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Mika McKinnon @mikamckinnon
, 27 tweets, 26 min read Read on Twitter
#Inktober index card 1: Relative dating is a snippet of simple magic. As soon as you stop to think logically, entire landscapes unravel in eagerness to tell you their story. #sciart #geology #teaching
#Inktober index card 2: #DonnaStrickland is the 3rd woman to EVER win the #NobelPrize in #Physics for her work on chirped pulse amplification, an engineering #optics technique to create short, intense laser bursts with broad industrial & medical applications. #sciart #cansci
#Inktober index card 3: I’m #TeamIce for #MinCup2018, infatuated with this simple & elegant mineral.

Here’s my interpretation of ice from chemical composition to melt molecules to crystal hexagons. I couldn’t find my blue pens for sketching the #thinsection. Shush.

Vote ice!
#Inktober index card 4: Default doodle of negative space.
#Inktober index card 5: Default doodle of space. #sciart

(When people ask for my autograph at conventions, they nearly always get a variant of this spaceship.)
#Inktober index card 6: Default doodle.

I’m pretty sure I have several hundred variations on this theme doodled on margins of notes since at least middle school, maybe earlier. Gears? Zippers? RNA & enzymes? Maybe #sciart, maybe not.
#inktober index card 7: My beloved landslides! 💚 Landslide runout analysis usually mixes topography, volume, & material (for both surface & slide) to determine #landslide #hazard. #geology #sciart
#inktober index card 8: Landslide runout analysis gets a wee bit funky off-planet.

It’s an adventure! ...with far too few case studies to narrow down more important factors, sigh. #landslide #hazard #sciart
#inktober index card 9: Coastal Engineering is all about understanding (& occasionally manipulating) where sediment is eroded & deposited.

The swash/backwash driving longshore drift is the subtle mechanics behind many lawsuits on lost beaches. #Geoengineering #sciart
#inktober index card 10: My students are taking an exam today.

Their stratigraphic section to untangle is far less evil than this. #geology #sciart #iteachgeo #stratigraphy
#inktober index card 11: Drumlins! Gotta love these teardrop-shaped periglacier landforms. #geomorphology #sciart

Read more:…
#inktober index card 12: Glaciers leave behind the strangest landforms with bizarre contour maps.

Teardrop-drumlins point in the direction of glacial flow. Odd, sinuous ridges are reminders of subglacial rivers. #geomorphology #sciart
#inktober index card 13: I’m always hypnotized by flower patterns, but I never create them myself. #sciart
#inktober index card 14: Dots? dots.

Or maybe cells with permeable membranes. TBD. #sciart
#inktober index car 15 is a bit of a fail: Turns out I have no idea how to schematically indicate chemical weathering.

#inktober index card 15: Another default doodle — I easily have hundreds of these gears scribbled along the edges of homework. #sciart
#inktober index card 17: Loose, dry souls can compress unevenly when wet. It’s an important part of #geoengineering to ID soft soils before building anything.

(This bit of #sciart was totally inspired by a lecture slide that’s been passed down for generations of EOS210.)
#inktober index card 18: Next week is faults & folds. I love structure (& the cool landforms you can get from differential weathering), but few sections are as easy to interpret as this.

#structure #geology #outcrop #sciart
#inktober index card 19: Doidle doodle doodle
#inktober index card 20: Home.

#Vancouver is a city of glacial till shot through with volcanic dykes. I’m on the north shore, out city clinging to the flanks of anancient volcano. A river delta sits to the south, sediment fresh & soggy.

#geology #sciart
#inktober index card 21: When mud dries out, the top layer shrinks, generating strain relieved by polygonal (often hexagonal) cracking. Desiccation cracks taper with depth, later infilling with other materials. #geology #sciart

(Look for similar in clouds, lava, & cheesecake!)
#inktober index card 22: Flood!

A river stays within its channel (+/-), but in extreme conditions will overflow to inundate its floodplain.

At least, it used to.
We engineer rivers to not flood as often now, which is cool except for (many) unintended consequences.

#inktober index card 23: It’s structural geology in class today, so we’re talking folds, faults, and allllll the jargon.

It’s easy to think of rocks as brittle & breaking (faults). It’s harder to imagine them as ductile & deforming (folds). #geo #sciart
#inktober index card 24: Structural geology, redux.

Under enough stress, rocks bend (ductile) or break (brittle). Faults “throw up & heave out!”

Under compression: reverse (& thrust) faults or folds

Under tension: normal faults

Under shear: strike-slip (not shown)

#inktober index card 25: Fault anatomy!

Footwall is where you stand.
Hangingwall is where you hang your lamp (or canary).

Hanging wall goes down? Normal fault
Hanging wall goes up? Reverse fault
No hanging wall? Strike-slip fault.
No movement? Fracture.

#geology #sciart
#inktober index card 26: Home, redux

BC is a subduction boundary where the Pacific dives under N America.

An accretionary wedge of sediments glom to the forearc margin of Vancouver Island while melting cold, wet oceanic plate feeds our mainland volcanic arc. #tectonics #sciart
#inktober index card 27: Home, but bigger

#BC is leftover bits scraped onto North America during subduction

The Rockies are a seam of folded, faulted rocks, with metamorphosed volcanics bracketing sediment-strewn valleys of accreted terrains & glacial detritus. #sciart #geology
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