The current knowledge of Paleozoic radiolarian ranges, proposed zonations, and faunal assemblages that have been used in biostratigraphy over the past few decades is compiled herein. More than 90 assemblages can currently be readily recognized and many of these, although regional in their construction, have elements that can be correlated throughout a widespread paleogeographic area. A number of the existing zonations utilize robust, relatively common, and easily recognized morphotypes that may be easily identified when they are moderately or even poorly preserved. These schemes are readily applied to deciphering stratigraphic complexities in complex orogenic belts. Other assemblages and zones summarized herein have been developed from well preserved materials, such as that from concretions, and their applicability to dating chert sequences remains relatively untested. Uneven geographic coverage is apparent, where some time periods are largely represented by only a few well known regional radiola... RÉSUMÉ Biostratigraphie des radiolaires du Paléozoïque. Les connaissances actuelles sur les répartitions stratigraphiques des radiolaires paléozoïques sont ici compilées, ainsi que les biozonations proposées et les assemblages fauniques utilisés en biostratigraphie au cours des dernières décennies. Plus de 90 assemblages peuvent actuellement être facilement reconnus et beaucoup d'entre eux, bien que régionaux dans leur construction, ont des éléments qui peuvent être corrélés à travers une région paléogéographique très répandue. Un certain nombre de zonations existantes utilisent des morphotypes robustes, relativement fréquents, et facilement reconnus, qui peuvent être aisément identifiés quand ils sont modérément ou même mal préservés. Ces schémas biostratigraphiques sont facilement appliqués afin de déchiffrer la complexité stratigraphique des ceintures orogéniques complexes. D'autres assemblages et des zones résumées ici ont été développés à partir de matériaux bien préservés, comme celui issu de concré...

Mechanisms by which hydrochemical changes occur after earthquakes are not well documented. We use the 2016–2017 central Italy seismic sequence, which caused notable hydrochemical transient variations in groundwater springs to address this topic, with special reference to effects on fractured carbonate aquifers. Hydrochemistry measured before and after the earthquakes at four springs at varying distances from the epicenters all showed immediate postmainshock peaks in trace element concentrations but little change in major elements. Most parameters returned to preearthquake values before the last events of the seismic sequence. The source of solutes, particularly trace elements, is longer residence time pore water stored in slow‐moving fractures or abandoned karstic flow paths. These fluids were expelled into the main flow paths after an increase in pore pressure, hydraulic conductivity, and shaking from coseismic aquifer stress. The weak response to the later earthquakes is explained by progressive depletion of high solute fluids as earlier shocks flushed out the stored fluids in the fractures. Spring δ ¹³ C _DIC values closest to a deep magma source to the west became enriched relative to preearthquake values following the 24 August event. This enrichment indicates input from deeply sourced dissolved CO ₂ gas after dilation of specific fault conduits. Differences in carbon isotopic responses between springs are attributed to proximity to the deep gaseous CO ₂ source. Most of the transient chemical changes seen in the three fractured carbonate aquifers are attributed to local shaking and emptying of isolated pores and fractures and are not from rapid upward movement of deep fluids.

Ongoing climate change is predicted to trigger major shifts in the geographic distribution of marine plankton species. However, it remains unclear whether species will successfully track optimal habitats to new regions, or face extinction. Here we show that one significant zooplankton group, the radiolaria, underwent a severe decline in high latitude species richness presaged by ecologic reorganization during the late Neogene, a time of amplified polar cooling. We find that the majority (71%) of affected species did not relocate to the warmer low latitudes, but went extinct. This indicates that some plankton species cannot track optimal temperatures on a global scale as assumed by ecologic models; instead, assemblages undergo restructuring and extinction once local environmental thresholds are exceeded. This pattern forewarns profound diversity loss of high latitude radiolaria in the near future, which may have cascading effects on the ocean food web and carbon cycle.

This chapter is to be used as companion text with the companion chapter, an illustrated catalogue of Paleozoic radiolarian genera found in this volume, and serves the purpose of giving the reader explanation for any taxonomic operations undertaken during the course of constructing the catalogue. These operations refer to the status of the genera as valid, junior synonym, homonym, nomen nudum, nomen dubium, or not Radiolaria. We also include diagnoses and/or descriptions in the original language published, English translations where needed, and locality and age information for the type material. RÉSUMÉ Taxonomie des genres de radiolaires paléozoïques. Cet article est un complément indispensable de la partie catalogue illustré des genres de radiolaires paléozoïques (article précédent) ; il a pour ambition de donner au lecteur toutes les informations taxonomiques nécessaires qui expliquent les changements introduits au cours de la construction du catalogue. Les statuts des genres, argumentés, sont fournis : valide, synonyme junior, homonyme, nomen nudum, nomen dubium, ou non radiolaire. De plus, il propose des traductions en Anglais des diagnoses ou définitions des genres publiées dans diverses langues et des informations sur la localité et l'âge du matériel type.

The purpose of this paper is to present a revised classification of Paleozoic radiolarians at the genus level in the form of a series of plates displaying the images of the type species of each genus. These photos are supplemented by an indication of the status of the genus decided by an international team of specialists in this fossil group (Chapter “The catalogue”). The catalogue itself is presented by orders and families. It is also possible to find a genus using the alphabetical list or the list according to the classification (Appendices 1 and 2). After some remarks that illustrate the complex task undertaken to reach a consensus, a “guide for users” is proposed. RÉSUMÉ Catalogue illustré et classification révisée des genres de radiolaires paléozoïques. Le but du présent document est de présenter une classification révisée des radiolaires du Paléozoïque à l'échelle des genres, sous la forme d'une série de planches présentant les images des espèces types. Ces images sont complétées par l'indication du statut du genre décidé par une équipe internationale de spécialistes de ce groupe fossile (chapitre « The catalogue »). Le catalogue est organisé par ordres et par familles, mais il est également possible de trouver un genre en utilisant la liste alphabétique ou celle suivant la classification (Annexes 1 et 2). Après quelques remarques montrant le travail complexe effectué pour aboutir à un consensus, un « guide pour les utilisateurs » est proposé.