Jump to content

Early Ordovician

From Wikipedia, the free encyclopedia
Early/Lower Ordovician
485.4 ± 1.9 – 470.0 ± 1.4 Ma
A map of Earth as it appeared 480 million years ago during the Early Ordovician, Tremadocian age
Chronology
Etymology
Chronostratigraphic nameLower Ordovician
Geochronological nameEarly Ordovician
Name formalityFormal
Usage information
Celestial bodyEarth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unitEpoch
Stratigraphic unitSeries
Time span formalityFormal
Lower boundary definitionFAD of the conodont Iapetognathus fluctivagus.
Lower boundary GSSPGreenpoint section, Green Point, Newfoundland, Canada
49°40′58″N 57°57′55″W / 49.6829°N 57.9653°W / 49.6829; -57.9653
Lower GSSP ratified2000[5]
Upper boundary definitionFAD of the conodont Baltoniodus triangularis
Upper boundary GSSPHuanghuachang section, Huanghuachang, Yichang, China
30°51′38″N 110°22′26″E / 30.8605°N 110.3740°E / 30.8605; 110.3740
Upper GSSP ratified2007[6]
Atmospheric and climatic data
Mean atmospheric O2 contentc. 11.5 vol %
(55 % of modern)

The Early Ordovician is the first epoch of the Ordovician period, corresponding to the Lower Ordovician series of the Ordovician system. It began after the Age 10 of the Furongian epoch of the Cambrian and lasted from 485.4 ± 1.9 to 470 ± 1.4 million years ago, until the Dapingian age of the Middle Ordovician. It includes Tremadocian and Floian ages.[7]

History

[edit]

International Commission on Stratigraphy (ICS) appointed working groups on the boundaries of the Ordovician subdivisions in 1974. The boundaries were established by the fauna of conodonts and/or graptolites. In 1995, the Subcommission on Ordovician Stratigraphy, with the support of 90% majority of voting members, adopted the division of the Ordovician system into three series: Lower, Middle and Upper. In the same year, it was decided to divide each of the three series into two global stages. Tetragraptus approximatus zone was chosen as the base of the upper stage of the Lower Ordovician by 95% of the votes.[8] Before the adoption of the international standard, the series from the chart of Britain, the type locality of the Ordovician system, were accepted by default as Ordovician subdivisions. In accordance with this scale, the Ordovician was divided into six series, of which the lower one, the Tremadocian, passed into the International Stratigraphic Chart (ISC) as the stage of the same name. The upper Arenig series corresponds to the upper part of the Lower and lower part of the Middle Ordovician global series. On the British chart, the boundaries of Ordovician subdivisions are determined by local stratigraphic and paleontological features that are poorly defined in the rest of the world. As a result, local series and stages, very different from the British standard, were identified on different paleoplates or modern continents.[9] In 2008,[10] the traditional British Ordovician subdivisions were replaced by seven new stages with defined GSSPs. Tremadocian and Floian stages were included in the Lower Ordovician series.[11][10] In 2011, the Russian regional stratigraphic chart was changed from the British to the international standard division of the Ordovician system.[12]

Definition

[edit]

The Global Boundary Stratotype Section and Point (GSSP) of the Lower Ordovician, which is also a GSSP of the Tremadocian stage and the whole Ordovician system, is established in the Green Point section in the west of the Newfoundland, Canada (49°40′58″N 57°57′55″W / 49.6829°N 57.9653°W / 49.6829; -57.9653) and corresponds to the first appearance datum (FAD) of the conodont Iapetognathus fluctivagus at the 101.8 m above the base of the outcrop. Doubts have been expressed about the identification of the index taxon, but it occurs below the Rhabdinopora and related graptolites.[13] The GSSP of the Floian, the second and last stage of the Lower Ordovician, is established in the Diabasbrottet Quarry, Sweden, (58°21′32″N 12°30′09″E / 58.3589°N 12.5024°E / 58.3589; 12.5024) and defined by FAD of the graptolite Tetragraptus approximatus.[14][13]

Two Auxiliary boundary Stratotype Sections and Points (ASSPs) were also established for the Lower Ordovician/Tremadocian: the first one in the Lawson Cove section in Millard County, Utah, USA, and the second one in the Xiaoyangqiao section, North China.[15][16] Both ASSPs were approved by the Subcommission on Ordovician Stratigraphy in 2016 and 2019, respectively, but, in 2021, the International Union of Geological Sciences (IUGS) proposed to deny the use of specific points and replace them by Standard Auxiliary Boundary Stratotypes (SABS) for more "flexible" correlations with GSSPs.[16]

Biostratigraphy

[edit]

The global stages of the Lower Ordovician, as well as of other series, are also subdivided into stage slices (time slices), which are corresponding to the base of conodont or graptolite zones. In addition to the global stages, the Tetragraptus approximatus Zone is also defined in the regional subdivisions of the UK and Australia, and the Didymograptus protobifidus Zone in those of North America, Australia and Baltoscandia.[11]

Conodont (c) and graptolite (g) zones of the Lower Ordovician:[11]
Series Stage (ICS) Stage slice
Lower Ordovician
 Floian Didymograptus protobifidus Zone (g)
Oepikodus evae Zone (c)
Tetragraptus approximatus Zone (g)
Tremadocian Paroistodus proteus Zone (c)
Paltodus deltifer Zone (c)
Iapetognathus fluctivagus Zone (c)

North America

[edit]

The following conodont zones are distinguished in Early Ordovician deposits of Boothia Peninsula, Canada (from upper to lower):[17]

  • Oepikodus communis and Reutterodus andinus (Ship Point Formation, Floian);
  • Rossodus manitouensis and Acodus deltatus/Oneotodus costatus (upper part of Turner Cliffs Formation, Tremadocian);
  • Cordylodus angulatus (lower part of Turner Cliffs, Tremadocian).

Asia

[edit]

Graptolite (g) and conodont (c) zonal subdivisions of southern Siberia (from upper to lower):[10][18]

  • Ps. angustifolius elongatus/E. broggeri (g), D. protobifidus (g), Ph. densus (g), upper part of Oepikodus evae (c), plus chitinozoan Conochitina raymondi Zone (Floian);
  • Lower part of Ph. densus (g), Ac. balticus (g), lower part of Oepikodus evae (c) (Floian);
  • T. approximatus (g), upper part of Paroistodus proteus (c) (Floian);
  • Lower part of Paroistodus proteus (c) (Tremadocian);
  • K. kiaeri/Ad. tenellus (g), B. ramosus/Tr. osloensis/Al. hyperboreus (g) (Tremadocian);
  • Iapetognathus fluctivagus (c) (Tremadocian).

Australia

[edit]

On the Australian scale, the global Lower Ordovician roughly corresponds to the Lancefieldian, Bendigonian, Chewtonian and lower Castlemainian stages.[19]

Approximate correlation of graptolite (g) and conodont (c) zones of New South Wales:[19]
Series Australian stage Zone
Lower Ordovician
 Castlemainian (lower part) Isograptus victoriae lunatus (g), upper part of Oepikodus evae (c)
Chewtonian Isograptus primulus (g), Oepikodus evae (c)
Didymograptus protobifidus (g), Oepikodus evae (c)
Bendigonian Upper part of Pendeograptus fruticosus (g), lowermost Oepikodus evae (c)
Lower parts of Pendeograptus fruticosus (g), uppermost Prioniodus elegans (c)
Pendeograptus fruticosus (g), Prioniodus elegans (c)
Lancefieldian Uppermost Tetragraptus approximatus (g), lowermost Prioniodus elegans (c)
Lower part of Tetragraptus approximatus (g), uppermost Paroistodus proteus (c)
Araneograptus murrayi (g), Paroistodus proteus (c)
Upper part of Aorograptus victoriae (g), lower part of Paroistodus proteus (c)
Lower part of Aorograptus victoriae (g), upper part of Paltodus deltifer (c)
Psigraptus jacksoni (g), lower part of Paltodus deltifer (c)
Anisograptus (g), upper part of Cordylodus angulatus (c)
Rhabdinopora fl abelliformis parabola (g), Cordylodus angulatus (c)
Lower part of Cordylodus angulatus (c)

Paleogeography

[edit]

The Iapetus Ocean, located between Gondwana, Laurentia and Baltica, reached over 4000 km in width at the beginning of the Ordovician. In the north, between eastern Laurentia and Siberia, it connected with Panthalassa, which covered about half the planet. Formed in late Cambrian, Rheic Ocean stretched between Gondwana and the microcontinent of Avalonia. Cuyania (northwest of today's Argentina) was located at low latitudes. Gondwana, already a large continent, consisted of today's South America, Africa, the Arabian Peninsula, India, eastern Australia and eastern Antarctica. Laurentia included the territories of Mexico, the USA, Canada, Greenland, Scotland and partly Ireland.[20] Laurentia was located in the tropical latitudes of the southern hemisphere; today's central Nevada and western Utah were covered by sea waters at the end of the Early Ordovician.[21]

Climate

[edit]

In 2007, Bassett et al. analyzed the oxygen isotope values of Early Ordovician strata of the Lange Ranch section in central Texas and concluded that tropical sea temperatures at that time could have reached 37°C or 42°C.[22] Similar results were recovered by Trotter et al. in 2008, after oxygen isotope analysis of conodonts from the four paleoplates located in the Early Ordovician at low latitudes.[23] Authors of the 2021 article give values in accordance with the study by Song et al. (2019): from 43.9°C 485 million years ago to 37.1°C 470 million years ago.[20][24] High temperatures that persisted throughout the Early Ordovician affected the biodiversification later, in the Middle Ordovician.[25] CO2 level in Early Ordovician atmosphere was high while oxygen levels varied from approximately 10% to 13%.[20]

Studies of oxygen isotopes from apatites (particularly conodont apatites from Nevada and Utah) show that at the end of the Early Ordovician the climate began to change from greenhouse to icehouse. These changes occurred gradually and were accompanied by fluctuations in sea surface temperature with an approximate duration of 104 to 107 years.[21] By the end of the Middle Ordovician, the surface of the low-latitude seas had cooled to temperatures comparable to today's equatorial ones.[23]

Major events

[edit]
See also: Tremadocian § Major events
See also: Floian § Major events

The Great Ordovician Biodiversification Event (GOBE), manifested in an increase in the diversity of marine life, occurred in Early Ordovician. Along with the Cambrian explosion and radiation in the early Mesozoic, it is the most significant biodiversification in the Phanerozoic eon.[26] This event occurred at different intervals depending on the groups of organisms and the geographical region, and, in fact, the GOBE refers to a whole complex of sequential and interconnected processes of evolution and migration of organisms. The first phase, associated with planktonic communities, probably began in the late Cambrian and ended in the late Early Ordovician. The Early Ordovician marks the beginning of the second phase, which affected the inhabitants of benthos.[26] One of the possible signs of the GOBE is the fossil reefs found in the Early Ordovician Dumugol Formation, South Korea. This reefs, built by the microorganisms and sponges of the genus Archaeoscyphia, are different from the Cambrian and early Tremadocian and this discovery confirm that reef communities occupied deeper-sea habitats as early as in the middle Tremadocian.[27] The radiation of marine life during the GOBE in the Early Ordovician was resulted by the transition from sulphidic to oxic conditions in the oceans of that time.[28]

Substantial older ("pre-GOBE") radiations are observed in the Early Ordovician sediments of South China. However, it is questionable, were they global or not.[20]

From the Furongian to the end of the Early Ordovician, 495-470 Ma, the Ollo de Sapo magmatic event occurred on the northwestern territory of Gondwana, which is now the Iberian Peninsula.[29]

Paleontology

[edit]

In Early Ordovician (Floian) strata of the San Juan Formation, Argentina, the oldest microfossils, known as calcisphers or calcitarchs, are present. Early forms reached 80 to 250 μm in diameter. Some of these organisms are probably algae. Calcitarchs lived in the subtidal zone, from coastal waves to shoals and reefs.[30] Algae of the genus Amsassia appeared. They already lived off the southern coast of Laurentia and Cuyania in the Early Ordovician, and later occupied an even wider range and disappeared only during the Ordovician-Silurian extinction. In Tremadocian, Amsassia inhabited small reefal mounds in shallow sea waters.[31] Discovered in the Floian strata of Newfoundland, coral-like fossils of Reptamsassia divergens and Reptamsassia minuta allows to judge the level of development of reef ecosystems of the Early Ordovician, since they are the oldest example of symbiotic intergrowth of modular species.[32]

Echinoderm diversity increased in the Early Ordovician: new classes appeared, including asteroids, ophiuroids, crinoids and diploporitans.[33] Various Early Ordovician echinoderms are found in the Fillmore Formation in Utah, USA, Fezouata Formation in Anti-Atlas, Morocco, and Saint-Chinian Formation in Montagne Noire, France.[34]

Aegirocassis, a large filter feeder of the Early Ordovician

Nektaspida have become less diverse after Cambrian. They most likely inhabited restricted or colder brackish seas in the Ordovician.[35] Tariccoia tazagurtensis is a member of this arthropod clade from the Lower Ordovician of Morocco.[35] In the same Fezouata Formation, Aegirocassis was discovered. This filter feeder arthropod reached over 2 m in length[36] and was the largest animal of its time.[37] Marrellomorphs, appeared in Cambrian, continued to exist in Early Ordovician.[38]

Cloacaspis

Soft-bodied and shelly organisms, including Cambrian relics as well as the new taxa of the Ordovician origin, constitute a fossil Liexi fauna, preserved in the Lower Ordovician Madaoyu Formation of Hunan, South China. Fossil specimens include bryozoans, sponges, echinoderms, polychaetes, graptolites, trilobites and conodonts.[39] Palaeoscolecidan worms, including Liexiscolex[40] and a possible Ottoia specimen, are of great interest.[39] Early Ordovician priapulids, similar to their Cambrian predecessors, are also known from northern China.[41]

In the deep-water sediments of the Early Ordovician (Floian) Al Rose Formation in the Inyo Mountains, California, the trilobite fauna have been discovered. Despite the low species diversity, this fauna is unique due to differences in the composition of families from more eastern complexes of the comparable age. Fossils identified as belonging to the Globampyx, Protopresbynileus, Carolinites, Cloacaspis, Geragnostus and Hintzeia genera. In the Early Ordovician, this territory was located near the paleocontinent of Laurentia.[42]

Mineral resources

[edit]

Oil and gas exploration is underway in the Early Ordovician Tongzi and Meitan formations in Sichuan Basin[43][44] and the Early Ordovician strata of the Tarim Basin, China.[45] In the Lower Ordovician of the Tarim Basin near Tazhong, oil accumulations are found at depths of up to 9000 m.[46]

References

[edit]
  1. ^ Wellman, C.H.; Gray, J. (2000). "The microfossil record of early land plants". Phil. Trans. R. Soc. B. 355 (1398): 717–732. doi:10.1098/rstb.2000.0612. PMC 1692785. PMID 10905606.
  2. ^ Korochantseva, Ekaterina; Trieloff, Mario; Lorenz, Cyrill; Buykin, Alexey; Ivanova, Marina; Schwarz, Winfried; Hopp, Jens; Jessberger, Elmar (2007). "L-chondrite asteroid breakup tied to Ordovician meteorite shower by multiple isochron 40 Ar- 39 Ar dating". Meteoritics & Planetary Science. 42 (1): 113–130. Bibcode:2007M&PS...42..113K. doi:10.1111/j.1945-5100.2007.tb00221.x.
  3. ^ Lindskog, A.; Costa, M. M.; Rasmussen, C.M.Ø.; Connelly, J. N.; Eriksson, M. E. (2017-01-24). "Refined Ordovician timescale reveals no link between asteroid breakup and biodiversification". Nature Communications. 8: 14066. doi:10.1038/ncomms14066. ISSN 2041-1723. PMC 5286199. PMID 28117834. It has been suggested that the Middle Ordovician meteorite bombardment played a crucial role in the Great Ordovician Biodiversification Event, but this study shows that the two phenomena were unrelated
  4. ^ "International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy. September 2023. Retrieved November 10, 2024.
  5. ^ Cooper, Roger; Nowlan, Godfrey; Williams, S. H. (March 2001). "Global Stratotype Section and Point for base of the Ordovician System" (PDF). Episodes. 24 (1): 19–28. doi:10.18814/epiiugs/2001/v24i1/005. Archived (PDF) from the original on 2024-03-25. Retrieved 2024-06-04.
  6. ^ Chen, Xu; Bergström, Stig; Zhang, Yuan-Dong; Fan, Jun-Xuan (2009). "The base of the Middle Ordovician in China with special reference to the succession at Hengtang near Jiangshan, Zhejiang Province, southern China" (PDF). Lethaia. 42 (2): 218–231. Bibcode:2009Letha..42..218C. doi:10.1111/j.1502-3931.2008.00148.x. Archived (PDF) from the original on 2024-01-06. Retrieved 2024-06-04.
  7. ^ "Latest version of international chronostratigraphic chart". International Commission on Stratigraphy. Retrieved 2024-06-04.
  8. ^ Barry D. Webby (1998). "Steps toward a global standard for Ordovician stratigraphy". Newsletters on Stratigraphy. 36 (1): 1-33. doi:10.1127/nos/36/1998/1.
  9. ^ Stanley Finney (2005). "Global Series and Stages for the Ordovician System: A Progress Report". Geologica Acta. 3 (4): 309-316.
  10. ^ a b c N. V. Sennikov; E. V. Lykova; O. T. Obut; T. Yu. Tolmacheva; N. G. Izokh (2014). "The new Ordovician stage standard as applied to the stratigraphic units of the western Altai–Sayan Folded Area". Russian Geology and Geophysics. 55 (2014): 971—988. Bibcode:2014RuGG...55..971S. doi:10.1016/j.rgg.2014.07.005.
  11. ^ a b c Stig M. Bergström; Xu Chen; Juan Carlos Gutiérrez-Marco; Andrei Dronov (2009). "The new chronostratigraphic classification of the Ordovician System and its relations to major regional series and stages and to δ13C chemostratigraphy". Lethaia. 42 (1): 97–107. Bibcode:2009Letha..42...97B. doi:10.1111/j.1502-3931.2008.00136.x.
  12. ^ Sennikov N. V.; Tolmacheva T. Yu.; Obut О. Т. (2013). "New standard of Ordovocian stages in the International Stratigraphic Chart and problems concerning its application for the territory of Russia". Всероссийское совещание-2013 [All-Russian conference 2013] (in Russian). Trofimuk Institute of Petroleum-Gas Geology and Geophysics SB RAS, VSEGEI: 97.
  13. ^ a b David A. T. Harper; Tõnu Meidla; Thomas Servais (May 10, 2023). "A short history of the Ordovician System: from overlapping unit stratotypes to global stratotype sections and points". Geological Society, London, Special Publications. 532 (1). The Geological Society of London: 13–30. Bibcode:2023GSLSP.532..285H. doi:10.1144/SP532-2022-285. Archived from the original on 2024-05-18.
  14. ^ Bergström, Stig M.; Anita Löfgren; Jörg Maletz (2004). "The GSSP of the Second (Upper) Stage of the Lower Ordovician Series: Diabasbrottet at Hunneberg, Province of Västergötland, Southwestern Sweden" (PDF). Episodes. 27 (4): 265–272. doi:10.18814/epiiugs/2004/v27i4/005. Archived (PDF) from the original on 2024-04-16. Retrieved 2024-06-04.
  15. ^ Xiaofeng Wang; Svend Stouge; Jörg Maletz; Gabriella Bagnoli; Yuping. Qi; Elena G. Raevskaya; Chuanshang Wang; Chunbo Yan (2021). "The Xiaoyangqiao section, Dayangcha, North China: the new global Auxiliary Boundary Stratotype Section and Point (ASSP) for the base of the Ordovician System". Episodes. 44 (4): 359–383. doi:10.18814/epiiugs/2020/020091. Archived from the original on 2022-12-01.
  16. ^ a b Martin J. Head; Marie-Pierre Aubry; Werner E. Piller; Mike Walker (2023). "The Standard Auxiliary Boundary Stratotype: a proposed replacement for the Auxiliary Stratotype Point in supporting a Global boundary Stratotype Section and Point (GSSP)" (PDF). Episodes. 46 (1): 35—45. doi:10.18814/epiiugs/2022/022012. Archived (PDF) from the original on 2024-02-02. Retrieved 2024-06-04.
  17. ^ Shunxin Zhang (2023). "Lower and Upper Ordovician conodont biostratigraphy and revised lithostratigraphy in the fault and fold zones of the Boothia Uplift, south-western Boothia Peninsula, Nunavut". Canadian Journal of Earth Sciences. 60 (8): 1143. Bibcode:2023CaJES..60.1143Z. doi:10.1139/cjes-2022-0134.
  18. ^ N. V. Sennikov (2022). "Zonal graptolite units of Ordovician, Russia" (in Russian). IPGG SB RAS (Novosibirsk). p. 49.
  19. ^ a b I. G. Percival; C. D. Quinn; R. A. Glen (September 2011). "A review of Cambrian and Ordovician stratigraphy in New South Wales". Quarterly Notes / Geological Survey of New South Wales (137): 1—41. ISSN 0155-3410.
  20. ^ a b c d L. Robin M. Cocks; Trond H. Torsvik (December 2021). "Ordovician palaeogeography and climate change". Gondwana Research. 100: 53—72. Bibcode:2021GondR.100...53C. doi:10.1016/j.gr.2020.09.008. hdl:10852/83447.
  21. ^ a b Maya Elrick (2022). "Orbital-scale climate changes detected in Lower and Middle Ordovician cyclic limestones using oxygen isotopes of conodont apatite". Palaeogeography, Palaeoclimatology, Palaeoecology. 603 (3–4): 111209. Bibcode:2022PPP...60311209E. doi:10.1016/j.palaeo.2022.111209.
  22. ^ Bassett, D.; Macleod, K.G.; Miller, J. F.; Ethington, R. L. (2007). "Oxygen isotopic composition of biogenic phosphate and the temperature of Early Ordovician seawater". PALAIOS. 22 (1): 98—103. Bibcode:2007Palai..22...98B. doi:10.2110/palo.2005.p05-089r.
  23. ^ a b Guillermo L. Albanesi; Christopher R. Barnes; Julie A. Trotter; Ian S. Williams; Stig M. Bergström (2020). "Comparative Lower-Middle Ordovician conodont oxygen isotope palaeothermometry of the Argentine Precordillera and Laurentian margins". Palaeogeography, Palaeoclimatology, Palaeoecology. 549: 109115. Bibcode:2020PPP...54909115A. doi:10.1016/j.palaeo.2019.03.016. hdl:1885/217374.
  24. ^ Haijun Song; Paul B. Wignall; Huyue Song; Xu Dai; Daoliang Chu (2019). "Seawater Temperature and Dissolved Oxygen over the Past 500 Million Years". Journal of Earth Science. 30 (2): 236—243. Bibcode:2019JEaSc..30..236S. doi:10.1007/s12583-018-1002-2.
  25. ^ Page C. Quinton; Laura Speir; James Miller; Raymond Ethington; Kenneth G. MacLeod (August 2018). "Extreme heat in the Early Ordovician". PALAIOS. 33 (8): 353—360. Bibcode:2018Palai..33..353Q. doi:10.2110/palo.2018.031.
  26. ^ a b Thomas Servais; David A. T. Harper (2018). "The Great Ordovician Biodiversification Event (GOBE): definition, concept and duration". Lethaia. 51 (2): 151—164. Bibcode:2018Letha..51..151S. doi:10.1111/let.12259.
  27. ^ Jongsun Hong; Jino Park; Daecheol Kim; Eunhyun Cho; Seung-Min Kim (2022). "Relatively deep subtidal microbial–lithistid sponge reef communities in Lower Ordovician rocks reveal early escalation of the Great Ordovician Biodiversification Event". Palaeogeography, Palaeoclimatology, Palaeoecology. 602. Bibcode:2022PPP...60211159H. doi:10.1016/j.palaeo.2022.111159.
  28. ^ Yiying Deng; Junxuan Fan; Shengchao Yang; Yukun Shi; Zhengbo Lu; Huiqing Xu; Zongyuan Sun; Fangqi Zhao; Zhangshuai Hou (2023). "No Furongian Biodiversity Gap: Evidence from South China". Palaeogeography, Palaeoclimatology, Palaeoecology. 618 (1): 111492. Bibcode:2023PPP...61811492D. doi:10.1016/j.palaeo.2023.111492.
  29. ^ Josep Maria Casas; J. Brendan Murphy; Teresa Sanchez-Garcia; Jacques de Poulpiquet; José-Javier Alvaro; A. Díez-Montes; Joan Guimerà (2023). "Does the Ollo de Sapo magmatic event support Furongian-Tremadocian mantle plume activity fringing NW Gondwana?". International Geology Review. 66 (10): 1956–1970. doi:10.1080/00206814.2023.2263787.
  30. ^ Florencia Moreno; Ana Mestre; Susana Heredia (May 2023). "Lower Ordovician calcareous microfossils from the San Juan Formation, Argentina: A new type of calcitarch and its paleoenvironmental implications". Andean Geology. 50 (2): 302—317. doi:10.5027/andgeoV50n2-3469. hdl:11336/223379.
  31. ^ Dong-Jin Lee; Robert J. Elias; Brian R. Pratt (2022). "Amsassia (calcareous alga) from the Lower Ordovician (Tremadocian) of western Newfoundland, and the biologic affinity and geologic history of the genus". Journal of Paleontology. 96 (1): 1—18. Bibcode:2022JPal...96....1L. doi:10.1017/jpa.2021.89.
  32. ^ Dong-Jin Lee; Robert Elias; Brian R. Pratt (2022). "Reptamsassia n. gen. (Amsassiaceae n. fam.; calcareous algae) from the Lower Ordovician (Floian) of western Newfoundland, and the earliest symbiotic intergrowth of modular species". Journal of Paleontology. 96 (3): 1—14. Bibcode:2022JPal...96..715L. doi:10.1017/jpa.2021.122.
  33. ^ Christophe Dupichaud; Bertrand Lefebvre; Claire H. Milne; Rich Mooi; Martina Nohejlova; Renaud Roch; Farid Saleh6; Samuel Zamora (2023). "Solutan echinoderms from the Fezouata Shale Lagerstätte (Lower Ordovician, Morocco): diversity, exceptional preservation, and palaeoecological implications". Frontiers in Ecology and Evolution. 11 (1290063): 1—19. doi:10.3389/fevo.2023.1290063.{{cite journal}}: CS1 maint: numeric names: authors list (link)
  34. ^ Christophe Dupichaud; Bertrand Lefebvre; Martina Nohejlová (2023). "Solutan echinoderms from the Lower Ordovician of the Montagne Noire (France): new data and palaeobiogeographic implications". Estonian Journal of Earth Sciences. 72 (1): 26—29. doi:10.3176/earth.2023.80.
  35. ^ a b Pérez-Peris, Francesc; Laibl, Lukáš; Lustri, Lorenzo; Gueriau, Pierre; Antcliffe, Jonathan B; Bath Enright, Orla G; Daley, Allison C (2020). "A new nektaspid euarthropod from the Lower Ordovician strata of Morocco". Geological Magazine. 158 (3): 509–517. doi:10.1017/s001675682000062x.
  36. ^ Van Roy, Peter; Daley, Allison C.; Briggs, Derek E. G. (2015). "Anomalocaridid trunk limb homology revealed by a giant filter-feeder with paired flaps". Nature. 522 (7554): 77–80. Bibcode:2015Natur.522...77V. doi:10.1038/nature14256. ISSN 0028-0836. PMID 25762145. S2CID 205242881.
  37. ^ Perkins, S. (2015-03-11). "Newly discovered sea creature was once the largest animal on Earth". AAAS. Archived from the original on 2023-08-13. Retrieved 2024-06-04.
  38. ^ Drage, Harriet B.; Legg, David A.; Daley, Allison C. (2023). "Novel marrellomorph moulting behaviour preserved in the Lower Ordovician Fezouata Shale, Morocco". Frontiers in Ecology and Evolution. 11. doi:10.3389/fevo.2023.1226924. ISSN 2296-701X.
  39. ^ a b Xiang Fang; Yingyan Mao; Qi Liu; Wenwei Yuan; Zhongyang Chen; Rongchang Wu; Lixia Li; Yuchen Zhang; Junye Ma; Wenhui Wang; Renbin Zhan; Shanchi Peng; Yuandong Zhang; Diying Huang (2022). "The Liexi fauna: a new Lagerstätte from the Lower Ordovician of South China". Proceedings of the Royal Society B. 289 (1978): 1—8. doi:10.1098/rspb.2022.1027. PMC 9277276. PMID 35858062.
  40. ^ Qi Liu; Rui-Wen Zong; Qinghui Li; Xiang Fang; Diying Huang (2023). "New palaeoscolecidian worms from the Lower Ordovician Madaoyu Formation with specialised morphological characters and functional morphology". Historical Biology: 1–12. doi:10.1080/08912963.2023.2278172.
  41. ^ Shan, Longlong; Harvey, Thomas H.P.; Yan, Kui; Li, Jun; Zhang, Yuandong; Servais, Thomas (2023). "Palynological recovery of small carbonaceous fossils (SCFS) indicates that the late Cambrian acritarch Goniomorpha Yin 1986 represents the teeth of a priapulid worm". Palynology. 47 (3). Bibcode:2023Paly...4757504S. doi:10.1080/01916122.2022.2157504. S2CID 254711455.
  42. ^ Richard A. Fortey; Ernesto E. Vargas-Parra; Mary L. Droser (2024). "Trilobites from the Al Rose Formation (Lower Ordovician, Inyo Mountains, California)—faunas marginal to the Great Basin". Journal of Paleontology: 1—14. doi:10.1017/jpa.2023.57.
  43. ^ Li Zhou; Hao Tang; Yading Li; Ruiqing Tao; Wei Yan; Tao Ma; Shuang Pan; Yi Du; Zhenbo Tan; Xuefei Yang (2023). "Reservoir characteristics and genesis of the Lower Ordovician Tongzi Formation in central Sichuan Basin, China". Frontiers in Earth Science. 10: 1—10. Bibcode:2023FrEaS..10.4491Z. doi:10.3389/feart.2022.984491.
  44. ^ Meihua Yang; Yinhui Zuo; Xiaodong Fu; Lei Qiu; Wenzheng Li; Jianyong Zhang; Ziyun Zheng; Jiazhen Zhang (2022). "Paleoenvironment of the Lower Ordovician Meitan Formation in the Sichuan Basin and Adjacent Areas, China". Minerals. 12 (1): 1—16. Bibcode:2022Mine...12...75Y. doi:10.3390/min12010075.
  45. ^ Lijun Gao; Jie Li; Guorong Li; Liyun Fu; Yongli Liu (2024). "Distribution and Genesis of the Deep Buried, Fractured and Vuggy Dolostone Reservoir in the Lower Ordovician Succession, North Tarim Basin, Northwestern China". Minerals. 14 (1): 58. Bibcode:2024Mine...14...58G. doi:10.3390/min14010058.
  46. ^ Wenyang Wang; Xiongqi Pang; Yaping Wang; Fujie Jiang; Ying Chen; Zhangxin Chen (2023). "Critical Condition of the Depth Limit of Oil Accumulation of Carbonate Reservoirs and Its Exploration Significance in the Lower Ordovician of the Tazhong Area in the Tarim Basin". ACS Omega. 9 (5): 1443–1453. doi:10.1021/acsomega.3c07793. PMC 10785319. PMID 38222632.

Further reading

[edit]
[edit]
Retrieved from "https://en.wikipedia.org/w/index.php?title=Early_Ordovician&oldid=1256636439"