Results 111 to 120 of about 92,675 (274)
The Chamrousse Ophiolite (Western Alps, France): Relict of a Devono‐Carboniferous Ocean
Terra Nova, EarlyView.ABSTRACT The Chamrousse ophiolite (Western Alps, France) is one of the best‐preserved Variscan relicts of Cambro‐Ordovician oceanisation within the northern Gondwana margin. This study presents new in situ U–Pb isotope analyses on zircon grains from that ophiolite, revealing that the oceanic stage in Chamrousse has occurred 150 Ma later than estimated.
Maureen Gunia +6 more
wiley +1 more source
The first report of South American edrioasteroids and the paleoecology and ontogeny of rhenopyrgid echinoderms [PDF]
, 2013 A new species of rhenopyrgid edrioasteroid Rhenopyrgus piojoensis sp. nov. is described form the Silurian (Lower Lud− low) Los Espejos Formation in the Precordillera of Argentina.
Heredia, Susana Emma +3 more
core +1 more source
Terra Nova, EarlyView.ABSTRACT Laser ablation U–Pb single zircon geochronology was applied to four peraluminous granite and granodiorite samples from the Bassiès pluton in the Central Pyrenees (France) yielding a wide range of concordant ages from early Carboniferous (Tournaisian, 351 Ma) to early Permian (Artinskian, 285 Ma).
Stephan Schnapperelle +5 more
wiley +1 more source
Clay mineralogy, chemistry, and diagenesis of late devonian K-bentonite occurrences in northwestern Turkey [PDF]
, 2015 Thin beds of tephra (K-bentonites) formed by the diagenesis of volcanic ash are exposed within the limestone-dolomitic limestone successions of the Yilanli formation at Zonguldak and Bartin in northwestern Turkey.
Bozkaya, Ömer +5 more
core +1 more source
Linguloidean brachiopods from the Lower Ordovician (Tremadocian) of northwestern Argentina [PDF]
, 2015 The new obolid Torobolus subplanus gen. et sp. nov., from the lower Temadocian Devendeus Formation, the new species Libecoviella tilcarensis and Leptembolon argentinum, and Ectenoglossa sp.
Benedetto, Juan Luis Arnaldo +1 more
core
Global Series and Stages for the Ordovician System: A Progress Report
Geologica Acta, 2005 There is no global standard set of chronostratigraphic/geochronologic subdivisions for the Ordovician System/Period. British series/epochs are often used as de facto nomenclature on stratigraphic correlation charts and geologic time scales. However, they
S. FINNEY
doaj +1 more source
Climate change and the selective signature of the Late Ordovician mass extinction [PDF]
, 2012 Selectivity patterns provide insights into the causes of ancient extinction events. The Late Ordovician mass extinction was related to Gondwanan glaciation; however, it is still unclear whether elevated extinction rates were attributable to record ...
Finnegan, Seth +3 more
core +3 more sources
A geochemical drainage survey of the Fleet granitic complex and its environs [PDF]
, 1978 A regional geochemical drainage reconnaissance programme was undertaken over 900 km2 of south-west Scotland centred on the Fleet granitic complex. Rocks of Ordovician and Silurian age outcrop over the area, into which have been intruded the Fleet and ...
Brown, M.J. +3 more
core
, 2014 We measured the He and Ne concentrations of 50 individual extraterrestrial chromite grains recovered from mid-Ordovician (lower Darriwilian) sediments from the Lynna River section near St. Petersburg, Russia. High concentrations of solar wind-like He and
Lindskog, Anders +4 more
core +1 more source