Fault-propagation folds: Geometry, kinematic evolution, and hydrocarbon traps

Journal Article · Fri Jun 01 04:00:00 EDT 1990 · AAPG Bulletin (American Association of Petroleum Geologists); (USA)

OSTI ID:6131149

Mitra, S ^[1]

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1. ARCO Oil and Gas Co., Plano, TX (USA)

Fault-propagation folding, a common folding mechanism in fold and thrust belts, occurs when a propagating thrust fault loses slip and terminates upsection by transferring its shortening to a fold developing at its tip. The propagation of thrusts is commonly characterized by the progressive tightening of the fold hinge and steepening of the front limb. Thickening of stratigraphically higher units in the early stages of folding is followed by localized thinning of the front limb in the late stages. The thrust fault may propagate through the undeformed units, along the synclinal axial plane, or through the forelimb of the anticline, depending on the tightness of the fold. Deeper thrusts commonly are abandoned upsection, and the slip transferred to steeper imbricates, resulting in the listric geometries of many thrust faults. The fold also can be transported over a ramp and onto an upper detachment, resulting in a transition to fault-bend folding. Fault-propagation folds with or without additional fold translation ran be distinguished from translated detachment folds by the detailed geometries of the hanging wall and footwall structures, and by the characteristic differences in their relations between fault slip and depth to detachment. Some important characteristics of fault-propagation folds are that they require no slip transfer in or out of the structure, involve a minimum amount of shortening, and have a relatively large depth to detachment, compared to other types of fault-related folds. Fault-propagation folds form important hydrocarbon traps in fold and thrust belts. Some common trap types include fold traps in the crestal area, and fault traps in the footwall and along imbricates on the forelimb and the backlimb of major basement-detached and basement-involved anticlines. Secondary traps also occur in intraplate and leading-edge structures within major thrust sheets. 22 figs., 1 tab.

• OSTI ID: 6131149
• Journal Information: AAPG Bulletin (American Association of Petroleum Geologists); (USA), Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (USA) Vol. 74:6; ISSN 0149-1423; ISSN AABUD
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
03 NATURAL GAS
030200 -- Natural Gas-- Reserves
Geology
& Exploration
ANTICLINES
GEOLOGIC DEPOSITS
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOLOGIC TRAPS
MINERAL RESOURCES
NATURAL GAS DEPOSITS
PETROLEUM DEPOSITS
RESOURCES