Selandian

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Selandian
61.6 – 59.2 Ma
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Chronology
Formerly part of Tertiary Period/System
Etymology
Name formalityFormal
Usage information
Celestial body Earth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unit Age
Stratigraphic unit Stage
Time span formalityFormal
Lower boundary definitionOnset of sea-level drop and carbon isotope shift
Lower boundary GSSPZumaia Section, Basque Country, Spain
43°17′57″N2°15′40″W / 43.2992°N 2.2610°W / 43.2992; -2.2610
Lower GSSP ratified2008 [3]
Upper boundary definitionBase of magnetic polarity chronozone C26n
Upper boundary GSSPZumaia Section, Basque Country, Spain
43°17′59″N2°15′39″W / 43.2996°N 2.2609°W / 43.2996; -2.2609
Upper GSSP ratified2008 [3]

The Selandian is a stage in the Paleocene. It spans the time between 61.6 and 59.2 Ma. It is preceded by the Danian and followed by the Thanetian. [4] Sometimes[ when? ] the Paleocene is subdivided[ by whom? ] in subepochs, in which the Selandian forms the "middle Paleocene".

Contents

Stratigraphic definition

The Selandian was introduced in scientific literature by Danish geologist Alfred Rosenkrantz in 1924. It is named after the Danish island of Zealand (Danish: Sjælland) given its prevalence there. [5]

The base of the Selandian is close to the boundary between biozones NP4 and NP5. It is slightly after the first appearances of many new species of the calcareous nanoplankton genus Fasciculithus (F. ulii, F. billii, F. janii, F. involutus, F. tympaniformis and F. pileatus) and close to the first appearance of calcareous nanoplankton species Neochiastozygus perfectus. At the original type location in Denmark the base of the Selandian is an unconformity. The official Global Boundary Stratotype Section and Point (GSSP) was established in the Zumaia section ( 43°18′N002°16′W / 43.300°N 2.267°W / 43.300; -2.267 ) at the beach of Itzurun in the Basque Country, northern Spain. [6]

The Global Boundary Stratotype Section and Point (GSSP) marking the lower boundary of the Selandian at Itzurun, Spain GSSP Golden spike Itzurun, Zumaia, Basque Country (02).jpg
The Global Boundary Stratotype Section and Point (GSSP) marking the lower boundary of the Selandian at Itzurun, Spain

The top of the Selandian (the base of the Thanetian) is laid at the base of magnetic chronozone C26n.

The Selandian Stage overlaps with the lower part of the Tiffanian North American Land Mammal Age, the Peligran, Tiupampan and lower Itaboraian South American Land Mammal Ages and part of the Nongshanian Asian Land Mammal Age. It is coeval with the lower part of the Wangerripian Stage from the Australian regional timescale.

The start of the Selandian represents a sharp depositional change in the North Sea Basin, where there is a shift to siliciclastic deposition due to the uplift and erosion of the Scotland-Shetland area after nearly 40 million years of calcium carbonate deposition. [7] This change occurs at the same time as the onset of a foreland basin formation in Spitsbergen due to compression between Greenland and Svalbard, [8] suggesting a common tectonic cause that altered the relative motions of the Greenland Plate and the Eurasian Plate. This plate reorganisation event is also manifest as a change in seafloor spreading direction in the Labrador Sea around this time. [9]

Fauna and Flora

The fauna of the Selandian consisted of giant snakes ( Titanoboa ), [10] crocodiles, champsosaurs, Gastornithiformes, [11] owls; and a few archaic forms of mammals, such as mesonychids, pantodonts, primate relatives plesiadapids, and multiberculates.

The flora was composed of cacti, ferns, and palm trees.

Related Research Articles

<span class="mw-page-title-main">Paleogene</span> First period of the Cenozoic Era (66–23 million years ago)

The Paleogene is a geologic period and system that spans 43 million years from the end of the Cretaceous Period 66 million years ago (Mya) to the beginning of the Neogene Period 23.03 Mya. It is the beginning of the Cenozoic Era of the present Phanerozoic Eon. The earlier term Tertiary Period was used to define the span of time now covered by the Paleogene Period and subsequent Neogene Period; despite no longer being recognized as a formal stratigraphic term, "Tertiary" still sometimes remains in informal use. Paleogene is often abbreviated "Pg".

The Late Cretaceous is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after creta, the Latin word for the white limestone known as chalk. The chalk of northern France and the white cliffs of south-eastern England date from the Cretaceous Period.

<span class="mw-page-title-main">Zanclean</span> Earliest age on the geologic time scale of the Pliocene era

The Zanclean is the lowest stage or earliest age on the geologic time scale of the Pliocene. It spans the time between 5.332 ± 0.005 Ma and 3.6 ± 0.005 Ma. It is preceded by the Messinian Age of the Miocene Epoch, and followed by the Piacenzian Age.

The Aquitanian is, in the International Commission on Stratigraphy's (ICS) geologic timescale, the oldest age or lowest stage in the Miocene. It spans the time between 23.03 ± 0.05 Ma and 20.43 ± 0.05 Ma during the Early Miocene. It was a dry, cooling period. The Aquitanian succeeds the Chattian and precedes the Burdigalian.

The Bartonian is, in the International Commission on Stratigraphy's (ICS) geologic time scale, a stage or age in the middle of the Eocene Epoch or Series. The Bartonian Age spans the time between 41.2 and37.71 Ma. It is preceded by the Lutetian and is followed by the Priabonian Age.

<span class="mw-page-title-main">Maastrichtian</span> Sixth and last age of the Late Cretaceous

The Maastrichtian is, in the ICS geologic timescale, the latest age of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval from 72.1 to 66 million years ago. The Maastrichtian was preceded by the Campanian and succeeded by the Danian.

The Serravallian is, in the geologic timescale, an age or a stage in the middle Miocene Epoch/Series, which spans the time between 13.82 Ma and 11.63 Ma. The Serravallian follows the Langhian and is followed by the Tortonian.

The Tortonian is in the geologic time scale an age or stage of the late Miocene that spans the time between 11.608 ± 0.005 Ma and 7.246 ± 0.005 Ma. It follows the Serravallian and is followed by the Messinian.

The Danian is the oldest age or lowest stage of the Paleocene Epoch or Series, of the Paleogene Period or System, and of the Cenozoic Era or Erathem. The beginning of the Danian is at the Cretaceous–Paleogene extinction event 66 Ma. The age ended 61.6 Ma, being followed by the Selandian.

The Thanetian is, in the ICS Geologic timescale, the latest age or uppermost stratigraphic stage of the Paleocene Epoch or Series. It spans the time between 59.2 and56 Ma. The Thanetian is preceded by the Selandian Age and followed by the Ypresian Age. The Thanetian is sometimes referred to as the Late Paleocene.

<span class="mw-page-title-main">Ypresian</span> First age of the Eocene Epoch

In the geologic timescale the Ypresian is the oldest age or lowest stratigraphic stage of the Eocene. It spans the time between 56 and47.8 Ma, is preceded by the Thanetian Age and is followed by the Eocene Lutetian Age. The Ypresian is consistent with the lower Eocene.

The Lutetian is, in the geologic timescale, a stage or age in the Eocene. It spans the time between 47.8 and41.2 Ma. The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it is sometimes referred to as the Middle Eocene Subepoch.

The Priabonian is, in the ICS's geologic timescale, the latest age or the upper stage of the Eocene Epoch or Series. It spans the time between 37.71 and33.9 Ma. The Priabonian is preceded by the Bartonian and is followed by the Rupelian, the lowest stage of the Oligocene.

The Chattian is, in the geologic timescale, the younger of two ages or upper of two stages of the Oligocene Epoch/Series. It spans the time between 27.82 and23.03 Ma. The Chattian is preceded by the Rupelian and is followed by the Aquitanian.

<span class="mw-page-title-main">Fur Formation</span> Marine geologial formation in Denmark

The Fur Formation is a marine geological formation of Ypresian age which crops out in the Limfjord region of northern Denmark from Silstrup via Mors and Fur to Ertebølle, and can be seen in many cliffs and quarries in the area. The Diatomite Cliffs is on the Danish list of tentative candidates for World Heritage and may become a World Heritage site. Fossils found in the Fur Formation are primarily housed at the Fossil and Mo-clay Museum on Mors Island, the Fur Museum on Fur Island, and the Natural History Museum of Denmark in Copenhagen.

A system in stratigraphy is a sequence of strata that were laid down together within the same corresponding geological period. The associated period is a chronological time unit, a part of the geological time scale, while the system is a unit of chronostratigraphy. Systems are unrelated to lithostratigraphy, which subdivides rock layers on their lithology. Systems are subdivisions of erathems and are themselves divided into series and stages.

The Paleocene, or Palaeocene, is a geological epoch that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the Paleogene Period in the modern Cenozoic Era. The name is a combination of the Ancient Greek παλαιός palaiós meaning "old" and the Eocene Epoch, translating to "the old part of the Eocene".

The Ieper Group is a group of rock strata in the subsurface of northwest Belgium. The group is subdivided into three marine formations, all formed during the Ypresian, a single age of the geologic timescale. Both age and group are named after the West Flemish town of Ypres, for which the Dutch name is "Ieper".

A hyperthermal event corresponds to a sudden warming of the planet on a geologic time scale.

References

  1. ↑ Zachos, J. C.; Kump, L. R. (2005). "Carbon cycle feedbacks and the initiation of Antarctic glaciation in the earliest Oligocene". Global and Planetary Change. 47 (1): 51–66. Bibcode:2005GPC....47...51Z. doi:10.1016/j.gloplacha.2005.01.001.
  2. ↑ "International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy.
  3. 1 2 Schmitz, B.; Pujalte, V.; Molina, E.; Monechi, S.; Orue-Etxebarria, X.; Speijer, R. P.; Alegret, L.; Apellaniz, E.; Arenillas, I.; Aubry, M.-P.; Baceta, J.-I.; Berggren, W. A.; Bernaola, G.; Caballero, F.; Clemmensen, A.; Dinarès-Turell, J.; Dupuis, C.; Heilmann-Clausen, C.; Orús, A. H.; Knox, R.; Martín-Rubio, M.; Ortiz, S.; Payros, A.; Petrizzo, M. R.; von Salis, K.; Sprong, J.; Steurbaut, E.; Thomsen, E. (2011). "The global Stratotype Sections and Points for the bases of the Selandian (Middle Paleocene) and Thanetian (Upper Paleocene Paleocene) stages at Zumaia, Spain". Episodes. 34 (4): 220–243. doi: 10.18814/epiiugs/2011/v34i4/002 .
  4. ↑ International Commission on Stratigraphy 2017
  5. ↑ Selandien, Den Store Danske Encyklopædi
  6. ↑ See for example Arenillas et al. (2008) or Bernaola et al. (2009) for a description of the Danian-Selandidan boundary
  7. ↑ Clemmensen A, Thomsen E (2005). "Palaeoenvironmental changes across the Danian–Selandian boundary in the North Sea Basin". Palaeogeography, Palaeoclimatology, Palaeoecology. 219 (3–4): 351–394. Bibcode:2005PPP...219..351C. doi:10.1016/j.palaeo.2005.01.005.
  8. ↑ Jones MT, Augland LE, Shephard GE, Burgess SD, Eliassen GT, Jochmann MM, Friis B, Jerram DA, Planke S, Svensen HH (July 2017). "Constraining shifts in North Atlantic plate motions during the Palaeocene by U-Pb dating of Svalbard tephra layers". Scientific Reports. 7 (1): 6822. Bibcode:2017NatSR...7.6822J. doi:10.1038/s41598-017-06170-7. PMC   5533774 . PMID   28754976.
  9. ↑ Oakey GN, Chalmers JA (2012). "A new model for the Paleogene motion of Greenland relative to North America: Plate reconstructions of the Davis Strait and Nares Strait regions between Canada and Greenland". Journal of Geophysical Research: Solid Earth. 117 (B10): B10. Bibcode:2012JGRB..11710401O. doi: 10.1029/2011jb008942 .
  10. ↑ Kwok R (4 February 2009). "Scientists find world's biggest snake". Nature News . doi: 10.1038/news.2009.80 .
  11. ↑ Koeberl C, MacLeod KG, eds. (2002). Catastrophic events and mass extinctions: Impacts and beyond. Geological Society of America. pp. 303–4.

Further reading

43°18′02″N2°15′34″W / 43.30056°N 2.25944°W / 43.30056; -2.25944

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