1.98−1.97 Ga) mafic sills. We provide first hand information on petrological and geochemical characteristics of these mafic sills together with a few NW-trending mafic dykes belong to the Jhansi swarm emplaced within the Bundelkhand craton, adjacent to the Bijawar basin. These Paleoproterzoic mafic intrusive rocks, i.e. sills and dykes, are believed to be integral parts of the Jhansi LIP, identified in the Bundelkhand craton. The studied mafic magmatic samples are medium- to coarse-grained and contain doleritic mineral compositions and textures. Geochemically, the mafic sill samples of the Bijawar basin, which belong to the Darguwan-Surjapura mafic sills (DSMS), are sub-alkaline basaltic-andesite to andesite in character. They are co-genetic in nature and show close geochemical similarities with a set of NW-trending mafic dykes (low-Ti) emplaced in the Bundelkhand craton. On the other hand, another set of NW-trending mafic dykes (high-Ti) of the Bundelkhand craton have distinct geochemical nature; likely to have different genetic history. The rare-earth element contents and trace-element modeling suggest that the DSMS and low-Ti dyke samples are likely to be derived from a melt generated ≥20 % melting of a shallower mantle source (spinel stability field), whereas the high-Ti dyke samples show their derivation from a melt generated through ≤15 % melting of the similar mantle source but at deeper level (garnet or garnet-spinel transition stability field); with a substantiate percentage of olivine fractionation of melts before crystallization. Their emplacement in an intracratonic tectonic regime and role of plume in the genesis of these rocks are suggested. The geochemical signature also indicates the role of an ancient (Archean) subduction event that has metasomatized the mantle before the cratonization. Their spatiotemporal correlation with other similar magmatic events of the globe indicate that the Bundelkhand craton was closer to the Karelia-Kola craton (Baltica Shield), North China craton and northern Superior craton, which could be part of the Columbia supercontinent, during its assembly.

据报道，印度盾构的元古代沉积盆地中广泛地记录了镁铁质侵入物（基岩和堤坝）。其中，比哈瓦尔盆地还被古元古代界（约1.98-1.97 Ga）基岩侵入。我们提供有关这些铁镁质基岩的岩石学和地球化学特征的第一手信息，以及一些西北向流行的铁质岩浆，这些岩质属于放置在比贾瓦尔盆地附近的邦德尔坎德克拉通内的詹西群。这些古元古代的镁铁质侵入岩，即基石和堤坝，被认为是在班德尔坎德克拉通中发现的詹西LIP的组成部分。研究的铁镁质岩浆样品为中等粒度至粗粒度，并且含有白云岩矿物成分和质地。从地球化学上看，比贾瓦尔盆地的铁镁基石样品，属于Darguwan-Surjapura铁镁基石（DSMS）的特征是亚碱性玄武质安山岩至安山岩。它们本质上是共生的，并且与在Bundelkhand克拉通中放置的一组西北趋势的镁铁岩岩浆（低Ti）显示出密切的地球化学相似性。另一方面，Bundelkhand克拉通的另一组西北趋势的铁镁质岩脉（高钛）具有独特的地球化学性质。可能有不同的遗传史。稀土元素含量和痕量元素模型表明，DSMS和低Ti堤坝样品可能源自熔岩产生的≥20％的较浅地幔源熔岩（尖晶石稳定性场），高钛堤样品显示出它们是由相似地幔源的≤15％熔化而产生的熔体衍生而来的，但含量更高（石榴石或石榴石-尖晶石转变稳定场）；结晶前熔体橄榄石分级的百分比相当可观。提出了它们在克拉通内部构造体系中的位置以及羽状岩在这些岩石的成因中的作用。地球化学特征还表明了古代的（Archean）俯冲事件的作用，该事件在克拉通化之前已被交化了地幔。它们与地球上其他类似岩浆事件的时空相关性表明，Bundelkhand克拉通在组装过程中更靠近卡累利阿-可乐克拉通（Baltica Shield），华北克拉通和北部上克拉通，它们可能是哥伦比亚超大陆的一部分。