Alleghenian


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Related to Alleghenian: Appalachian Orogen

Alleghenian

[¦al·ə¦gān·ē·ən]
(geology)
Lower Middle Pennsylvanian geologic time.
References in periodicals archive ?
The progradation of gravelly braidplain deposits into northeastern Ohio (producing a coarsening-upward sequence) may suggest reduced tectonic subsidence for the Appalachian foreland basin at this time in this region, as supported by studies suggesting southward shifting of tectonic loads in the Alleghenian fold-and-thrust belt at this time (Robinson and Prave 1995).
Skehan and Rast (1990) suggested that the Bulgarmarsh terrane may have been thrust northwestward over the Pennsylvanian Narragansett Basin along the Beaverhead shear zone during the Alleghenian orogeny.
39]Ar ages from the Narragansett Basin and southern Rhode Island basement terrane: their bearing on the extent and timing of Alleghenian tectonothermal events in New England.
The contacts of the WRF with the Halifax Formation lie within broad Alleghenian shear zones.
Peak-metamorphic porphyroblasts pre-d ate a transposition fabric developed in bounding Alleghenian shear zones.
1992) show that the higher grade, western portio n of the belt was remetamorphosed in the Alleghenian, making the discrimination of overprinting fabrics difficult to interpret.