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Callan Bentley's Snapshots

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  1. A closer look

    Snapshot Title: A closer look
    Taken by: Callan Bentley

    Image: Kink banding in Laurel Formation of Rock Creek Shear Zone, Broad Branch, Washington, DC
    Image Owner: Callan Bentley



    Description:

    For a view of this face, check out this GigaPan shot on the same day:
    gigapan.com/gigapans/128476



  2. Stray fold hinge

    Snapshot Title: Stray fold hinge
    Taken by: Callan Bentley

    Image: Kink banding in Laurel Formation of Rock Creek Shear Zone, Broad Branch, Washington, DC
    Image Owner: Callan Bentley



    Description:

    To get a better view of this face, try another GigaPan shot the same day, but from a different perspective: gigapan.com/gigapans/128419



  3. Kink
  4. Kink

    Snapshot Title: Kink
    Taken by: Callan Bentley

    Image: Kink banding in Laurel Formation of Rock Creek Shear Zone, Broad Branch, Washington, DC
    Image Owner: Callan Bentley



    Description:

    This kink band is at a conjugate angle relative to the big, prominent one a few inchest to the left.



  5. Stretched

    Snapshot Title: Stretched
    Taken by: Callan Bentley

    Image: Kink banding in Laurel Formation of Rock Creek Shear Zone, Broad Branch, Washington, DC
    Image Owner: Callan Bentley



    Description:

    quartzite clast.



  6. 2 kinks and a stretched clast

    Snapshot Title: 2 kinks and a stretched clast
    Taken by: Callan Bentley

    Image: Kink banding in Laurel Formation of Rock Creek Shear Zone, Broad Branch, Washington, DC
    Image Owner: Callan Bentley



    Description:

    A nice little ensemble.



  7. Intense kinking

    Snapshot Title: Intense kinking
    Taken by: Callan Bentley

    Image: Kink banding in Laurel Formation of Rock Creek Shear Zone, Broad Branch, Washington, DC
    Image Owner: Callan Bentley



    Description:

    About an apparent 90 degree angle here between the kink band foliation and the main foliation that surrounds it.



  8. Kink band

    Snapshot Title: Kink band
    Taken by: Callan Bentley

    Image: Kink banding in Laurel Formation of Rock Creek Shear Zone, Broad Branch, Washington, DC
    Image Owner: Callan Bentley



    Description:

    The foliation has been "kinked" in a band about an inch thick.



  9. Kink band

    Snapshot Title: Kink band
    Taken by: Callan Bentley

    Image: Kink banding in Laurel Formation of Rock Creek Shear Zone, Broad Branch, Washington, DC
    Image Owner: Callan Bentley



    Description:

    The foliation has been "kinked" here.



  10. Scale

    Snapshot Title: Scale
    Taken by: Callan Bentley

    Image: Klingle Valley metaconglomerate, Laurel Formation, Rock Creek Shear Zone, Washington, DC
    Image Owner: Callan Bentley



    Description:

    This pencil serves as a sense of scale. It's in a hollow, so it's mostly blurry, though thankfully that implies the rock around it should be in focus... Black bars along the side each measure 1 cm.



  11. Clast

    Snapshot Title: Clast
    Taken by: Callan Bentley

    Image: Klingle Valley metaconglomerate, Laurel Formation, Rock Creek Shear Zone, Washington, DC
    Image Owner: Callan Bentley



    Description:

    With well-defined edges.



  12. Clast with internal layering

    Snapshot Title: Clast with internal layering
    Taken by: Callan Bentley

    Image: Klingle Valley metaconglomerate, Laurel Formation, Rock Creek Shear Zone, Washington, DC
    Image Owner: Callan Bentley



    Description:

    Pre-existing metamorphic foliation? Sedimentary bedding? Volcanic flow banding?



  13. Stretched clast

    Snapshot Title: Stretched clast
    Taken by: Callan Bentley

    Image: Klingle Valley metaconglomerate, Laurel Formation, Rock Creek Shear Zone, Washington, DC
    Image Owner: Callan Bentley



    Description:

    Felsite? Quartzite?



  14. Stretched clast

    Snapshot Title: Stretched clast
    Taken by: Callan Bentley

    Image: Klingle Valley metaconglomerate, Laurel Formation, Rock Creek Shear Zone, Washington, DC
    Image Owner: Callan Bentley



    Description:

    Looks like a dark mica-rich schist cobble?



  15. Pseudomorph

    Snapshot Title: Pseudomorph
    Taken by: Callan Bentley

    Image: Klingle Valley metaconglomerate, Laurel Formation, Rock Creek Shear Zone, Washington, DC
    Image Owner: Callan Bentley



    Description:

    Sericite after staurolite (retrograde metamorphism)



  16. Scale

    Snapshot Title: Scale
    Taken by: Callan Bentley

    Image: Klingle Valley metaconglomerate, Laurel Formation, Rock Creek Shear Zone, Washington, DC
    Image Owner: Callan Bentley



    Description:

    This pencil has one-centimeter black bars along its side.



  17. Stretched clast

    Snapshot Title: Stretched clast
    Taken by: Callan Bentley

    Image: Kink banding in Laurel Formation of Rock Creek Shear Zone, Broad Branch, Washington, DC
    Image Owner: Callan Bentley



    Description:

    Maybe with a second clast fused into it at lower left?



  18. Stretched clast

    Snapshot Title: Stretched clast
    Taken by: Callan Bentley

    Image: Kink banding in Laurel Formation of Rock Creek Shear Zone, Broad Branch, Washington, DC
    Image Owner: Callan Bentley



    Description:

    What is the axial ratio of this clast, as expressed on this surface?



  19. 1 inch

    Snapshot Title: 1 inch
    Taken by: Callan Bentley

    Image: Kink banding in Laurel Formation of Rock Creek Shear Zone, Broad Branch, Washington, DC
    Image Owner: Callan Bentley



    Description:

    On a scale card provided by the Virginia DGMR.



  20. Scale pencil

    Snapshot Title: Scale pencil
    Taken by: Callan Bentley

    Image: Kink banding in Laurel Formation of Rock Creek Shear Zone, Broad Branch, Washington, DC
    Image Owner: Callan Bentley



    Description:

    Slightly blurry, due to its location in a hollow, but the rock is in focus! 1 cm demarcations on the side of the pencil.



  21. Kinked foliation

    Snapshot Title: Kinked foliation
    Taken by: Callan Bentley

    Image: Kink banding in Laurel Formation of Rock Creek Shear Zone, Broad Branch, Washington, DC
    Image Owner: Callan Bentley



    Description:

    Right at the fracture. Right at the transition between brown and gray.



  22. Stretched mafic clasts

    Snapshot Title: Stretched mafic clasts
    Taken by: Callan Bentley

    Image: Kink banding in Laurel Formation of Rock Creek Shear Zone, Broad Branch, Washington, DC
    Image Owner: Callan Bentley



    Description:

    Not as obvious to the eye as the milky quartz stretched clasts / boudins, but these dark colored clasts are present, too.



  23. Big clasts

    Snapshot Title: Big clasts
    Taken by: Callan Bentley

    Image: Kink banding in Laurel Formation of Rock Creek Shear Zone, Broad Branch, Washington, DC
    Image Owner: Callan Bentley



    Description:

    Or boudins?



  24. Pop

    Snapshot Title: Pop
    Taken by: Callan Bentley

    Image: Kink banding in Laurel Formation of Rock Creek Shear Zone, Broad Branch, Washington, DC
    Image Owner: Callan Bentley



    Description:

    A bubble caught in the moment of popping!



  25. Foliation

    Snapshot Title: Foliation
    Taken by: Callan Bentley

    Image: Kink banding in Laurel Formation of Rock Creek Shear Zone, Broad Branch, Washington, DC
    Image Owner: Callan Bentley



    Description:

    These highly foliated rocks are part of the Rock Creek Shear Zone, a ductile "fault" running north-south through NW DC.



  26. Kensington Tonalite boulder

    Snapshot Title: Kensington Tonalite boulder
    Taken by: Callan Bentley

    Image: Kink banding in Laurel Formation of Rock Creek Shear Zone, Broad Branch, Washington, DC
    Image Owner: Callan Bentley



    Description:

    Derived from outcrops upstream at the contact between the Kensington Tonalite and Laurel Formation.



  27. Kink within a kink

    Snapshot Title: Kink within a kink
    Taken by: Callan Bentley

    Image: Kink banding in Laurel Formation of Rock Creek Shear Zone, Broad Branch, Washington, DC
    Image Owner: Callan Bentley



    Description:

    Back out a bit for the larger kink's context.



  28. Big kink band

    Snapshot Title: Big kink band
    Taken by: Callan Bentley

    Image: Kink banding in Laurel Formation of Rock Creek Shear Zone, Broad Branch, Washington, DC
    Image Owner: Callan Bentley



    Description:

    bounded by fractures



  29. Fold hinge

    Snapshot Title: Fold hinge
    Taken by: Callan Bentley

    Image: Kink banding in Laurel Formation of Rock Creek Shear Zone, Broad Branch, Washington, DC
    Image Owner: Callan Bentley



    Description:

    Almost indiscernible



  30. Small kink band

    Snapshot Title: Small kink band
    Taken by: Callan Bentley

    Image: Kink banding in Laurel Formation of Rock Creek Shear Zone, Broad Branch, Washington, DC
    Image Owner: Callan Bentley



    Description:

    Overprinting foliation



  31. Stretched clast

    Snapshot Title: Stretched clast
    Taken by: Callan Bentley

    Image: Kink banding in Laurel Formation of Rock Creek Shear Zone, Broad Branch, Washington, DC
    Image Owner: Callan Bentley



    Description:

    Within metagraywacke matrix.



  32. Scale

    Snapshot Title: Scale
    Taken by: Callan Bentley

    Image: Kink banding in Laurel Formation of Rock Creek Shear Zone, Broad Branch, Washington, DC
    Image Owner: Callan Bentley



    Description:

    Scale card from the Virginia DGMR, with inches and centimeters demarcated along the top and bottom edges.



  33. Scale pencil

    Snapshot Title: Scale pencil
    Taken by: Callan Bentley

    Image: Kink banding in Laurel Formation of Rock Creek Shear Zone, Broad Branch, Washington, DC
    Image Owner: Callan Bentley



    Description:

    Black bars along the side are each one centimeter in length.



  34. Rust

    Snapshot Title: Rust
    Taken by: Callan Bentley

    Image: Tuscarora Sandstone exposed at Hanging Rock Anticline, West Virginia
    Image Owner: Callan Bentley



    Description:

    Diagenetic deposits of iron oxides highlight bedding.



  35. Cross-bedding

    Snapshot Title: Cross-bedding
    Taken by: Callan Bentley

    Image: Hanging Rock Anticline, east side
    Image Owner: Callan Bentley



    Description:

    Which way was the current flowing?



  36. Prius

    Snapshot Title: Prius
    Taken by: Callan Bentley

    Image: Hanging Rock Anticline, east side
    Image Owner: Callan Bentley



    Description:

    dorsal fin



  37. Offset

    Snapshot Title: Offset
    Taken by: Callan Bentley

    Image: Hanging Rock Anticline, east side
    Image Owner: Callan Bentley



    Description:

    Whose fault is this offset?



  38. Cross-beds

    Snapshot Title: Cross-beds
    Taken by: Callan Bentley

    Image: Tuscarora Sandstone exposed at Hanging Rock Anticline, West Virginia
    Image Owner: Callan Bentley



    Description:

    Which was was the current flowing when these sands were deposited?



  39. Scale

    Snapshot Title: Scale
    Taken by: Callan Bentley

    Image: Tuscarora Sandstone exposed at Hanging Rock Anticline, West Virginia
    Image Owner: Callan Bentley



    Description:

    Pencil w/ 1-cm demarcations along the side.



  40. Meso-scale fold

    Snapshot Title: Meso-scale fold
    Taken by: Callan Bentley

    Image: Folded strata of the Silurian Tonoloway Formation
    Image Owner: Callan Bentley



    Description:

    in strongly-laminated layer



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