Formation and stratigraphic facies distribution of Early Jurassic iron oolite deposits from west central Nevada, USA

Sedimentary analysis of the Ferguson Hill Member in the Sinemurian-aged Sunrise Formation was conducted in the Gabbs Valley Range of Nevada, U.S.A. Iron ooids were examined by transmitted light microscopy and electron scanning microscopy and found to consist of chamosite/berthierine and amorphous silica in cortical layers. The iron ooids were found in a transgressive phase across several facies, indicating their formation is likely controlled more by the geochemical rather than the physical environment. This data set includes thin section images of iron ooids from the strata investigated that were used to do point counts and make ooid measurements, the raw counts and measurements summarized in a spreadsheet, and additional SEM photos and EDXA analysis.

本次研究针对美国内华达州加布斯谷山脉地区早侏罗世西涅穆尔阶（Sinemurian）日出组（Sunrise Formation）的弗格森山段（Ferguson Hill Member）开展了沉积学分析。通过透射光显微镜（transmitted light microscopy）与扫描电子显微镜（electron scanning microscopy，SEM）对铁质鲕粒（iron ooids）进行观测后发现，其皮层由鲕绿泥石（chamosite）/贝得石（berthierine）与无定形二氧化硅（amorphous silica）构成。铁质鲕粒赋存于多沉积相的海侵阶段（transgressive phase）中，表明其形成过程更易受地球化学环境而非物理环境调控。本数据集包含研究层位中铁质鲕粒的薄片图像（thin section images，用于开展点计数法（point counts）与鲕粒测量（ooid measurements））、汇总于电子表格（spreadsheet）中的原始计数与测量数据，以及额外的扫描电子显微镜照片与能量色散X射线能谱分析（EDXA，Energy Dispersive X-ray Analysis）结果。