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Search Results: 1 - 10 of 53 matches for " conodonts "
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Oberfassanische (mitteltriassische) Conodonten aus Kalken südlich von Slugovo, Südslowenien
Anton Ramov?
Geologija , 1995,
Abstract: Schwarze, ziemlich stark dislozierte plattige Kalke im verlassenen Steinbruch südlich von Slugovo an der Strasse Cajnarje-Lovranovo, nord stlich von Cerknica,Südslowenien, führen eine kleine interessante Conodontenfauna der Budurovignathus truempyi A.-Z. Budurovignathus lipoldi n. sp., Neogondolella slugovensisn. sp. und Paragondolella ?trammeri (Kozur, 1972) werden beschrieben. hnliche conodontenführende Kalke waren in diesem Gebiet nicht bekannt.
Epigondolella pseudodiebeli (Kozur, 1972) (Conodonta) aus den oberen Amphiclin-Schichten oberhalb Po e, Westslowenien
Anton Ramov?
Geologija , 1997,
Abstract:
Primeros conodontes de la Formación Tambolar (Facies Pachaco), Silúrico de la Precordillera Argentina, y sus implicancias bioestratigráficas
Mestre,Ana;
Ameghiniana , 2009,
Abstract: the present contribution deals with the first late silurian conodonts recovered from the tambolar formation (pachaco facies), central precordillera. this conodont association suggests a late ludfordian-early pridoli age (late silurian) and is composed of zieglerodina? cf. zellmeri carls, slavik y valenzuela-ríos, 2007; dapsilodus obliquicostatus (branson and mehl, 1933), wurmiella cf. excavata (branson and mehl), delotaxis cf. elegans (walliser, 1964) and belodella sp., which are described and illustrated in this paper. this association and especially the presence of zieglerodina? cf. zellmeri suggests a early pridoli age (late silurian) for these deposits.
Nuevos registros de graptolitos y conodontes ordovícicos de las formaciones Estancia San Isidro y Empozada, quebrada San Isidro, Precordillera de Mendoza, Argentina
Ortega,Gladys; Albanesi,Guillermo L.; Heredia,Susana E.; Beresi,Matilde S.;
Ameghiniana , 2007,
Abstract: the san isidro creek is a classical locality for the study of the ordovician system in the precordillera of mendoza province. the estancia san isidro and empozada formations bear allochthonous rocks, cambrian-ordovician in age, within an ordovician shaly matrix. graptolites, conodonts, and trilobites are abundant in these units. the present contribution deals with a late darriwilian graptolite association, which was collected from the green-greyish shaly facies of the estancia san isidro formation at the northern flank of san isidro creek. this fauna refers to the pterograptus elegans zone or probably correlates with the hustedograptus teretiusculus zone, which was documented for other areas of the precordillera. the graptolite assemblage is composed of diplograptids dominated by archiclimacograptus mitchell, and a low proportion of glossograptids and dichograptids. it allows us to assign a late darriwilian age for the time interval including the deposition of the olistostromes of the estancia san isidro formation. at the southern margin of the san isidro creek, a conglomerate bed close to the top of the estancia san isidro formation yielded an early darriwilian conodont fauna, referred to the lower lenodus variabilis zone or slightly older. this fauna reveals the age of clasts that make up the conglomerate. early floian graptolites from allochthonous shales in the basal empozada formation are described. the conodont amorphognathus cf. ordovicicus branson and mehl, recorded from the lower member of the empozada formation together with graptolites of the dicellograptus complanatus zone, indicates a late katian age for the autochthonous strata.
Triassic conodonts of the Slovenian Basin
Stanko Buser,Tea Kolar-Jurkov?ek,Bogdan Jurkov?ek
Geologija , 2007,
Abstract: Slovenian Basin was formed during the Ladinian following disintegration of the Slovenian Carbonate Platform. It persisted continuously until the Late Cretaceous. Several conodont asscociations were recognized within the Triassic rocks of the Slovenian Basin. Stratigraphically significant species belong to the genera Budurovignathus, Epigondolella, Gladigondolella, Metapolygnathus, Misikella, Neogondolella, Nicoraella, Norigondolellaand Paragondolella.
Conodont biostratigraphy in the Middle–Upper Ordovician boundary beds of Estonia
Viira, Viive
Estonian Journal of Earth Sciences , 2008,
Abstract: Conodonts of the uppermost Uhaku, the Kukruse, and the lower Haljala stages (uppermost Darriwilian and lower Sandbian) of Estonia are discussed. The distribution of conodonts within the Pygodus serra, P. anserinus, and Amorphognathus tvaerensis zones is considered on the basis of 2 outcrop and 15 drill core sections. Judging by the Global Stratotype Section, F gels ng, Sweden, the base of the Upper Ordovician Series should be lower than the first appearance of A. tvaerensis. The Estonian material shows that elements of A. tvaerensis from the lowermost range of the species are of a morphotype similar to A. inaequalis. It is proposed that the A. inaequalis Subzone be upgraded to the A. inaequalis Zone. The best level for the Middle–Upper Ordovician boundary in Estonia is at the lower boundary of the Kukruse Stage below the appearance of A. tvaerensis and/or A. inaequalis.
Ordovician conodont diversity in the northern Baltic
Peep M?nnik,Viive Viira
Estonian Journal of Earth Sciences , 2012, DOI: 10.3176/earth.2012.1.01
Abstract: The diversity data presented in this paper are based on recently revised collections of conodonts from outcrops (northern Estonia) and core sections of Estonia and western and northern Latvia. Based on variations in the abundance of taxa, four intervals with different general trends in diversity changes can be recognized in the Ordovician part of the succession: (1) the proavus–crassus zones and (2) crassus–anserinus zones, both intervals forming quite distinct diversity cycles; (3) the variabilis–ventilatus zones, characterized in general by stable diversity values, and (4) the ventilatus Zone–the topmost Ordovician, with a steady increase in diversity up to the ordovicicus Zone, followed by a decline during the End-Ordovician Extinction Event. Diversity was lowest in the earliest and latest Ordovician but reached maximum values at the end of the Early Ordovician radiation of conodonts, in the middle and upper Darriwilian, and just before the start of the End-Ordovician Extinction Event. Four supersequences (transgressive–regressive cycles) are proposed here for the northern Baltic Ordovician succession. The diversity changes recognized in the conodont succession demonstrate general correlation with these supersequences: boundaries between supersequences are characterized by low diversity values; diversity increases more or less rapidly in the lower, transgressive parts of the supersequences and decreases in their upper parts.
Primer registro de conodontes ashgillianos en la Precordillera (Argentina)
Heredia,Susana;
Ameghiniana , 2008,
Abstract: a reworked conodont fauna from the empozada formation (mendoza precordillera) which belongs to the caradoc-ashgill (british series from the upper ordovician) interval is reviewed. for the first time amorphognathus cf. ordovicicus branson & mehl, 1933 is identified in argentina. this species together with a. superbus, define the late caradoc-earliest ashgill of the precordillera. the recovered conodont fauna is similar in composition with those of the british province of the north atlantic realm, suggesting close relationships between both areas.
La Subzona de Periodon gladysi (Conodonta) en el Ordovícico Medio de Precordillera: su evaluación
Mestre,Ana; Heredia,Susana;
Serie correlaci?3n geol?3gica , 2009,
Abstract: the periodon "gladysi" subzone is defined as the lower par of the lenodus variabilis zone in the ordovician biostratigraphic scheme of argentina. the review and evaluation of conodont elements that are composing the species p. "gladysi" albanesi allow recognizing p conodont elements of microzarkodina ozarkodella lindstr?m. a nomen nudun for the species p. gladysi" and the nullity of the mentioned subzone is proposed here. besides, the presence of the species m. ozarkodella defines the upper part of the eoplacognathus pseudoplanus zone in the upper most level of san juan formation at section of cerro poterillo and portezuelo de yanso at the san juan precordillera.
Estratigrafía y bioestratigrafía del Ordovícico Medio del río Las Chacritas, Precordillera Central de San Juan
Heredia,Susana; Beresi,Matilde; Mestre,Ana;
Serie correlaci?3n geol?3gica , 2011,
Abstract: two ordovician carbonate formations are recognized in the las chacritas creek (sierra de la trampa, central precordillera). the lithostratigraphic nomenclature is analyzed and revised, the las aguaditas formation is proposed for the carbonate succession that is overlying the san juan formation. the middle darriwilian conodont faunas recovered from the studied stratigraphic interval allowed the usage of the baltic biostratigraphic chart: the eoplacognathus pseudoplanus and the eoplacognathus suecicus zones. the contact between the san juan and las aguaditas formations is analyzed and correlation is possible with several localities of the central precordillera.
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