The Ramgarh structure (rim-to-rim diameter ~2.4 km) in the Vindhyan Supergroup of sedimentary rocks (including sandstone, shale and minor limestone) of the Mesoproterozoic age in the west-central India, is India’s third confirmed asteroid impact crater. This eroded structure is roughly rectangular in shape and resembles to the Barringer Crater, USA. The presence of central peak and its current crater diameter/depth ratio of ~12 well corroborate the range (10–20) of terrestrial complex asteroid impact craters. The mm-sized, iron-rich (FeO ~50 wt.% in average), spherule-like particles, recovered from the alluvium inside the Ramgarh structure, have internal morphology similar to those of the accretionary lapilli described in known impact craters. The in-situ LA-ICP-MS analyses also suggested high Co–Ni (up to 13,000 and 2500 ppm, respectively)-rich areas locally within these spherules/lapilli. A few non-in-situ, mm-sized particles, recovered from the rim of the structure show the presence of coesite, one of the diagnostic indicators of shock metamorphism. A few fragments of iron-rich, Ca–Al–silicate glasses recovered from the soil inside the structure and outside of the western crater rim include the presence of dendritic magnetite with occasional inclusions of relict native iron. Our microprobe analyses confirm that these metallic irons contain high proportions of Co (~350–3000 ppm), Ni (~200–4000 ppm) and Cu (~2200–7000 ppm) and possibly could be the relict component of a Cu-rich iron meteorite impactor. The field observation and relative enrichment of compatible and incompatible trace elements in the spherule-like substance (recovered from the alluvium inside the Ramgarh structure) as compared to target rocks suggests that hydrothermal activity played an important role in the evolution of the crater.

印度中西部中元古代的沉积岩（包括砂岩，页岩和次要石灰岩）的Vindhyan超群中的Ramgarh结构（边缘到边缘直径约2.4 km）是印度第三次确认的小行星撞击坑。这种侵蚀的结构大致呈矩形，类似于美国的Barringer Crater。中心峰的存在及其当前的陨石坑直径/深度比约为12，这充分证实了地面复杂小行星撞击坑的范围（10–20）。从Ramgarh结构内部的冲积层中回收的mm尺寸，富铁（平均FeO约为50 wt。％）的球形颗粒，其内部形态类似于已知撞击坑中描述的增生性lapilli的形态。在原位LA-ICP-MS分析还表明，在这些小球/羊膜中局部富含Co-Ni（分别高达13,000和2500 ppm）。一些非原位从结构边缘回收的，毫米大小的颗粒显示存在堇青石，这是冲击变质的诊断指标之一。从结构内部和西部火山口边缘外的土壤中回收的一些富含铁的Ca-Al-硅酸盐玻璃碎片包括树枝状磁铁矿的存在，偶尔还夹杂着残留的天然铁。我们的探针分析证实，这些金属铁含有高比例的Co（〜350–3000 ppm），Ni（〜200–4000 ppm）和Cu（〜2200–7000 ppm），并且可能是富含Cu的残留成分铁陨石撞击器。