27 September 2011
The geologic timescale: Where did those names come from? Here’s some etymological information I share with my Historical Geology students so that the names become meaningful symbols of ideas, rather than simply of bunch of nonsensical gibberish to memorize…
Phanerozoic eon – Greek for “visible life”
Cenozoic era – Greek for “new life”
Quaternary – Latin for “fourth”
Holocene – Greek for “entirely new”
Pleistocene – Greek for “mostly new”
Neogene – Greek for “new birth / generation”
Pliocene – Greek for “more new”
Miocene – Greek for “less new”
Paleogene – Greek for “ancient birth / generation”
Oligocene – Greek for “few new”
Eocene – Greek for “dawn of the new”
Paleocene – Greek for “ancient new”
* Tertiary (Latin for “third”) is an archaic term left over from the Wernerian chronology. It is no longer officially used as part of the geologic timescale.
Mesozoic era – Greek for “middle life”
Cretaceous — Latin word for chalk (“creta”) and was first applied to extensive deposits of this age that form white cliffs along the English Channel between Great Britain and France.
Jurassic – named after the Jura Mountains between France and Switzerland, where rocks of this age were first studied.
Triassic – refers to the threefold division of rocks of this age in Germany.
Paleozoic era – Greek for “ancient life”
Permian – named after the province of Perm, Russia, where rocks of this age were first studied
Carboniferous – named after the high carbon content of coal-bearing strata of this age in the United Kingdom
Pennsylvanian (US usage)– named after the state of Pennsylvania (USA), where rocks of this age are widespread
Mississippian (US usage)– named after the Mississippi River valley (USA), which contains good exposures of rocks of this age
Devonian – named after Devon, England (UK), where rocks of this age were first studied
Silurian – named after a Celtic tribe called the Silures (UK).
Ordovician – named after a Celtic tribe called the Ordovices (UK).
Cambrian – Roman name for Wales (UK), where rocks of this age were first studied
Precambrian* – all the time prior to the start of the Cambrian (not a formal era/eon name)
* synonymous with “Cryptozoic” – Greek for “hidden life”
Proterozoic eon – Greek for “former life”
Neoproterozoic – Greek for the “new” Proterozoic
Mesoproterozoic – Greek for the “middle” Proterozoic
Paleoproterozoic – Greek for the “ancient” Proterozoic
Archean eon – Greek for “ancient”
Hadean eon – Greek for “hellish” or “unseen” (the Netherworld)
Here’s a Geologic Names handout that I use in my Historical Geology class — feel free to use it if it’s useful to you. Typically, I pass it out in conjunction with page 2 of this excellent geologic timescale visualization from the Kentucky Geological Survey.