Description
Lithology describes the geochemical, mineralogical, and physical properties of rocks. It plays a key role in many processes at the Earth surface, especially the fluxes of matter to soils, ecosystems, rivers, and oceans. TheLithological map of the World is based on the Global Lithological Map database v1.1 (GLiM, Hartmann and Moosdorf, 2012). Scale: 1:35 000 000
Main map in Eckert IV projection
GLiM represents the rock types of the emerged surface of the Earth using 1,235,400 polygons assembled from 92 regional geological maps, translated into lithological units using additional literature. According to the GLiM, the total surface of continents and islands is covered by 64 % sediments (a third of which is carbonates), 13% metamorphics, 7% plutonics, and 6% volcanics, and 10% are covered by water or ice. The high resolution of theGLiM allows observation of regional lithological distributions which often vary from the global average. The GLiMenables regional analysis of Earth surface processes at global scales. A coarse gridded version of the GLiM is available at the PANGEA Database, the original GIS data are downloadable.
This map was assembled from geological maps with a resolution of 1:1 000 000 or finer, with a national extent or larger. However, if no suitable national geological map of the required quality was available, either coarser maps were used (e.g. in Africa), or finer maps assembled (e.g. the combined state geological maps of the preliminary geological map database of the conterminous U.S.A.). This leads to that the map does not represent one consistent scale (Inlet-map: Scales of regional data). Its ‘average’ scale is 1:3,750,000. The combination of maps results in artificial geological boundaries at administrative borders. Although these are not esthetically satisfactory and certainly not scientifically meaningful in most cases, they were not smoothed for feasibility reasons and because the authors of the map do not want to change the criteria used by the local expert geologists. An additional limitation of the map compilation is the representation of the Quaternary cover. Similarly to the map scale, also the representative depth of the map is heterogeneous. The Quaternary is addressed differently in a geological map, some maps omitting it entirely, some only to a certain thickness (e.g. 2 meters) and others including it entirely.
The digital resolution of the data of most regions represented in the Lithological Map of the World is higher than the graphic representation of the printed map at the scale of 1: 35 000 000. Thus, the online version of the map allows zooming into more details than observable here, as in the case of Hawaii. The improved representation of tropical islands compared to previous global lithological maps (Bluth and Kump, 1991; Amiotte-Suchet et al., 2003; Dürr et al., 2005) is a major asset of this map. Those islands are often underrepresented al scale, because of their small individual size.
