Another way to cook rocks: in water!

Remember the blogpost where experiments were compared to cooking? Well, we can take that parallel even further and use more water to heat the rock with! As I mentioned in a previous post, rocks at the seafloor can get altered when fluids move through them. We call these hydrothermal systems, which can have spectacular venting sites on the seafloor. One way to find out more about the process behind these systems is studying natural examples that underwent hydrothermal fluid circulation; another way is by trying to reproduce these processes in the lab. But how can we do this when water is involved? Continue reading

Behind the scenes: starting a petrological experiment!

AC-2-img-1
1. A: Gold capsules (not bullets) containing rock and fluid, 2 cm in length. B: Balance used to weigh capsules and their content

I had never thought experimental petrology could resemble cooking to such an extent. With some imagination you can replace the basic ingredients of your favourite pie recipe and use a rather special type of oven to make the magic happen. Actually, every experiment has its own experimental “cooking” setup, with the desired quantities of components raised to specific pressures and temperatures that will (hopefully) lead your experiment to success. Continue reading

How to reproduce inner Earth pressure and temperature in a laboratory

Earth’s inner structure
Earth’s inner structure.

Drilling allows us to collect samples from the inner Earth, which provide us an idea of its composition and internal hidden processes.The deepest scientific drilling on Earth reached 12.262 km into the crust (Kola Superdeep Borehole in Russia), but what does it represent? The Earth has a radius of 6,378 km which is significantly greater than the 12 km of crust drilled at depth in Russia (Image 1). However it is extremely costly, time consuming, and for the moment there is no existing technology that would allow us to drill deep in the upper mantle (from 5 to 100 km deep). Therefore in order to complete our knowledge of Earth’s interior, geologists have to use different strategies, for example geophysical imaging. Another, less known possibility is experimental petrology, or “how to cook your own rocks”. Continue reading