Английская Википедия:Bear Valley Strip Mine

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Файл:Bear Valley Strip Mine 1.jpg

View of the Bear Valley Strip Mine from the north wall facing southeast, with the "Whaleback" in center

Шаблон:Commons category The Bear Valley Strip Mine is an abandoned coal strip mine located in Coal Township, Northumberland County, to the southwest of the town of Shamokin, Pennsylvania. It lies in the Western Middle Field of the Anthracite belt in the Ridge-and-Valley Appalachians, where the Pennsylvanian Llewellyn Formation is exposed. The property is owned by the Reading Anthracite Company.

Structural geology

The coal and other overlying rock has been removed by mining down to a resistant sandstone bed, revealing the three-dimensional structures of folding and faulting caused by the Alleghany Orogeny. Students of geology have visited the location for decades due to the quality of exposures.

The central anticline in the valley is often called the "Whaleback".

The sequence of structural deformation is outlined as follows:

Stage	Deformation event
I	Joint formation in coal
II	Joint formation with quartz fiber fillings in sandstone and ironstone
III	Pressure solution and primary crenulation cleavage
IV	Conjugate wrench and wedge faults form
V	Large-scale folding
VI	Extensional jointing and faulting

Gallery

• Concretions in the south wall

  Concretions in the south wall

• View of the east wall from the Whaleback

  View of the east wall from the Whaleback

• Slickensides on a fault plane, south wall. Lens cap 5.8 cm wide.

  Slickensides on a fault plane, south wall. Lens cap 5.8 cm wide.

• Upright Sigillaria in dipping sandstone and shale beds of the north wall. A so-called "Polystrate fossil".

  Upright Sigillaria in dipping sandstone and shale beds of the north wall. A so-called "Polystrate fossil".

• Another image of the south wall and Whaleback

  Another image of the south wall and Whaleback

• Stigmaria root fossils

  Stigmaria root fossils

References

Шаблон:Mine-stub Шаблон:NorthumberlandCountyPA-geo-stub