the.com/stratigraphy
Reading Earth's diary, one dirt page at a time, oldest entries on the bottom.
means The study of rock and soil layers to work out the order and timing of Earth's past events.
from Built from Latin 'stratum' (something laid down, spread out — from 'sternere,' to spread) plus Greek '-graphia' (writing or description). So literally 'the writing of layers.' The term took shape alongside geology's growth as a science, as scholars realized rock beds stacked up in sequence could be read like a timeline — each layer a sentence in a much older, much slower book.
- core rule
- undisturbed layers stack oldest at bottom, newest on top
- named by
- Nicolas Steno, 17th century, staring at rock layers
- big use
- dates fossils, oil deposits, and ice-age climate shifts
- plot twist
- folding and faulting can flip the whole timeline upside down