Archean cratons display spatial and temporal changes in the composition and thickness of the crust, which has important implications for intracrustal differentiation, attainment of long-term stability, and operation or absence of plate tectonics. The geodynamic reason(s) for these changes, though, is a controversial subject. To address this issue, the present contribution investigates the spatial and temporal changes in granitoid compositions of the well-exposed Singhbhum Craton. It reports new zircon U-Pb and Lu-Hf, and whole-rock geochemical data on Paleoarchean granitoids from some of the less-studied parts of the Singhbhum Craton. The new information is then collated with previously reported data from the central part (cratonic core) of the Singhbhum Craton to illustrate the spatial and temporal changes in granitoid chemistry, using selected major oxide and pressure-sensitive elemental ratios. Temporal changes in the characteristics of the granitoids suggest that the crust building in Singhbhum Craton possibly started in a relatively thin oceanic plateau with the emplacement of low-pressure TTGs and diorites during ∼3.53–3.47 Ga. The ∼3.47–3.42 Ga period marks a gradual increase in crustal thickness, inferred from progressively increasing Al₂O₃ and pressure-sensitive trace element ratios of the TTGs. Subsequently, as a result of protracted mantle upwelling and consequent juvenile TTG addition, the composition of the bulk continental crust differentiated into a more evolved felsic composition by ∼3.35 Ga, when the first potassic granite was emplaced. Spatial distribution of the granitoids suggests partial convective overturn (contemporaneous sinking of greenstones and diapiric rise of shallow- to mid-crustal granitoid domes) played a role in bringing the older as well as juvenile TTGs to a melting depth, generating ∼3.35–3.25 Ga spatially restricted high-silica, high-potassic, low-pressure K-rich granite and transitional granitoid domes. TTG magmatism also continued contemporaneously during this period. During ∼3.33–3.32 Ga, continental crust in Singhbhum Craton reached the maximum thickness, inferred from the formation of high-pressure (or low-HREE) TTGs. Afterward, possibly delamination of dense lower crustal residue caused the crust to become thinner, as recorded by progressively low-pressure K-rich granite and transitional granitoid emplacement until ∼3.28 Ga. Near the end of Paleoarchean (∼3.26–3.25 Ga), the crust became thicker again, further yielding high-pressure TTGs and K-rich granites. We suggest an oceanic plateau-like setting (characterized by relatively inefficient heat extraction compared to a modern-day subduction zone) where plume magmatism and delamination of anatectic residues of crustal melting caused the time-transgressive thickening and thinning of the continental crust, respectively. This process resulted in change in melting depth and, in turn, in the granitoid chemistry. Therefore, the Paleoarchean crustal architecture and the bulk crustal composition of the Singhbhum Craton controlled the temporal change in granitoid chemistry in an ongoing tectonic regime (partial convective overturn-dominated setting) without any distinct tectonic shift.

太古宙克拉通表现出地壳成分和厚度的时空变化，对地壳内分异、长期稳定性的实现以及板块构造的运行与否具有重要意义。然而，这些变化的地球动力学原因是一个有争议的话题。为了解决这个问题，目前的贡献调查了花岗岩的时空变化曝光良好的辛格布姆克拉通的成分。它报告了新的锆石 U-Pb 和 Lu-Hf，以及来自 Singhbhum Craton 一些研究较少的部分的古太古代花岗岩的全岩地球化学数据。然后将新信息与先前报道的辛格布姆克拉通中部（克拉通核心）的数据进行比较，以使用选定的主要氧化物和压力敏感元素比率来说明花岗岩化学的空间和时间变化。花岗岩特征的时间变化表明，辛格布姆克拉通地壳的形成可能始于相对薄的海洋高原，伴随着低压TTG和闪长岩在~3.53-3.47 Ga期间。~3.47-3.42 Ga时期标志着地壳厚度的逐渐增加，这是从逐渐增加的Al ₂O₃和TTG的压敏微量元素比率推断出来的。随后，由于长时间的地幔上涌和随后的幼年TTG添加，当第一个钾花岗岩就位时，大块大陆地壳的成分分化为更演化的长英质成分约3.35 Ga 。花岗岩的空间分布表明部分对流翻转（同期下沉的绿岩和浅至中地壳花岗岩穹顶的底辟隆起）在将较老的和年轻的 TTG 带入熔融深度方面发挥了作用，产生了~3.35-3.25 Ga 空间受限的高硅、高钾、低压富钾花岗岩和过渡花岗岩穹顶。TTG岩浆作用 also continued contemporaneously during this period. During ∼3.33–3.32 Ga, continental crust in Singhbhum Craton reached the maximum thickness, inferred from the formation of high-pressure (or low-HREE) TTGs. Afterward, possibly delamination of dense lower crustal residue caused the crust to become thinner, as recorded by progressively low-pressure K-rich granite and transitional granitoid emplacement until ∼3.28 Ga. Near the end of Paleoarchean (∼3.26–3.25 Ga), the crust became thicker again, further yielding high-pressure TTGs and K-rich granites. We suggest an oceanic plateau-like setting (characterized by relatively inefficient heat extraction compared to a modern-day subduction zone) where plume magmatism and delamination of anatectic residues of crustal melting caused the time-transgressive thickening and thinning of the continental crust, respectively. This process resulted in change in melting depth and, in turn, in the granitoid chemistry. Therefore, the Paleoarchean crustal architecture and the bulk crustal composition of the Singhbhum Craton controlled the temporal change in granitoid chemistry in an ongoing tectonic regime (partial convective overturn-dominated setting) without any distinct tectonic shift.