Fold trap regime

Exploring for Oil and Gas Traps
Series	Treatise in Petroleum Geology
Part	Traps, trap types, and the petroleum system
Chapter	Classification of exploration traps
Author	Richard R. Vincelette, Edward A. Beaumont, Norman H. Foster
Link	Web page
Store	AAPG Store

Classes and definitions

The proposed classes in the fold trap regime are monocline, local dome, regional dome, local nose, regional nose, local anticline, regional anticline, and syncline. The following outline shows the classes, some of the subclasses, style, and their definitions. The Subclasses listed are not inclusive but represent the more common types of fold traps and show how the proposed classification scheme can be developed and defined.

Regime	Class	Subclass	Styles
Fold; A fold trap is formed by syn- or postdepositional processes that deform geological surfaces into a curved or nonplanar arrangement.	Local anticline	Fault bounded or cross faulted	Relief, symmetry, internal faulting, internal geometry
		Simple
	Monocline; A fold that occurs where strata dip or flex from the horizontal in one direction only and are not a part of a anticline or syncline. A monocline can form only part of the trap closure and must combine with other elements for closure.
	Regional nose; A short plunging anticline without closure. A trap where a nose is a trapping element must combine with other elements to have closure.
	Local nose
	Regional dome; Circular or elliptical anticline many miles in diameter.
	Local dome; Circular or elliptical anticline
	Regional anticline; Elongate convex upward fold.
	Syncline; Elongate concave upward fold.

Families

Based on their genesis, folds can be divided into two superfamily categories: tectonic and nontectonic. The table below presents the superfamilies, families, and subfamilies and their definitions for anticlinal fold traps. As with fold classes, the fold families listed below are not inclusive but merely represent the more common fold families.

Regime	Class	Superfamily	Family	Subfamily	Variety
Fold	Local Anticline	Tectonic; Folds resulting from deformation by tectonic processes such as compression or extension.	Compressional fold; Formed by compressive tectonic deformation.	Cratonic-basin fold	Paleostructure
					Inverted
				Thrust-belt fold
				Foreland fold
			Transpressional fold	Single phase
				Paleostructure
				Inverted structure
			Structural drape fold; Form over a deeper structural feature such as a fault block.
			Extensional fold; Form by extensional tectonic deformation.	Rollover anticline; Form as a result of rollover into a listric normal fault.
			Basement uplift
		Nontectonic; Folds result from deformation by nontectonic processes such as uplift by intrusion or diapirism, differential compaction, salt withdrawal, salt solution, or meteoric impact.	Intrusive core; Dome or anticline form as a result of intrusion.	Salt dome or anticline; Form as a result of uplift by salt movement.
				Shale dome or anticline; Form as a result of a shale diapir.
				Igneous dome; Form as a result of igneous intrusion.
			Differential-compaction (drape) anticline; Form by the differential compaction of sediments over a buried structure such as a reef or horst.
			Salt-solution anticline; Form as a result of salt dissolution.
			Salt-withdrawal anticline; Form as a result of salt movement out of an area.
			Astrobleme; Form as result of the impact of a meteor.

See also

• Structural trap system
• Fault trap regime
• Fracture traps
• Fracture trap regime

External links

find literature about Fold trap regime

• Original content in Datapages
• Find the book in the AAPG Store