1- Hadean: 4600 to 3800 million years ago.
"Hadean" derives from Hades, Greek for "unseen" or "Hell" and suggesting the
underworld or referring to the conditions on Earth at the time. The geologist Preston
Cloud coined the term in 1972, originally to label the period before the earliest-known
rocks. W. B. Harland later coined an almost synonymous term: the "Priscoan period".
Other older texts simply refer to the eon as the Pre-Archaean, while during much of the
19th and 20th centuries, the term "Azoic" (meaning without or before life) was
commonly used.
Priscoan: http://www.customtoolbarbuttons.com/en_google_toolbar_buttons/Priscoan
2- Precambrian: 4600 to 550 million years
Of or belonging to the geologic time period between Hadean Time and the Cambrian
Period, often subdivided into the Archean and Proterozoic eras, comprising most of the
earth's history and marked by the appearance of primitive forms of life. See table at
geological time
.
2.1- Archean:
Of or belonging to the earlier of the two divisions of Precambrian time, from
approximately 3800 to 2500 million years ago, marked by an atmosphere with little free
oxygen, the formation of the first rocks and oceans, and the development of unicellular
life. See table at geological time. 2. Of or relating to the oldest known rocks, those of the
Precambrian Eon, that are predominantly igneous in composition.
http://www.bartleby.com/61/59/A0405900.html
Greek arkhaikos, old-fashioned, from arkhaios, ancient, from arkh , beginning, from
arkhein, to begin.
2.2- Proterozoic:
Of or relating to the later of the two divisions of Precambrian time, from approximately
2500 billion to 570 million years ago, marked by the buildup of oxygen and the
appearance of the first multicellular eukaryotic life forms. See table at geological time..
Early 20c: from Greek proteros earlier + zoe life + -ic..
Phanerozoic Eon: a grouping of the next three Era.
Of or relating to the geologic time period from approximately 570 million years ago to
the present, comprising the Paleozoic, Mesozoic, and Cenozoic eras, and marked by an
abundance of fossil evidence of life, especially higher forms, in the corresponding rocks.
See table at geological time..
ETYMOLOGY:Greek
phaneros, visible (from phainein, to cause to appear) + –zoic.
3- Paleozoic: 550 to 250 million years
Of, belonging to, or designating the era of geologic time that includes the Cambrian,
Ordovician, Silurian, Devonian, Mississippian, Pennsylvanian, and Permian periods and
is characterized by the appearance of marine invertebrates, primitive fishes, land plants,
and primitive reptiles. See table at geological time.
ETYMOLOGY: paleo: long ago, earlier; zoic: life
3.1- Cambrian:
Of or belonging to the geologic time, system of rocks, or sedimentary deposits of the first
period of the Paleozoic Era, characterized by desert land areas, warm seas, and rapid
early diversification of marine life resulting in the rise of almost all modern animal phyla.
See table at geologic time.
ETYMOLOGY:From
Medieval Latin Cambria, Wales, alteration of Cumbria, from Welsh
Cymry. Adj., sense 2, and n., sense 2, after Cambria.
3.2- Ordovician:
geological period following the Cambrian and preceding the Silurian, 1879, coined by
Eng. geologist Charles Lapworth (1842-1920) from L. Ordovices, name of an ancient
British tribe in North Wales. The period so called because rocks from it first were studied
extensively in the region around Bala in North Wales. The tribe's name is Celtic, lit.
"those who fight with hammers,"
ETYMOLOGY: from Celt. base *ordo "hammer" + PIE *wik- "to fight, conquer" (cf.
victor).
3.3- Silurian:
Of or belonging to the geologic time, system of rocks, or sedimentary deposits of the
third period of the Paleozoic Era, characterized by the development of jawed fishes, early
invertebrate land animals, and land plants. See table at geologic time.
1708, "pertaining to the Silures," from L. Silures "ancient British tribe inhabiting
southeast Wales." Geological sense is from 1835, coined by Sir Roderick Impey
Murchison (1792-1871) because rocks of this period are especially frequent in Wales.
ETYMOLOGY: from silures, an ancient people of southwest Wales, where the rocks
were first identified
3.4- Devonian:
Of or belonging to the geologic time, system of rocks, or sedimentary deposits of the
fourth period of the Paleozoic Era, characterized by the development of lobe-finned
fishes, the appearance of amphibians and insects, and the first forests. See table at
geologic time.
ETYMOLOGY: 1837, as a geological era, from the English county of Devon (south of
England), where the Old Red Sandstone formations of that age are prominent. The county
name is O.E. Defena(scir), late 9c., "(territory of the) Dumnonii," a Celtic name.
3.5- Carboniferous:
ETYMOLOGY: the geological period (1830) is from a word formed in Eng. 1799 from
L. carbo (gen. carbonis) "coal" (see carbon) + -ferous "producing, containing." The great
coal beds of Europe were laid down during this period.
3.5.1- Pennsylvanian:
Of or belonging to the geologic time, system of rocks, or sedimentary deposits of the
sixth period of the Paleozoic Era, characterized by the development of the amniotic egg,
the diversification of amphibians, and widespread swamp forests. See table at geologic
time.
American colony, later U.S. state, 1681, lit. "Penn's Woods," a hybrid formed from the
surname Penn (Welsh, lit. "head") + L. sylvania (see sylvan). Not named for William
Penn, the proprietor, but, on suggestion of Charles II, for Penn's late father, Admiral
William Penn (1621-70), who had lent the king the money that was repaid in the form of
land for a Quaker settlement in America. Penn wanted to call it New Wales, but the
king's secretary, a Welshman of orthodox religion, wouldn't hear of it. Pennsylvania
Dutch is attested from 1824. Pennsylvanian in ref. to a geological system is attested from
1891.
ETYMOLOGY: sylvan: 1565, "deity of the woods," from M.Fr. sylvain, from L. silvanus
"pertaining to wood or forest" (originally only in silvanæ "goddesses of the woods"),
from silva "wood, forest, grove," of unknown origin. Adj. meaning "of the woods" is
attested from 1580. Silvanus was used by the Romans as the proper name of a god of
woods and fields, identified with Pan. Spelling with -y- infl. by Gk. hyle "forest," from
which the L. word was supposed to derive.
3.5.2- Mississipian:
Of or belonging to the geologic time, system of rocks, or sedimentary deposits of the fifth
period of the Paleozoic Era, characterized by the submergence of extensive land areas
under shallow seas. See table at geologic time. 2. The Mississippian Period. Also called
Lower Carboniferous.
3.6- Permian:
Of or belonging to the geologic time, system of rocks, or sedimentary deposits of the
seventh and last period of the Paleozoic Era, characterized by the formation of the
supercontinent Pangaea, the rise of conifers, and the diversification of reptiles and ending
with the largest known mass extinction in the history of life. See table at geologic time.
ETYMOLOGY:After Perm
Oblast, a region of west-central Russia. 1841, "pertaining to the
uppermost strata of the Paleozoic era," named by British geologist Sir Roderick Impey
Murchison (1792-1871) for the region of Perm in northwestern Russia, where rocks from
this epoch are found.
4.0- Mesozoic: from 250 to 65 millions.
Of, belonging to, or designating the era of geologic time that includes the Triassic,
Jurassic, and Cretaceous periods and is characterized by the development of flying
reptiles, birds, and flowering plants and by the appearance and extinction of dinosaurs.
See table at geologic time.
ETYMOLOGY: Mesos: middle; zoe: life
4.1- Triassic:
Of or belonging to the geologic time, system of rocks, or sedimentary deposits of the first
period of the Mesozoic Era, characterized by the diversification of land life, the rise of
dinosaurs, and the appearance of the earliest mammals. See table at geologic time.
1841, from Ger., coined 1841 by Ger. geologist Friedrich August von
Alberti (1795-1878), from Gk. trias "triad," because it is divisible (in Germany) into three
groups. Late Latin trias, triad (from the subdivision of this period into three parts); see
triad + –ic.
ETYMOLOGY:
4.2- Jurassic:
Of or belonging to the geologic time, rock series, or sedimentary deposits of the second
period of the Mesozoic Era, in which dinosaurs continued to be the dominant land fauna
and the earliest birds appeared. See table at geological time.
ETYMOLOGY: "geological period between the Triassic and the Cretaceous," 1833, from
Fr. Jurassique, lit. "of the Jura Mountains," between France and Switzerland, whose
limestones were laid down during this period.
4.3- Cretaceous:
Of or belonging to the geologic time, system of rocks, and sedimentary deposits of the
third and last period of the Mesozoic Era, characterized by the development of flowering
plants and ending with the sudden extinction of the dinosaurs and many other forms of
life. See table at geologic time. 2. cretaceous Of, containing, or resembling chalk.
c.1675, adj., "chalky," from L. cretaceus "chalky," from creta "chalk." As a geological
period (with a capital C-), it was first used 1832. The extensive chalk beds of
southeastern England were laid down during the Cretaceous.
ETYMOLOGY:From
Latin cretaceus, chalky, from creta, chalk, from Creta (terra), Cretan
(earth).
5- Cenozoic: 65 millions years to present
Of, belonging to, or designating the latest era of geologic time, which includes the
Tertiary Period and the Quaternary Period and is characterized by the formation of
modern continents, glaciation, and the diversification of mammals, birds, and plants. See
table at geologic time.
ETYMOLOGY: from Greek kainos new + zoe life.
5.1- Tertiary:
Tertiary Of or belonging to the geologic time, system of rocks, or sedimentary deposits
of the first period of the Cenozoic Era, characterized by the appearance of modern flora
and of apes and other large mammals. See table at geologic time.
The geological sense (with capital T-) of "era after the Mesozoic" (which formerly was
called the Secondary) is attested from 1794, after It. terziari, used in this sense 1760 by It.
geologist Giovanni Arduino (1714-1795).
ETYMOLOGY:Latin
terti rius, from tertius, third. See trei- in Appendix I.
5.1.1- Paleocene:
Of or belonging to the geologic time, rock series, or sedimentary deposits of the first
epoch of the Tertiary Period, marked by the appearance of placental mammals and
continental collisions leading to the formation of the Rocky Mountains and the
Himalayas. See table at geologic time.
ETYMOLOGY: geological epoch preceding the Eocene, 1877, from Fr. paléocène
(Schimpter, 1874), coined from paleo- old, ancient,+ Gk. kainos "new." It is, thus, the
"old new" age.
5.1.2- Eocene:
Of or belonging to the geologic time, rock series, or sedimentary deposits of the second
epoch of the Tertiary Period, characterized by warm climates and the rise of most modern
mammalian families. See table at geologic time.
"second epoch of the Tertiary Period," coined in Eng. 1831, from Gk. eos "dawn" (see
eohippus) + kainos "new;" along with Miocene and Pliocene, by William Whewell.
5.1.2- Oligocene:
Of or belonging to the geologic time, rock series, or sedimentary deposits of the third
epoch of the Tertiary Period, characterized by futher development of modern mammalian
fauna, including the rise of the true carnivores and their gradual replacement of the
creodonts. See table at geologic time.
ETYMOLOGY: 1859, "pertaining to the Tertiary period between the Eocene and the
Miocene," coined in Ger. (1854), from Gk. oligos "small, little, few" (of unknown origin)
+ kainos "recent."
5.1.3- Miocene:
Of or belonging to the geologic time, rock series, or sedimentary deposits of the fourth
epoch of the Tertiary Period, characterized by the development of grasses and grazing
mammals. See table at geologic time. NOUN: The Miocene Epoch or its system of
deposits.
ETYMOLOGY: "geological period between the Oligocene and Pliocene," 1831, irregular
formation from Gk. meion "less, small" + kainos "new, recent."
"A typical example of the monstrosities with which scientific men in want of a label for
something, and indifferent to all beyond their own province, defile the language. The
elements of the word are Greek, but not the way they are put together, nor the meaning
demanded of the compound." [Fowler]
5.1.4- Pliocene:
Of or belonging to the geologic time, rock series, or sedimentary deposits of the last
epoch of the Tertiary Period, characterized by the appearance of distinctly modern
animals. See table at geologic time.
ETYMOLOGY: 1833, from Gk. pleion "more" + kainos "new."
5.2- Quaternary:
Quaternary Of or belonging to the geologic time, system of rocks, or sedimentary
deposits of the second period of the Cenozoic Era, from the end of the Tertiary Period
through the present, characterized by the appearance and development of humans and
including the Pleistocene and Holocene epochs. See table at geologic time.
ETYMOLOGY: In geological sense, attested from 1843, proposed 1829 by Fr. geologist
Jules Pierre François Stanislas Desnoyers (1800-1887) as name for "the fourth great
epoch of geological time," but since it only comprises the age of man, and the other
epochs are many hundred times longer, not all accepted it.
5.2.1- Pleistocene:
ETYMOLOGY: "pertaining to the glacial period," 1839, coined by Lyell from Gk.
pleistos "most" (superl. of polys "much;" see poly-) + kainos "new."
5.2.2- Holocene:
"epoch that began 10,000 years ago and continues today," 1897, from Fr. holocène
(1867), from Gk. holo-, comb. form of holos "whole" (see safe (adj.)) + kainos "new,
recent."
References:
www.bartleby.com
www.ethyologydictionnary.com