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Till identification and geology

Unsorted, unstratified sediment deposited directly by glacial ice without reworking by meltwater. Till consists of a heterogeneous mixture of grain sizes from clay to boulders, with angular to subangular clasts in a fine-grained matrix. It is the primary deposit of continental glaciation and forms moraines, drumlins, and ground moraine sheets. Till composition reflects the lithology of the rocks over which the glacier traveled. Field: glacial geology. Example: The thick deposits of Laurentide till blanketing southern Ontario and the northern United States contain a mix of limestone, granite, and gneiss clasts reflecting the diverse bedrock traversed by the ice sheet as it advanced from the Canadian Shield.. Related terms: Moraine, Glacial, Drumlin, Outwash.

Sources, scope & corrections

These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.

Editorial owner
GeoMiner
Last updated
2026-03-30T15:19:42.096023+00:00
Review status
Published; not independently peer-reviewed
  • USGS Thesaurus — U.S. Geological Survey. Controlled earth-science terminology used to describe USGS information resources.
  • Glossary of Geologic Terms — U.S. National Park Service. Geologic definitions prepared by the NPS Geologic Resources Inventory.

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Common questions

What does Till mean in geology?
Unsorted, unstratified sediment deposited directly by glacial ice without reworking by meltwater. Till consists of a heterogeneous mixture of grain sizes from clay to boulders, with angular to subangular clasts in a fine-grained matrix. It is the primary deposit of continental glaciation and forms moraines, drumlins, and ground moraine sheets. Till composition reflects the lithology of the rocks over which the glacier traveled.
What is an example of Till?
The thick deposits of Laurentide till blanketing southern Ontario and the northern United States contain a mix of limestone, granite, and gneiss clasts reflecting the diverse bedrock traversed by the ice sheet as it advanced from the Canadian Shield.
Which earth-science field uses the term Till?
Till is used in glacial geology.
Which terms are related to Till?
Related terms in this reference are Moraine, Glacial, Drumlin, Outwash.

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