Early History and Settlement Room - Born from Stress and Strain

Born from Stress and Strain

Natural forces have shaped the Shenandoah Valley landscape creating a distinct mix of geological strata, soil types, drainage patterns, and terrain.

The Virginia landscape began forming roughly 600 million years ago when huge landmasses broke apart and an ancient ocean formed. A series of continental collisions followed, creating mountain ranges as tall as the Himalayas. Wind and rain eroded these ranges. Over time, the eroded sediments compressed the mud into shale, sand inot sandstone and calcium carbonate into limestone.

The dynamic forces that sculpted the Valley left behind a natural travel corridor, an abundance of limestone and flowing water. Over the millenia, people have exploited these resrouces to develop farms, road systems, towns and centers of commerce.

CONCORDANT AND DISCORDANT STRATA MODEL

The relationship between two series of strata in this model displays that, on the one hand, the bedding is concordant within each series (i.e. it is parallel in adjancent beds); whereas on the other hand, the upper series (A) lies discordantly (i.e. at an angle in relationship to the underlying beds). This sort of discordance (or angular unconformity) provides that an interval of time elapsed between the deposition of the two series of beds. During that time, the older (underlying) beds (B) were dislocated and partially eroded and developed an erosional surface where subsequent new sediments were deposited and lithified (A).