Composition of crystals from Ponte Nova Mafic-Ultramafic Alkaline Massif (PNAM) SE, Brazil

We present major, trace and Sr isotopic data of feldspar crystals from various intrusions within the potassic Ponte Nova Mafic-Ultramafic Alkaline Massif (PNAM; 86.7 Ma), which exhibit varying degrees of contamination by the crustal country rock. Additionally, we provide compositional data of biotite, amphibole, ilmenite, and magnetite from the PNAM. We also include data of a few feldspars and biotite crystals of the country rock, which comprises a Precambrian calc-alkaline granite from the Serra da Água Limpa batholith. The crystals in 30- to 120-µm polished thin sections were analyzed using EMP, LA-ICP-MS, LA-MC-ICP-MS, and TIMS. Prior to analysis, chemical zonings, resorption features, and mineral inclusions were identified through optical and scanning electron microscope to ensure their avoidance during analysis.

本研究展示了来自不同侵入体中长石晶体的主量、微量元素和Sr同位素数据，这些侵入体位于钾质波登诺瓦中-超基性碱性岩体（PNAM；距今86.7百万年）内，并表现出不同程度的受地壳围岩污染。此外，我们还提供了PNAM中白云母、角闪石、钛铁矿和磁铁矿的成分数据。同时，我们还包含了来自围岩的少数长石和白云母晶体的数据，这些围岩由来自塞尔拉达亚瓜利马玄武岩体的前寒武纪钙碱性花岗岩组成。通过对30至120微米抛光薄片中的晶体进行电子探针显微分析（EMP）、激光剥蚀电感耦合等离子体质谱（LA-ICP-MS）、激光剥蚀多接收器电感耦合等离子体质谱（LA-MC-ICP-MS）和热电离质谱（TIMS）分析，确保了在分析过程中避免化学分带、溶蚀特征和矿物包体的干扰。在分析前，通过光学显微镜和扫描电子显微镜识别化学分带、溶蚀特征和矿物包体，以确保分析过程中避免其影响。