Middle Ordovician Conodont Biostratigraphy of Australasia

Author(s):  
Yong Yi Zhen
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.


1989 ◽  
Vol 63 (1) ◽  
pp. 92-107 ◽  
Author(s):  
Jeffrey A. Bauer

Conodonts from the upper Burgen, Tyner, and Fite Formations (Middle Ordovician) of eastern Oklahoma include two new species, Phragmodus harrisi and Plectodina tynerensis. The conodont fauna indicates that the upper Burgen through middle Tyner is Whiterockian (pre- to earliest Chazyan) and that the upper Tyner–Fite is probably Kirkfieldian in age.The Whiterockian Burgen–Tyner preserves a regressive succession of shoreface, lagoonal, and intertidal deposits. That change is reflected by the conodont succession, which shows replacement of a fauna dominated by species of Neomultioistodus, Scandodus?, and Paraprioniodus by one dominated by species of Phragmodus, Plectodina, and Erismodus.Carbonate deposits of the Kirkfieldian(?) upper Tyner and Fite Formations follow a major hiatus and reflect shallow, subtidal to intertidal conditions. The conodont fauna is composed of species of Aphelognathus, Plectodina, Curtognathus, Erismodus, and Oulodus, among others.


GFF ◽  
2018 ◽  
Vol 140 (1) ◽  
pp. 44-54 ◽  
Author(s):  
Rong-Chang Wu ◽  
Mikael Calner ◽  
Oliver Lehnert ◽  
Anders Lindskog ◽  
Michael Joachimski

2017 ◽  
Vol 91 (2) ◽  
pp. 294-317
Author(s):  
James Loch ◽  
Raymond Ethington

AbstractThe outcrop at Whiterock Canyon Narrows, Nevada, is the stratotype for the Middle Ordovician Whiterockian Series in Laurentia. Contrasts in the distribution of trilobites and conodonts between two parallel sections at the stratotype demonstrate the presence of an unconformity separating Ibexian faunas (the historic trilobite Zone J, the more recent restricted “Pseudocybele nasuta” trilobite Zone, theReutterodus andinusconodont Zone) from overlying Whiterockian faunas (Zone L, thePsephosthenaspis pseudobathyurustrilobite Zone, theOrthidiellabrachiopod Zone, theTripodus combsiconodont Zone). The unconformity represents the erosional loss of a minimum of 10 m of shale and bedded limestone within the upper Ninemile Formation. In comparison to more continuous section in the Ibex region, Utah, the equivalent to the thinPsephosthenaspis microspinosatrilobite Zone and, possibly, the uppermost interval of the underlying “P.nasuta” Zone are missing.Illaenus welchinew species is described from the Whiterockian faunas of the upper Ninemile and Antelope Valley formations.


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