Amsassia (calcareous alga) from the Lower Ordovician (Tremadocian) of western Newfoundland, and the biologic affinity and geologic history of the genus

2021 ◽  
pp. 1-18
Author(s):  
Dong-Jin Lee ◽  
Robert J. Elias ◽  
Brian R. Pratt
Keyword(s):  
South China ◽  
Geologic History ◽  
Shallow Marine ◽  
Middle Ordovician ◽  
Calcareous Alga ◽  
Tarim Block ◽  
Lower Ordovician ◽  
History Of ◽  
Argentine Precordillera ◽  
Extinct Group

Abstract Modular coral-like fossils from Lower Ordovician (Tremadocian) thrombolitic mounds in the St. George Group of western Newfoundland were initially identified as Lichenaria and thought to include the earliest tabulate corals. They are here assigned to Amsassia terranovensis n. sp. and Amsassia? sp. A from the Watts Bight Formation, and A. diversa n. sp. and Amsassia? sp. B from the overlying Boat Harbour Formation. Amsassia terranovensis n. sp. and A. argentina from the Argentine Precordillera are the earliest representatives of the genus. Amsassia is considered to be a calcareous alga, possibly representing an extinct group of green algae. The genus originated and began to disperse in the Tremadocian, during the onset of the Great Ordovician Biodiversification Event, on the southern margin of Laurentia and the Cuyania Terrane. It inhabited small, shallow-marine reefal mounds constructed in association with microbes. The paleogeographic range of Amsassia expanded in the Middle Ordovician (Darriwilian) to include the Sino-Korean Block, as well as Laurentia, and its environmental range expanded to include non-reefal, open- and restricted-marine settings. Amsassia attained its greatest diversity and paleogeographic extent in the Late Ordovician (Sandbian–Katian), during the culmination of the Great Ordovician Biodiversification Event. Its range included the South China Block, Tarim Block, Kazakhstan, and Siberia, as well as the Sino-Korean Block and Laurentia, and its affinity for small microbial mounds continued during that time. In the latest Ordovician (Hirnantian), the diversity of Amsassia was reduced, its distribution was restricted to non-reefal environments in South China, and it finally disappeared during the end-Ordovician mass extinction. UUID: http://zoobank.org/ef0abb69-10a6-46de-8c78-d6ec7de185fe

Basal Cambrian microfossils from the Yangtze Gorges area (South China) and the Aksu area (Tarim block, northwestern China)

2009 ◽  
Vol 83 (1) ◽  
pp. 30-44 ◽  
Author(s):  
Lin Dong ◽  
Shuhai Xiao ◽  
Bing Shen ◽  
Chuanming Zhou ◽  
Guoxiang Li ◽  
...  
Keyword(s):  
Geographic Distribution ◽  
South China ◽  
Northwestern China ◽  
Cambrian Explosion ◽  
Filamentous Cyanobacteria ◽  
Primary Producers ◽  
Tarim Block ◽  
Eukaryotic Phytoplankton ◽  
History Of ◽  
Wide Geographic Distribution

The basal Cambrian marks the beginning of an important chapter in the history of life. However, most paleontological work on the basal Cambrian has been focused on skeletal animal fossils, and our knowledge about the primary producers—cyanobacteria and eukaryotic phytoplankton (e.g., acritarchs)—is limited. In this research, we have investigated basal Cambrian acritarchs, coccoidal microfossils, and cyanobacteria preserved in phosphorites and cherts of the Yanjiahe Formation in the Yangtze Gorges area (South China) and the Yurtus Formation in the Aksu area (Tarim Block, northwestern China). Our study confirms the occurrence in these two formations of small acanthomorphic acritarchs characteristic of the basal CambrianAsteridium–Comasphaeridium–Heliosphaeridium(ACH) assemblage. These acritarchs include abundantHeliosphaeridium ampliatimi(Wang, 1985) Yao et al., 2005, commonYurtusia uniformisn. gen. and n. sp., and rareComasphaeridium annulare(Wang, 1985) Yao et al., 2005. In addition, these basal Cambrian successions also contain the clustered coccoidal microfossilArchaeophycus yunnanensis(SonginLuo et al., 1982) n. comb., several filamentous cyanobacteria [Cyanonema majusn. sp.,Oscillatoriopsis longaTimofeev and Hermann, 1979, andSiphonophycus robustum(Schopf, 1968) Knoll et al., 1991], and the tabulate tubular microfossilMegathrix longusL. Yin, 1987a, n. emend. Some of these taxa (e.g.,H. ampliatum, C. annulare, andM. longus) have a wide geographic distribution but occur exclusively in basal Cambrian successions, supporting their biostratigraphic importance. Comparison between the stratigraphic occurrences of microfossils reported here and skeletal animal fossils published by others suggests that animals and phytoplankton radiated in tandem during the Cambrian explosion.

Early orthoceratoid cephalopods from the Argentine Precordillera (Lower-Middle Ordovician)

2007 ◽  
Vol 81 (6) ◽  
pp. 1266-1283 ◽  
Author(s):  
Björn Kröger ◽  
Matilde S. Beresi ◽  
Ed Landing
Keyword(s):  
New Species ◽  
Southern Hemisphere ◽  
North China ◽  
North China Block ◽  
Middle Ordovician ◽  
Strong Affinity ◽  
Middle Latitudes ◽  
The North ◽  
Lower Ordovician ◽  
Argentine Precordillera

The Early and Middle Ordovician Orthocerida and Lituitida of Precordilleran Argentina are described, and their systematics and paleogeographic significance are revised. These cephalopods show a strong affinity to coeval faunas of North China, suggesting a location of the Precordillera at middle latitudes in the Southern Hemisphere east of the North China block and relatively close to the Gondwanan margin during the early Middle Ordovician. The descriptive terminology of characters of the septal necks, the position and shape of the siphuncule, and the shape of the connecting ring is improved. The distribution of these characters support an emendation of the Baltoceratidae, Sactorthoceratidae, and Proteoceratidae. Braulioceras n. gen. (Sactorthoceratidae) and Palorthoceras n. gen. (Orthoceratidae) are erected. The new species Braulioceras sanjuanense, Eosomichelinoceras baldisii, Gangshanoceras villicumense, and Rhynchorthoceras minor are proposed. Palorthoceras n. gen. from the Lower Ordovician Oepikodus evae Zone represents the earliest known orthocerid.

Integrated conodont biostratigraphy and carbon isotope chemostratigraphy in the Lower–Middle Ordovician of southern Sweden reveals a complete record of the MDICE

2016 ◽  
Vol 154 (2) ◽  
pp. 334-353 ◽  
Author(s):  
RONGCHANG WU ◽  
MIKAEL CALNER ◽  
OLIVER LEHNERT
Keyword(s):  
North America ◽  
Carbon Isotope ◽  
South China ◽  
North China ◽  
Southern Sweden ◽  
Conodont Biostratigraphy ◽  
Middle Ordovician ◽  
The Core ◽  
Core Section ◽  
Argentine Precordillera

AbstractOne of the few and most complete records of the MDICE (Middle Darriwilian Isotope Carbon Excursion) is herein documented from Baltoscandia. Based on a core section penetrating the condensed Lower–Middle Ordovician succession (~46 m) on the island of Öland, southeastern Sweden, we provide an integrated scheme for carbon isotope chemostratigraphy (313 samples) and conodont biostratigraphy (29 samples) for this period. The carbonate succession in the Tingskullen core records 12 conodont zones and 6 subzones, including theOepikodus evae, Trapezognathus diprion, Baltoniodus triangularis, B. navis, B. norrlandicus, Lenodus antivariabilis, L. variabilis, Yangtzeplacognathus crassus, Eoplacognathus pseudoplanus(Microzarkodina hagetianaandMicrozarkodina ozarkodellasubzones),E. suecicus, Pygodus serra(E. foliaceus, E. reclinatus, E. robustusandE. lindstroemisubzones) andPygodus anserinuszones in ascending order. The δ13Ccarbrecord reveals an apparently complete record of the MDICE, including a rising limb, a well-defined peak and a falling limb. The anomaly covers a thickness ofc. 27 m in the core and spans theEoplacognathus pseudoplanus, E. suecicus, Pygodus serraandP. anserinusconodont zones. Combined with the new, detailed conodont biostratigraphy, the MDICE in the Tingskullen core can be used for detailed correlation with successions from Baltica, North America, the Argentine Precordillera, South China and North China.

Stromatoporoids: Geologic History

1983 ◽  
Vol 7 ◽  
pp. 167-172
Author(s):  
Carl W. Stock
Keyword(s):  
Great Majority ◽  
Clear Picture ◽  
Late Devonian ◽  
Marine Environments ◽  
Geologic History ◽  
Shallow Marine ◽  
Middle Ordovician ◽  
To Come

The great majority of the published work on the paleontology of the stromatoporoids has appeared since 1950. This influx of information has made possible a fairly clear picture of their evolution. As mentioned earlier by Stearn, stromatoporoids were quite abundant in shallow marine environments from the Middle Ordovician through the Late Devonian. These are referred to as the “Paleozoic stromatoporoids.” The record of Carboniferous stromatoporoids is sparse, but they began to come back in the Permian, and were common again through much of the Mesozoic, until disappearing at the the end of the Cretaceous. The Permian through Cretaceous forms shall be referred to as the “Mesozoic stromatoporoids.”

The tectonics and depositional history of the Ordovician and Silurian rocks of Notre Dame Bay, Newfoundland

1985 ◽  
Vol 22 (4) ◽  
pp. 607-618 ◽  
Author(s):  
R. J. Arnott ◽  
W. S. McKerrow ◽  
L. R. M. Cocks
Keyword(s):  
Strike Slip ◽  
Late Ordovician ◽  
Island Arc ◽  
The West ◽  
Depositional History ◽  
Middle Ordovician ◽  
The North ◽  
Lower Ordovician ◽  
History Of ◽  
Ophiolitic Rocks

In the Notre Dame Bay region, ophiolitic rocks underlie a thick sequence of Lower Ordovician volcanic-arc rocks to the north of the Lobster Cove – Chanceport Fault. Neither this fault nor the Lukes Arm – Sops Head Fault shows evidence of very large strike-slip movements, as parts of the same arc, together with much arc-derived detritus, straddle both faults. Towards the east, this arc-derived detritus becomes more distal in aspect and passes laterally into the Dunnage Mélange. During the Middle Ordovician Epoch (late Llandeilo and early Caradoc), most areas show a marked decrease in volcanic activity and in the amount of coarse detritus deposited. Coarse turbidites reappear, at different times in different areas, during the Late Ordovician. These are related to several fault-bounded basins and to movements on the Lukes Arm – Sops Head Fault. Many of these faults, particularly in the east, are marked by olistostromes, several of which can be dated by fossils as Late Ordovician and Early Silurian. The whole region, between the Reach Fault on the east and the Baie Verte – Brompton Line on the west, has a stratigraphic unity. If it has been moved by strike slip relative to the Long Range, then any such fault must lie to the west of the Baie Verte – Brompton Line. The interpretation of an Early Ordovician island arc moving above an easterly directed subduction zone is in accord with both the geochemical and palaeontological evidence. The Notre Dame Bay region may have been converted into a transform-dominated margin in the Late Ordovician and Early Silurian in a manner analogous to the oblique slip tectonic regimes of the Californian and New Zealand margins during the Tertiary, with a precursor of the Reach Fault marking the edge of the continent after the Notre Dame island arc had collided with North America.

The “earliest tabulate corals” are not tabulates

Geology ◽  
2020 ◽  
Author(s):  
Robert J. Elias ◽  
Dong-Jin Lee ◽  
Brian R. Pratt
Keyword(s):  
Evolutionary History ◽  
Late Ordovician ◽  
Time Span ◽  
Cambrian Explosion ◽  
Middle Ordovician ◽  
Early Ordovician ◽  
Calcareous Alga ◽  
History Of ◽  
Geological Factors ◽  
Tabulate Corals

Putative tabulate-like corals dating to the Cambrian Explosion are not true tabulates. Early Ordovician fossils identified as Lichenaria and previously accepted as the earliest tabulate corals actually belong to Amsassia, which may be a calcareous alga. The earliest definite tabulates appeared in the latest Middle Ordovician as part of the Great Ordovician Biodiversification Event, prior to the earliest confirmed occurrence of tabulate species that do belong to Lichenaria in the Late Ordovician. With Cambrian (Epoch 2) tabulate-like fossils being separated from the appearance of true tabulates by a time span of ~50 m.y., a direct phylogenetic connection is unlikely. Thus, the prevailing understanding of the origin and evolutionary history of tabulate corals needs to be reconsidered. The appearance of both major groups of Paleozoic corals, tabulates and rugosans, at the same time on separate paleocontinents must be taken into account in determining biological and geological factors involved in the Great Ordovician Biodiversification Event.

Evidence for a Caledonian orogeny in Poland

1994 ◽  
Vol 85 (2) ◽  
pp. 131-142 ◽  
Author(s):  
J. D. Johnston ◽  
J. A. Tait ◽  
G. J. H. Oliver ◽  
F. C. Murphy
Keyword(s):  
Central And Eastern Europe ◽  
The Czech Republic ◽  
Middle Ordovician ◽  
Continental Scale ◽  
Holy Cross Mountains ◽  
Tectonic History ◽  
Iapetus Ocean ◽  
Lower Ordovician ◽  
History Of ◽  
Lower Palaeozoic

AbstractThe Lower Palaeozoic tectonic history of central and eastern Europe is poorly understood because of extensive Variscan and/or Alpine reworking. The trace of the Tornquist Sea, the SE arm of the Lower Palaeozoic Iapetus Ocean, extended from NE Britain to Asia Minor. The site of this ocean is constrained by the tectonostratigraphy and faunal provinciality of Lower Palaeozoic inliers in northern Czechoslovakia, and southern Poland. In this paper, the collage of contrasting tectonostratigraphic histories of terranes in the Lower Palaeozoic of Poland is reviewed. Fossil evidence demonstrates that the Holy Cross Mountains and the Krakovian Belt display Lower Ordovician and Lower Devonian angular unconformities. Faunal data suggest that the Tornquist Suture Zone must lie south of the Holy Cross and between Upper Silesia and the Barrandian of the Czech Republic. Between these areas, in the Sudeten Mountains, a continental scale sinistral mylonite zone (along the line of the Intra-Sudetic Fault) was periodically active between the Middle Ordovician and the Upper Triassic. Various dismembered ophiolite, island arc and batholith terranes from alongside the Intra-Sudetic Fault have Ordocivian and Silurian magmatic and metamorphic zircon isotopic and fossil ages. Thus the often stated view that deformation in the Sudetes is Variscan (i.e. post-Middle Devonian) must be called into question. It is proposed instead that the Tornquist Suture is located within the Sudeten mountains, and as in the Holy Cross Mountains, much of the observed deformation is post-Cambrian and pre-Gedinnian in age, i.e. Caledonian.

scholarly journals First Middle Ordovician conodont record related to key graptolites from the western Puna, Argentina: perspectives for an integrated biostratigraphy and correlation of the Central Andean Basin

2020 ◽  
Vol 47 (1) ◽  
pp. 144 ◽  
Author(s):  
Blanca A. Toro ◽  
Susana E. Heredia ◽  
Nexxys C. Herrera Sánchez ◽  
Florencia Moreno
Keyword(s):  
High Resolution ◽  
South China ◽  
Middle Portion ◽  
Middle Ordovician ◽  
Lower Ordovician ◽  
Conodont Fauna ◽  
First Time ◽  
Overlying Strata

Recent biostratigraphic studies on the western argentine Puna recorded the Middle Ordovician conodont Baltoniodus cf. B. navis (Lindström) for first time, related to key graptolite taxa of the Central Andean Basin. The analyzed material comes from the lower and middle thirds of the turbidite succession exposed at the Huaytiquina section, Salta Province, which was previously assigned to the “Coquena” Formation. The conodont fauna was recovered from the calcareous sandstone beds intercalated in the middle portion of this unit, and it is composed by species of the genera Baltoniodus, Gothodus, Trapezognathus, Drepanoistodus, Drepanodus, and Protopanderodus, among others. The conodont association indicates a middle Dapingian (Dp2) age, linking the conodonts of the Argentine Puna with those from Baltoscandinavia and South China. The conodont productive levels also contain graptolites assignable to Tetragraptus bigsbyi (Hall) and Isograptus sp. They are located overlying strata bearing Azygograptus lapworthi Nicholson and underlying deposits with Xiphograptus lofuensis (Lee). The graptolite associations are indicating a Dapingian age (Dp1-Dp2) for the lower and middle portions of the “Coquena” Formation. The current findings from the western Puna, as well as the record of Azygograptus lapworthi related to the early Dapingian (Dp1) index conodont Baltoniodus triangularis in the Argentine Cordillera Oriental, are suggesting that a high-resolution correlation between both geomorphological regions is possible. This also documents that the Cordillera Oriental as well as the Puna were connected parts of the Central Andean Basin, during the interval from the Lower Ordovician (Floian) to the Middle Ordovician (Dapingian), instead of corresponding to the source and infill sectors of the basin, respectively. Furthermore, the regional and global correlations are discussed, and the potential of the Ordovician successions of the Argentine Puna for future advances on conodont-graptolite high-resolution biostratigraphy is highlighted.

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