Summary of Conodont Biostratigraphy of the Silurian System of North America

Author(s):  
Carl B. Rexroad ◽  
Robert S. Nicoll
2016 ◽  
Vol 154 (2) ◽  
pp. 334-353 ◽  
Author(s):  
RONGCHANG WU ◽  
MIKAEL CALNER ◽  
OLIVER LEHNERT

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.


1999 ◽  
Vol 18 (1) ◽  
pp. 17-25 ◽  
Author(s):  
Nadia Maziane ◽  
Kenneth T. Higgs ◽  
Maurice Streel

Abstract. New palynological data have been obtained from the Late Famennian Evieux and Comblain au Pont Formations of the Chanxhe section located in the Ourthe Valley in the eastern part of the Dinant Basin. In the light of this new data the stratigraphic ranges of several zonally important miospore taxa are now significantly different to those previously recorded. This has necessitated a re-evaluation and revision of the late Famennian miospore zonation scheme for this region. Apiculiretusispora verrucosa and Vallatisporites hystricosus are now found to occur below the inception of Retispora lepidophyta. Consequently, a new biozone, the Apiculiretusispora verrucosa–Vallatisporites hystricosus VH Biozone is described for the late Fa2c interval. The problematical relationship between the Retispora lepidophyta– Apiculiretusispora verrucosa LV Biozone and the Retispora lepidophyta–Knoxisporites literatus LL Biozone is resolved, and part of the LL Biozone is now considered equivalent to the LV Biozone, which it consequently replaces. The Retispora lepidophyta–Indotriradites explanatus LE Biozone is recorded from the upper part of the Comblain au Pont Formation. A continuous succession of miospore zones is now established for the late Famennian Fa2c/Fa2d interval which permits more accurate correlations with other regions in Europe and North America. Correlation with the standard conodont biostratigraphy shows that the base of LL Miospore Biozone is correlated with the middle or late expansa Conodont Biozone and the base of LE Miospore Biozone with the early to middle praesulcata Conodont Biozone.


Author(s):  
Peter Dahlqvist ◽  
Stig M. Bergström

ABSTRACTThe Late Ordovician–Early Silurian succession in Jämtland includes the marine Kogsta Siltstone, which is unconformably overlain by the shallow-water Ede Quartzite that grades into the open-marine Berge Limestone. A Hirnantia shelly fauna dates the uppermost Kogsta Siltstone as Hirnantian, and shelly fossils indicate an Aeronian age for the Berge Limestone. Biostratigraphically highly diagnostic conodonts of the early-middle Aeronian Pranognathus tenuis Zone provide the first firm date of the Upper Ede Quartzite and the lowermost Berge Limestone. The Lower Ede Quartzite has not yielded fossils, but sedimentological data suggest it to be of Hirnantian age and reflect the glacio-eustatic low-stand. The contact between the Lower and Upper Ede Quartzite, here taken to be the Ordovician–Silurian boundary, appears to be an unconformity associated with a stratigraphic gap that at least includes the Rhuddanian Stage. The biostratigraphically important conodonts Pranognathus tenuis, Kockelella? manitoulinensis, and Pranognathus siluricus are recorded from Sweden for the first time, and these and other conodonts are used for correlations with coeval units in Europe and North America. In a regional review of Aeronian conodont faunas, three intergrading, apparently depth-related, conodont biofacies are recognised, the Jämtland conodonts representing the one characteristic of the shallowest water.


2010 ◽  
Vol 147 (5) ◽  
pp. 641-651 ◽  
Author(s):  
STIG M. BERGSTRÖM ◽  
SACHIKO AGEMATSU ◽  
BIRGER SCHMITZ

AbstractApart from a single study of the early Katian δ13C chemostratigraphy in two regions in China, no investigations of the Sandbian and Katian chemostratigraphy have been published from anywhere in Asia. A recent study of the conodont biostratigraphy of the classical Ordovician succession on Langkawi Islands, peninsular Malaysia, showed the presence there of strata coeval with those having the Guttenberg Carbon Excursion (GICE) on the Yangtze Platform. In an effort to establish for the first time the presence of this widespread δ13C excursion in southern Asia, a series of samples from the upper part of the Kaki Bukit Formation was isotopically analysed. This resulted in the discovery of a conspicuous δ13C excursion with peak values of ~ 2 ‰ above the baseline values. The excursion is located just above theBaltoniodus alobatusSubzone and near the level of the first appearance ofHamarodus europaeus, hence the same stratigraphic position as the GICE on the Yangtze Platform. Using the GICE, the Malaysian study interval is closely correlated with the GICE intervals at three localities representing an approximately 23 000 km long transect from Malaysia across Baltoscandia to central North America. This shows the usefulness of δ13C chemostratigraphy to clarify previously obscure stratigraphic relationships between geographically very widely separated localities.


2011 ◽  
Vol 48 (3) ◽  
pp. 619-643 ◽  
Author(s):  
Shunxin Zhang

Southampton Island was located on the north margin of the Hudson Bay Basin, one of the largest Paleozoic sedimentary basins in North America. The Upper Ordovician sequence on the island includes the Bad Cache Rapids and Churchill River groups and the Red Head Rapids Formation; the latter contains three oil shale intervals in its lower part, which may have significant potential as hydrocarbon source rocks, but their precise biostratigraphic position remains unclear. Numerous conodont elements from 14 localities allow establishment of four interval zones throughout the Upper Ordovician on Southampton Island: the Belodina confluens and Pseudobelodina v. vulgaris zones in the Bad Cache Rapids Group, which are correlative to the upper Edenian – lowest Richmondian Stage; the Amorphognathus ordovicicus Zone from the uppermost Bad Cache Rapids Group to the top of Churchill River Group to the lower Richmondian Stage; and the Rhipidognathus symmetricus Zone in the Red Head Rapids Formation to the upper Richmondian Stage. The oil shale intervals in the lower Red Head Rapids Formation exposed at Cape Donavan, Sixteen Mile Brook, and Boas River on Southampton Island are correlated with the lower R. symmetricus Zone of the upper Richmondian Stage, not the Maysvillian–Richmondian Stage as previous interpreted. The “Boas River shale” and “Sixteen Mile Brook shale” biostratigraphically and lithostratigraphically equate to the Cape Donovan lower and middle oil shale intervals, respectively. The conodont data and continuous sections across the boundaries between the different lithostratigraphic units have proved the presence of Maysvillian strata on Southampton Island, rather than absence as previously interpreted.


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