Global Geochemical Database for Critical Metals in Black Shales

The Global Geochemical Database for Critical Metals in Black Shales (CMIBS) contains new geochemical data compilations for fine-grained sedimentary rocks in which each geologic material sample has one “best value” determination for each analyzed species, greatly improving speed and efficiency of use (Granitto and others, 2013). The CMIBS was created and designed to compile and integrate geochemical data from seven continents in order to facilitate petrologic studies, mineral resource assessments and mineral exploration, definition of geochemical baseline values and statistics, environmental impact assessments, paleobiological studies and paleoenvironmental trends through Earth history. and studies in human health and environmental geochemistry. The primary goal was to compile geochemical data for stratigraphic rock sequences containing dominantly fine-grained clastic rocks with appreciable organic carbon (>0.5 weight percent), collectively termed and referred to herein as “black shale facies samples” but comprised of all fine-grained clastic rocks such as argillite, mudstone, claystone, and their low-medium grade metamorphic equivalents. In some cases, minor other lithologies within the stratigraphic sequences such as limestone,coal,or tuff layers are also included. The particular focus of the database was on black shale facies samples in regions and stratigraphic sequences known to contain high concentrations of “critical metals” such as Ni, Mo, PGE, Se, U, and V. Therefore, this relational database serves as a data archive in support of present and future geologic and geochemical studies of critical metals in black shale facies samples, although a wide range of inorganic elements other than the above mentioned “critical metals” are included. The database contains data tables in two different formats describing historical and new quantitative and qualitative geochemical analyses. The analytical results were determined by more than 130 laboratory and field analytical methods on 89,877 samples, of which 89,443 are rock, 170 are geologic material, 121 are sediment, 92 are soil and 2 are organic samples. The non-rock samples were included in the database because they were usually related to the black shale facies samples below them stratigraphically (in drill core, for example). Many of the samples are organic rich to the point that they are actually coal samples. More than 75 percent of the samples were collected by U.S. Geological Survey (USGS) personnel and analyzed in USGS laboratories or, under contracts, in commercial analytical laboratories. These data represent analyses of samples collected as part of various USGS programs and projects from 1961 through 2014. The CMIBS includes historical geochemical data originally archived in the USGS Rock Analysis Storage System (RASS) database, used from the mid-1960s through the late 1980s and the USGS PLUTO database used from the mid-1970s through the mid-1990s. All of these data are currently maintained in the USGS National Geochemical Database (NGDB). Retrievals from the NGDB were used to generate more than 3/4 of the CMIBS data set. Also included in the CMIBS are data from 11,084 samples of the Canadian Mining Industry Research Organization (CAMIRO) Project 08E04: Geochemistry of Shales as Vectors to Ore Deposits. This global black shale facies dataset was shared with the USGS for inclusion in the CMIBS. Bibliographic research for geochemical data of black shale facies yielded data from 11,697 additional samples published in numerous professional journals, theses and databases. The data of the CMIBS were checked for accuracy regarding sample location, sample media type, and analytical methods used.黑色页岩关键金属全球地球化学数据库（Global Geochemical Database for Critical Metals in Black Shales，简称CMIBS）收录了细粒沉积岩的全新地球化学数据汇编，每份地质样品针对每一项分析组分均给出唯一的「最佳值」测定结果，大幅提升了数据库的使用效率与便捷性（格拉尼托等，2013）。CMIBS的构建目标是整合全球七大洲的地球化学数据，以支持岩石学研究、矿产资源评价与勘查、地球化学基准值与统计特征厘定、环境影响评价、古生物学研究以及地球历史中古环境演化趋势分析，同时服务于人类健康与环境地球化学相关研究。本数据库的核心目标是汇编以富有机质（有机碳含量≥0.5wt%）为主的细粒碎屑岩地层序列的地球化学数据，这类样品统一被称为「黑色页岩相样品」，涵盖所有细粒碎屑岩类，包括泥板岩、泥岩、黏土岩及其低-中级变质对应岩类。部分地层序列中伴生的次要岩性，如灰岩、煤层或凝灰岩夹层，也被纳入数据库。数据库的重点关注对象为已知赋存高浓度「关键金属」（如镍、钼、铂族元素、硒、铀及钒）的区域与地层序列中的黑色页岩相样品。因此，该关系型数据库可作为数据存档平台，支撑当前及未来针对黑色页岩相样品中关键金属的地质与地球化学研究，同时也收录了上述关键金属之外的多种无机元素数据。数据库包含两种格式的数据表，涵盖历史与最新的定量、定性地球化学分析结果。这些分析结果通过130余种实验室与现场分析方法，对89877份样品完成测定，其中岩石样品89443份、地质样品170份、沉积物样品121份、土壤样品92份、有机样品2份。非岩石类样品被纳入数据库的原因在于，它们通常在地层序列中与下伏的黑色页岩相样品密切相关（例如钻井岩心序列中的样品）。部分样品的有机碳含量极高，实际已属于煤样范畴。超过75%的样品由美国地质调查局（U.S. Geological Survey，简称USGS）人员采集，并在美国地质调查局实验室或委托商业分析实验室完成测试。这些数据源自1961年至2014年间，美国地质调查局各类计划与项目中采集的样品的分析结果。CMIBS还收录了原始存档于美国地质调查局岩石分析存储系统（Rock Analysis Storage System，简称RASS）数据库（1960年代中期至1980年代末使用）以及USGS PLUTO数据库（1970年代中期至1990年代中期使用）中的历史地球化学数据。目前所有此类数据均由美国地质调查局国家地球化学数据库（National Geochemical Database，简称NGDB）进行维护。CMIBS中超过四分之三的数据均源自从NGDB中调取的数据集。CMIBS同时收录了加拿大矿业工业研究组织（Canadian Mining Industry Research Organization，简称CAMIRO）08E04项目「作为矿床找矿矢量的页岩地球化学」中11084份样品的数据。该全球黑色页岩相数据集被共享至美国地质调查局，并入CMIBS数据库。通过对黑色页岩相地球化学数据的文献调研，还补充收录了11697份已发表于各类专业期刊、学位论文及数据库中的样品数据。CMIBS中的所有数据均经过核查，以确保样品位置、样品介质类型及所用分析方法的准确性。