Integrated structural, metamorphic, and geochronological data indicate that the evolution of the Southern Marginal Zone (SMZ) of the Limpopo Complex of southern Africa was controlled by a single Neoarchean high-grade tectono-metamorphic event. The exhumation history reflected by the high-grade rocks is determined by their location relative to the contact with the low-grade rocks of the Kaapvaal Craton. Exhumation of granulites far north from this contact is recorded by a decompression-cooling (DC) pressure-temperature (P-T) path linked to steep southward-verging thrusts related to the Hout River Shear Zone. This P-T path traverses from P ~8 kbar, T ~825 °C to P ~5 kbar, T ~550 °C and reflects exhumation of the SMZ in the interval ca. 2.68–2.64 Ga. P-T paths for granulites close to this contact are characterized by a distinct inflection at P ~6 kbar, T ~700 °C that exhibits near-isobaric cooling (IC) to T ~580 °C. The IC stage is linked to low-angle, out-of-sequence, southward-verging thrusts that developed in the interval 2.63–2.6 Ga. The thrust-controlled exhumation of the SMZ furthermore is demonstrated by the convergence at P ~6 kbar, T ~700 °C of DC P-T paths in the hanging wall with prograde P-T loops in the footwall of the steeply southward-verging Hout River Shear Zone, and by the establishment of a retrograde isograd and zone of rehydrated granulites in the hanging wall derived from the dehydration of the low-grade rocks in the footwall. A composite deformation-pressure-temperature-time (D-P-T-t) diagram provides evidence in support of a tectonic model for the evolution of the Limpopo Complex that involves early crustal thickening and peak metamorphic conditions followed by doming and diapirism related to gravitational redistribution mechanisms.

Integrated geological studies in the Central Zone of the Limpopo Complex formed the basis for the construction of a composite deformation (D)–pressure (P)– temperature (T)–time (t) (D-P-T-t) diagram that shows the following: First, in the Neoarchean the Central Zone probably underwent high-pressure (HP) (P >14 kbar, T ~950 °C) conditions followed by near isothermal decompression to ultrahigh- temperature conditions (UHT) (T ~1000 °C, P ~10 kbar), before ca. 2.68 Ga. Second, the post-peak exhumation history linked to two distinct decompression cooling stages commenced at ca. 2.68 Ga and ended before the emplacement of the Bulai Pluton at ca. 2.61 Ga. Stage 1 started at P ~9 kbar, T = 900 °C, and culminated with the emplacement of leucocratic anatectic granitoids at ca. 2.65 Ga. Stage 2, linked to the development of major SW-plunging sheath folds and related shear zones, started at P ~6 kbar, T ~700 °C and ended at P ~5 kbar, T ~550 °C, before ca. 2.61 Ga. The rocks resided at the mid-crustal level for more than 600 m.y. before they were again reworked at ca. 2.02 Ga by a Paleoproterozoic event. This event commenced with isobaric (P ~5 kbar) reheating (T ~150 °C) of the rocks related to the emplacement at ca. 2.05 Ga of magma linked to the Bushveld Igneous Complex. This was followed by final exhumation of the Central Zone. The Neoarchean high-grade event that affected the Limpopo Complex is linked to a Himalayan-type collision of the Kaapvaal and Zimbabwe Cratons that resulted in over-thickened unstable crust and the establishment of HP and UHT conditions. This unstable crust initially responded to the compressional event by thrust-driven uplift and spreading of the marginal zones onto the two adjacent granite-greenstone cratons. The post-peak exhumation history was probably driven by a doming-diapiric mechanism (gravitational redistribution).