Gennaeocrinus tariatensis, a new Emsian (Devonian) monobathrid crinoid from the Tarvagatay Terrane of Mongolia

Gennaeocrinus tariatensis new species is an Emsian (Devonian) monobathrid crinoid described from the Tarvagatay Terrane of Mongolia and part of the Central Asian Orogenic Belt. The Tarvagatay Terrane is an arc terrane that accreted to the southern margin of the Siberian Craton. Gennaeocrinus tariatensis was collected from the Emsian Tariat Formation, a terrigenous sequence of conglomerates, sandstones, and siltstones. Associated faunas include brachiopods, molluscs, and rare tabulate corals. Although Gennaeocrinus is well known from the Emsian–Givetian of North America, this is the first occurrence of the genus outside Laurussia. Mongolia is a large country with many terranes having varied paleogeographic, sedimentological, and tectonic histories; but reports of Paleozoic echinoderms are rare. The crinoid occurrence from the Tariat Formation is from the same age as previously described Emsian crinoids from the Chuluum Formation but differs significantly in sedimentology, paleogeography, and paleolatitude. UUID: http://zoobank.org/d87cb083-4360-41e5-ac90-1b8ef625a31d

Quantative calcareous nannofossil biostratigraphy of Bay Akrotiri section (Cefallinia island, W. Greece). Tracing the gephyrocapsid size-trend in an early Pleistocene terrigenous sequence

Bay Akrotiri section represents a thick terrigenous sequence laying along the southern part of Paliki peninsula (southwest Cefallinia). The data of the calcareous nannofossil quantitative analysis indicate that the studied sediments are ranging in terms of age between 1.95 Ma and 1.238 Ma approximately. The provided distribution patterns clearly depict an apparent evolutionary lineage close to the Plio/Pleistocene boundary, from small Gephyrocapsa placoliths to larger forms of gephyrocapsids.

The so called "triassic breccias" of the Ionian zone in Greece and Albania: Their stratigraphie position and the ensuing tectonic implications

Field observations are reported which show that: 1) at least part of the so called "Triassic breccias" of the Ionian isopic zone actually represent a local variant of the basal breccias of a Middle-Upper Miocene marine terrigenous sequence; 2) other portions of the same Miocenic basal breccias have been often mistaken in the past for some other looking-like terrane of different age (from Jurassic to Quaternary!). Since some currently accepted inferences on the time-sequence of both sedimentary and tectonic events ensuing from the above misunderstandings become questionable, new field investigation should be extended to the entire Ionian zone with due regard to the above terranes.

The mineralised springs of the Adriatic region, central Italy

In the Adriatic region of central Italy, there are many mineralised (salt and sulphureous) springs, often used for therapeutic purposes. The hydrogeological characteristics of the springs and their tectonic set-up are examined in this paper. The salt springs generally emerge from the Plio-Pleistocene and Messinian deposits. The waters emerging from the Messinian deposits originate from marine waters subjected to evaporation. This leads to the precipitation of gypsum and formation of brines isolated by clayey deposits. Even the salt waters emerging from the Plio-Pleistocene deposits originate from marine waters trapped in the arenaceous Pliocene deposits. The waters are subjected to an ultra-filtration process through the clayey membrane with the formation of brines. The study reveals that the springs are located in the main thrust fronts, and the springs with higher salinity emerge in the thrusts that squeezed out the brine waters from the post-orogenic Plio-Pleistocene sequence. The sulphureous springs emerge from the Messinian and Plio-Pleistocene deposits and from the Apennine Meso-Cenozoic limestone ridges. The sulphureous springs emerging from the terrigenous sequence are connected with the Messinian evaporites, while the sulphureous springs emerging from the limestone ridges are related to the Messinian and Triassic evaporite deposits of the Umbrian-Marchean sequence. In the emergence zones of the salt waters, typical mud volcanoes or puddles are present due to suspended mud in the waters. Generally, the sulphureous springs emerge along streams whose waters are whitish and emit the typical smell because of sulphur precipitation.

Graphite occurrences in the low-pressure/high-temperature metamorphic belt of the Sierra de Aracena (southern Iberian Massif)

Four distinct associations of graphite have been identified in the low-pressure, high-temperature belt of the Sierra de Aracena (SW Spain). Syngenetic occurrences include: (1) stratiform graphite mineralization within a calc-silicate series; (2) disseminated graphite within a terrigenous sequence; and (3) ‘restitic’ graphite within anatectic tonalites and their enclaves. Epigenetic graphite occurs as (4) veins cross-cutting mafic granulites.Graphite in all types of occurrences is highly crystalline, with the c parameter close to 6.70 Å. Such c values correspond to temperatures of formation of ∼800°C. The thermal properties of graphite are also typical of well-ordered graphite and provide DTA exothermic maxima ranging from 810 to 858°C depending on the mode of occurrence. The differences among the temperatures of formation estimated by graphite geothermometry, the position of the exothermic maximum in the DTA curves, and petrologic geothermometers are discussed in terms of the applicability of graphite geothermometry to granulite-facies rocks. Carbon isotope analysis yields δ13C values in the range from −31.6 to −21.4% for syngenetic graphite of types I, II and III attributable to biogenically-derived carbon. The heavier signatures for graphite in vein occurrences (δ13C= −17.7 to −18.3%) with respect to syngenetic graphites suggest that isotopically heavy carbonic species were incorporated into the metamorphic fluids (probably as a consequence of decarbonation reactions of the calc-silicate rocks) from which graphite precipitated into the veins. These fluids were strongly channelled through structural pathways.

A stratigraphical and faunal revision of the Ordovician–Silurian strata of the Percé area, Quebec

The Ordovician–Silurian strata of the Percé area are assigned to the Matapédia Group. They occur in a southwestern monoclinal sequence, unconformably overlying Cambrian strata, and are assigned to the Pabos and White Head formations. The Pabos Formation is preponderantly a terrigenous sequence, whereas the White Head is preponderantly a carbonate sequence. The Pabos strata of this area are included in the new Rouge Member, in which four brachiopod-dominated communities are recognized: the Dalmanella, Catazyga, Sowerbyella, and Epitomyonia communities, within which trilobites occur sporadically. The White Head Formation is divided into three new limestone members and a new mudstone member. The basal Burmingham Member has yielded a Catazyga Community and a Sowerbyella-like Community. The Côte de la Surprise Member is composed of mudstones with the previously described Hirnantia Community. The Rouge, Burmingham, and Côte de la Surprise members are Ashgillian (Upper Ordovician), but the uppermost two members of the White Head Formation, the L'Irlande and Des Jean members, are Llandoverian. They yield an Acernaspis Community, assigned a paleoecological position intermediate between those of the Clorinda and graptolite communities. The Matapédia Group limestones and shales in the structurally complex northeastern sequence are informally termed the Grande Coupe beds. These beds are partly or wholly time-correlative with the Rouge and Burmingham members but were deposited in deeper water. A Stenopareia Community includes the highly fossiliferous Grande Coupe beds, with a local development of the Foliomena Community. The Percé area is unique within the Quebec Appalachians because the strata of the Matapédia Group are highly fossiliferous, with distinct European affinities in the Ordovician, and because the monoclinal sequence is a deepening-upward sequence, probably to the north and west of deeper water clastics.