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Callan Bentley's Snapshots

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  1. 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.



  2. 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.



  3. 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.



  4. Pyrolusite
  5. 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



  6. 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



  7. 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



  8. 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



  9. Scale

    Snapshot Title: Scale
    Taken by: Callan Bentley

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



    Description:

    This is 1 cm wide.



  10. 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?



  11. 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.



  12. 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?



  13. 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



  14. 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...



  15. 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?



  16. 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.



  17. 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?



  18. 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



  19. 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?



  20. 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.



  21. 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.



  22. 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.



  23. 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



  24. 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.



  25. 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.



  26. 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?



  27. Stratigraphy of spherule

    Snapshot Title: Stratigraphy of spherule
    Taken by: Callan Bentley

    Image: Spherulitic felsite, Shetland
    Image Owner: Callan Bentley



    Description:

    Multilayer gobstopper



  28. Scale

    Snapshot Title: Scale
    Taken by: Callan Bentley

    Image: Spherulitic felsite, Shetland
    Image Owner: Callan Bentley



    Description:

    This black bar is 1 cm tall.



  29. 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.



  30. Spherule

    Snapshot Title: Spherule
    Taken by: Callan Bentley

    Image: Spherulitic felsite, Shetland
    Image Owner: Callan Bentley



    Description:

    with radiating structure.



  31. Sense of scale

    Snapshot Title: Sense of scale
    Taken by: Callan Bentley

    Image: Spherulitic felsite, Shetland
    Image Owner: Callan Bentley



    Description:

    1 cm width



  32. Garnet

    Snapshot Title: Garnet
    Taken by: Callan Bentley

    Image: Garent-bearing anorthosite
    Image Owner: Callan Bentley



    Description:

    Along boundary between other two minerals.



  33. Augite

    Snapshot Title: Augite
    Taken by: Callan Bentley

    Image: Garent-bearing anorthosite
    Image Owner: Callan Bentley



    Description:

    pyroxene



  34. Plagioclase

    Snapshot Title: Plagioclase
    Taken by: Callan Bentley

    Image: Garent-bearing anorthosite
    Image Owner: Callan Bentley



    Description:

    feldspar



  35. Scale

    Snapshot Title: Scale
    Taken by: Callan Bentley

    Image: Garent-bearing anorthosite
    Image Owner: Callan Bentley



    Description:

    1 cm black bar.



  36. Animal analogy?

    Snapshot Title: Animal analogy?
    Taken by: Callan Bentley

    Image: Felsic spherulite from Shetland
    Image Owner: Callan Bentley



    Description:

    Is it more like a hedgehog, an echidna, or a porcupine?



  37. Radial crystals

    Snapshot Title: Radial crystals
    Taken by: Callan Bentley

    Image: Felsic spherulite from Shetland
    Image Owner: Callan Bentley



    Description:

    in a spherulite



  38. Spherule structure

    Snapshot Title: Spherule structure
    Taken by: Callan Bentley

    Image: Felsic spherulite from Shetland
    Image Owner: Callan Bentley



    Description:

    These spherules are primary igneous textural elements in this felsic rock. They consist of radial "hedgehogs" of crystals clustered around a common point of nucleation.



  39. Scale

    Snapshot Title: Scale
    Taken by: Callan Bentley

    Image: Felsic spherulite from Shetland
    Image Owner: Callan Bentley



    Description:

    This is 1 cm wide.



  40. Stylolite

    Snapshot Title: Stylolite
    Taken by: Callan Bentley

    Image: Ulster White Limestone ("The Chalk") with belemnite fossil
    Image Owner: Callan Bentley



    Description:

    Pressure solution seam



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