Quaternary Sediments 1:50,000 Ireland (ROI) ITM

In terms of time scale in geology, Quaternary is the present-day time and it began 2.6 million years ago. A lot of this time period relates to the Ice Age. Quaternary sediments are the soft material that has been deposited during this time. In Ireland much of this is related to the movement of glaciers and ice sheets. The main types of sediments shown on the map are tills (boulder clays), gravels, sands and peat. Over most parts of Ireland, these sediments cover the bedrock (solid rock at or below the land surface). Geologists map and record information from the shallow sediments which can be seen at or near the surface. This information along with boreholes (a deep narrow round hole drilled in the ground), geophysical data (information on the physical properties of the Earth's surface and subsurface e.g. magnetics, gravity and electromagnetics) and geochemical data (chemical properties) is used to create the map. Areas are drawn on a map to show where sediments are found. We collect new data to update our map and use data made available from other sources. This map is to the scale 1:50,000 (1cm on the map relates to a distance of 500m). It is a vector dataset. Vector data portray the world using points, lines, and polygons (areas). The sediments data is shown as polygons. Each polygon holds information on the sediment type, sediment code and its unique identifier.从地质时间尺度来看，第四纪（Quaternary）是现今地质时代，其始于260万年前，该时期的绝大多数时段与冰河时期重合。 第四纪沉积物（Quaternary sediments）是该时期沉积形成的松散物质。在爱尔兰境内，此类沉积物的形成多与冰川及冰盖的运动密切相关。本地图展示的主要沉积物类型包括冰碛物（tills，即漂砾黏土（boulder clays））、砾石、砂与泥炭。在爱尔兰绝大多数区域，此类沉积物覆盖于基岩（bedrock，即地表或地下的固态岩石）之上。 地质学家会对地表或近地表出露的浅部沉积物开展测绘并记录相关信息。此类测绘记录数据结合钻孔（boreholes，即地面钻探的深窄圆孔）数据、地球物理数据（geophysical data，指地球地表及地下的物理属性信息，例如磁法、重力与电磁法数据）与地球化学数据（geochemical data，指化学属性信息），共同用于本地图的编制。地图中将划定相应区域以标示沉积物的分布点位。 本团队会采集新数据以更新地图，并整合其他公开渠道获取的相关数据。 本地图的比例尺为1:50000（即地图上1厘米对应实地距离500米）。 本数据集为矢量数据集（vector dataset）。矢量数据通过点、线与多边形（面域）来表征地理空间。 沉积物数据以多边形图层形式呈现，每个多边形均包含沉积物类型、沉积物编码及唯一标识符等相关信息。