sedimentary
Conglomerate
Conglomerate
Composed of rounded clasts (pebbles, cobbles) cemented together by a finer-grained matrix (sand, silt, clay) or chemical cement (silica, calcite, iron oxide). Hardness varies depending on clast and matrix composition.
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Physical properties
Composed of rounded clasts (pebbles, cobbles) cemented together by a finer-grained matrix (sand, silt, clay) or chemical cement (silica, calcite, iron oxide). Hardness varies depending on clast and matrix composition.
Formation & geological history
Forms in environments where water transport is strong enough to move large, rounded clasts, such as riverbeds, alluvial fans, or beach environments. Over time, these sediments are buried and lithified.
Uses & applications
Used historically as a building material or aggregate if durable enough. Often collected by rockhounds for its textural variety and sometimes studied by geologists to understand ancient depositional environments.
Geological facts
The rounded nature of the clasts in a conglomerate distinguishes it from breccia, which contains angular clasts. The degree of rounding indicates the amount of transport the clasts underwent before deposition.
Field identification & locations
Identified by its distinctive appearance of rounded rocks embedded in a finer matrix. Clast composition can provide clues about the source area.
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