0000000000170098
AUTHOR
Jau-chyn Liao
Descripción de los conodontos del Givetiense y Frasniense inferior (Devónico) de Renanué (Pirineos Aragoneses)
Se estudia el contenido en conodontos del Givetiense y Frasniense inferior en la sección Renanué (Pirineos Aragoneses). Como resultado se describen 28 taxones de Polygnathus, Icriodus, Skeletognathus y Klapperina. De éstos, 21 se describen e ilustran por primera vez en la sección Renanué. Esta sucesión de conodontos permitirá una subdivisión bioestratigráfica detallada del intervalo estudiado. A Givetian and Early Frasnian conodont sequence from Renanué section is presented. As a result, 28 taxa belonging to Polygnathus, Icriodus, Skeletognathus and Klapperina are described. 21 taxa are described and illustrated for the first time from Renanué section. This conodont succession will allow a …
Polygnathids (Conodonta) around the Pragian/Emsian boundary from the Dacun-1 section (central Guangxi, South China)
AbstractThe base of the Emsian, which is defined by the first appearance of the conodont Polygnathus kitabicus, has never been successfully demonstrated in the South China Block (including Guangxi and eastern Yunnan). As a result, we studied conodonts from the lowermost part of the Shizhou Member of the Yukiang Formation at the Dacun-1 section in the Liujing area, Guangxi. This new investigation has revealed a conodont fauna only consisting of Polygnathus pireneae, P. sokolovi, P. kitabicus, P. sp. and Pandorinellina exigua philipi, which can be assigned to the uppermost part of the pireneae Zone and the lowermost part of the kitabicus Zone in ascending order. The Pragian/Emsian boundary at…
Upper Eifelian and Givetian (Middle Devonian) conodont sequence at Renanué (Aragonian Pyrenees, Spain): a relevant section for Givetian Chronostratigraphy
Emsian (Lower Devonian) conodonts from the Daliantang Formation at Daliantang, southeastern Yunnan, China
Abstract The lower/upper Emsian boundary witnessed prominent diversification of biostratigraphically important genera Polygnathus Hinde, Caudicriodus Bultynck, and Latericriodus Muller. In contrast, conodonts previously reported around this boundary from the South China Block were characterized by relatively low species or subspecies diversity, and only a few widely distributed and extensively studied zone-defining taxa were recorded. In this paper, conodonts from the Daliantang Formation at the Daliantang section (Guangnan, southeastern Yunnan), one of the representative sections of the transitional facies between the benthic Xiangzhou facies and the pelagic Nandan facies, are investigated…
Sucesión de Polygnátidos (Conodontos) del Emsiense (Devónico Inferior) en los Pirineos Centrales Españoles
A comprehensive conodont study of five sections of Emsian age, carried out in the Spanish Central Pyrenees, has revealed an important succession of polygnathids that can be used for identifying basal boundaries of globally recognized biozones. This succession consists of Polygnathus excavatus excavatus, Po. gronbergi, Po. nothoperbonus, Po. mashkovae, Po. laticostatus, and the new species Polygnathus luciae that allows the identification of the excavatus, nothoperbonus and laticostatus Zones. The nothoperbonus Zone is further subdivided into Lower and Upper nothoperbonus subzones, relying upon the lowest occurrence of Po. mashkovae. These biostratigraphic data from the Spanish Central Pyren…
Givetian (Middle Devonian) historical bio- and chronostratigraphical subdivision based on conodonts
The conodont record supports the intended threefold subdivision of the Givetian as envisaged by the International Subcommision on Devonian Stratigraphy into Lower, Middle and Upper Givetian substages. The lower boundary of the Lower Givetian Stage coincides with the lower boundary of the Givetian and it is recognized with the entry of Polygnathus hemiansatus. The lower boundary of the Middle Givetian is identified with the entry of either P. varcus or P. rhenanus. The base of the Upper Givetian is defined with the entry of Schmidtognathus hermanni. The historical review shows the conceptual evolution from a stage with just one and a half zones to one with ten zones that are the basis for th…
Conodonts from Late Devonian island arc settings (Baruunhuurai Terrane, western Mongolia)
Abstract Upper Devonian marine deposits of the Baruunhuurai Terrane in western Mongolia represent island arc settings, which yielded a diverse conodont assemblage of 30 taxa, including species of Ancyrognathus (as well as one new species), Icriodus, Mehlina, Polygnathus and Palmatolepis. Biodiversity analysis of Ancyrognathus, Pelekysgnathus, Mehlina and Icriodus shows that the Mongolian conodont assemblage consists of two endemic and few cosmopolitan taxa. Representatives of the otherwise globally distributed genus Pelekysgnathus are absent. An important factor influencing the regional distribution of conodont taxa seems to be the siliciclastic-dominated sedimentation of the Baruunhuurai T…
Chondrichthyan microremains from the Givetian of the Aragonian Pyrenees (Spain)
Keywords .-L owervarcus Zone, Middle varcus Zone, Teeth, Scales, Squamation pattern, Phoebodus fastigatus. Abstract .-AL ower andbasal Middle varcus Zone (Givetian, Middle Devonian) vertebrate association consisting of chondrichtyan teeth and scales of the genus Phoebodus is documented for the first time from the Aragonian Pyrenees of Spain. This record suggests that different teeth morphologies that were previously treated as separate taxa could be grouped in Phoebodus fastigatus. Moreover, the teeth and scales association is in agreement with the previously recons- tructed squamation pattern of this taxon.
Conodont biostratigraphy of the Yujiang Formation (Emsian, Lower Devonian) at Shizhou, Guangxi, South China
Abstract We study conodonts from the upper part of the Shizhou Member of the Yujiang Formation in Liujing area for the first time. Relatively abundant conodonts were collected from six sampling levels located between the uppermost part of the Shizhou Member to the lowermost part of the Daliancun Member at the Shizhou section, Liujing, Guangxi. The material includes Polygnathus excavatus excavatus Carls and Gandl, P. excavatus ssp. 114 Carls and Valenzuela-Rios, P. nothoperbonus Mawson, P. perbonus (Philip) as well as “ Ozarkodina ” midundenta (Wang and Ziegler) and “ O. ” prolata Mawson. The lowest record of P. nothoperbonus is documented 0.35 m below the boundary between the Shizhou and Da…
Graphic correlation of the upper Eifelian to lower Frasnian (Middle-Upper Devonian) conodont sequences in the Spanish Central Pyrenees and comparison with composite standards from other areas
Warming or cooling in the Pragian? Sedimentary record and petrophysical logs across the Lochkovian–Pragian boundary in the Spanish Central Pyrenees
Abstract High-resolution petrophysical correlation methods were applied, for the first time, to mid-Paleozoic rocks of the Pyrenees. The methods included magnetic susceptibility measurements (MS), gamma-ray spectrometry (GRS), and alignment of MS logs using the dynamic time-warping (DTW) algorithm. Conodont biostratigraphy provided the basic framework necessary for work with the GRS and MS logs. Despite differences in the sediment patterns and accumulation/erosion rates, the logs from two selected sections in the Spanish Central Pyrenees show a striking symmetry that correlates well with the previously published logs from the Barrandian area in the Czech Republic. The high similarity betwee…
The middle and upper Lochkovian (Lower Devonian) conodont successions in key peri-Gondwana localities (Spanish Central Pyrenees and Prague Synform) and their relevance for global correlations
Detailed correlation, based on conodont sequences, between middle and upper Lochkovian carbonate successions from two key peri-Gondwanan regions, the Spanish Central Pyrenees and the Prague Synform, is attained for the first time. This correlation facilitates the definition of tie points for further multidisciplinary studies that seek to establish high-resolution temporal subdivision and global correlation. Some intervals have a precision of less than 0.5 Ma, which is significantly greater than in previous studies. The estimated elapsed time considered herein is about 3.2 Ma and is subdivided into five major zones of global scope: transitanstrigonicus, trigonicus-kutscheri, kutscheri-pandor…
Upper Givetian and Frasnian (Middle and Upper Devonian) conodonts from Ampriú (Aragonian Pyrenees, Spain): global correlations and palaeogeographic relations
This report describes for the first time a part of the Middle and Upper Devonian conodont sequence of the Sierra Negra Subfacies in the Aragonian Pyrenees (Spain), establishing the basis for further sound correlations both across the distinct Pyrenean facies and subfacies and on other relevant world areas. The description of 20 conodont taxa and their stratigraphical distribution permits recognition of two separate time intervals. The older one corresponds to the lower Upper Givetian (Middle Devonian), hermanni to crista- tus ectypus zones. The younger interval is uppermost Lower Frasnian to lower Middle Frasnian (Upper Devonian) and is equivalent to MN4-MN6 zones. The combination of litho-…