The
Zanclean is the lowest stage or earliest age on the
geologic time scaleThe geologic time scale provides a system of chronologic measurement relating stratigraphy to time that is used by geologists, paleontologists and other earth scientists to describe the timing and relationships between events that have occurred during the history of the Earth...
of the
PlioceneThe Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...
. It spans the time between 5.332 and 3.6 Ma ± 0.005 Ma (million years ago). It is preceded by the
MessinianThe Messinian is in the geologic timescale the last age or uppermost stage of the Miocene. It spans the time between 7.246 ± 0.005 Ma and 5.332 ± 0.005 Ma...
age of the
MioceneThe Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
epochAn epoch is a subdivision of the geologic timescale based on rock layering. In order, the higher subdivisions are periods, eras and eons. We are currently living in the Holocene epoch...
, and followed by the
PiacenzianThe Piacenzian is in the international geologic timescale the upper stage or latest age of the Pliocene. It spans the time between 3.6 ± 0.005 Ma and 2.588 ± 0.005 Ma...
age.
The Zanclean can be correlated with regionally used stages, such as the Tabianian or Dacian of
Central EuropeCentral Europe or alternatively Middle Europe is a region of the European continent lying between the variously defined areas of Eastern and Western Europe...
. It also corresponds to the late
HemphillianThe Hemphillian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology , typically set from 10,300,000 to 4,900,000 years BP, a period of . It is usually considered to overlap the Tortonian epoch of the Late...
to mid-
BlancanThe Blancan North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology , typically set from 4,750,000 to 1,808,000 years BP, a period of .. It is usually considered to start in the early-mid Pliocene epoch and end...
North American Land Mammal AgesThe North American Mammal Ages establishes a geologic timescale for prehistoric North American fauna beginning 66.5 Ma during the Paleocene and continuing through to the Late Pleistocene...
. In
CaliforniaCalifornia is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, the Zanclean roughly corresponds to the mid-Delmontian Californian Stage of from 7.5 To 2.9 Ma ago.
Definition
The Zanclean stage was introduced by Giuseppe Seguenza in 1868. It is named after
Zancla, the pre-
RomanThe Roman Empire was the post-Republican period of the ancient Roman civilization, characterised by an autocratic form of government and large territorial holdings in Europe and around the Mediterranean....
name for the
ItalianItaly , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
city of Messina on
SicilySicily is a region of Italy, and is the largest island in the Mediterranean Sea. Along with the surrounding minor islands, it constitutes an autonomous region of Italy, the Regione Autonoma Siciliana Sicily has a rich and unique culture, especially with regard to the arts, music, literature,...
.
The base of the Zanclean (and the Pliocene series) lies with the top of magnetic chronozone Cr3 (about 100.000 years before the Thvera normal subchronozone C3n.4n). The base is also close to the
extinctionIn biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
level of the calcareous nannoplankton species
Triquetrorhabdulus rugosus (the base of
biozoneBiostratigraphic units or Biozones are intervals of geological strata that are defined on the basis of their characteristic fossil taxa....
CN10b) and the first appearance of nannoplankton
Ceratolithus acutus is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It lived during the later part of the Arenig stage of the Ordovician Period, approximately 478 to 471 million years ago....
. The GSSP for the Zanclean is in the vicinity of the ruins of the ancient city of
Heraclea MinoaHeraclea Minoa , in Sicily, was an ancient Greek city, situated on the south coast of the island, at the mouth of the river Halycus , 25 km west of Agrigentum , near modern Montallegro...
on
SicilySicily is a region of Italy, and is the largest island in the Mediterranean Sea. Along with the surrounding minor islands, it constitutes an autonomous region of Italy, the Regione Autonoma Siciliana Sicily has a rich and unique culture, especially with regard to the arts, music, literature,...
,
ItalyItaly , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
.
The top of the Zanclean stage (the base of the Piacenzian stage) is at the base of magnetic chronozone C2An (the base of the Gauss chronozone and at the
extinctionIn biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
of the
planktonPlankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...
ic forams
Globorotalia margaritae and
Pulleniatina primalis.
Events of the Zanclean
- The Zanclean flood
The Zanclean flood is a flood theorized to have refilled the Mediterranean Sea 5.33 million years ago, at the beginning of the Zanclean age, between the Miocene and Pliocene, which ended the Messinian salinity crisis...
marked the beginning of the age and the end of the Messinian, as water poured in from the Atlantic OceanThe Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
through the Strait of GibraltarThe Strait of Gibraltar is a narrow strait that connects the Atlantic Ocean to the Mediterranean Sea and separates Spain in Europe from Morocco in Africa. The name comes from Gibraltar, which in turn originates from the Arabic Jebel Tariq , albeit the Arab name for the Strait is Bab el-Zakat or...
to delugeIn geomorphology, an outburst flood, which is a type of megaflood, is a high magnitude, low frequency catastrophic flood involving the sudden release of water. During the last deglaciation, numerous glacial lake outburst floods were caused by the collapse of either ice sheets or glaciers that...
the Mediterranean BasinIn biogeography, the Mediterranean Basin refers to the lands around the Mediterranean Sea that have a Mediterranean climate, with mild, rainy winters and hot, dry summers, which supports characteristic Mediterranean forests, woodlands, and scrub vegetation...
and end the Messinian EventThe Messinian Salinity Crisis, also referred to as the Messinian Event, and in its latest stage as the Lago Mare event, was a geological event during which the Mediterranean Sea went into a cycle of partly or nearly complete desiccation throughout the latter part of the Messinian age of the Miocene...
, a period about 5.96 Ma ago in the Messinian age of the Miocene epoch when the Mediterranean SeaThe Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...
had evaporated partly or completely.
Literature
;
1998:
The Global Standard Stratotype section and Point (GSSP) of the Piacenzian Stage (Middle Pliocene), Episodes,
21(2): pp 88-93. (
eds.) (2005)
A Geologic Time Scale 2004 Cambridge University Press, Cambridge, UK, ISBN 0-521-78142-6.;
1868:
La Formation Zancléenne, ou recherches sur une nouvelle formation tertiaire, Bulletin de la Societé Géologique de France, séries 2,
25: 465-485. ;
2000:
The base of the Zanclean Stage and of the Pliocene Series, Episodes,
23(3): pp 179-187.
External links