Life on board of a scientific drilling vessel

Today, we are getting an impression of how daily life is on board of a scientific drilling vessel. At the moment Carlotta is on board the Joides Resolution, one of the scientific drilling ships of the International Ocean Discovery Program (IODP). She is part of the Expedition 360 Southwest Indian Ridge with its goal to drill into rocks of the lowermost oceanic crust and the crust-mantle transition zone (see blogpost about the oceanic crust). The SW Indian Ridge is a very slow spreading ridge (that means that the oceanic plates diverge about 8 mm/yr), located south-east of Madagascar (see image 1). The expedition started on 30th November, leaving Colombo and will end 30th of January once Port Louis will be reached. You see, this is quite a long time she is spending at sea!

I asked Carlotta a few question about how it is to be part of such an adventure and how it feels to work on a ship that moves all the time with the same group of people for 2 months!

Image 1: Map showing the start (Colombo) and end (Port Louis) points of the cruise (in orange) as well as the transition (yellow dots) from Sri Lanka southwards to the drilling spot (dot in red). Map taken from IODP.

Behind the scenes: starting a petrological experiment!

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.

How to reproduce inner Earth pressure and temperature in a laboratory

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”.