Early continent-building processes on Earth are challenging to investigate, particularly since juvenile felsic crust formed during the Early Archean (4.0–3.2 Ga) is rarely preserved. Thus, associated sedimentary records are of fundamental importance, although in many cases these have been metamorphosed and reworked to various degrees since deposition. Here we present new petrological and zircon and monazite U–Pb age data from one of the Earth's oldest ‘khondalite’ (granulite-facies aluminous metapelite) belt, which we define as the Mercara khondalite belt, and associated charnockite and mafic granulite from the Mercara suture, the collision zone welding the Coorg and Western Dharwar Blocks in southern India. Petrologic analyses and phase equilibria modelling of the khondalites and associated charnockite and mafic granulite reveal a clockwise pressure–temperature (P–T) path with a peak temperature of above ca. 900 °C, and pressures up to 12 kbar. Detrital zircon grains in the metasedimentary rocks have magmatic cores with oscillatory zoning and ages up to ca. 3.5 Ga, and metamorphic overgrowths with ages of 3.1–3.0 Ga. Monazite in the khondalites yield identical metamorphic ages in the range of 3.1 to 3.0 Ga. Some of these rocks are overprinted by a younger thermal event at ca. 2.8–2.6 Ga. We correlate the high P–T metamorphism with the subduction-collision history between the northern margin of the Mercara block and the Western Dharwar Craton during the Mesoarchean, which indicates that plate tectonics had been established on Earth by at least ca. 3.1 Ga, in agreement with many independent lines of evidence. The Mesoarchean Mercara khondalite belt signals emergence of continents on the early Earth with active drainage systems leading to the deposition of voluminous detritus. The ca. 3.1 to 3.0 Ga (ultra) high temperature and high pressure metamorphism also coincides with the timing of assembly of the Earth's oldest supercontinent Ur

地球上早期的大陆建设过程具有挑战性，特别是由于在古代太古宙时期（4.0-3.2 Ga）形成的幼年长英质地壳很少被保存，这尤其具有挑战性。因此，相关的沉积记录具有根本的重要性，尽管在许多情况下，自沉积以来，这些记录已被变形并进行了不同程度的处理。在这里，我们提供了来自地球上最古老的“方铅矿”（粒状相铝质变质岩）带之一的新的岩石学，锆石和独居石U-Pb年龄数据，我们将其定义为Mercara khondalite带，以及来自Mercara的伴生菱镁矿和镁铁矿粒岩缝合，碰撞区焊接了印度南部的Coorg和Western Dharwar块。P–T）路径，其峰值温度高于约。900°C，压力最高12 kbar。准沉积岩中的碎屑锆石颗粒具有岩浆岩心，并具有振荡带，其年龄可长达约30年。3.5 Ga和年龄在3.1–3.0 Ga的变质过度生长。高岭岩中的独居石在3.1至3.0 Ga范围内具有相同的变质年龄。2.8–2.6 Ga。我们将高P–T与相关在Mesoarchean时期Mercara块北缘与Western Dharwar Craton之间具有俯冲碰撞历史的变质作用，这表明至少在大约大约1个月的时间内板块构造在地球上已经建立。3.1 Ga，与许多独立证据相一致。Mesoarchean Mercara khondalite带通过活跃的排水系统指示了地球早期大陆的出现，导致大量碎屑沉积。该ca。3.1至3.0 Ga（超）高温高压变质作用也与地球最古老的超大陆Ur的组装时间相吻合