A preliminary Alleghanian tectonothermal sequence for the Appalachian fold and thrust belt
- Univ. of South Carolina, Columbia, SC (United States). Earth Sciences and Resources Inst.
- Westinghouse Savannah River Co., Aiken, SC (United States)
- Geological Survey, Reston, VA (United States). National Center
A preliminary Alleghanian tectonothermal sequence has been developed for the Appalachian fold and thrust belt along a transect where the sequence of macro-structural features (major thrusts and folds) is known from detailed mapping. Combining this sequence with detailed meso- and micro-structural, thermal, and geochronologic data suggests that all major thrusts/ thrust systems evolved as part of a sequence of events that propagates toward the foreland: (1) initiation of layer-parallel shortening; (2) initiation of fault-propagation folding during the thermal maximum; (3) breakthrough of the major thrust of a fault-propagation fold accompanied by thermal decline in the hanging-wall thrust sheet; (4) initiation of hanging-wall and footwall imbrication (may be either fault-bend or fault-propagation folding)--of particular importance is destruction or flattening of the footwall syncline of a fault-propagation fold during ramp smoothing so that the post-deformational footwall often resembles the rigid ramp observed in a fault-bend fold; (5) fault-propagation or fault-bend folding on structurally lower thrusts/thrust systems produces dome and basin structures on higher thrust sheets emplaced earlier in the sequence. Preliminary work along a transect across the Cordilleran fold and thrust belt suggests that connection of fault-propagation folding with a thermal peak and thrust breakthrough followed by destruction of the footwall-syncline are both important events in development of each major thrust/thrust system during the Late Cretaceous deformational sequence.
- OSTI ID:
- 5723646
- Report Number(s):
- CONF-921058-; CODEN: GAAPBC
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Vol. 24:7; Conference: 1992 annual meeting of the Geological Society of America (GSA), Cincinnati, OH (United States), 26-29 Oct 1992; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
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