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Callan Bentley's Snapshots

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  1. Kinky crenulations

    Snapshot Title: Kinky crenulations
    Taken by: Callan Bentley

    Image: Harpers Formation exposed at Glasscock Gap, Virginia (Outdoor Lab)
    Image Owner: Callan Bentley



    Description:

    Closely-spaced folds



  2. Crenulation folds

    Snapshot Title: Crenulation folds
    Taken by: Callan Bentley

    Image: Harpers Formation exposed at Glasscock Gap, Virginia (Outdoor Lab)
    Image Owner: Callan Bentley



    Description:

    Kinky folds



  3. Bedding vs. cleavage

    Snapshot Title: Bedding vs. cleavage
    Taken by: Callan Bentley

    Image: Harpers Formation exposed at Glasscock Gap, Virginia (Outdoor Lab)
    Image Owner: Callan Bentley



    Description:

    Bedding is subhorizontal here, curving over to moderately-dipping (to the left / west) at far left. Cleavage is uniformly to the opposite direction (east) at a moderate to steep angle.



  4. Scale

    Snapshot Title: Scale
    Taken by: Callan Bentley

    Image: Harpers Formation exposed at Glasscock Gap, Virginia (Outdoor Lab)
    Image Owner: Callan Bentley



    Description:

    Pencil for scale. Black rectangles along the side of the pencil are each one centimeter long.



  5. Hackles

    Snapshot Title: Hackles
    Taken by: Callan Bentley

    Image: Weverton Formation atop Biscuit Mountain (Outdoor Lab)
    Image Owner: Callan Bentley



    Description:

    A small array of hackles decorates the face of the outcrop here. These "ruffle" like features form at the edge of fractures as they open up.



  6. Big, bold scour

    Snapshot Title: Big, bold scour
    Taken by: Callan Bentley

    Image: Weverton Formation atop Biscuit Mountain (Outdoor Lab)
    Image Owner: Callan Bentley



    Description:

    Note the asymmetry (possibly due to top-to-the-left shearing) and the lack of internal cross-bedding.



  7. Skulking scour

    Snapshot Title: Skulking scour
    Taken by: Callan Bentley

    Image: Weverton Formation atop Biscuit Mountain (Outdoor Lab)
    Image Owner: Callan Bentley



    Description:

    Small scour with 1 or 2 internal cross-beds, hiding in the shadows....



  8. Bedding vs. cleavage

    Snapshot Title: Bedding vs. cleavage
    Taken by: Callan Bentley

    Image: Weverton Formation atop Biscuit Mountain (Outdoor Lab)
    Image Owner: Callan Bentley



    Description:

    Bedding is shallowly dipping to the right (east), while cleavage is moderately dipping to the right (east). This relationship suggests the bedding is right-side-up (i.e., it has not been bodily flippe...



  9. Laminations

    Snapshot Title: Laminations
    Taken by: Callan Bentley

    Image: Weverton Formation atop Biscuit Mountain (Outdoor Lab)
    Image Owner: Callan Bentley



    Description:

    Fine-scale layering is apparent in this outcrop.



  10. Overturned cross-beds?

    Snapshot Title: Overturned cross-beds?
    Taken by: Callan Bentley

    Image: Weverton Formation atop Biscuit Mountain (Outdoor Lab)
    Image Owner: Callan Bentley



    Description:

    These cross beds appear to have been sufficiently sheared (top to the left) that they were tectonically inverted.



  11. Cuspate/lobate folds?

    Snapshot Title: Cuspate/lobate folds?
    Taken by: Callan Bentley

    Image: Weverton Formation atop Biscuit Mountain (Outdoor Lab)
    Image Owner: Callan Bentley



    Description:

    Along the base of the quartz-rich bed (top of the dark-mineral-rich bed), with axial planes that appear to be parallel (within the plane of this outcrop, anyhow) with the cleavage.



  12. ?????

    Snapshot Title: ?????
    Taken by: Callan Bentley

    Image: Weverton Formation atop Biscuit Mountain (Outdoor Lab)
    Image Owner: Callan Bentley



    Description:

    Not sure what to make of this. Any ideas?



  13. ???

    Snapshot Title: ???
    Taken by: Callan Bentley

    Image: Weverton Formation atop Biscuit Mountain (Outdoor Lab)
    Image Owner: Callan Bentley



    Description:

    Are these cross-beds steeply inclined toward the east (indicating the sand was deposited by west-to-east directed currents)? Or is this cleavage differentially developed in a graded bed (more quartz s...



  14. Cross-bedding

    Snapshot Title: Cross-bedding
    Taken by: Callan Bentley

    Image: Weverton Formation atop Biscuit Mountain (Outdoor Lab)
    Image Owner: Callan Bentley



    Description:

    A suite of cross-beds are preserved in scours within the quartzite here. While most indicate apparent east-to-west current flow, the set at upper right show the opposite. The tangential and truncated ...



  15. Trough-like scour

    Snapshot Title: Trough-like scour
    Taken by: Callan Bentley

    Image: Weverton Formation atop Biscuit Mountain (Outdoor Lab)
    Image Owner: Callan Bentley



    Description:

    A semi-circular white shape lined with dark minerals shows a current scour into pre-existing sedimentary layering prior to lithification. The asymmetry of these scours (western edge gently sloping rel...



  16. Scale

    Snapshot Title: Scale
    Taken by: Callan Bentley

    Image: Weverton Formation atop Biscuit Mountain (Outdoor Lab)
    Image Owner: Callan Bentley



    Description:

    The black and yellow rectangles that run along the side of this pencil are each 1 centimeter in length.



  17. Bedding / cleavage

    Snapshot Title: Bedding / cleavage
    Taken by: Callan Bentley

    Image: Outcrop of Weverton Formation quartzite atop Biscuit Mountain, Pond Mountains (South of Thoroughfare Gap), Virginia
    Image Owner: Callan Bentley



    Description:

    Both bedding and foliation (weak cleavage) dip moderately to the east a this site, though the bedding dips more shallowly than the cleavage.



  18. Tafoni II

    Snapshot Title: Tafoni II
    Taken by: Callan Bentley

    Image: Outcrop of Weverton Formation quartzite atop Biscuit Mountain, Pond Mountains (South of Thoroughfare Gap), Virginia
    Image Owner: Callan Bentley



    Description:

    More tafoni on the vertical sides of these outcrops.



  19. Tafoni

    Snapshot Title: Tafoni
    Taken by: Callan Bentley

    Image: Outcrop of Weverton Formation quartzite atop Biscuit Mountain, Pond Mountains (South of Thoroughfare Gap), Virginia
    Image Owner: Callan Bentley



    Description:

    There are plenty of lovely examples of tafoni-style weathering in these outcrops, and opferkessel solution pans, too.



  20. Scale

    Snapshot Title: Scale
    Taken by: Callan Bentley

    Image: Outcrop of Weverton Formation quartzite atop Biscuit Mountain, Pond Mountains (South of Thoroughfare Gap), Virginia
    Image Owner: Callan Bentley



    Description:

    Pencil with 1-centimeter black bars along the side.



  21. Mole Hill

    Snapshot Title: Mole Hill
    Taken by: Callan Bentley

    Image: Physiography of the central Appalachians
    Image Owner: Callan Bentley



    Description:

    An Eocene volcanic plug. Youngest volcanics on the east coast.



  22. Thoroughfare Gap

    Snapshot Title: Thoroughfare Gap
    Taken by: Callan Bentley

    Image: Physiography of the central Appalachians
    Image Owner: Callan Bentley



    Description:

    The Bull Run Mountains are breached here by Broad Run.



  23. Browntown Valley

    Snapshot Title: Browntown Valley
    Taken by: Callan Bentley

    Image: Physiography of the central Appalachians
    Image Owner: Callan Bentley



    Description:

    A "bite" taken out of the Blue Ridge front.



  24. Canaan Valley

    Snapshot Title: Canaan Valley
    Taken by: Callan Bentley

    Image: Physiography of the central Appalachians
    Image Owner: Callan Bentley



    Description:

    A high-elevation valley sometimes nicknamed "the Canadian Valley" for its volumnious winter snowstorms.



  25. Trellis

    Snapshot Title: Trellis
    Taken by: Callan Bentley

    Image: Physiography of the central Appalachians
    Image Owner: Callan Bentley



    Description:

    drainage pattern



  26. Veach Gap

    Snapshot Title: Veach Gap
    Taken by: Callan Bentley

    Image: Physiography of the central Appalachians
    Image Owner: Callan Bentley



    Description:

    Great anticlines exposed in here. For instance: gigapan.com/gigapans/98833



  27. Entrenched meanders

    Snapshot Title: Entrenched meanders
    Taken by: Callan Bentley

    Image: Physiography of the central Appalachians
    Image Owner: Callan Bentley



    Description:

    of the North Fork of the Shenandoah River.



  28. Better exposure?

    Snapshot Title: Better exposure?
    Taken by: Callan Bentley

    Image: View SSW from Duncan Knob, George Washington National Forest, Virginia
    Image Owner: Callan Bentley



    Description:

    I shot another GigaPan right after this one, and exposed it less, meaning that this area (South Page Valley) is more detailed and interesting:
    gigapan.com/gigapans/127564



  29. South Fork

    Snapshot Title: South Fork
    Taken by: Callan Bentley

    Image: View SSW from Duncan Knob, George Washington National Forest, Virginia
    Image Owner: Callan Bentley



    Description:

    of the Shenandoah River



  30. Page Valley

    Snapshot Title: Page Valley
    Taken by: Callan Bentley

    Image: View SSW from Duncan Knob, George Washington National Forest, Virginia
    Image Owner: Callan Bentley



    Description:

    I picked this exposure to bring out the details here in the South Page Valley. Roughly the same view can be seen in this more-exposed GigaPan:
    gigapan.com/gigapans/127565



  31. Sharp contact

    Snapshot Title: Sharp contact
    Taken by: Callan Bentley

    Image: View SSW from Duncan Knob, George Washington National Forest, Virginia
    Image Owner: Callan Bentley



    Description:

    My Swiss Rock Hammer deduces that the contact between the overlying Massanutten Sandstone and the underlying unit (presumably the upper Martinsburg Formation) is uncommonly sharp here.



  32. "The Knob"

    Snapshot Title: "The Knob"
    Taken by: Callan Bentley

    Image: View SSW from Duncan Knob, George Washington National Forest, Virginia
    Image Owner: Callan Bentley



    Description:

    A distinctive landform above Mt. Jackson, Virginia - distinctive and easy to spot from I-81.



  33. Contact

    Snapshot Title: Contact
    Taken by: Callan Bentley

    Image: View SSW from Duncan Knob, George Washington National Forest, Virginia
    Image Owner: Callan Bentley



    Description:

    between Massanutten Sandstone and underlying rock unit (Cub Sandstone / upper Martinsburg?).



  34. The Knob

    Snapshot Title: The Knob
    Taken by: Callan Bentley

    Image: View SSW from Duncan Knob, George Washington National Forest, Virginia
    Image Owner: Callan Bentley



    Description:

    above Mt. Jasckson, Virginia



  35. Scale

    Snapshot Title: Scale
    Taken by: Callan Bentley

    Image: Contact between Fauquier Formation marble and Catoctin Formation greenstone, near Lime Kiln Road, Virginia
    Image Owner: Callan Bentley



    Description:

    Each black rectangle along the side of this pencil measures 1 centimeter in length.



  36. Scale

    Snapshot Title: Scale
    Taken by: Callan Bentley

    Image: Contact between Fauquier Formation marble and Catoctin Formation greenstone, near Lime Kiln Road, Virginia
    Image Owner: Callan Bentley



    Description:

    Each black rectangle along the side of this pencil is 1 centimeter in length.



  37. Scale

    Snapshot Title: Scale
    Taken by: Callan Bentley

    Image: Contact between Fauquier Formation marble and Catoctin Formation greenstone, near Lime Kiln Road, Virginia
    Image Owner: Callan Bentley



    Description:

    Each black rectangle along the side of this pencil is 1 centimeter in length.



  38. Scale

    Snapshot Title: Scale
    Taken by: Callan Bentley

    Image: Contact between Fauquier Formation marble and Catoctin Formation greenstone, near Lime Kiln Road, Virginia
    Image Owner: Callan Bentley



    Description:

    Each black rectangle is 1 cm long.



  39. Sign, sign

    Snapshot Title: Sign, sign
    Taken by: Callan Bentley

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



    Description:

    Really: everywhere, a sign.



  40. Sign, sign

    Snapshot Title: Sign, sign
    Taken by: Callan Bentley

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



    Description:

    Everywhere a sign.



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