Alessandro Grippo, Ph.D. STRATIGRAPHY Part 3 How can I compare "deep time" to something more familiar? What do all those names mean?   Understanding deep time Last Updated  •  March 31, 2015    The concept of "deep time" is not very easy to grasp: it might settle in the back of our minds as a period extremely remote but then, when we look at the numbers for Eras and Periods we realize that there is an abyss of time even between those Eras and Periods. We are used to "long time intervals" of tens, hundreds, maybe thousands of years, time intervals that refer to human history either personal history (of a single person or of her/his family and friends), or the history of human civilization. To give a better idea of what "deep time" means, I built this figure. In here, I compressed Earth's history within the boundaries of different ages of a human being. Whether you are a very young person or an older adult, you can find out how old were you when an Eon or an Era changed into another. Age 0, that is the time when you were born, is at the bottom of the columns and is matched to Earth's origin. Your actual age (rounded to 10) is in purple at the top of the columns. Let's say for instance that you are 20: take a look at the 20 years column. When you compress Earth's age in 20 years, you are as old as Earth. For instance, dinosaurs became extinct at the Mesozoic/Cenozoic boundary, and that is when you, and Earth, were 19 years and 8 months old. You can soon realize from this figure that most of what we know about Earth's history is relatively recent: in fact, not much information is available from when Earth, and you, were much younger.   the meaning of the names of the Geological Time Scale Last Updated  •  March 31, 2015    The development of the Geological Time Scale as we know it today can be probably attributed to R. Murchison, who defined the Silurian System in 1835 on the basis of its fossil content. EONS (EONOTHEMS) The term Phanerozoic comes from the Greek phaneros (evident, visible) and zoikos (animal), zoion (living being). It thus means "period of evident life". This reflects the fact that fossils, remains of ancient life forms, become abundant in the rock record during this time. The term Proterozoic comes from the Greek proteros (former, earlier) and zoikos (animal), zoion (living being). It thus means "period of ancient life". The Proterozoic is in fact a time during which life is present but its fossils are small, scattered, and in general not very evident (see the definition of Phanerozoic). The Proterozoic ends at the base of the Cambrian, the first Period of the Phanerozoic. The Archean is an Eon that started right after the Hadean, 4 my ago, and ended 2.5 by ago. Both these dates are chronometric (that is, they have been not been established through fossils). The meaning of Archean comes from the word "archaic", or very old, primitive. It thus mean a very ancient, primitive time interval. The Hadean is to the oldest geologic Eon. Starting at about 4.6 billion years ago (by), it ends at around 4 by (or 3.8 by according to different authors). This limit is defined chronometrically and not biostratigraphically. The name of this Eon derives from Hades, the Greek unseen world, or hell; the term implies the "hellish" conditions that existed on Earth during this time. The name was chosen by Preston E. Cloud, Jr. in 1972. ERAS (ERATHEMS) The name Cenozoic comes from the Greek kainos (new) and zoikos (animal), zoion (living being). It thus means "(period of) new life". The name Mesozoic comes from the Greek meso (in between, middle) and zoikos (animal), zoion (living being). It thus means "(period of) middle life". The name Paleozoic comes from the Greek palaios (old) and zoikos (animal), zoion (living being). It thus means "(period of) old life". PERIODS (SYSTEMS) Cenozoic The name Quaternary (G. Arduino, 1760) is the only remnant of an ancient classification that included the Primary (now Paleozoic), Secondary (now Mesozoic) and Tertiary (now Cenozoic) Eras. The Quaternary was also an Era but it has been reduced to the rank of a Period belonging to the Cenozoic. The International Commission on Stratigraphy is actually debating the opportunity of renaming it. The term Neogene (Hoernes, 1853) simply means "new-born" in ancient Greek. The term Paleogene simply means "ancient-born" in ancient Greek. Mesozoic The term Cretaceous (d'Halloy, 1822) comes from the Latin creta, or chalk. It means thus "the time of the chalk", and it originated because of the abundance of chalk of this age in the Paris Basin, in France The term Jurassic (Von Humboldt, 1795) originates from the Jura Mountains, a mountain chain located between Switzerland and France The term Triassic (Von Alberti, 1834) comes from the Latin Trias, meaning a System organized in three parts named, from the bottom to the top, Buntsandstein (German for New Red Sandstone), Muschelkalk (German for mussel limestone, or shell limestone) and Keuper (an old German miner name for "iridiscent marls", a marl being a mixture between shale and limestone). Paleozoic The Permian (Murchison, 1841) was named after rocks from the Perm Basin, in Russia. Some sources mantain that Murchison wanted to make a reference to the ancient kingdom of Permia, rather than the city of Perm itself; in any case, that lost kingdom is today part of a Russian federal republic whose capital is the city of Perm The Pennsylvanian (Williams, 1891) is named after the state of Pennsylvania, in the USA* The Mississippian (Williams, 1891) owes its name to the fact that rocks of this age crop out in the Mississippi valley in the USA* *please note that the names Pennsylvanian and the Mississippian are only used in the United States in place of the Carboniferous The Carboniferous (Phillips, 1835) was so named because of the abundance of coal (carbon) identified in rocks of this age in western Europe The name for the Devonian (Murchison and Sedgwick, 1840) comes from the region of Devon, in England, UK The term Silurian (Murchison, 1835) comes from the Latin Silures (an ancient Celt population of Wales, in the UK) The term Ordovician (Lapworth, 1879) comes from the Latin Ordovices (an ancient Celt population of Wales, in the UK) The term Cambrian (Sedgwick, 1835) comes from the Latin word Cambria (the ancient name of Wales, in the UK) CENOZOIC EPOCHS (SERIES) The term Anthropocene (Zalasiewicz et al., 2008) is by no means official and it has been proposed in February 2008 in GSA Today. The Anthropocene denotes the current interval of anthropogenic global environemntal change, starting with the Industrial Revolution in England in the late 1800s, and it canbe identified on stratigrapfic grounds. record, Its meaning comes from the Greek andros (meaning "man") and kainos (meaning "recent") and means man-influenced recent times. The term Holocene (Internation Geological Congress, 1885), also called Recent or Postglacial in the past, comes from the Greek words holos (meaning "whole") and kainos (meaning "recent"), thus referring to fact that this epoch is the most recent division of Earth history The term Pleistocene (Lyell, 1833) comes from the Greek words pleistos (meaning "most") and kainos (meaning "recent"), and it refers to the fact that rocks of this age contained the highest amount of recent species when compared to older Neogene rocks The term Pliocene (Lyell, 1833) comes from the Greek words pleios (meaning "more") and kainos (meaning "recent"), referring to the fact that more recent species were found in these rocks than in those of the Miocene The term Miocene (Lyell, 1833) comes from the Greek words meios (meaning "less") and kainos (meaning "recent"), referring to the fact that fewer recent species were found in these rocks than in those of more recent age The term Oligocene (von Beyrich, 1854) comes from the Greek words oligos (meaning "few" or "scanty") and kainos (meaning "recent"), and refers to the small number of modern animals that originated during this relatively recent epoch The term Eocene (Lyell, 1833) comes from the Greek words Eos (meaning "dawn") and Kainos (meaning "recent"), and indicates the rise, or dawn of recent life The term Paleocene (Schimper, 1874) comes from the Greek words palaios, meaning "ancient" or "old", and kainos, meaning "recent", and it refers to the oldest epoch of recent life. CENOZOIC and MESOZOIC AGES (STAGES) Quaternary Pleistocene Upper is simply the uppermost age (or stage) of the Pleistocene Ionian comes from the Ionian Sea, Italy Calabrian comes from the Calabria region, Italy Gelasian comes from Gela, Caltanissetta, Italy Neogene Pliocene Piacenzian comes from Piacenza, Italy Zanclean comes from Zancla, the pre-Roman name for Messina, Italy Miocene Messinian comes from Messina, Italy Tortonian comes from Tortona, Alessandria, Italy Serravallian comes from Serravalle Scrivia, Alessandria, Italy Langhian comes from the Langhe region of Italy Burdigalian comes from Burdigala, the Latin name of Bordeaux, France Aquitanian comes from the Aquitaine region of France Paleogene Oligocene Chattian comes from the Latin Chatti, an ancient tribe from Kassel, Germany Rupelian comes from the Rupel River, in Belgium Eocene Priabonian comes from Priabona, Vicenza, Italy Bartonian comes from the Barton Beds, in Hampshire, England, UK Lutetian comes from Lutetia, the Latin name for Paris, France Ypresian comes from Ypres, Belgium Paleocene Thanetian comes from the Thanet Sands, on the Isle of Thanet, England, UK Selandian comes from the Seeland, in Denmark Danian comes from Denmark Cretaceous Upper Cretaceous Maastrichtian comes from Maastricht, The Netherlands Senonian comes from Sens, France Campanian comes from Champagne, France Santonian comes from Saintonge, France Coniacian comes from Cognac, France Turonian comes from Touraine, France Cenomanian comes from Cenomanum, the Latin name of Le Mans, France Lower Cretaceous Albian comes from Aube, France Aptian comes from Apt, France Barremian comes from Barreme, France Neocomian comes from Neocomum, the Latin name of Neuchatel, Switzerland Hauterivian comes from Hauterive, Switzerland Valanginian comes from Valangin, Switzerland Berriasian comes from Berrias, France Jurassic Upper Jurassic Tithonian comes from the Greek Tithonus, a mithologic figure who fell in love with the goddess of dawn. The Tithonian appears in fact at the dawn of the Cretaceous Kimmeridgian comes from Kimmerdige, England, UK Oxfordian comes from Oxford, England, UK Middle Jurassic Callovian comes from Kellaway, England, UK Bathonian comes from Bath, England, UK Bajocian (d'Orbigny, 1852) comes from Bajeux, France Aalenian (Mayer-Eimar, 1864) comes from Aalen, in Germany Lower Jurassic Toarcian comes from Thouars, France Pliensbachian comes from Pliensbach, Germany Sinemurian (Oppel, 1856) comes from Semur, France Hettangian (Oppel, 1856) comes from Hettange, France Triassic Upper Triassic Rhaethian comes from the Rhaetic Alps, in Italy, Austria and Switzerland Norian comes from the name of a Roman province in present-day Austria Carnian comes from Carinthia and Carnia, region in the Alps of Austria and Italy Middle Triassic Ladinian comes from the Italian Ladini, a people living in the Italian Alps Anisian comes from the Anisus River in the Alps of Austria Lower Triassic Olenekian comes from the Olenyok (or Olenek) River in Siberia, Russia Induan comes from the Indus River, in Pakistan Go to part 1 | Go to part 2 | Go to the Notes Page | Go to the Home Page © Alessandro Grippo, 1994-2015