Gravity tectonic removal of cover of Blue Ridge anticlinorium to form Valley and Ridge province

摘要

Chiefly on the basis of comparative amounts of foreshortening of the Valley and Ridge and Blue Ridge provinces, it is proposed that the eastern Valley and Ridge strata are the remnants of the former cover of the Blue Ridge anticlinorium. This cover slumped to the northwest (by gravity tectonic denudation) as the western Piedmont-eastern Blue Ridge was tilted gently to the northwest during the Alleghany orogeny, probably during the Permian Period. In a later phase of the Alleghany deformation, the Blue Ridge anticlinorium formed, and throughout much of its length it was thrust over the Valley and Ridge province as a result of continued pressure from the southeast. Arguments are presented that the anticlinorium configuration of the Blue Ridge area did not develop until after deposition of the Paleozoic strata in the Appalachian basin.