Macrostrat
Macrostrat aggregates and distributes data about rock “units,” where a unit represents a body of rock or sediment that is distinct from adjacent units (genetically, lithologically, chronologically). Unit attributes include lithologies, environments of formation, minerals, measurements, chronostratigraphic time intervals, and lithostratigraphic names and hierarchies. Unit data originates from literature (e.g. An important resource for information about North American rock units. Not digitally accessible without an institutional login.) and government databases (e.g. The U.S. Geologic Names Lexicon is a compilation of names and descriptions of geologic units maintained by the National Geologic Map Database. Geographic scope is the United States.). Macrostrat also maintains a compiled global geologic map, using regional geologic maps as source data. Units intersect with geologic map data at a geographic location as a “column.” These columns are an interpretation layer generated by Macrostrat and used to facilitate research.
Macrostrat is developed by a small team based at the University of Wisconsin Madison in the Department of Geoscience. It is primarily a data aggregator rather than an authoritative source.
TIP Macrostrat is a useful tool to discover more information about rock units, particularly those in the United States. It can be very helpful for understanding historic and synonymized unit names, and for finding references to the literature and other primary sources that originally described a given unit. Macrostrat presents information in a visually rich interface.
Coverage and gaps
For lithostratigraphy, Macrostrat’s geologic map coverage is global at the smallest map scale. In total, Macrostrat hosts 2.3 million geologic map polygons from more than 200 primary sources, all integrated into one global map. Lithostratigraphic names and hierarchies have the best coverage in North America, New Zealand, the Caribbean, the Deep Sea, and parts of South America. In total, Macrostrat has 36,000 lithostratigraphic names stored, most of which are derived from modified versions of the USGS National Geologic Map Database, Australian Lexicon, Canadian Weblex, and British Geological Survey Lexicon stratigraphic lexicons. Macrostrat columns cover approximately 15% of the global continental crust, most of which is in North America. Macrostrat’s geologic map has significant geographic gaps for larger map scales in eastern Asia (Japan, Laos, Cambodia, Malaysia, Philippines, Indonesia, Papua New Guinea, southern India, eastern China, eastern Mongolia, etc.) as well as southern South America (anything south of Santiago in Chile and Argentina).
For chronostratigraphy, Macrostrat maintains digitizations of 36 timescales, both global and regional.
Data reuse
Macrostrat provides data under a Creative Commons Attribution 4.0 International license (CC-BY-4.0), and suggests additionally acknowledging the original references for data presented by Macrostrat.
Paper describing Macrostrat and recommended as a mechanism to cite Macrostrat as resource.