Monday, January 14, 2019

How The Metamorphosis of Iron Leads to Life

I was cutting yet another trail on the property when I ran into this snarl of steel cable, right where my trail was going.

This time I was cutting my serpentine way through a neglected sliver of our property between the county road and the electric-coop right of way. I was at the top of a hill looking through the fence and down into the cut the county road sits in.

As it's far too large to be used in fence-building, the only other thing up there besides the road, I suspect this 3/4 inch cable had some sort of association to the road-builders that cut a notch through the top of this hill. The road has been there for 150 years and, according to the 78 year old neighbor on the ranch to the south, he remembers the road being "improved" with cuts and fills some 60 to 65 years ago.

Maybe the cable was wound around the spools of a steam-shovel ripping a slash through the hill and there was a back-lash which snarled it all up, or perhaps it was used in an attempt to drag some stuck piece of equipment out of a mud-hole and this is the leftovers when it snapped under the pressure. Whatever it was used for back then, right about the time I was just learning to walk, something must have gone wrong for the crew to abandon it here in the woods; right in the path of my new trail.

I made a brief attempt to pull it up but over the years the ground and tree-roots have swallowed much of it and I lost the wrestling match.

OK, so in actuality, it kicked my ass. . .

I could have re-routed my trail around it, but the woods are thick up here and I was already one heartbeat away from an ambulance ride due to trying to drag it out of the ground, so instead, while the cable continues to slowly morph back into the earth it came from, I decided to designate it as part of my daily regime, using it as a balance and agility-improving obstacle as I dance my way through the foot-snatching loops while I'm doing my laps around the property. (Yeah, I know, a pretty pathetic excuse. But hey, you do whatcha gota do.) 

Iron Ore docks in Duluth Minnesota 1915. They are not much different today and are used to transfer Iron Ore (Now days taconite) from rail to lake freighter.

OK, I know that I titled this post with the word metamorphosis, which is a biological process and the iron this steel cable was made with is an element, but I'm actually not using the word incorrectly, at least not entirely.

In its day the Henry Ford II, a self unloader, was considered one of the prettiest of the lake freighters
I grew up in the land of iron mines and the lake freighters hauling ore to smelters, but even so, like many, at least those that stopped and thought about it, I just assumed the iron being ripped out of the ground had something to do with the earth's iron core and volcanic activity. It wasn't until later, and no thanks to our school system of the day, that I discovered that that is wrong. And that the truth is actually quite fascinating.

The iron ore we mine is from sedimentary rocks not the igneous rock of cooling magma. Yep, that's right, Iron ore comes from rock formed by stuff settling out of water.

Some 1.8 billion years ago (Yep, that's illon with a B!) the earth's oceans were chocked full of dissolved iron and it wasn't going anywhere because there was virtually no dissolved oxygen in those waters.. Then along came photosynthesizing algae, eventually followed by its more complex cousins, all creating oxygen which didn't even have time to unpack its bags before combining with the iron (Yep, there's the biological connection) forming hematite or magnetite, the two main iron ore types, which settled to the sea floor.

In the image above the grey bands are hematite, high-grade ore, and the red are jasper, a low-grade ore that today is processed to extract taconite which is then turned into iron. The hypothesis is that the banding might have something to do with seasonal effects on the oxygen producing organisms.

But the thing to remember is that it wasn't until the vast amounts of dissolved iron had all been settled out and stopped hogging the oxygen, that there was enough O2 left over for the rest of us, for any carbon-based, non-photosynthesis life. There is no limestone older than iron ore deposits because there were no corals, forams, and mollusks around to form limestone because of free iron. And it wasn't until much later that there was enough oxygen making it into the atmosphere to support non-aquatic life.

In other words, all of the earth's higher forms of biological activity had to wait on elemental iron to get out of the way before they could get their start.

As I sat up there on the top of the hill looking at the flakes of steel cable embedded into my palms from ineffectually tugging on it and thinking about how old those elemental particles were compared to my own, less-than-a-speck-in-the-eye, biologic lifespan, my mind was blown. 

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