December 2, 2011
For Scale
Posted by Evelyn Mervine
Lens Cap for scale on a carbonated peridotite outcrop in Oman, 2009.
When geologists take photographs of rocks, they often include items to indicate scale. When I’m doing fieldwork, I generally use a ruler or a hammer to indicate scale. Sometimes, I use other items such as my field notebook or my camera lens cap. When I’m not doing fieldwork and I wander across some interesting rocks, I use anything available to indicate scale– from flip-flops to coins to my own hands and feet.
Below are a collection of scale pictures taken during my geological wanderings over the past several years. You can read some of my musings on scale in this older post of mine The Scale of Things.
Hand for scale on a sedimentary outcrop showing filled-in burrows (trace fossils), South Africa, 2011.
Ruler for scale on a manganese-covered basalt boulder, Indian Ocean, 2007.
Coin for scale on a granite wall, South Africa, 2011.
Coin for scale on a xenolith in granite, South Africa, 2011.
Hand for scale holding granite saprolite, South Africa, 2011.
Finger for scale on a loosely-consolidated sedimentary rock, South Africa, 2011.
Chisel for scale on a travertine deposit, Oman, 2009.
Geologist for scale next to a travertine pillar, Oman, 2009.
Field notebook for scale on carbonated peridotite, Oman, 2009.
Sharpie pen for scale next to a carbonate-serpentine vein in peridotite, Oman, 2009.
Hammer for scale on top of a travertine formation, Oman, 2009.
Bottle (trash found in stream) for scale in an alkaline streambed, Oman, 2009.
Rite-in-the-Rain ruler for scale on carbonated peridotite, Oman, 2009.
Geologist for scale in front of some sandstone cross-bedding, South Africa, 2010.
Hand for sale next to some rock art hands on sandstone, South Africa, 2010.
Foot for scale on sandstone, Red Rocks, Nevada, 2011.
Foot for scale on limestone, Wyoming, 2011.
Sunglasses for scale on sandstone, South Africa, 2009.
Geologist for scale in front of sandstone cross-bedding, South Africa, 2009.
Flip-flop for scale next to a pot hole, South Africa, 2011.
Dogs, when available, can also make good scales.
Mia and the dinosaur
what’s the story with the pot hole? is that man made or natural? I know nature can make some pretty cool round holes.
That’s a natural pothole in the Brandywine River in the Cederberg Mountains. The sandstone along that river is covered in natural potholes– perhaps I’ll write up a separate post on that topic sometime.
Whenever possible I put a plastic dinosaur in the picture just because I like saying ‘dinosaur for scale’
Please don’t use coins as scales. Coins can vary considerably in size, and if you don’t know which currency it is, you probably won’t know the size, and so you might as well not have the scale as it is next to useless. For this reason Wikipedia / Wikimedia suggests people don’t use coins as a scale in their photos, as – for example – I as a Brit have no idea how big a US quarter is. http://commons.wikimedia.org/wiki/Category:Images_with_coins_to_indicate_scale
It’s not difficult to make a pocket-sized scale marked in centimetres and/or inches, say 10 or 15cm long, laminate it and keep it with your camera. Everyone knows what centimetres are (I hesitate to say inches as well, as the US seems the only country doggedly sticking to them nowadays); not everyone knows how big a dime is.