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Earth and Space Sciences · Glossary

What is Cyclostratigraphy and astronomical tuning?

Also known as: cyclostratigraphy · astronomical tuning

Definition 16.9 University Earth and Space Sciences — Year 3 · Chapter 16 — Sequence Stratigraphy

Cyclostratigraphy identifies and measures regular cycles in sedimentary successions and interprets them as records of periodic forcing, mainly the variations of the Earth’s orbit and axis. Astronomical tuning assigns ages to a succession by matching its cycles, one by one, to a computed astronomical series (eccentricity, obliquity, precession or insolation), which turns the cycles into an age model.

Periodograms of the benthic oxygen-isotope stack LR04 in two windows (detrended, Hann taper, normalised to the largest peak); dotted lines mark periods of 100, 41, 23 and 19\, kyr. (a) The last million years: the 100\, kyr band dominates. (b) From 2.5 to 1.25\, Ma: the 41\, kyr obliquity dominates.
Periodograms of the benthic oxygen-isotope stack LR04 in two windows (detrended, Hann taper, normalised to the largest peak); dotted lines mark periods of 100, 41, 23 and 19 kyr19\,\mathrm{kyr}. (a) The last million years: the 100 kyr100\,\mathrm{kyr} band dominates. (b) From 2.5 to 1.25 Ma1.25\,\mathrm{Ma}: the 41 kyr41\,\mathrm{kyr} obliquity dominates.
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