Chapter 7 · Try it yourself

Core Driller

The seafloor is buried under a slow snowfall of sand, dust, shells and even metal, and it never gets cleaned up. Push a hollow pipe into it and pull it back out, and you have a core: a stack of layers with the newest at the top and the oldest at the bottom. Pick a place, drill, and read what the mud remembers.

Five drilling sites

Seafloor cross-section.

Not to scale: five far-apart places stitched into one strip so you can compare their depths. The dashed line is the carbonate compensation depth (CCD). Tap a numbered site to pick it.

Choose a drilling site

Your cores so far

  • None yet.

Every core is 10 m long unless the drill hits rock. Watch how much time fits in the same 10 m.

The core

No core yet.

Pick a site and drill

Each site sits in a different part of the ocean: near land or far from it, under rich or empty surface water, shallow or deep. Those three things decide what piles up on the bottom.

Simplified model: every core is 10 m long (unless it hits rock) and the layers are illustrative, chosen to show the typical sediment at each kind of site. Accumulation rates are rough textbook values (Webb, Introduction to Oceanography, 12.6): coarse lithogenous sediment near land about 1 m or more per 1,000 years, biogenous ooze about 1 cm per 1,000 years, abyssal clay about 1 mm per 1,000 years. Real rates vary a lot from place to place. The CCD is usually about 4–4.5 km deep and much shallower near the poles (Webb 12.6); this page draws it at about 4,500 m, rising toward Antarctica. Manganese nodule growth of about 1–10 mm per million years and the metals they contain: Clarion–Clipperton Zone summaries of International Seabed Authority data.