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Mafic rocks are the most common type of igneous rocks on Earth, however, constraining the crystallization age of mafic rocks can be challenging. Apatite is a common accessory phase in mafic rocks and is amenable to dating using the U–Pb system. However, the U–Pb system in apatite has a relatively low closure temperature (∼350°-550 °C) and is therefore prone to resetting by later thermal and metasomatic events. Here, a recently developed Lu Hf dating method using laser ablation reaction-cell mass spectrometry is applied to apatite from mafic rocks. The Lu Hf system in apatite has a higher closure temperature (∼650°-750 °C) compared to U–Pb, increasing the chances of obtaining primary crystallization ages. Furthermore, the laser-ablation method allows rapid data collection compared to traditional solution-based Lu Hf dating techniques. Four study areas were selected to compare the Lu Hf vs U–Pb systematics of apatite in mafic igneous rocks: the Paleoproterozoic Sudbury Igneous Complex (Canada), the Neoproterozoic Borborema Province (NE Brazil), the Paleoproterozoic Fennoscandian Shield (Finland), the Archean Yilgarn Craton and adjacent Mesoproterozoic Albany Fraser Orogen (Western Australia). For all analyzed samples that have apatite trace element compositions typical of an undisturbed primary mafic igneous lithology, the Lu Hf system retains primary igneous apatite crystallization ages, whereas the U–Pb system in the same grains often records isotopic disturbance or a cooling age. In few cases, the Lu Hf system has also been disturbed in response to recrystallization, however, such disturbance is readily detected with trace element data. Hence, this study demonstrates the potential of laser ablation apatite Lu Hf dating to obtain primary crystallization ages for otherwise difficult to date mafic rocks. • First study on Lu-Hf systematics for apatite from mafic rocks • U U-Pb system in apatite readily resets by thermal and metasomatic events • Lu Lu-Hf system is robust to volume diffusion < ∼660–730 °C, retaining primary crystallization ages. • Deformation leading to recrystallization 'resets' both U U-Pb and Lu Lu-Hf systems in apatite. • Apatite trace element data to differentiate isotopic disturbances related to recrystallisation versus volume diffusion [ABSTRACT FROM AUTHOR]

• Archean and Paleoproterozoic rocks emerge within the Neoproterozoic Araguaia Belt-AB. • Northern AB exhibits Mesoarchean (2.93–2.87 Ga) and 1.86 Ga granitic gneisses. • Southern AB shows Rhyacian orthogneisses (2.06 Ga) and 1.87 Ga deformed granite. • Northern and southern basement already formed a single crustal segment by the Orosirian. • This Archean/Paleoproterozoic basement integrated the Amazonian Craton. Archean and Paleoproterozoic basement rocks are exposed in the Araguaia Belt, a Neoproterozoic orogen bordering the eastern portion of the Amazonian Craton. Zircon LA-MC-ICPMS U-Pb and Lu-Hf isotopic systematics allowed a more accurate dating of the basement rocks and investigating the evolution of this large Archean/Paleoproterozoic crustal segment and discuss the relationship with the southeastern Amazonian Craton. Archean TTG orthogneisses (2.93 to 2.87 Ga) prevail in the northern belt while distinct magmatic events generated their protoliths in approximately 60 Ma. Zircon Hf model ages (~3.0 to 3.4 Ga) and Ɛ Hf(2.87-2.93) from −4.3 to +5.3 suggest crustal reworking of Mesoarchean juvenile sources, with the subordinated contribution of older crust. A Mesoarchean source is also indicated by the Hf model ages (2.93–3.25 Ga) and Ɛ Hf(−1.86 Ga) from −4.8 to −1.6 of a 1.86 Ga granitic gneiss intrusive in the Archean TTG. An orthogneiss and an intrusive granitoid from southern segment of the belt were dated 2.06 Ga and 1.87 Ga, respectively. The Hf model ages (2.65–2.86 Ga) determined for these rocks, the Ɛ Hf(-2.06 Ga) (−4.8 to −1.6) for the orthogneiss and the Ɛ Hf(1.87 Ga) (−15.8 to −9.7) found for the granitoid reveal a dominant crustal source for the southern basement rocks. The Archean and Paleoproterozoic basement constituted a single crustal segment by the Orosirian, since both segments present intrusive granites of this geological period. The Archean orthogneisses of the Araguaia Belt and the granitoids of the Carajás Province Mesoarchean domains in southeastern Amazonian Craton share some similarities, such as the TTG affinity magmatism formed in a relatively similar time interval, the Orosirian intrusive granites, and the Mesoarchean juvenile source. Therefore, the basement rocks cropping out in the northern segment of the Araguaia Belt may represent portions of the adjacent Amazonian Craton. [ABSTRACT FROM AUTHOR]