Isotopic (Sr, Nd, Pb) characteristics of the archean metasomatized mantle—source of the Panozero massif, Karelia

This work addresses the isotopic heterogeneity of the Archean lithospheric mantle by the example of high-Mg, moderate-alkali, LILE and LREE-enriched Panozero sanukitoid massif, which is located in the Central Karelia, southeastern Baltic Shield. Initial Nd and Sr isotope characteristics were determined for mantle source of the massif. ?_Nd(T) in the source are plotted below DM line, varying from + 0.7 to + 1.4 (+1.1, on average). The ⁸⁷Sr/⁸⁶Sr(T) ～ 0.7017 significantly exceeds that of depleted mantle and reflects change of Rb/Sr ratio in the source due to metasomatic reworking of mantle. Data on Pb isotope composition of potassium feldspars indicate that source of monzonites of the Panozero Massif had lower μ (²³⁸U/²⁰⁴Pb) = 8 and higher (²³⁸Th/²³²U) = 4.05 relative to primitive mantle.     

A Local Anomaly of the Stress State of the Earth’s Crust before the Strong Earthquake (M = 7.1) of July 5, 2019, in the Area of Ridgecrest (Southern California)

Doklady Earth Sciences - The evolution of the stress–strain state of the Earth’s crust in Southern California during the preparation period (from January 1, 2019 until August 15, 2019)...     

Provenance of the northern part of the Kahramanmaraş Peripheral Foreland Basin (Miocene,S Turkey)

The Miocene Kahramanmara? Peripheral Foreland Basin (KPFB) resemble to classic foreland basin model, with small differences. In the classic model, both the accretionary wedge and foredeep extend lengthways parallel to the plate margin. In addition, accretionary wedge includes wedge top basin or piggy back basin that extends parallel to foredeep. However, the accretionary wedge of the KPFB contains small half-graben type basins that obliquely intersect the plate margin between the Arabian Plate and the Anatolide–Taurides Platform (due to the irregular shape of the plate boundary). Tectonic lineaments controlled the shape and orientation of these basins and larger main depocentre of the KFPB, which were predominantly filled with deep-sea sediments. This paper focuses on the provenance of features of the KFPB, predominantly was fed from the northern basin margin, while also aiming to resolve the complex basin evolution that occurred during the Miocene.Clasts of Palaeozoic and Mesozoic limestone and ophiolites are common components of the confined deep-water clastic systems, which evolved as elongated trenches in the north-western sector of the KPFB during the Early-Middle Miocene. During the Middle Miocene, continuous thrusting of the northern basin margin to south caused depocentre migration to south-east, through the basin interior. At that time, the north-east and central depocentres of the KPFB were filled primarily by clasts of ophiolite and metamorphic units. The tectonic control on basin fill architecture can be observed anywhere in the KFPB. The principal tectonic features controlled the geometry and orientation of the canyon, the channel geometry of the deep-water slope on the northern basin margin, the frequency and distribution of slump-slide-debris flows and the overall pattern of sedimentation cycles in the stratigraphy of the slope and the central basin floor. Some basin sectors have continuously reactivated and as a result, different sediment entry points with substantial local accumulation of sediment and deformation have evolved on the slope and basin floor. Three scales of provenance were used to investigate the source rock: (a) field-based observation and analysis of conglomerate clasts, (b) modal analysis of sandstone facies and (c) geochemical analysis, all of which were in agreement.     

New Data on the Early Riphean Age (U–Pb,Shrimp-II) of Acid and Basic Effusives of the Gulf of Finland (Sommers Island,Russia)

Doklady Earth Sciences - This work presents data on the age of the volcanites of Sommers Island located to the south of the submarine extension of the Vyborg massif, as potential comagmates of...     

Provenance of Upper Devonian clastic (meta)sediments of the Böllstein Odenwald (Mid-German-Crystalline-Zone,Variscides)

International Journal of Earth Sciences - Detrital zircons separated from paragneisses of the northern Böllstein Odenwald (Mid-German Crystalline Zone, Variscides) yielded Cambrian to Upper...     

U-Pb isotopic study of the gabbronorite–anorthosite drusite (coronite) body of Vorony Island (Kandalaksha Archipelago,the White Sea)

The Precambrian Belomorian mobile belt located between the Karelian craton and the Lapland–Umba granulite belt contains large amount of small rootless mafic–ultramafic intrusions, which are dispersed over a large area and distinguished as the Belomorian drusite (coronite) complex. U-Pb dating of magmatic zircon and metamorphic rutile from the drusite body on Vorony Island showed that it was crystallized at 2460 ± 11 Ma and metamorphosed at 1775 ± 45 Ma. Petrographic and geochemical data confirm that the parental magmas of the drusites belong to the siliceous high-magnesian (boninite-like) series, which also was responsible for the formation of large layered plutons in stable domains of the Baltic Shield.     

Trace element modelling of the origin and evolution of the Oyaca‐Boyalik volcanic rocks (NE of Haymana,Ankara, Turkey)

Lower Miocene Boyalik volcanic rocks, situated approximately 80 km south of Ankara, exhibit both alkaline and calc‐alkaline characteristics. Alkaline products are trachybasaltic and trachyandesitic, whereas calc‐alkaline products are dacitic. The phenocrysts in the dacites consist primarily of plagioclase and hornblende, with lesser amounts of biotite. The groundmass contains plagioclase and quartz microcrysts. Trachyandesites are mainly composed of plagioclase and biotite phenocrysts with a groundmass of alkali feldspar microlites and minor clinopyroxene microcrysts. Trachybasalts are mainly composed of olivine and plagioclase phenocrysts, with minor clinopyroxene phenocrysts associated with alkali feldspar, plagioclase and clinopyroxene microlites and microcrysts in the groundmass. Oxides are common accessory phases in all products. Boyalik volcanic rocks have essentially homogeneous incompatible trace element patterns with variable Nb and Th anomalies, enrichment in Rb, Ba, K, La, Ce and Nd, and positive Sr anomalies. Some trace element ratios (e.g. Ba/Ta, Ba/Nb, Th/U and Ce/Pb) are variable among the series. For instance, dacites and trachyandesites have higher Ba/Ta (724–2509), Ba/Nb (45–173) and Th/U (3.5–8.7) and lower Ce/Pb (7.1–3.9) values than the trachybasalts. Trace element data indicate that the series are chemically distinct but probably were derived from a common lithospheric mantle source via variable degrees of partial melting. The magmas then underwent a process of evolution involving assimilation and fractional crystallization (AFC) during ascent to the surface. Although trachyandesites and dacites were generated from a lithospheric mantle source via ～1% and ～1.5% to ～5% degrees of partial melting, respectively, trachybasalts were derived from the same source via higher degrees of partial melting (～20%) with neglegible crustal contamination. Boyalik volcanism is linked to an intracontinental transpressional setting. However, the overall geochemical features are consistent with derivation from a mantle source that records earlier Eocene subduction between the Sakarya continental fragment and the K?r?ehir block during time.     

Hydrogeochemical study of the thermal and mineralized waters of the Banaz (Hamamboğazi) area,western Anatolia,Turkey

The Hamamboğazi spa in western Turkey was built around natural hot springs with discharge temperatures in the range of 30–54°C; the waters have near neutral pH values of 6.50–7.10 and a TDS content between 2,694 and 2,982 mg/l. Thermal water with a temperature of 47.5–73°C has been produced at 325 l/s from five wells since 1994, causing some springs to go dry. A management plan is required in the study area to maximize the benefits of this resource, for which currently proposed direct uses include heating in the district and greenhouses, as well as balneology in new spas in the area. The best use for the water from each spring or well will depend on its temperature, chemistry and location. The thermal waters are mixed Na–Mg–HCO₃–SO₄ fluids that contain a significant amount of CO₂ gas. The chemical geothermometers applied to the Hamamboğazi thermal waters yield a maximum reservoir temperature of 130°C. Isotope results (¹⁸O, ²H, ³H) indicate that the thermal waters have a meteoric origin: rainwater percolates downward along fractures and faults, is heated at depth, and then rises to the surface along fractures and faults that act as a hydrothermal conduit. The basement around the Banaz Hamamboğazi resort is comprised of Paleozoic metamorphic schist and marbles exposed 8 km south and 15 km north of Banaz. Mesozoic marble, limestone and ophiolitic complex are observed a few km west and in the northern part of Banaz. These units were cut at a depth of 350–480 m in boreholes drilled in the area. Overlying lacustrine deposits are composed of fine clastic units that alternate with gypsum, tuff and tuffites of 200–350 m thickness. The marble and limestones form the thermal water aquifer, while lacustrine deposits form the impermeable cap.     

Paleoenvironment and Origin of the Sedimentary Phosphorite of the Yurtus Formation (Early Cambrian, Sugetbrak Phosphorite Deposit, Tarim Basin)

Please refer to the attachment(s) for more details.     

REE and isotope (Sr,S, and Pb) geochemistry to constrain the genesis and timing of the F–(Ba–Pb–Zn) ores of the Zaghouan District (NE Tunisia)

The F–(Ba–Pb–Zn) ore deposits of the Zaghouan District, located in NE Tunisia, occur as open space fillings or stratabound orebodies, hosted in Jurassic, Cretaceous and Tertiary layers. The chondrite-normalized rare earth element (REE) patterns may be split into three groups: (i) “Normal marine” patterns characterizing the wallrock carbonates; (ii) light REE (LREE) enriched (slide-shaped) patterns with respect to heavy REE (HREE), with small negative Ce and Eu anomalies, characteristic of the early ore stages; (iii) Bell-shaped REE patterns displaying LREE depletion, as well as weak negative Ce and Eu anomalies, characterizing residual fluids of subsequent stages. The ⁸⁷Sr/⁸⁶Sr ratios (0.707654–0.708127 ± 8), show that the Sr of the epigenetic carbonates (dolomite, calcite) and ore minerals (fluorite, celestite) are more radiogenic than those of the country (Triassic, Jurassic, Cretaceous, lower Miocene) sedimentary rocks. The uniformity of this ratio, throughout the District, provides evidence for the isotopic homogeneity and, consequently, the identity of the source of the mineralizing fluids. This signature strongly suggests that the radiogenic Sr is carried by Upper Paleozoic basinal fluids.The δ³⁴S values of barite, associated to mineralizations, are close to those of the Triassic sea water (17‰). The δ³⁴S values of sulfide minerals range from − 13.6‰ to + 11.4‰, suggesting two sulfur-reduced end members (BSR/TSR) with a dominant BSR process.Taking account of the homogeneity in the Pb-isotope composition of galenas (18.833–18.954 ± 0.001, 15.679–15.700 ± 0.001 and 38.690–38.880 ± 0.004, for the ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb ratios respectively), a single upper crustal source for base-metals is accepted. The Late Paleozoic basement seems to be the more plausible source for F–Pb–Zn concentrated in the deposits. The genesis of the Zaghouan District ore deposits is considered as the result of the Zaghouan Fault reactivation during the Late Miocene period.     

Taxonomy and palaeoecology of brachiopods from the South-Helvetic zone of the Fäneren region (Lutetian, Eocene, NE Switzerland)

Terebratuloid and cancellothyridoid brachiopods from the South-Helvetic Lutetian (Eocene) of the Fäneren region (NE Switzerland) are described: Carneithyris subregularis (Quenstedt) and two forms of Terebratulina s.l. under open nomenclature. Several species of Alpine and non-Alpine origin, related to Carneithyris subregularis, like Terebratula kickxi Galeotti, Terebratula aequivalvis Schafhäutl and Terebratula hilarionis Davidson show characters, which compare well with Carneithyris subregularis. Two of them, T. aequivalvis and T. hilarionis, are assigned to the genus Carneithyris. The stratigraphy and lithology of the sediments in the study area are reassessed. Life habits and palaeoecology of the brachiopods are discussed. C. subregularis apparently was a free living brachiopod without attachment to the substrate, as indicated by massive accumulations of callosities in the posterior parts of the shell. The variability of the cardinal process, as seen in the studied Carneithyris group can be interpreted as a morphological element to enlarge the surface of attachment of strong diductor muscles in relation to the internal thickening of the individual.     

Secondary aspects of the harnessing of the Rh?ne (not considering the question of energy)

Since a 1921 law the harnessing of the Rhône River from Lyon to the Mediterranean has been directed by a national company composed of the public sector (fromthe valley) as well as of various consumers or distributors of current such as the SNCF or the EDF. This company, the National Company of the Rhône (CNR), was a precursor to the establishment of the TVA in the United States, although it did not begin operations until aftetr the TVA due to prolonged technical negotiations and to the difficulties involved in locating financial support in a period of economic crisis. Even though the utilization of hydraulic power constitutes the prime aim of the CNR, it has also focused on navigation, irration and other agricultural uses from the outset.This article will not further discuss the hydro-electric stations on the Rhône which usually supply more than 22% of French hydro-electric output from thirteen stations now in operation (total power is 2,350 MW and annual average output is 13,000 GWh). This paper will treat the question of the nature and importance of the side effects of the harnessing of the Rhône apart from its essential energy function.     

First representative of the genus Helius Lepeletier and Serville, 1828 (Diptera,Limoniidae) from the Lower Cretaceous Álava amber (Spain)

Helius alavensis sp. nov., one of the oldest representative of the genus Helius Lepeletier and Serville, 1828 (Diptera: Limoniidae), is described from the Álava amber (Lower Cretaceous, upper Albian), northern Spain. This is the first representative of the subfamily Limoniinae and of the genus Helius described from this fossil resin.     

Determination of deterioration of the main facade of the Ferit Paşa Cistern by non-destructive techniques (Konya,Turkey)

Building stones have long been one of the most widely used construction materials in the world. Building stones used in historical monuments are deteriorated partly or completely depending on the environmental and atmospheric effects. In recent years, non-destructive test methods have been used to assess deterioration of building stones used in historical monuments. Gödene stone is one of the building stones being widely used in the historical buildings in the Konya region, Central Anatolia. The most deterioration effects are observed in the Ferit Pa?a Cistern among the historical structures built with Gödene stone in the region. The aim of this study is to assess the deteriorating effects in the street façade of the Ferit Pa?a Cistern via non-destructive testing methods (Schmidt hardness rebound value, P-wave velocity, humidity measurement and thermal imaging) and create maps of deteriorated features. Turkey’s historic places are integrated to Turkish culture, efforts are made to conserve heritage through rehabilitation. Therefore, this study will help developers and federal managers during the project planning stage by providing technical data.     

U‒Pb Age of Sphene and the Petrochemical,Mineralogical, and Geochemical Features of Alkaline Rocks of the Bogdo Complex (Arctic Siberia)

Doklady Earth Sciences - In the northern part of the Siberian Platform, east of the Anabar Shield, several massifs of alkaline rocks with carbonatites identified (Tomtor, Bogdo, Promezhutochnyi)...     

Tremolite–calcite veins in the footwall of the Simplon Fault,Antigorio Valley,Lepontine Alps (Italy)

The lowermost units of the nappe pile of the Lepontine Alps crop out in the Antigorio valley in the footwall of the Simplon Fault. The whole orthogneiss section of the Antigorio Unit is exposed on both sides of the valley, sandwiched between the Mesozoic metasedimentary sequences of the Baceno unit below and the Tèggiolo unit above. The petrography and mineral composition of tremolite–calcite veins occurring in dolomite marble in both metasedimentary sequences were investigated. Tremolite–calcite (with lesser talc and minor phlogopite) veins have rhythmic banded texture. Banding is due to cyclic differences in modal abundances and fabric of tremolite and calcite. These veins are very similar to those occurring in dolomite rafts within the Bergell granite and it is inferred that they formed by the same “fracture-reaction-seal” mechanism. Veins formed by reaction of a silica-rich aqueous fluid with the host dolomite marble along fractures. According to thermo-barometric calculations, based on electron microprobe analyses, reaction occurred at temperatures between 450 and 490°C and minimum pressure of 2–3 kbar. Such temperature conditions occurred in this footwall region of the Simplon Fault Zone around 15 Ma, during exhumation and cooling of the nappe pile and a transition to brittle behaviour. Aqueous, silica-rich fluids concentrated along fractures, forming tremolite–calcite veins in the dolomite marbles and quartz veins in the orthogneiss.     

Activation of Formation of Hydrocarbon Fluidizites under the Conditions of Shear Geodynamic Regime of the Caspian Region (Russian–Kazakh Sector,Russia)

Geotectonics - The paper presents the results of the study of objects spatially related to extremely high hydrocarbon (HC) emissions identified in the North Caspian Sea. The analysis of variable...     

U–Pb (SHRIMP) Zircon Age of Granitoid Pebbles from the Kukkarauk Conglomerates of the Vendian Asha Group (Alatau Anticlinorium,Southern Urals)

Doklady Earth Sciences - The lack of reliable geochronological data for the Vendian deposits of the Urals and other regions is one reason why there is still uncertainty in the age estimates of the...