Unprecedented U–Pb-Th SHRIMP and Lu–Hf isotopic data in zircon from Tandilia basement rocks, Argentina: new insights into Palaeoproterozoic and Neoproterozoic crustal reworking of the Río de la Plata craton

IF 2.7 2区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Precambrian Research Pub Date : 2025-11-01 Epub Date: 2025-10-13 DOI:10.1016/j.precamres.2025.107941

Melisa Angeletti , Martim Chichorro , Antonio Castro , María Cristina Frisicale , Rita Solá , Luis Vicente Dimieri , Juan Cruz Martínez

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Abstract

We present new geochronological zircon data from the Siempre Amigos Hill (SAH), a small but representative portion of Tandilia Terrane within the Río de la Plata Craton (RPC). U-Pb-Th SHRIMP data indicate a heterogeneous Palaeoproterozoic (Rhyacian) crust. A garnet-bearing granite (2165 ± 16 Ma) hosts felsic (2108 ± 13.6 Ma) to intermediate gneiss protolith (2104 ± 8 Ma), andesite with a sanukitoid signature (2094 ± 47 Ma) and granulites or charnockites. Additionally, calc-alkaline granitoids (2092 ± 13 Ma) intruded, as a result of differentiation from an igneous mafic sanukitoid source. Localised low-temperature shear zones affected the sequence. Lu-Hf isotopic data for the post-orogenic stage (< 2.1 Ga) complement previous results, showing progressive negative _ƐHf_(t) values. These isotopes suggest post-orogenic transtension. New Neoproterozoic ages (652 ±37 Ma, 618.4 ±11.2 Ma and 686 ±60 Ma) from granites, with low-to-very low zircon Th/U ratios, are presented as evidence of U-Th-Pb systems overprinting by Neoproterozoic (Cryogenian) thermal-hydrothermal events. Those Neoproterozoic ages are, within analytical uncertainty, equivalent to the 656 ± 19 Ma metamorphic age obtained for the Palaeoproterozoic granulite. These new Neoproterozoic ages, suggests a thermal perturbation linked either to the collision of the Nico Pérez Terrane against the passive margin of RPC, or the Neoproterozoic evolution of the Ventania System basement during the Brasiliano/ Pan-African orogeny.

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阿根廷Tandilia基底锆石中前所未有的U-Pb-Th SHRIMP和Lu-Hf同位素数据：Río de la Plata克拉通古元古代和新元古代地壳改造的新见解

本文介绍了在Río de la Plata克拉通（RPC）内的坦迪利亚地体（Tandilia Terrane）的一个小而有代表性的部分——Siempre Amigos Hill （SAH）的锆石年代学数据。U-Pb-Th SHRIMP数据显示古元古代（流纹）地壳非均质。含石榴石花岗岩（2165±16 Ma）含有长英质（2108±13.6 Ma）至中间片麻岩原岩（2104±8 Ma）、麻质特征的安山岩（2094±47 Ma）和麻粒岩或绿粒岩。此外，钙碱性花岗岩类（2092±13 Ma）侵入，这是火成岩基性砂质类源分化的结果。局部低温剪切带影响了序列。造山后阶段（< 2.1 Ga）的Lu-Hf同位素数据与之前的结果相补充，显示出负的ƐHf(t)值。这些同位素提示造山后伸展作用。新元古代花岗岩年龄（652±37 Ma, 618.4±11.2 Ma和686±60 Ma），锆石Th/U比值低至极低，是新元古代（低温）热液事件对U-Th- pb体系叠加的证据。在分析不确定度范围内，这些新元古代的年龄与古元古代麻粒岩的656±19 Ma变质年龄相当。这些新的新元古代年龄表明，热扰动可能与Nico psamurez地块与RPC被动边缘的碰撞有关，也可能与巴西利亚诺/泛非造山运动期间文塔尼亚系统基底的新元古代演化有关。

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来源期刊

Precambrian Research 地学-地球科学综合

CiteScore

7.20

自引率

28.90%

发文量

325

审稿时长

12 months

期刊介绍： Precambrian Research publishes studies on all aspects of the early stages of the composition, structure and evolution of the Earth and its planetary neighbours. With a focus on process-oriented and comparative studies, it covers, but is not restricted to, subjects such as: (1) Chemical, biological, biochemical and cosmochemical evolution; the origin of life; the evolution of the oceans and atmosphere; the early fossil record; palaeobiology; (2) Geochronology and isotope and elemental geochemistry; (3) Precambrian mineral deposits; (4) Geophysical aspects of the early Earth and Precambrian terrains; (5) Nature, formation and evolution of the Precambrian lithosphere and mantle including magmatic, depositional, metamorphic and tectonic processes. In addition, the editors particularly welcome integrated process-oriented studies that involve a combination of the above fields and comparative studies that demonstrate the effect of Precambrian evolution on Phanerozoic earth system processes. Regional and localised studies of Precambrian phenomena are considered appropriate only when the detail and quality allow illustration of a wider process, or when significant gaps in basic knowledge of a particular area can be filled.