Global Unconsolidated Sediments Map Database v1.0 (shapefile and gridded to 0.5° spatial resolution)

Mapped unconsolidated sediments cover half of the global land surface. They are of considerable importance for many Earth surface processes like weathering, hydrological fluxes or biogeochemical cycles. Ignoring their characteristics or spatial extent may lead to misinterpretations in Earth System studies. Therefore, a new Global Unconsolidated Sediments Map database (GUM) was compiled, using regional maps specifically representing unconsolidated and quaternary sediments. The new GUM database provides insights into the regional distribution of unconsolidated sediments and their properties. The GUM comprises 911,551 polygons and describes not only sediment types and subtypes, but also parameters like grain size, mineralogy, age and thickness, where available. Previous global lithological maps or databases lacked detail for reported unconsolidated sediment areas or missed large areas, and reported a global coverage of 25 to 30%, considering the ice-free land area. Here, alluvial sediments cover about 23% of the mapped total ice-free area, followed by aeolian sediments (~21%), glacial sediments (~20%), and colluvial sediments (~16%). A specific focus during the creation of the database was on the distribution of loess deposits, since loess is highly reactive and relevant to understand geochemical cycles related to dust deposition and weathering processes. An additional layer compiling pyroclastic sediment is added, which merges consolidated and unconsolidated pyroclastic sediments. The compilation shows latitudinal abundances of sediment types related to climate of the past.

已测绘的松散沉积物覆盖全球陆地表面的一半，对风化、水文通量及生物地球化学循环等诸多地球表面过程至关重要。忽略其特征或空间分布范围，可能导致地球系统研究中的误读。为此，我们利用专门表征松散及第四纪沉积物的区域地图，编制了全新的全球松散沉积物地图数据库（Global Unconsolidated Sediments Map database，简称GUM）。该数据库可揭示松散沉积物的区域分布特征及其属性，包含911,551个多边形要素，不仅描述了沉积物的类型与亚类，还在数据可得时提供粒度、矿物组成、年代及厚度等参数信息。此前的全球岩性图或数据库要么对已报告的松散沉积物区域缺乏细节，要么遗漏大片区域，且在考虑无冰陆地面积时，其全球覆盖率仅为25%至30%。本研究中，冲积物约占已测绘无冰陆地总面积的23%，其次是风积物（约21%）、冰川沉积物（约20%）及崩积物（约16%）。数据库构建时特别关注黄土沉积分布——因其反应活性高，对理解粉尘沉积与风化过程相关的地球化学循环意义重大。此外，新增的火山碎屑沉积物图层整合了固结与松散的火山碎屑沉积物数据。本次编制成果揭示了不同沉积物类型的纬度丰度特征，且这些特征与过去的气候相关。

搜集汇总

背景与挑战

背景概述

该数据集是一个全球未固结沉积物地图数据库(GUM)，详细描述了沉积物类型、亚型及相关参数，特别关注黄土沉积物的分布，并包含火山碎屑沉积物层，为地球表面过程研究提供了重要数据支持。