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Callan Bentley's Snapshots

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  1. Spheroidal weathering

    Snapshot Title: Spheroidal weathering
    Taken by: Callan Bentley

    Image: "Cub Sandstone" (Uppermost Martinsburg Formation), near Catherine Furnace, Virginia
    Image Owner: Callan Bentley



    Description:

    A nice example.



  2. 1 cm

    Snapshot Title: 1 cm
    Taken by: Callan Bentley

    Image: "Cub Sandstone" (Uppermost Martinsburg Formation), near Catherine Furnace, Virginia
    Image Owner: Callan Bentley



    Description:

    A second sense of scale.



  3. 1 cm
  4. Asterisk

    Snapshot Title: Asterisk
    Taken by: Callan Bentley

    Image: Pillow Basalts at Kirby Cove
    Image Owner: Robin Rohrback-Schiavone



    Description:

    between 5 pillows



  5. Edge of a pillow

    Snapshot Title: Edge of a pillow
    Taken by: Callan Bentley

    Image: Pillow Basalts at Kirby Cove
    Image Owner: Robin Rohrback-Schiavone



    Description:

    Note the radial fracture array.



  6. An original upright fold...

    Snapshot Title: An original upright fold...
    Taken by: Callan Bentley

    Image: Recumbent anticline in the Edinburg Formation, Page County, Virginia
    Image Owner: Callan Bentley



    Description:

    ...that was sheared westward into recumbency? That's the interpretation of Steve Whitmeyer (JMU) and his students. See discussion in the 2012 VGFC field guide:
    csmres.jmu.edu/Geollab/Whitmeyer Will open in a new tab or window...



  7. An overturned upright fold?

    Snapshot Title: An overturned upright fold?
    Taken by: Callan Bentley

    Image: Recumbent anticline in the Edinburg Formation, Page County, Virginia
    Image Owner: Callan Bentley



    Description:

    That's the interpretation of Steve Whitmeyer (JMU) and his students. See discussion in the 2012 VGFC field guide:
    csmres.jmu.edu/Geollab/Whitmeyer/web/documents/VGFC%202012.pdf Will open in a new tab or window



  8. Bedding plane

    Snapshot Title: Bedding plane
    Taken by: Callan Bentley

    Image: Recumbent anticline in the Edinburg Formation, Page County, Virginia
    Image Owner: Callan Bentley



    Description:

    This bed is upright.



  9. Another view

    Snapshot Title: Another view
    Taken by: Callan Bentley

    Image: Recumbent anticline in the Edinburg Formation, Page County, Virginia
    Image Owner: Callan Bentley



    Description:

    This a more zoomed-out view of this same site here: gigapan.com/gigapans/125604



  10. Stylolites

    Snapshot Title: Stylolites
    Taken by: Callan Bentley

    Image: Recumbent anticline in the Edinburg Formation, Page County, Virginia
    Image Owner: Callan Bentley



    Description:

    Hidden in the shadows.



  11. Calcite veins

    Snapshot Title: Calcite veins
    Taken by: Callan Bentley

    Image: Recumbent anticline in the Edinburg Formation, Page County, Virginia
    Image Owner: Callan Bentley



    Description:

    White on the gray limestone background.



  12. Cleavage refraction

    Snapshot Title: Cleavage refraction
    Taken by: Callan Bentley

    Image: Recumbent anticline in the Edinburg Formation, Page County, Virginia
    Image Owner: Callan Bentley



    Description:

    Note the different angles cleavage takes as it traverses these beds.



  13. Cleavage/bedding intersection

    Snapshot Title: Cleavage/bedding intersection
    Taken by: Callan Bentley

    Image: Recumbent anticline in the Edinburg Formation, Page County, Virginia
    Image Owner: Callan Bentley



    Description:

    Maybe some of the cleavage is being exploited as a zone of weakness to facilitate outer arc extension, too.



  14. Pencil for scale

    Snapshot Title: Pencil for scale
    Taken by: Callan Bentley

    Image: Recumbent anticline in the Edinburg Formation, Page County, Virginia
    Image Owner: Callan Bentley



    Description:

    This is a mechancial pencil with 1-cm bars along the side.



  15. A closer view

    Snapshot Title: A closer view
    Taken by: Callan Bentley

    Image: Recumbent anticline in the Edinburg Formation, Page County, Virginia
    Image Owner: Callan Bentley



    Description:

    I shot another GigaPan closer in (fewer trees in the way): gigapan.com/gigapans/125605



  16. Outcrop maintenance

    Snapshot Title: Outcrop maintenance
    Taken by: Callan Bentley

    Image: Skinners Butte Columnar Basalt
    Image Owner: Robin Rohrback-Schiavone



    Description:

    Good work! A victory for the rocks over the pesky vegetation that would obscure them.



  17. Arrest lines

    Snapshot Title: Arrest lines
    Taken by: Callan Bentley

    Image: Skinners Butte Columnar Basalt
    Image Owner: Robin Rohrback-Schiavone



    Description:

    Fracture propagation arrest ('stopping') lines on the sides of the column. Each of these represents the spot where the basalt went from being unbroken (below) to broken (above).



  18. A job for...

    Snapshot Title: A job for...
    Taken by: Callan Bentley

    Image: Recumbent anticline in the Edinburg Formation, Page County, Virginia
    Image Owner: Callan Bentley



    Description:

    ...the Farm Boss.



  19. Recumbent syncline

    Snapshot Title: Recumbent syncline
    Taken by: Callan Bentley

    Image: Recumbent anticline in the Edinburg Formation, Page County, Virginia
    Image Owner: Callan Bentley



    Description:

    Fold faces the opposite direction of the "main" fold in this quarry.



  20. Cleavage refraction

    Snapshot Title: Cleavage refraction
    Taken by: Callan Bentley

    Image: Recumbent anticline in the Edinburg Formation, Page County, Virginia
    Image Owner: Callan Bentley



    Description:

    Compare the cleavage orientation from left to right across this snapshot.



  21. Outer arc extension

    Snapshot Title: Outer arc extension
    Taken by: Callan Bentley

    Image: Recumbent anticline in the Edinburg Formation, Page County, Virginia
    Image Owner: Callan Bentley



    Description:

    These extensional fractures are very similar to those seen at another overturned anticline: Swift Dam. Check it out and compare the two: gigapan.com/gigapans/83143



  22. Hinge

    Snapshot Title: Hinge
    Taken by: Callan Bentley

    Image: Recumbent anticline in the Edinburg Formation, Page County, Virginia
    Image Owner: Callan Bentley



    Description:

    Axial plane is horizontal...



  23. Bedding?

    Snapshot Title: Bedding?
    Taken by: Callan Bentley

    Image: Rhosydd slate mine incline wagon
    Image Owner: Willy Eckerslyke



    Description:

    It looks like there is some compositional layering dipping to the left here. Is that bedding?



  24. Harpers Formation

    Snapshot Title: Harpers Formation
    Taken by: Callan Bentley

    Image: Chapman's Mill, Thoroughfare Gap, Virginia
    Image Owner: Callan Bentley



    Description:

    Behind the mill to the north is a railroad cut exposing the Harpers Formation.



  25. Weverton Formation

    Snapshot Title: Weverton Formation
    Taken by: Callan Bentley

    Image: Chapman's Mill, Thoroughfare Gap, Virginia
    Image Owner: Callan Bentley



    Description:

    Cambrian beach sand fused to quartzite during Alleghanian mountain building.



  26. Bolt in a hole

    Snapshot Title: Bolt in a hole
    Taken by: Callan Bentley

    Image: Chapman's Mill, Thoroughfare Gap, Virginia
    Image Owner: Callan Bentley



    Description:

    Keeping the structure standing requires some modern modifications.



  27. Broad Run

    Snapshot Title: Broad Run
    Taken by: Callan Bentley

    Image: Chapman's Mill, Thoroughfare Gap, Virginia
    Image Owner: Callan Bentley



    Description:

    This stream cuts across Bull Run Mountain with the Thoroughfare Gap water gap.



  28. Learn more...

    Snapshot Title: Learn more...
    Taken by: Callan Bentley

    Image: Chapman's Mill, Thoroughfare Gap, Virginia
    Image Owner: Callan Bentley



    Description:

    ...about the history of this site:
    www.chapmansmill.org Will open in a new tab or window/



  29. Another perspective

    Snapshot Title: Another perspective
    Taken by: Callan Bentley

    Image: Chapman's Mill, Thoroughfare Gap, Virginia
    Image Owner: Callan Bentley



    Description:

    To get another look at the mill from this spot, check out this second GigaPan:
    gigapan.com/gigapans/125419



  30. Plumose structure

    Snapshot Title: Plumose structure
    Taken by: Callan Bentley

    Image: Chapman's Mill, Thoroughfare Gap, Virginia
    Image Owner: Callan Bentley



    Description:

    The front face of this door-jamb-forming block is defined by a joint that propagated from left to right.



  31. Pulley

    Snapshot Title: Pulley
    Taken by: Callan Bentley

    Image: Chapman's Mill, Thoroughfare Gap, Virginia
    Image Owner: Callan Bentley



    Description:

    With a wooden wheel?



  32. Website

    Snapshot Title: Website
    Taken by: Callan Bentley

    Image: Chapman's Mill, Thoroughfare Gap, Virginia
    Image Owner: Callan Bentley



    Description:

    Learn more about the history of this site at:
    www.chapmansmill.org Will open in a new tab or window/



  33. Pencil for scale

    Snapshot Title: Pencil for scale
    Taken by: Callan Bentley

    Image: Chapman's Mill, Thoroughfare Gap, Virginia
    Image Owner: Callan Bentley



    Description:

    Mechanical pencil with 1-cm black bars on the side.



  34. Basalt cobble

    Snapshot Title: Basalt cobble
    Taken by: Callan Bentley

    Image: Waterfall Formation boulder
    Image Owner: Callan Bentley



    Description:

    with rounded corners



  35. 1 cm

    Snapshot Title: 1 cm
    Taken by: Callan Bentley

    Image: Waterfall Formation boulder
    Image Owner: Callan Bentley



    Description:

    One-centimeter-long black bar on the side of a mechanical pencil, to serve as a sense of scale.



  36. Rounded basalt cobble

    Snapshot Title: Rounded basalt cobble
    Taken by: Callan Bentley

    Image: Waterfall Formation boulder
    Image Owner: Callan Bentley



    Description:

    Clearly tumbled some distance before deposition.



  37. Amygdules

    Snapshot Title: Amygdules
    Taken by: Callan Bentley

    Image: Waterfall Formation boulder
    Image Owner: Callan Bentley



    Description:

    Volcanic vesicles later filled with mineral deposits (before a chunk of the basalt that includes them was broken off and tumbled (getting rounded) and then deposited on an alluvial fan (to become part...



  38. 1 cm

    Snapshot Title: 1 cm
    Taken by: Callan Bentley

    Image: Waterfall Formation boulder
    Image Owner: Callan Bentley



    Description:

    One-centimeter bar marked on the side of a mechanical pencil, to provide a sense of scale.



  39. Pencil for scale

    Snapshot Title: Pencil for scale
    Taken by: Callan Bentley

    Image: Harpers Formation, Throroughfare Gap, Virginia
    Image Owner: Callan Bentley



    Description:

    Mechanical pencil with centimeter-long black bars marked along the side.



  40. Sheridan geology vehicle

    Snapshot Title: Sheridan geology vehicle
    Taken by: Callan Bentley

    Image: Sheridan College dinosaur quarry, south of Buffalo Wyoming.
    Image Owner: Callan Bentley



    Description:

    Every geology department should have an SUV for field work!



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