Callan Bentley

@callanbentley

"bluebirds, bluegrass, blueschist, blue state, bluesky" Community college geology professor in Charlottesville, Virginia, USA

1.128 Folgt3.406 Follower3.721 Posts

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Callan Bentley@callanbentley· 28d

The bigger of the two marmots I saw today.

Callan Bentley@callanbentley· 28d

Halite casts in Helena Formation limestone on an arête east of Siyeh Pass, GNP, Montana ⚒️

Callan's hand holds up a tan slab of find – grained sedimentary rock with numerous Y shaped and H shaped and boxy dark forms. These are the casts of halide hoppers.

Callan Bentley@callanbentley· 29d

Man, this place... ⚒️

Callan Bentley@callanbentley· 29d

Contact between Helena formation limestone (top, tan) and intrusive diorite sill (lower, dark), Glacier National Park, Montana. ⚒️

Talons fingers provide a sense of scale too and now crop of rock that shows a dark lower half and a tan upper half

Callan Bentley@callanbentley· 29d

Exceptionally round mud chip rip-ups in Grinnell Formation quartzite, Glacier National Park, Montana. ⚒️

A pen serves as a sense of scale next to a white rock with many red dots. Two of the red dots are large and very round

Callan Bentley@callanbentley· 29d

Horodyskia, an enigmatic "string of beads" primary sedimentary structure in the Appekunny Formation of GNP, interpreted by some as the oldest eukaryotic fossil on Earth. ⚒️

Callan's scale pencil next to a slab of fine grained rock with a regular series of ~3mm circles next to it.

Callan Bentley@callanbentley· 29d

Sunset on a full day.

A layer of textured brilliant orange clouds catches the evening light above a mountain range

Callan Bentley@callanbentley· 29d

Really nice cross laminated ripples in Belt sandstone + argillite. Zoom in on the details! ⚒️

Photograph of a vertical cross section through sedimentary strata, with Callan's fingers for scale. In the middle is a body of sandstone that is capped with little peaks of sandstone: ripples that are buried beneath subsequent red mud.

Callan Bentley@callanbentley· Jul 12

Basaltic dike cutting through red Belt argillite strata in little prickly pear canyon, Montana. ⚒️

Layered horizontal sedimentary rocks cut across by a diagonal dark seam

Callan Bentley@callanbentley· Jul 11

Hiked up Sourdough Canyon south of Bozeman, in the Gallatin Range, to view this amazing garnet-bearing amphibolite. ⚒️

A large rock buried in the soil with a pencil for scale. The pencil has black bars on its side that are 1 cm long. The rock is mostly black/dark gray, but it has ~40% of its volume made up by large, well formed reddish-colored garnet crystals that show as polygonal cross sections.

Close up of the rock - showing an area particularly rich in the big blocky reddish garnet crystals, surrounded by much finer grained black and white minerals (amphibole and plagioclase feldspar, probably). The pencil tip provides a sense of scale.

Callan Bentley@callanbentley· Jul 11

Pints and burritos at my favorite Bozeman watering hole.

A pint of Amber Ale emblazoned with SHINE BEER SANCTUARY next to a tinfoil wrapped burrito

Callan Bentley@callanbentley· Jul 10

Trying to figure out what's going on here... Is this supposed to be a cat?

An aerial view of an open landscape, with green grass growing in polygonal fields/meadows. One is bare, and has several pointy corners, and in the middle two small shapes like eyes and a ^ shape that maybe is a capital A or a mammal nose/mouth?

Callan Bentley@callanbentley· Jul 10

Back in Bozeman! ⚒️

The central Bridger Range of Montana, with the Gallatin Valley in the background

Callan Bentley@callanbentley· Jul 9

Yes! In this other shot, you can see the embolus at the tip of each pedipalp:

A burly black spider gripping the edge of a blue plastic basket. At the tip of his two front feelers (pedipalps), there are red apostrophe-shaped organs that are used for transferring sperm to female trapdoor spiders.

Callan Bentley@callanbentley· Jul 9

One of mine attended this amazing weeklong ocean core boot camp! ⚒️

Luke, with his orange hair and orange PVCC Geology Club t-shirt, points at a poster

Callan Bentley@callanbentley· Jul 8

Trapdoor spider rescued from the pool:

A robust spider, like a tarantula but less hairy.

Callan Bentley@callanbentley· Jul 8

Baby Turkey Vulture in a hollow tree. #birds 🪶

A look into a hollow tree, where a wary juvenile vulture of black and white and gray looks out.

Closer look at the juvenile vulture's neck and head.

Callan Bentley@callanbentley· Jul 7

A nice pavement outcrop showing a sequence of multiple geologic events, exposed at Exit Glacier in Alaska. ⚒️

Raw photo showing Callan's hiking boot providing a sense of scale next to a pavement outcrop of bedded sedimentary rock with striations, overlain by gravel.

Annotated photo showing Callan's hiking boot providing a sense of scale next to a pavement outcrop of bedded sedimentary rock (traces of beds highlighted in green) and offset by a yellow fault, with striations (purple) on the outcrop surface, overlain by gravel (red).

Callan Bentley@callanbentley· Jul 2

A current of air, a billion grains of sand... Let time work its magic, and patterns emerge. ⚒️

Callan Bentley@callanbentley· Jul 1

What is going on with this illustration of a "sand grain" though?

Screenshot of a New York Times graphic illustrating the size of "SpudCells" - comparing it to a grain of pollen and an extremely elongated, faceted "Fine grain of sand"

Callan Bentley@callanbentley· Jul 1

Trace fossils in Valdez Group turbidites (bottom of the bedding plane view), Indian Point, Alaska (Turnagain Arm north shore): ⚒️

Unannotated photo of a slab of gray fine-grained sedimentary rock, with a hand for scale. The rock's bedding plane shows numerous hemicylindrical projections, interpreted to be half-casts of crawling trace fossils.

Annotated photo of a slab of gray fine-grained sedimentary rock, with a hand for scale. The rock's bedding plane shows numerous hemicylindrical projections, highlighted in yellow, interpreted to be half-casts of crawling trace fossils.

Callan Bentley@callanbentley· Jun 29

Yaquina Head lighthouse, framed by dead tree on the beach at Starfish Cove, Oregon:

A foggy headland with a lighthouse, with a beach and dead wood in the foreground.

Callan Bentley@callanbentley· Jun 29

May I recommend this tool in your fight?

BRAUN CHIPMUNK CRUSHER dirty old machine.

Callan Bentley@callanbentley· Jun 25

Horrors lurking in the shed.

Large fishing spider with tape measure for scale in inches. The spider is 4 in longer so

Callan Bentley@callanbentley· Jun 25

Brown Pelican trio flying along the coast of Oregon. 🪶🌊

Three pelicans in flight with sea below and ranks of mountains in the misty distance.

Callan Bentley@callanbentley· Jun 25

Bald eagle with its head screwed on up-side-down. Newport, Oregon. 🪶

An adult bald eagle flying (talons on the bottom, visible from underneath) but with its head twisted 170 degrees so its bottom mandible is on top.
(It's watching some gulls warily)

Callan Bentley@callanbentley· Jun 25

Some #birds offshore of Oregon - Surf Scoter, Common Murre, Heerman's Gull, Pigeon Guillemot. 🪶

A weird looking sea duck with an enormous colorful bill

A penguin-like bird which is brightly lit. It has a line going backward from its eye like a chisel groove.

A black white and gray gull that looks as if it is wearing lipstick.

A flying black and white bird with red legs carrying a fish in its beak

Callan Bentley@callanbentley· Jun 24

STEMSEAS2YC team trying on their immersion suits (Gumby Suits) at the start of our expedition. 🌊

Fourteen people wearing bright red full body Neoprene suits open only at the face

Callan Bentley@callanbentley· Jun 23

A shot from a few weeks ago, on the north shore of Turnagain Arm, Alaska: ⚒️

Callan and two other people stand on top of a 20 foot high cliff of gray layered rock. Beyond them is calm water and snowcapped mountains.

Callan Bentley@callanbentley· Jun 22

Really great experience co-leading STEMSEAS 2YC 2026 with these excellent educators. ⚒️🌊