Stratabound

Stratabound is a geological term used to describe ore deposits whose mineralization is confined to a single stratigraphic unit within a sedimentary sequence. In such deposits, the ore body is bounded vertically by the top and bottom boundaries of the host bed or beds and typically trends parallel to bedding. Because the mineralization is tied to the stratigraphy, the deposit commonly follows the bedding and can extend laterally for long distances along strike while its vertical extent is limited by the thickness of the host stratigraphic unit.

Formation and controls: Mineralizing fluids migrate through a sedimentary sequence and precipitate metals where chemical conditions favor deposition within the preferred bed. Lithology plays a key role, with permeability, porosity, and redox conditions influencing ore precipitation. Diagenetic or hydrothermal processes may be involved, but the defining feature is confinement to a specific stratigraphic horizon rather than lateral spreading beyond that horizon.

Morphology and minerals: Stratabound ore bodies are typically tabular or bedded, with sharp vertical terminations at stratigraphic boundaries. The mineral assemblage can vary with environment and host rock, ranging from sulfide minerals such as sphalerite and galena in Zn-Pb deposits to oxides or carbonates in other settings.

Exploration and significance: The stratabound character guides exploration by focusing on mapping and sampling of the target stratigraphic unit, assessing lateral continuity along bedding, and drilling along strike. Economic potential depends on ore grade, the thickness of the host bed, and the extent of favorable facies within the stratigraphic interval.

Relation to other terms: The term is often discussed in relation to stratiform deposits; while stratiform emphasizes shape, stratabound emphasizes confinement to a stratigraphic unit. Some deposits may be described by both concepts.