Comments on: New Project Aims to Drill to the Earth’s Mantle, 3.7 Miles Down

By: JohnD

JohnD — Wed, 10 Oct 2012 17:39:26 +0000

I’m sorry – I forgot to provide a link for the IODP’s workshop into the questions that sparcboy raises:
http://campanian.iodp.org/MantleFrontier/0_Reaching_the_Mantle_Frontier_Workshop_Report.pdf

By: JohnD

JohnD — Wed, 10 Oct 2012 13:26:41 +0000

Sparcboy, it is my understanding that the main reason for drilling away from the mid-ocean ridge has little to do with the mantle and much to do with the technology. It is very difficult to drill into a hard material, such as basalt. The drill is likely to slip and the hole will make very little progress; anyone who has ever tried to drill a hole into a ceramic tile will understand the problem. The drilling program is trying to do that in the dark by remote control.

By moving away from the ridge to a location with a modicum of sediment, they are able to establish a hole where the drilling is (relatively) easy and can use that to stabilize drilling as they go deeper. In addition, this moves the drilling away from the region of most intense hydrothermal flow, which reduces the possibility of a fluid-induced blowout or hole loss.

So the drillers are balancing the need for recent mantle material against the need for an operation that is safe and lower cost.

By: sparcboy

sparcboy — Tue, 09 Oct 2012 17:47:18 +0000

John, it seems the most recent mantle material would be that being exuded at a mid-oceanic ridge, a process captured on film. In a brief search of the web, I could not find any details explaining the need to drill for mantle material as opposed to collecting it at a mid-oceanic ridge. As you seem to be more knowledgeable on this subject, a link would be much appreciated. Thanks in advance.

By: JohnD

JohnD — Mon, 08 Oct 2012 13:53:45 +0000

Sparcboy, though none of the commercial wells in the Gulf of Mexico have deliberately drilled into the mantle, the physics of drilling doesn’t change. The reason that they are avoiding the crust is in order to get mantle material that is as recent as possible.

And why should the oil companies donate materials if their methods (which would be far more valuable as they will save time, materials, and money) are ignored?

Mihai, the samples of mantle material will probably be different than what is obtained from volcanoes. Most volcanoes are sourced from deeper in the mantle and the magma undergoes differentiation on the way up. This will be an opportunity to see what the mantle is like near the mantle-lithosphere boundary.

By: mihai

mihai — Thu, 04 Oct 2012 21:24:03 +0000

won’t the samples they get from the mantle be identical to the magma you can get from volcanoes?

By: sparcboy

sparcboy — Thu, 04 Oct 2012 20:02:02 +0000

The objective of this project is to acquire samples, via cores, near the mantle. As stated, the engineering is designed to drill through as little crust as possible. None of the wells drilled in the Gulf of Mexico come anywhere near the mantle.

It would be nice if Exxon, Shell, BP, etc. would proactively donate funds, equipment and engineering expertise to the project, if they already haven’t.

By: JohnD

JohnD — Thu, 04 Oct 2012 16:45:21 +0000

the IODP’s drilling vessel, the Chikyu, set a world record by drilling almost 7,000 feet below the seafloor off Japan and bringing up rock samples That's not as impressive as it sounds. In the Gulf of Mexico, oil companies have been drilling much deeper than that for decades. In 200, the Deepwater Horizon drilled to 35,050 ft or five times deeper than the IODP. Sadly, the scientific community has refused to learn from the oil industry (witness the ORION program's insistence on developing new platforms instead of using industry standard ones that would have cut costs by a factor of ten).