Item talk:Q41261

Definitions

One of the things we are attempting to do in the GeoKB is harmonize between multiple different knowledge organization systems. The Wikibase framework we are using is not a strict semantic knowledge organization platform, giving us some flexibility in both incorporating content from such systems but also connecting dots with other frameworks. In the case of rock types or lithology, we are attempting to blend the best usable information from several sources while building a working platform for our use in USGS in all of the areas where we need to reference and link to rock type concepts.

This item represents the top of the hierarchy for "rock types" in the GeoKB. It is classified in a couple of different ways derived from the sources we are incorporating, starting with the Geoscience Ontology. The upper-level classification starting with "entity > endurant" that we have used is one approach to blending formal common core ontology concepts into the Wikibase model. There may be more appropriate ways to handle this that we will explore over time, particularly as we start bringing in entities that may expose flaws in our organizatiobnal logic.

As with other cases, we leverage the flexible documentation capacity in the underlying Wikimedia system to help support freeform documentation such as the following definitions to help better understand this particular item and what we mean by it.  

from Geoscience Ontology

An amount of rock material: consisting of an aggregation of grains composed of mineral, glass, or other rock material. General concept for any rock, sediment, or other solid constituent of the Earth. This is the 'top' of the lithology hierarchy comprised of standard rock names, and should be used to indicate 'any rock or unconsolidated lithic material'.

from IUGS Simple Lithology

Consolidated aggregate of one or more Earth Materials, or a body of undifferentiated mineral matter, or of solid organic material. Includes mineral aggregates such as granite, shale, marble; glassy matter such as obsidian; and organic material such a coal. Excludes unconsolidated materials.

from Mindat

A rock is a naturally-occurring solid aggregate of one or more minerals, mineraloids or, in some cases, organic material. Sediments are the unconsolidated equivalent of these. Other related materials, including some man-made materials, are included within this categorization, along with the major classifications for meteorites.

Strictly, any naturally formed aggregate or mass of mineral matter, whether or not coherent, constituting an essential and appreciable part of the Earth's crust. Ordinarily, a consolidated or coherent and relatively hard, naturally formed mass of mineral matter; stone. In instances, a single mineral forms a rock, such as calcite, serpentine, kaolin, and a few others, but the vast majority of rocks consist of several minerals. It can include glasses and mineraloids eg. obsidian, or solid organic material, e.g., coal.

Reference: American Geosciences Institute