boulder clay
Học thuậtThân thiện
Definition
Noun 1. Unstratified glacial deposit: A type of soil or sediment directly deposited by a glacier, characterized by its lack of distinct layers (unstratified). It is a heterogeneous mixture of particles of vastly different sizes, including clay, sand, gravel, and boulders.
Usage
This is a technical geological term. It is used to describe a specific type of glacial deposit found in landscapes shaped by past ice sheets. * The landscape was formed from boulder clay left behind after the last ice age. * Excavations for the new road revealed a thick layer of boulder clay. * The poor drainage in this area is due to the impermeable boulder clay beneath the soil.
Advanced Usage
- Synonym: The term till is a more common and precise synonym in geology. "Boulder clay" is often considered a layperson's or older term for glacial till.
- The geologist identified the material as till, also known as boulder clay.
Variants and Related Words
- Till (n.): The standard geological term for unsorted, unstratified glacial sediment.
- Glacial drift (n.): A broader term for all material (stratified and unstratified) transported and deposited by glaciers.
- Moraine (n.): A distinct landform (a ridge or mound) composed of glacial till.
Synonyms
- Till
- Glacial till
Notes
- "Boulder clay" is a compound noun. The definition provided explains this specific geological term. It is not defining the separate words "boulder" or "clay" in isolation.
- The key characteristics are its unsorted nature (all particle sizes mixed together) and its unstratified nature (no visible layers), which distinguish it from sediments deposited by water.
Noun
- unstratified soil deposited by a glacier; consists of sand and clay and gravel and boulders mixed together