Picture it and write: The history at our feet.
It is that time again for another picture it and write from ermilia’s blog here. Again the rules are you take the picture and write a piece about it. To reiterate, the picture is not mine. Here is my attempt. Enjoy! Joe
The history at your feet
All rocks tell a story. That’s what Professor Kelly would tell us during freshman geology lectures. I supposed we understood what he meant, in theory. But I didn’t really grasp what he was on about until we went on our third year field-trip, all the way to Tenerife, in the Canary islands.
We had all gone, figuring the three days we were going to spend actually in the field were worth the four we were going to spend on the beach and in the clubs. The first place we visited was a large mountain by the name of El Tiede, it was a Decade volcano, one to watch.
Prof. Kelly was in his element, pointing at the various rocks and formations asking us to identify what they were. “That black stuff over there, what is it?” “Basalt Professor!” “And the grey material there?” “Compacted ash!” “And this porous rock here?” “Pumice stone professor!”
In time, we reached a ledge about half way up the volcano. There Professor Kelly bade us to stop and look out over the vista. “Remember I told you that rocks tell you a story? Tell the story of here.”
Julie, the swot started by pointing out a long streak of black going into the distance “Basalt flow! Lava eruption, slow flowing!” Prof. Kelly nodded approvingly “And what about the yellow-white region beside it?” I ventured “Pumice stone, Pyroclastic flow, fast flowing.” “Not bad Joe! Can you see anything else?” I looked, puzzled at the whitish expanse. Then something came to me “The pumice crosses over the Basalt! The pyroclastic flow happened after the lave eruption!”
“Very good!” Prof. Kelly Answered “Notice how the rest of the plain had a grey colour, what does that tell us?” Julie again “That there had been ash fall there before that!” He grinned “Exactly! So now you can see that there is a basic story here. But the rocks can tell us more! Follow me!”
We hiked back down the mountain. With the professor regaling us with how we could derive the age, and the origin of the rocks through stratigraphy and isotope analysis. “If you’re lucky” he said as he approached a small hole on the brush-filled plain, “Then you can find even smaller, almost personal tales. Look at this” We all approached the hole and looked in.
Down there was a collection of rocks, forming a square, like the foundations of a house. They looked blackened. Professor Kelly’s voice became quieter, “The rocks tell us a story. It can tell us some of their story. The ash had been falling here for millions of years, but they didn’t know that. They only knew that this place was fertile, the perfect spot to grow crops. The first eruption happened in the spring, red-hot lava travelled down the edge of the volcano, slow but unstoppable. But the miracles of topography it missed this house and they must have thanked god that they had been spared. But it was only the beginning. Five months later the volcano erupted again. Much more violently than the first time.” He pointed at the ledge we had looked out from. “A whole side of the mountain had blasted off forming s flow of millions of tons of superheated ash and rubble, travelling at over four hundred miles an hour. Straight down here.” He looked again into the hole “They must have just had time to get into their house before the flow. It would have done them no good. The roof would have smashed in in an instant. This place was found my a man digging a well nearly twenty years ago. Right there they found what might have been a meal, bread, burned to charcoal and beside it some charred bones, of at least two people. The rocks tell us their story. And what they tell us might help and prevent scenes like this happening again.”
That last line hit us like a ton of bricks. The science, the art of geology became more real, more immense then it had ever been before. All rocks tell a story. That is a line that I have kept with me ever since. And is what I tell my own students, so many years later. As I show them the history at our feet.