Geochemistry of Late Cambrian-Early Ordovician fluvial to shallow marine sandstones, western Tasmania, Australia: Implications for provenance, weathering, tectonic settings, and chemostratigraphy

2016 ◽  
Vol 50 (2) ◽  
pp. 197-210 ◽  
Author(s):  
S. A. Mahmud ◽  
S. Naseem ◽  
M. Hall ◽  
Khalid A. Almalki
Keyword(s):  
Shallow Marine ◽  
Early Ordovician ◽  
Late Cambrian ◽  
Tectonic Settings

Early Ordovician alkali-ultramafic Zhilandy complex (Central Kazakhstan): structure and age of formation

2019 ◽  
Vol 484 (1) ◽  
pp. 61-65
Author(s):  
R. M. Antonuk ◽  
A. A. Tretyakov ◽  
K. E. Degtyarev ◽  
A. B. Kotov
Keyword(s):  
Complex Formation ◽  
Central Asian Orogenic Belt ◽  
Early Cambrian ◽  
Early Ordovician ◽  
Late Cambrian ◽  
Central Asian ◽  
Geochronological Study ◽  
Three Stages ◽  
Late Neoproterozoic ◽  
Quartz Monzodiorites

U–Pb geochronological study of amphibole-bearing quartz monzodiorites of the alkali-ultramafic Zhilandy complex in Central Kazakhstan, whose formation is deduced at the Early Ordovician era (479 ± 3 Ma). The obtained data indicate three stages of intra-plate magmatism in the western part of the Central Asian Orogenic Belt: Late Neoproterozoic stage of alkali syenites of the Karsakpay complex intrusion, Early Cambrian stage of ultramafic-gabbroid plutons of the Ulutau complex formation, and Late Cambrian–Early Ordovician stage of formation of the Zhilandy complex and Krasnomay complex intrusions.

New Monoplacophora (Mollusca) from Late Cambrian and Early Ordovician of Missouri

1986 ◽  
Vol 60 (3) ◽  
pp. 606-626 ◽  
Author(s):  
Bruce L. Stinchcomb
Keyword(s):  
New Species ◽  
New Genus ◽  
New Genera ◽  
New Genus And Species ◽  
Upper Cambrian ◽  
Early Ordovician ◽  
New Family ◽  
Late Cambrian ◽  
Lower Ordovician ◽  
A New Species

Fourteen new species and six new genera of the molluscan class Monoplacophora are described from the Upper Cambrian Potosi and Eminence formations and the Lower Ordovician Gasconade Formation of the Ozark Uplift of Missouri and some new biostratigraphic horizons are introduced. A new superfamily, the Hypseloconellacea nom. trans. Knight, 1956, and a new family, the Shelbyoceridae, are named. The genus Proplina is represented by five new species: P. inflatus, P. suttoni from the Cambrian Potosi Formation, P. arcua from the Cambrian Eminence Formation and P. meramecensis and P. sibeliusi from the Lower Ordovician Gasconade Formation. A new genus and species in the subfamily Proplininae, Ozarkplina meramecensis, is described from the Upper Cambrian Eminence Formation. Four new monoplacophoran genera in the superfamily Hypseloconellacea and their species are described, including: Cambrioconus expansus, Orthoconus striatus, Cornuella parva from the Eminence Formation, and Gasconadeoconus ponderosa, G. waynesvillensis, G. expansus from the Gasconade Formation. A new genus in the new family Shelbyoceridae, Archeoconus missourensis, is described from the Eminence Formation and a new species of Shelbyoceras, S. bigpineyensis, is described from the Gasconade Formation.

Tectonic controls on late Cambrian-Early Ordovician deposition in Cordillera oriental (Northwest Argentina)

2020 ◽  
Vol 109 (6) ◽  
pp. 1897-1920 ◽  
Author(s):  
Romain Vaucher ◽  
N. Emilio Vaccari ◽  
Diego Balseiro ◽  
Diego F. Muñoz ◽  
Antoine Dillinger ◽  
...  
Keyword(s):  
Early Ordovician ◽  
Northwest Argentina ◽  
Late Cambrian

Variation on cranidial shape ofParabolinella argentinensisKobayashi (Trilobita, Olenidae) from the Tremadocian of northwestern Argentina: taxonomic implications

2016 ◽  
Vol 90 (4) ◽  
pp. 672-688 ◽  
Author(s):  
Daniela S. Monti ◽  
María del Huerto Benítez ◽  
Mariano A. Ramirez
Keyword(s):  
Principal Components ◽  
Buenos Aires ◽  
Type Locality ◽  
Graphical Representations ◽  
Northwestern Argentina ◽  
Early Ordovician ◽  
Late Cambrian ◽  
Wide Range ◽  
Taxonomic Implications ◽  
The University

AbstractThe late Cambrian-Early Ordovician sequences of the Cordillera Oriental in northwestern Argentina are extensive and highly fossiliferous. The olenid trilobiteParabolinella argentinensisKobayashi sensu Harrington and Leanza, 1957 was reported from a great number of Tremadocian localities and includes a wide range of morphologies. Based on specimens collected from the type locality (Purmamarca, Jujuy) and the quebrada Moya (Huacalera, Jujuy), as well as on material of the Harrington and Leanza collections in the University of Buenos Aires, classic morphometry and geometric morphometry methods were used to evaluate the variability in the cranidium ofP.argentinensis. The results obtained from the two methodologies are similar. Both analyses allowed the review of the diagnosis ofP.argentinensis, and the distinction of two new morphologies:Parabolinella clarisaen. sp. andParabolinella pompadourisn. sp. The results show how morphogeometrics distinguishes more clearly the three morphotypes and provides graphical representations of the differences between those groups and how from the representations plus the correlation between classical variables and principal components, new diagnostic characters that distinguish the three morphospecies, can be identified.

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