minibasins

Minibasins are small-scale sedimentary basins bounded by faults within a larger tectonically active basin. They form as localized subsidence occurs, driven by extensional tectonics, fault growth, and, in salt-rich regions, halokinetic movement of the underlying salt. In salt tectonics, differential loading and gravity sliding create a mosaic of minibasins separated by reverse or listric faults, allowing isolated accommodation space for sediment.

They commonly occur in rifted margins, foreland basins, and especially inside large evaporite provinces where moving salt creates numerous minibasins, with growth faults generating rollover structures and dip closure. Minibasins are typically filled with stacked sedimentary sequences, progradational or retrogradational deposits, and may record multiple flooding events and unconformities.

The geometry is bounded by faults and unconformities; internal architecture includes growth strata and sometimes rollover anticlines at the fault tips. Their size varies from tens of meters to several kilometers in length.

In petroleum geology, minibasins can host reservoirs and hydrocarbon traps, with seals provided by shale or salt. They are often identified in seismic data by distinctive fault-block geometry, stratigraphic truncations, and rollovers. Understanding minibasin evolution helps reconstruct regional subsidence history and sediment transport, as well as guides exploration strategies in salt-affected basins.

Terminology varies in the literature; some authors use minibasin to refer to the smallest elements within a rift or salt-influenced basin, while others use it for localized sub-basins within a larger basin.