FLYSCH ASTRONOMY

Highly revealing cycles

The flysch in Zumaia is neatly arranged. The limestone and marl are cyclically interbedded in a well-defined pattern that mirrors Milankovitch’s astronomical movements.

These variations control the amount of energy we receive from the sun and therefore Earth’s climate cycles and sedimentation on the ocean floor.

The flysch provides a detailed snapshot of the climate 60 million years ago. It is the music of the spheres set in stone.

Milankovitch’s astronomical cycles

20,000 years

Precession cycle

Each rotation lasts for around 20,000 years and results in limestone-marl couplets. This makes the flysch a highly precise clock for measuring geologic time.

Each layer is 10,000 years old!

Eccentricity cycle

Earth’s orbit oscillates between more circular and elliptical shapes. This eccentricity varies every 100,000 years and has resulted in 5 neatly arranged groups of limestone-marl couplets, each representing 20,000 years.