The Aptian Crato Member of the Araripe Basin is a 50-m-thick succession of laminated limestones alternated with siliciclastic rocks. This unit has been receiving attention worldwide mainly because it is one of the most famous fossil Konservat-Lagerstätten, where were identified well-preserved paleofauna and paleoflora. Clay mineralogy and lithogeochemical data have been widely used in paleoenvironmental, paleoclimatic and provenance reconstructions. However, these techniques were not systematically used to study the Crato Member rocks. This study reports the mineralogical and lithogeochemical characterization of the Crato Member lutites looking for paleoenvironmental, paleoclimatic, and provenance reconstructions. Facies analysis, X-ray diffractometry, lithogeochemical, and scanning electron microscopy studies were carried out on thirteen Crato Member lutite samples in the Três Irmãos quarry, near Nova Olinda County. Regional arid paleoclimate conditions were identified using clay mineral assemblages and two paleoenvironmental models with subtle paleoprecipitation and provenance differences were interpreted. In the lower Três Irmãos quarry, a tidal-dominated delta mouth bar facies succession coincident with a clay mineral association with lesser kaolinite contents was identified, which indicates drier conditions. Lithogeochemical data suggests provenance from Archean felsic rocks. In the upper Três Irmãos quarry, a marginal paleolagoon facies succession coincident with a clay mineral association with higher kaolinite contents was recognized, which indicates wetter conditions. Lithogeochemical data indicate provenance from mixed Post-Archean to Archean felsic-mafic rocks. The paleolagoon water was interpreted as brackish and sudden paleosalinity increases indicated seawater inputs, which were also responsible for raising the paleolagoon water table in the marginal paleolagoon facies succession, which presented paleoenvironmental proxies suggesting a more expressive marine character.

Araripe盆地的Aptian Crato成员是一系列厚度为50 m的层状石灰岩，与硅质碎屑岩交替。这个单位已收到世界各地的关注，主要是因为它是最著名的化石之一Konservat - Lagerstätten，其中发现保存完好的古珊瑚和古植物。粘土矿物学和岩石地球化学数据已广泛用于古环境，古气候和物源重建中。但是，这些技术并未系统地用于研究Crato成员岩石。这项研究报告了Crato成员黄铁矿的矿物学和岩性化学特征，它们正在寻找古环境，古气候和物源重建。在新奥林达县附近的TrêsIrmãos采石场的13个Crato成员褐铁矿样品上进行了相分析，X射线衍射，岩化化学和扫描电子显微镜研究。利用粘土矿物组合确定了区域干旱和古气候条件，并解释了两种具有微细的古沉淀作用的古环境模型，并解释了物源差异。在特雷斯伊马索斯（TrêsIrmãos）较低的采石场中，发现了一个以潮汐为主的三角洲口相岩相演替，同时伴有粘土矿物缔合体和高岭石含量较低，这表明该地区较干燥。岩石地球化学数据表明来自太古宙长英质岩石的物源。在特雷斯伊尔马奥斯（TrêsIrmãos）采石场的上部，发现了边缘的古礁岩相演替，其粘土矿物协会的高岭石含量较高，这表明条件较湿。岩石地球化学数据表明，从混合后的Archean到Archean的长英质-镁铁质岩的物源。