Formation

{
  "id": "MLC-T-ENV-011580",
  "term": "Formation",
  "field": "Environment",
  "definition": "1. A group of similar consolidation (that is, relatively solid) rocks of unconsolidated (that is, relatively loose) minerals.\n\n2. A layer of rock that is made up of a certain type of rock or a combination of types.\n\n3. A geological formation is a body of earth material with distinctive and characteristic properties and a degree of homogeneity in its physical properties. A formation may be a made of rock or of unconsolidated material such as sand, gravel and clay and can be mapped on the earth's surface or traced in the subsurface.\n\n4. Used in well-logging literature in a general sense to refer to all material penetrated by a drill hole without regard to its lithology or structure; used in a stratigraphic sense, formation refers to a named body of rock strata with unifying lithologic features.\n\n5. A geological formation is a body of earth material with distinctive and characteristic properties and a degree of homogeneity in its physical properties.\n\n6. A body of rock of considerable extent with distinctive characteristics that allow geologists to map, describe, and name it.\n\n7. The fundamental unit in the local classification of rocks into geologic units based on similar characteristics in lithology, which is the description of rocks on the basis of such characteristics as color, mineralogic composition, and grain size. Formations may represent rocks deposited during short or long time intervals, may be composed of materials from several sources, and may include breaks in deposition. Formations typically are named after geographic localities where they were first studied or described.\n\n8. Body of rock characterized by a degree of lithologic homogeneity which is prevailingly, but not necessarily, tabular and is mappable on the earth’s surface or traceable in the subsurface.\n\n9. Body of consolidated or unconsolidated rock characterized by a degree of lithologic homogeneity which is prevailingly, but not necessarily, tabular and is mappable on the earth’s surface or traceable in the subsurface.",
  "subject": "Water",
  "references": [
    "Drinking Water Technical & Legal Terms",
    "Underground Injection Control Glossary",
    "Underground Injection Control Terms",
    "Environmental Geophysics Glossary",
    "Glossary: Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources; EPA Draft Plan to Study the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources Glossary at www.yosemite.gov/sab",
    "USGS Geology in the Parks",
    "USGS Definition of Terms at pubs.usgs.gov/ha/ha747/.../definition.pdf",
    "40 CFR 146.3 (CFR 2018)",
    "40 CFR 144.3 (CFR 2018)"
  ],
  "url": "https://mlchart.com/terminology/environment/formation/"
}