Alaska Geochemical Database Version 2.0 (AGDB2) - Including "Best Value" Data Compilations for Geochemical Data for Rock, Sediment, Soil, Mineral, and Concentrate Sample Media

The Alaska Geochemical Database Version 2.0 (AGDB2) contains new geochemical data compilations in which each geologic material sample has one "best value" determination for each analyzed species, greatly improving speed and efficiency of use. Like the Alaska Geochemical Database (AGDB) before it, the AGDB2 was created and designed to compile and integrate geochemical data from Alaska in order to facilitate geologic mapping, petrologic studies, mineral resource assessments, definition of geochemical baseline values and statistics, environmental impact assessments, and studies in medical geology. This relational database, created from the Alaska Geochemical Database (AGDB) that was released in 2011, serves as a data archive in support of present and future Alaskan geologic and geochemical projects, and contains data tables in several different formats describing historical and new quantitative and qualitative geochemical analyses. The analytical results were determined by 85 laboratory and field analytical methods on 264,095 rock, sediment, soil, mineral and heavy-mineral concentrate samples. Most 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 1962 through 2009. In addition, mineralogical data from 18,138 nonmagnetic heavy mineral concentrate samples are included in this database. The AGDB2 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 National Geochemical Database (NGDB). Retrievals from the NGDB were used to generate most of the AGDB data set. These data were checked for accuracy regarding sample location, sample media type, and analytical methods used. This arduous process of reviewing, verifying and, where necessary, editing all USGS geochemical data resulted in a significantly improved Alaska geochemical dataset. USGS data that were not previously in the NGDB because the data predate the earliest USGS geochemical databases, or were once excluded for programmatic reasons, are included here in the AGDB2 and will be added to the NGDB. The AGDB2 data provided here are the most accurate and complete to date, and should be useful for a wide variety of geochemical studies. The AGDB2 data provided in the linked database may be updated or changed periodically.

阿拉斯加地球化学数据库2.0版（Alaska Geochemical Database Version 2.0，AGDB2）收录了全新的地球化学数据汇编，其中每份地质物质样本针对每种分析元素均配有唯一“最优值”测定结果，大幅提升了使用效率与便捷性。其研发初衷与前代阿拉斯加地球化学数据库（Alaska Geochemical Database，AGDB）一致，旨在汇编整合阿拉斯加地区的地球化学数据，以服务于地质填图、岩石学研究、矿产资源评价、地球化学基准值与统计特征界定、环境影响评价以及医学地质学研究。
该关系型数据库依托2011年发布的初代AGDB构建，作为数据存档库支撑当前及未来阿拉斯加地质与地球化学相关项目，包含多种格式的数据表，用于描述历史及最新的定量、定性地球化学分析结果。本次数据集涵盖264095份岩石、沉积物、土壤、矿物及重矿物精矿样本，其分析结果通过85种实验室与现场分析方法测定得到。多数样本由美国地质调查局（U.S. Geological Survey，USGS）人员采集，并于USGS实验室或通过合同委托商业分析实验室完成检测。这些数据对应1962年至2009年间，USGS各类项目与计划中采集的样本分析结果。
此外，本数据库还收录了18138份非磁性重矿物精矿样本的矿物学数据。AGDB2收录了原始存档于USGS岩石分析存储系统（Rock Analysis Storage System，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）的历史地球化学数据。目前所有此类数据均存储于国家地球化学数据库（National Geochemical Database，NGDB）中，多数初代AGDB数据集即通过从NGDB中调取数据构建而成。
研发团队针对样本位置、样本介质类型及所用分析方法对这些数据进行了准确性核验。这一针对USGS所有地球化学数据的审核、验证及必要修正的繁琐流程，最终产出了大幅优化后的阿拉斯加地球化学数据集。部分此前因早于USGS初代地球化学数据库的建立时间，或因项目规划原因未被纳入NGDB的USGS数据，本次均收录于AGDB2中，后续也将补充至NGDB。
本次发布的AGDB2数据集是截至目前最为准确与完整的版本，可广泛应用于各类地球化学研究。本关联数据库中提供的AGDB2数据集将定期进行更新与修订。