When in Earth's history did the concentration of rare earths concentrating in deep-sea muds occur?

The depositional age of deep-sea sediments is considered to be an important clue to elucidate the formation mechanism of deep-sea mud enriched in rare-earth elements ("REY-rich mud"), and furthermore, to predict its distribution in the global ocean.

Ichthyoliths, microfossils of fish teeth and denticles, are a kind of microfossils in deep-sea sediments that has been studied since the 1970s as a constraint on the depositional age of pelagic clays (see photo).

Ohta et al. (2020) Scientific Reports

However, traditional research methods required enormous amount of time and effort to pick the fossils from sediment samples and to determine their names.

To overcome this challenge, we are conducting research to automate the observation of fossils using deep learning (AI).

Mimura et al. (2022) have established a system to detect only tooth fossils from slide images containing various particles by combining a model that estimates the contour of particles from microscope images and a model that predicts their class from clipped individual particle images.

In future, we aim to establish a system that can more finely classify the detected fossils and more accurately determine their ages based on a large amount of image data.