A repetitive sequence of rock layers or sediments that formed in response to periodic environmental changes, often seen in coal-bearing strata from ancient seas and swamps.
From Greek 'kyklos' (circle, repetition) + '-them' (a geological suffix meaning layers/strata), describing rocks that show cyclical patterns of deposition.
Cyclothems proved that Earth's climate has naturally cycled for millions of years—geologists reading layered rocks can see evidence of ancient sea-level changes repeating over and over like nature's own rhythm.
Complete word intelligence in one call. Free tier — 50 lookups/day.