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Callan Bentley's Snapshots

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  1. Sense of scale

    Snapshot Title: Sense of scale
    Taken by: Callan Bentley

    Image: Differential Weathering, Sideling Hill, Maryland
    Image Owner: Marissa Dudek



    Description:

    Field notebook for scale.



  2. Double trouble

    Snapshot Title: Double trouble
    Taken by: Callan Bentley

    Image: Spechty Kopf Diamictite, Sideling Hill, Maryland
    Image Owner: Marissa Dudek



    Description:

    Two outsized clasts in close proximity.



  3. Sense of scale

    Snapshot Title: Sense of scale
    Taken by: Callan Bentley

    Image: Spechty Kopf Diamictite, Sideling Hill, Maryland
    Image Owner: Marissa Dudek



    Description:

    Mechanical pencil w/ 1-cm markings



  4. Outsized clast

    Snapshot Title: Outsized clast
    Taken by: Callan Bentley

    Image: Spechty Kopf Diamictite, Sideling Hill, Maryland
    Image Owner: Marissa Dudek



    Description:

    Big chunk 'floating' in the clay-rich matrix.



  5. Outsized clast

    Snapshot Title: Outsized clast
    Taken by: Callan Bentley

    Image: Spechty Kopf Diamictite, Sideling Hill, Maryland
    Image Owner: Marissa Dudek



    Description:

    Big chunk in the clay-rich matrix



  6. Eutaxitic lens

    Snapshot Title: Eutaxitic lens
    Taken by: Callan Bentley

    Image: Huckleberry Ridge Tuff, Madison Valley, Montana
    Image Owner: Callan Bentley



    Description:

    Squashed blob of frothy pumice.



  7. Compaction

    Snapshot Title: Compaction
    Taken by: Callan Bentley

    Image: Huckleberry Ridge Tuff, Madison Valley, Montana
    Image Owner: Callan Bentley



    Description:

    Eutaxitic lens wrapping around the top of a stiff phenocryst.



  8. Scale

    Snapshot Title: Scale
    Taken by: Callan Bentley

    Image: Huckleberry Ridge Tuff, Madison Valley, Montana
    Image Owner: Callan Bentley



    Description:

    This is 1 cm tall.



  9. Sense of scale

    Snapshot Title: Sense of scale
    Taken by: Callan Bentley

    Image: Portrush: hornfels (contact metamorphosed Lias shale) above Portrush gabbroic/doleritic sill
    Image Owner: Callan Bentley



    Description:

    Black bars on the side of this pencil are each 1 cm long.



  10. Sense of scale

    Snapshot Title: Sense of scale
    Taken by: Callan Bentley

    Image: Portrush: hornfels (contact metamorphosed Lias shale) above Portrush gabbroic/doleritic sill
    Image Owner: Callan Bentley



    Description:

    Mechanical pencil w/ 1-cm black bars along its side.



  11. Sense of scale

    Snapshot Title: Sense of scale
    Taken by: Callan Bentley

    Image: Portrush: hornfels (contact metamorphosed Lias shale) above Portrush gabbroic/doleritic sill
    Image Owner: Callan Bentley



    Description:

    Pencil w/ 1 cm black bars along its side.



  12. Crack

    Snapshot Title: Crack
    Taken by: Callan Bentley

    Image: Dropstones in weakly-lithified "silt-ite" from Looking Glass Highway, east of Glacier National Park
    Image Owner: Callan Bentley



    Description:

    indication of the weak state of lithification in this sample.



  13. Empty socket

    Snapshot Title: Empty socket
    Taken by: Callan Bentley

    Image: Dropstones in weakly-lithified "silt-ite" from Looking Glass Highway, east of Glacier National Park
    Image Owner: Callan Bentley



    Description:

    where a pebble popped out.



  14. Quartzite pebble

    Snapshot Title: Quartzite pebble
    Taken by: Callan Bentley

    Image: Dropstones in weakly-lithified "silt-ite" from Looking Glass Highway, east of Glacier National Park
    Image Owner: Callan Bentley



    Description:

    with pyrolusite dendrites on one side.



  15. Pyrolusite
  16. Appekuny Formation

    Snapshot Title: Appekuny Formation
    Taken by: Callan Bentley

    Image: Dropstones in weakly-lithified "silt-ite" from Looking Glass Highway, east of Glacier National Park
    Image Owner: Callan Bentley



    Description:

    Green argillite



  17. Grinnell Formation

    Snapshot Title: Grinnell Formation
    Taken by: Callan Bentley

    Image: Dropstones in weakly-lithified "silt-ite" from Looking Glass Highway, east of Glacier National Park
    Image Owner: Callan Bentley



    Description:

    Red argillite



  18. Grinnell Formation

    Snapshot Title: Grinnell Formation
    Taken by: Callan Bentley

    Image: Dropstones in weakly-lithified "silt-ite" from Looking Glass Highway, east of Glacier National Park
    Image Owner: Callan Bentley



    Description:

    Reddish quartzite



  19. Scale

    Snapshot Title: Scale
    Taken by: Callan Bentley

    Image: Dropstones in weakly-lithified "silt-ite" from Looking Glass Highway, east of Glacier National Park
    Image Owner: Callan Bentley



    Description:

    This black bar is 1 cm wide



  20. Scale

    Snapshot Title: Scale
    Taken by: Callan Bentley

    Image: Portrush sill: gabbro/diabase
    Image Owner: Callan Bentley



    Description:

    This is 1 cm wide.



  21. Really rounded pebbles

    Snapshot Title: Really rounded pebbles
    Taken by: Callan Bentley

    Image: Felsic intrusion with xenoliths
    Image Owner: Callan Bentley



    Description:

    This spot is high above the beach. How did these pebbles get so well rounded?



  22. Differential weathering

    Snapshot Title: Differential weathering
    Taken by: Callan Bentley

    Image: Felsic intrusion with xenoliths
    Image Owner: Callan Bentley



    Description:

    The felsic stuff (~granite) stands up to the wind's abrasion better than the more mafic constituents, making the granite weather out in positive relief.



  23. Xenolith variation

    Snapshot Title: Xenolith variation
    Taken by: Callan Bentley

    Image: Felsic intrusion with xenoliths
    Image Owner: Callan Bentley



    Description:

    Freshly stoped vs. mostly assimilated?



  24. Sense of scale

    Snapshot Title: Sense of scale
    Taken by: Callan Bentley

    Image: Felsic intrusion with xenoliths
    Image Owner: Callan Bentley



    Description:

    This is a lens cap for a 35 mm camera



  25. Blotchy

    Snapshot Title: Blotchy
    Taken by: Callan Bentley

    Image: A second view of the felsite intrusion
    Image Owner: Callan Bentley



    Description:

    There was a lot of this texture in the area, too - I interpret it as magma immiscibility resulting in the "Dalmatian" polka-dotting, then highlighted by differential weathering of the two compositions...



  26. Anatexis?

    Snapshot Title: Anatexis?
    Taken by: Callan Bentley

    Image: A second view of the felsite intrusion
    Image Owner: Callan Bentley



    Description:

    Interesting texture here - is this evidence of partial melting?



  27. Xenoliths

    Snapshot Title: Xenoliths
    Taken by: Callan Bentley

    Image: A second view of the felsite intrusion
    Image Owner: Callan Bentley



    Description:

    Nice array of mafic fragments/shards caught up in the granitic (felsic) dike.



  28. Relative dating

    Snapshot Title: Relative dating
    Taken by: Callan Bentley

    Image: A second view of the felsite intrusion
    Image Owner: Callan Bentley



    Description:

    Which of the two rock units is older, the light-colored one or the dark-colored one?



  29. Lens cap

    Snapshot Title: Lens cap
    Taken by: Callan Bentley

    Image: A second view of the felsite intrusion
    Image Owner: Callan Bentley



    Description:

    To provide a sense of scale



  30. Sediment

    Snapshot Title: Sediment
    Taken by: Callan Bentley

    Image: Felsite intrusion, Iceland
    Image Owner: Callan Bentley



    Description:

    What can you say about the sediment at this site?



  31. Inclusions

    Snapshot Title: Inclusions
    Taken by: Callan Bentley

    Image: Felsite intrusion, Iceland
    Image Owner: Callan Bentley



    Description:

    Shards of mafic rock (xenoliths) would allow relative dating on the principle of inclusions - the broken pieces must be of the older rock, and the felsic rock that surrounds them must be younger.



  32. Cross cutting relationships

    Snapshot Title: Cross cutting relationships
    Taken by: Callan Bentley

    Image: Felsite intrusion, Iceland
    Image Owner: Callan Bentley



    Description:

    The felsic rock must be younger than the more mafic rock it cuts across.



  33. Lens cap

    Snapshot Title: Lens cap
    Taken by: Callan Bentley

    Image: Felsite intrusion, Iceland
    Image Owner: Callan Bentley



    Description:

    To serve as a sense of scale.



  34. Dark layers

    Snapshot Title: Dark layers
    Taken by: Callan Bentley

    Image: Microbially-induced sedimentary structures, Barberton Greenstone Belt, South Africa
    Image Owner: Callan Bentley



    Description:

    are microbial mat fossils



  35. Scale

    Snapshot Title: Scale
    Taken by: Callan Bentley

    Image: Microbially-induced sedimentary structures, Barberton Greenstone Belt, South Africa
    Image Owner: Callan Bentley



    Description:

    This black bar is 1 cm wide.



  36. Hinges

    Snapshot Title: Hinges
    Taken by: Callan Bentley

    Image: Igneous Intrusions in Gneiss, Clear Creek Canyon, Colorado
    Image Owner: Robin Rohrback



    Description:

    A bunch of fold hinges, disharmonically all piled up.



  37. Leucosome cross-cutting foliation

    Snapshot Title: Leucosome cross-cutting foliation
    Taken by: Callan Bentley

    Image: Igneous Intrusions in Gneiss, Clear Creek Canyon, Colorado
    Image Owner: Robin Rohrback



    Description:

    Evidence of migmatization?



  38. Stratigraphy of spherule

    Snapshot Title: Stratigraphy of spherule
    Taken by: Callan Bentley

    Image: Spherulitic felsite, Shetland
    Image Owner: Callan Bentley



    Description:

    Multilayer gobstopper



  39. Scale

    Snapshot Title: Scale
    Taken by: Callan Bentley

    Image: Spherulitic felsite, Shetland
    Image Owner: Callan Bentley



    Description:

    This black bar is 1 cm tall.



  40. Scale

    Snapshot Title: Scale
    Taken by: Callan Bentley

    Image: Green Tuff from Jawbone Flats, Oregon
    Image Owner: Callan Bentley



    Description:

    This black bar is 1 cm tall.



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