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Callan Bentley's Snapshots

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  1. Recessive weathering

    Snapshot Title: Recessive weathering
    Taken by: Callan Bentley

    Image: Sykesville Formation, Chain Bridge Flats, DC
    Image Owner: Callan Bentley



    Description:

    of a chlorite-rich clast



  2. Mafic clast

    Snapshot Title: Mafic clast
    Taken by: Callan Bentley

    Image: Sykesville Formation, Chain Bridge Flats, DC
    Image Owner: Callan Bentley



    Description:

    No reaction rim, though



  3. Slickensides

    Snapshot Title: Slickensides
    Taken by: Callan Bentley

    Image: Sykesville Formation, Chain Bridge Flats, DC
    Image Owner: Callan Bentley



    Description:

    Common feature in these rocks.



  4. Two squashed clasts

    Snapshot Title: Two squashed clasts
    Taken by: Callan Bentley

    Image: Sykesville Formation, Chain Bridge Flats, DC
    Image Owner: Callan Bentley



    Description:

    Ellipsoidal.



  5. Light-colored clasts

    Snapshot Title: Light-colored clasts
    Taken by: Callan Bentley

    Image: Sykesville Formation, Chain Bridge Flats, DC
    Image Owner: Callan Bentley



    Description:

    Some with reaction rims, others (milky quartz) with no obvious reaction rim.



  6. Clast

    Snapshot Title: Clast
    Taken by: Callan Bentley

    Image: Sykesville Formation, Chain Bridge Flats, DC
    Image Owner: Callan Bentley



    Description:

    of milky quartz



  7. Felsic clast

    Snapshot Title: Felsic clast
    Taken by: Callan Bentley

    Image: Sykesville Formation, Chain Bridge Flats, DC
    Image Owner: Callan Bentley



    Description:

    Must be older than the Sykesville Formation that includes it.



  8. Big tabular clast

    Snapshot Title: Big tabular clast
    Taken by: Callan Bentley

    Image: Sykesville Formation, Chain Bridge Flats, DC
    Image Owner: Callan Bentley



    Description:

    A big slabby chunk of quartzite included in the metagraywacke/schist matrix.



  9. Hammer for scale

    Snapshot Title: Hammer for scale
    Taken by: Callan Bentley

    Image: Sykesville Formation, Chain Bridge Flats, DC
    Image Owner: Callan Bentley



    Description:

    Here is the butt end of the hammer.



  10. Reaction rim

    Snapshot Title: Reaction rim
    Taken by: Callan Bentley

    Image: Sykesville Formation, Chain Bridge Flats, DC
    Image Owner: Callan Bentley



    Description:

    Another signal of chemical re-equilibration between clast and matrix.



  11. Mafic clast w/ reaction rim

    Snapshot Title: Mafic clast w/ reaction rim
    Taken by: Callan Bentley

    Image: Sykesville Formation, Chain Bridge Flats, DC
    Image Owner: Callan Bentley



    Description:

    Amphibolite?



  12. Milky quartz inclusions

    Snapshot Title: Milky quartz inclusions
    Taken by: Callan Bentley

    Image: Sykesville Formation, Chain Bridge Flats, DC
    Image Owner: Callan Bentley



    Description:

    exposed on the plane of foliation.



  13. Hammer for scale

    Snapshot Title: Hammer for scale
    Taken by: Callan Bentley

    Image: Sykesville Formation, Chain Bridge Flats, DC
    Image Owner: Callan Bentley



    Description:

    Top of the handle



  14. Students

    Snapshot Title: Students
    Taken by: Callan Bentley

    Image: Gastropod duplex w/ people for scale
    Image Owner: Callan Bentley



    Description:

    Zack, Matt, and Jake, checking out the structural geology.



  15. Percussion marks

    Snapshot Title: Percussion marks
    Taken by: Callan Bentley

    Image: Second Generation Quartz, Billy Goat Trail
    Image Owner: Marissa Dudek



    Description:

    Great examples.



  16. Percussion marks

    Snapshot Title: Percussion marks
    Taken by: Callan Bentley

    Image: Second Generation Quartz, Billy Goat Trail
    Image Owner: Marissa Dudek



    Description:

    Bouncing cobbles in the ancient Potomac River slammed into this postively-weathering vein to make these features.



  17. A closer look

    Snapshot Title: A closer look
    Taken by: Callan Bentley

    Image: Faulted- Tonoloway
    Image Owner: Alan Pitts



    Description:

    Details here:
    gigapan.com/gigapans/174628



  18. Slogan

    Snapshot Title: Slogan
    Taken by: Callan Bentley

    Image: Syncline Fold, Corridor H
    Image Owner: Marissa Dudek



    Description:

    Resolution's good enough to read off the fine print on the license plate.



  19. Fault

    Snapshot Title: Fault
    Taken by: Callan Bentley

    Image: Syncline Fold, Corridor H
    Image Owner: Marissa Dudek



    Description:

    A big difference in bedding orientation in upper left of snapshot relative to lower right, and an oxidized zone of rubble in between. Fault!



  20. Beautiful brach

    Snapshot Title: Beautiful brach
    Taken by: Callan Bentley

    Image: Fossils in Reynolds Limestone, Mauch Chunk Formation
    Image Owner: Marissa Dudek



    Description:

    Exterior



  21. Eye

    Snapshot Title: Eye
    Taken by: Callan Bentley

    Image: Helderberg Limestone, Corridor H, West Virginia
    Image Owner: Callan Bentley



    Description:

    This one has an iris!



  22. Hmmm

    Snapshot Title: Hmmm
    Taken by: Callan Bentley

    Image: Helderberg Limestone, Corridor H, West Virginia
    Image Owner: Callan Bentley



    Description:

    What's up with these half-spherical concavities?



  23. Microcave

    Snapshot Title: Microcave
    Taken by: Callan Bentley

    Image: Helderberg Limestone, Corridor H, West Virginia
    Image Owner: Callan Bentley



    Description:

    Looks like a good site for a bird nest?



  24. Differential dissolution

    Snapshot Title: Differential dissolution
    Taken by: Callan Bentley

    Image: Helderberg Limestone, Corridor H, West Virginia
    Image Owner: Callan Bentley



    Description:

    Some of these strata are more soluble than others.



  25. Clover

    Snapshot Title: Clover
    Taken by: Callan Bentley

    Image: Helderberg Limestone, Corridor H, West Virginia
    Image Owner: Callan Bentley



    Description:

    in bloom



  26. Flowers

    Snapshot Title: Flowers
    Taken by: Callan Bentley

    Image: Helderberg Limestone, Corridor H, West Virginia
    Image Owner: Callan Bentley



    Description:

    A small bouquet



  27. Extensional veins

    Snapshot Title: Extensional veins
    Taken by: Callan Bentley

    Image: Helderberg Limestone, Corridor H, West Virginia
    Image Owner: Callan Bentley



    Description:

    Filled w/ pure white calcite



  28. Intersecting joint sets

    Snapshot Title: Intersecting joint sets
    Taken by: Callan Bentley

    Image: Helderberg Limestone, Corridor H, West Virginia
    Image Owner: Callan Bentley



    Description:

    A conjugate set?



  29. Dissolution

    Snapshot Title: Dissolution
    Taken by: Callan Bentley

    Image: Helderberg Limestone, Corridor H, West Virginia
    Image Owner: Callan Bentley



    Description:

    on joint surfaces. Also, oxidation.



  30. Art

    Snapshot Title: Art
    Taken by: Callan Bentley

    Image: Helderberg Limestone, Corridor H, West Virginia
    Image Owner: Callan Bentley



    Description:

    My two-year-old's depiction of Darth Vader. 2015. Medium: gravel and carpaint.



  31. PATC

    Snapshot Title: PATC
    Taken by: Callan Bentley

    Image: Helderberg Limestone, Corridor H, West Virginia
    Image Owner: Callan Bentley



    Description:

    Potomac Appalachian Trail Club sticker on the GigaPanMobile.



  32. Breakage

    Snapshot Title: Breakage
    Taken by: Callan Bentley

    Image: Millboro Climbing Ripples
    Image Owner: Robin Rohrback



    Description:

    This sample readily parts along bedding planes, but will also break across bedding planes if it needs to.



  33. Scale

    Snapshot Title: Scale
    Taken by: Callan Bentley

    Image: Millboro Climbing Ripples
    Image Owner: Robin Rohrback



    Description:

    1 cm wide



  34. Change in thickness

    Snapshot Title: Change in thickness
    Taken by: Callan Bentley

    Image: Millboro Climbing Ripples
    Image Owner: Robin Rohrback



    Description:

    Watch how the light colored lamination goes from relatively thick (on inclined surface - the slipface of the Devonian ripple) to thin on the downstream gentler slope.



  35. PATC logo

    Snapshot Title: PATC logo
    Taken by: Callan Bentley

    Image: Mauch Chunk Formation, showing Reynolds Limestone Member
    Image Owner: Callan Bentley



    Description:

    Potomac Appalachian Trail Club sticker in the window of the GigaPanMobile.



  36. Rockfall

    Snapshot Title: Rockfall
    Taken by: Callan Bentley

    Image: Mauch Chunk Formation, showing Reynolds Limestone Member
    Image Owner: Callan Bentley



    Description:

    The biggest pieces go the furthest...



  37. Jeff & Bridget

    Snapshot Title: Jeff & Bridget
    Taken by: Callan Bentley

    Image: Mauch Chunk Formation, showing Reynolds Limestone Member
    Image Owner: Callan Bentley



    Description:

    GigaPanners in training examine the base of the Reynolds Limestone.



  38. Root traces

    Snapshot Title: Root traces
    Taken by: Callan Bentley

    Image: Mauch Chunk Formation, Corridor H, West Virginia
    Image Owner: Callan Bentley



    Description:

    Reduced chemistry cross-cutting surrounding oxidized sediment.



  39. Concentric ribs

    Snapshot Title: Concentric ribs
    Taken by: Callan Bentley

    Image: Mauch Chunk Formation, Corridor H, West Virginia
    Image Owner: Callan Bentley



    Description:

    Conchoidal fracture.



  40. Scale

    Snapshot Title: Scale
    Taken by: Callan Bentley

    Image: Georgetown Intrusive Suite, Rock Creek Park, Washington, DC
    Image Owner: Callan Bentley



    Description:

    1 cm long



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