The eastern Indian shield consists of Archaean Singhbhum Craton and Proterozoic Chhotanagpur Gneissic Complex sandwiching the Singhbhum Mobile Belt. Since the cratonization of the Singhbhum Craton in Archaean, the growth of the eastern Indian shield took place in time and space through tectono-magmatic processes. The stability of cold and thick lithosphere is fundamental to long-term survival of cratons, whereas the geophysical studies have detected the lithosphere-asthenosphere boundary (LAB) under the eastern Indian shield at depths too shallow to be called stable. We analysed the terrestrial Bouguer gravity anomaly, and satellite-based free-air anomaly, geoid undulation, and elevation data to ascertain the 2D lithospheric density structure across the region. Our density model illustrates that the density inhomogeneity exists in the crust across the three tectonic domains of the eastern Indian shield. The derived crustal model shows an upper and lower crustal density variation from 2740 to 2770 kg/m³, and from 2930 to 2940 kg/m³, respectively, and a reasonably smooth Moho at 37–41 km depth. Towards the north, the Moho undulates from 40 to 43 km under the foreland Ganga basin, whereas in the south, it varies from 38 to 30 km under the Eastern Ghats Mobile Belt and lastly moves to ~20 km in the Bay of Bengal. In the southern part of the Singhbhum Craton, an undissipated lithospheric mantle root is found at a depth of ~150 km. Otherwise, the LAB shallows to ~132 km in the northern Singhbhum Craton and Singhbhum Mobile Belt and then thickens to about 135–140 km depth beneath the Chhotanagpur Gneissic Complex. The foreland Ganga basin toward the extreme north is characterized by a more in-depth LAB lying at a depth of over 200 km. The LAB, in the Bay of Bengal, is at a depth of 112–125 km, except for the Kolkata coast (135 km). Moderate crustal density difference in various crustal domains, as well as an almost smooth crust-mantle boundary at 37–40 km depth, suggests the effect of substantial mafic–ultramafic crustal intrusion and together with the thin (135–140 km) lithosphere reinforces the evidence of thermo-chemical processes that controlled the lithospheric modification in the eastern Indian shield.

印度东部的盾牌由夹着Singhbhum移动带的古生界Singhbhum Craton和元古代Chhotanagpur片麻岩复合体组成。自古生的Singhbhum Craton克拉通化以来，东印度盾的生长是通过构造-岩浆作用过程在时间和空间上发生的。寒冷和厚厚的岩石圈的稳定性是克拉通长期生存的基础，而地球物理研究已经检测到印度东部盾构下的岩石圈-软流圈边界（LAB）的深度太浅而不能称为稳定。我们分析了地面布格重力异常，基于卫星的自由空气异常，大地水准面波动和高程数据，以确定整个区域的二维岩石圈密度结构。我们的密度模型表明，在印度东部盾构的三个构造域中的地壳中存在密度不均匀性。导出的地壳模型显示出上下地壳密度在2740至2770 kg / m之间变化³和2930至2940 kg / m ³，以及在37-41 km深度的合理光滑的莫霍面。Moho向北，在前陆Ganga盆地下起伏40至43 km，而在南部，它在东高止山脉活动带下起伏38至30 km，最后移至孟加拉湾约20 km。在Singhbhum Craton的南部，发现了约150 km深度的未消散的岩石圈地幔根。否则，LAB在Singhbhum Craton和Singhbhum移动带北部变浅至132 km，然后在Chhotanagpur片麻岩复合体下方增厚至135-140 km。走向最北端的前陆恒河盆地的特征是，它位于200多公里深处，有一个更深入的实验室。LAB位于孟加拉湾，除加尔各答海岸（135公里）外，深度为112-125公里。