Definition

Noun: - A type of shale, a fine-grained sedimentary rock, that is characterized by a high content of humic acids. These are organic acids derived from the decomposition of plant or animal matter.

Usage

• Geology/Soil Science: The term is used specifically to classify a sedimentary rock layer based on its chemical composition, indicating it formed in an environment with abundant organic material.
  • The geologists identified a layer of humic shale in the cliff face, suggesting an ancient swampy environment.
  • Humic shale is often studied for its potential to yield hydrocarbons or for understanding past ecosystems.

Advanced Usage

• "humic shale formation": Refers to the geological process or the specific stratum where this rock is found.
  • The humic shale formation in this basin is a key source rock for natural gas.

Variants and Related Words

• Shale (n): A general term for a fine-grained sedimentary rock that splits into thin layers.
• Humic Acid (n): The dark organic acids that are a major component of humic substances in soil, peat, and sedimentary rocks.
• Bituminous Shale (n): A related type of shale rich in bitumen, another organic component.

Synonyms

• Organic-rich shale: A more general descriptive term.
• Carbonaceous shale: A closely related type, often rich in carbon, though not exclusively humic acids.

Related Phrases/Compounds

• Humic substances: The broader category of organic compounds to which humic acids belong.
• Black shale: A shale dark in color, often due to high organic content, which may include humic shale.

Noun

1. shale that is rich in humic acids