A clinoform is a two-dimensional surface with a sigmoidal (sloped) geometry that is characteristic of basin margin strata. They are timelines that represent a moment in geological time. clinoforms can be recognized in seismic, well log and outcrop data and are used to define basin margins, stacking patterns and shelf-edge trajectories. Paleo basin depths and relative sea level fluctuations are also inferred from the heights and geometries of clinoforms. For these reasons, clinoforms are crucial for sequence stratigraphy and basin analysis.

 Schematic diagram of a clinoform with some key parameters highlighted.
 
 Ancient basin margin clinoforms imaged on seismic data. Data from offshore New Zealand (Giant foresets formation). 

The term clinoform was first used by John Rich in 1951. According to his definition, the clinoform is the sloping surface extending from wave base down to the generally flat basin floor. His definition has since been expanded to describe the complete proximal to distal basin margin geometry. They are considered to exist on many different scales. In some cases, clinforms are fractally organized in spatial hierarchy.

clinothem stata are demarcated by clinoforms. Compaction, differential compaction and sediment loading of clinothem strata can affect clinoform geometries.

Patruno, S. and Helland-Hansen, W., 2018. clinoforms and clinoform systems: Review and dynamic classification scheme for shorelines, subaqueous deltas, shelf edges and continental margins. Earth-science reviews, 185, pp.202-233.

Rich, J.L., 1951. Three critical environments of deposition, and criteria for recognition of rocks deposited in each of them. Geological Society of America Bulletin, 62(1), pp.1-20.

Steel, R.J., Olsen, T., Armentrout, J.M. and Rosen, N.C., 2002, December. clinoforms, clinoform trajectories and deepwater sands. In sequence-stratigraphic models for exploration and production: Evolving methodology, emerging models and application histories: Gulf Coast Section SEPM 22nd Research Conference, Houston, Texas (pp. 367-381).