Results 31 to 40 of about 66,668 (274)

Conodont biostratigraphy of the Crawford Group, Southern Uplands, Scotland [PDF]

, 2002
Extensive new conodont collections from the Crawford Group, the oldest succession in the Southern Uplands of Scotland, support the previously documented biostratigraphical ages for the included formations.
Armstrong, Howard A., Barron, Hugh F., Floyd, James D., Tingqing, Lu   +3 more
core   +1 more source

Early Tremadocian cephalopods from Santa Rosita Formation in NW Argentina: the oldest record for South America [PDF]

Acta Palaeontologica Polonica, 2023
We describe early Tremadocian (Kainella meridionalis Biozone) cephalopods from the Cordillera Oriental, Jujuy, NW Argentina. They consist of numerous small specimens collected at the Quebrada de Arenal, Trancas section, near the town of Tilcara, in the
MARCELA CICHOWOLSKI, N. EMILIO VACCARI, ALEXANDER POHLE, DANIEL A. MORÓN ALFONSO, ROMAIN VAUCHER, BEATRIZ G. WAISFELD   +5 more
doaj   +1 more source

Detrital-zircon geochronology and provenance of the Ocloyic synorogenic clastic wedge, and Ordovician accretion of the Argentine Precordillera terrane [PDF]

, 2015
The Precordillera terrane in northwestern Argentina is interpreted to be anexotic (Laurentian) continental fragment that was accreted to western Gondwanaduring the Ordovician. One prominent manifestation of the subductionand collision process is a Middle?
Astini, Ricardo Alfredo, McClelland, William C., Mueller, Paul A., Thomas, William A.   +3 more
core   +1 more source

Systematics, morphology, and appendages of an Early Ordovician pilekiine trilobite Anacheirurus from Fezouata Shale and the early diversification of Cheiruridae [PDF]

Acta Palaeontologica Polonica, 2021
Pilekiines are the earliest diverging members of the successful trilobite family Cheiruridae. The pilekiine genus Anacheirurus is characterized by sub-quadratic to sub-oval glabella, pitted genae, and a distinct trunk with elongated pleural spines in ...
FRANCESC PÉREZ-PERIS, LUKÁŠ LAIBL, MURIEL VIDAL, ALLISON C. DALEY   +3 more
doaj   +1 more source

Tectonic history of the South Tannuol Fault Zone (Tuva region of the northern Central Asian Orogenic Belt, Russia) : constraints from multi-method geochronology [PDF]

, 2020
In this study, we present zircon U/Pb, plagioclase and K-feldspar Ar-40/Ar-39 and apatite fission track (AFT) data along the South Tannuol Fault Zone (STFZ).
De Grave, Johan, Mikhailova, Polina, Nachtergaele, Simon, Van Ranst, Gerben, Vetrov, Evgeny, Vetrova, Natalia, Zhimulev, Fedor   +6 more
core   +1 more source

Rifting and arc-related early Paleozoic volcanism along the North Gondwana margin: geochemical and geological evidence from Sardinia (Italy) [PDF]

, 2012
Three series of volcanic rocks accumulated during the Cambrian to Silurian in the metasediment-dominated Variscan basement of Sardinia. They provide a record of the changing geodynamic setting of the North Gondwana margin between Upper Cambrian and ...
BUZZI L, FUNEDDA A., GAGGERO L, OGGIANO G   +3 more
core   +1 more source

Contrasting Early Ordovician assembly patterns highlight the complex initial stages of the Ordovician Radiation

Scientific Reports, 2022
The Early Ordovician is a key interval for our understanding of the evolution of life on Earth as it lays at the transition between the Cambrian Explosion and the Ordovician Radiation and because the fossil record of the late Cambrian is scarce.
Farid Saleh, Pauline Guenser, Corentin Gibert, Diego Balseiro, Fernanda Serra, Beatriz G. Waisfeld, Jonathan B. Antcliffe, Allison C. Daley, M. Gabriela Mángano, Luis A. Buatois, Xiaoya Ma, Daniel Vizcaïno, Bertrand Lefebvre   +12 more
doaj   +1 more source

EVENT STRATIGRAPHY AND CORRELATION PROBLEMS OF THE ORDOVICIAN STRATA OF GORNY ALTAI AND SALAIR

Геодинамика и тектонофизика, 2021
Study of the Ordovician sedimentary sequences of Gorny Altai and Salair has revealed lithological and paleontological features correlating with global sedimentary events:(1) The Acerocare Regressive Event (an initial event in the Early Tremadocian);(2 ...
N. V. Sennikov, O. T. Obut, E. V. Lykova, A. V. Timokhin, R. A. Khabibulina, T. A. Shcherbanenko   +5 more
doaj   +1 more source

Note complementaire sur les echinodermes ordoviciens de Sierra Morena

Estudios Geologicos, 1986
[fr] Une nouvelle espéce du genre Calix est décrite, le genre Batalleria est redécrit, la présence de Phlyctocystis dans les Monts de Toléde-Sierra Morena est confirmée, et celle de Destombesia est signalée.
J. Chauvel, B. Meléndez
doaj   +1 more source

Metal enrichment in lithologically complex black shales: a case study from the Tremadocian of NE Estonia [PDF]

Estonian Journal of Earth Sciences, 2021
Significantly elevated U, Mo, Zn and Pb contents characterize the Early Ordovician black shales in the Sillamäe area, NE Estonia. The presence of silty interlayers with sulphidic mineralization and authigenic carbonates suggests unique physicochemical ...
Rutt Hints, Siim Pajusaar, Kristjan Urtson, Merlin Liiv, Toivo Kallaste   +4 more
doaj   +1 more source