Rock from the Skiddaw Group, of Ordovician (Tremadocian) age, at Scawgill Bridge quarry in Cumbria, England, UK
The Tremadocian is the lowest stage of Ordovician. Together with the later Floian Stage it forms the Lower Ordovician Epoch. The Tremadocian lasted from 485.4 to 477.7 million years ago. The base of the Tremadocian is defined as the first appearance of the conodont species Iapetognathus fluctivagus at the Global Boundary Stratotype Section and Point (GSSP) section on Newfoundland.[7]
^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.
^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.
^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
^"Chart/Time Scale". www.stratigraphy.org. International Commission on Stratigraphy.
^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 2024-04-15.
^Bergström, M.; Löfgren, Anita; Maletz, Jörg (December 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 2023-06-20. Retrieved 2024-04-15.
^"GSSP Table - Paleozoic Era". Archived from the original on 2023-10-08.
The Tremadocian is the lowest stage of Ordovician. Together with the later Floian Stage it forms the Lower Ordovician Epoch. The Tremadocian lasted from...
Furongian series. It follows the Jiangshanian and precedes the Ordovician Tremadocian Stage. The proposed lower boundary is the first appearance of the trilobite...
The Ordovician Period in Britain was traditionally broken into Early (Tremadocian and Arenig), Middle (Llanvirn (subdivided into Abereiddian and Llandeilian)...
(2018). "High resolution trilobite biostratigraphy for the early late Tremadocian (Tr2) interval (Early Ordovician) Santa Rosita Formation, Argentine Cordillera...
as dictyonema argillite, dictyonema oil shale, dictyonema shale, or Tremadocian black shale) is a marinite-type black shale of sapropelic origin. It...
conodonts belonging to the genus Iapetognathus. It existed during the Tremadocian Age (485.4 million years ago) of the Ordovician. It is an important index...
Species belonging to the Phacopina lived from the Lower Ordovician (Tremadocian) through the end of the Upper Devonian (Famennian). The one unique feature...
Angeles. Santa Rosita Formation, a geological formation (upper Furongian–Tremadocian) in the Tilcara Range, Cordillera Oriental of Jujuy, Argentina Santa...
"Feeding traces related to shells from the Prague Basin, Czech Republic (Tremadocian to early Darriwilian, Ordovician)". Palaeogeography, Palaeoclimatology...
Coryphidium is an extinct genus of acritarchs. C. elegans is from the Tremadocian, the lower age of the Ordovocian of Morocco. Acritarchs from Klabava...
of ridges (Taylor 1984). Marcusodictyon occurs on late Cambrian and Tremadocian lingulate brachiopods of Baltica (Vinn 2015). Taylor, P.D. (1984). Marcusodictyon...
that spans the Tremadocian and Floian epochs. Two stratigraphic intervals of the formation are fossiliferous: the lower is Late Tremadocian and sits 260...
rocks. The Global Boundary Stratotype Section and Point (GSSP) of the Tremadocian stage and the all Ordovician system is defined in the Green Point section...
Miaolingian series of the Cambrian and precedes the Lower Ordovician Tremadocian Stage. It is subdivided into three stages: the Paibian, Jiangshanian...
formation in Bavaria, Germany. It preserves fossils dating back to the Tremadocian stage of the Ordovician period. Trilobites Agerina alkleini Echinosphaerites...
trilobites of the family Raphiophoridae that lived during the Early Tremadocian of Alberta, Canada. It is known only from a cranidium with a large, keel-shaped...
Floian is the second stage of the Ordovician Period. It succeeds the Tremadocian with which it forms the Lower Ordovician epoch. It precedes the Dapingian...
trilobites of the family Raphiophoridae that lived during the Early Tremadocian of Vermont, United States. The generic epithet is a compound word of...
The Tucumilla Formation is a Tremadocian geologic formation of southern Bolivia. The sandstones, shales and siltstones crop out in the José María Avilés...
slender arms without pinnules. They range from the Early Ordovician (Tremadocian) to Middle Permian, reaching their highest diversity during the Late...
Aegirocassis Temporal range: Late Tremadocian, 480 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓ Fossil holotype Reconstruction of Aegirocassis benmoulai Scientific...
sequence of metasedimentary rocks of Cambro-Ordovician (Furongian to Tremadocian) age found in northern and western Anglesey and the adjacent Holy Island...
Ottoia Temporal range: Miaolingian–Furongian (Tremadocian?) PreꞒ Ꞓ O S D C P T J K Pg N Reconstruction of Ottoia prolifica. The anterior portion of Ottoia...
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