scholarly journals Novel U-Pb isotopic zircon data on the rhyolite of the Saf’yanovskoe Cu-Zn deposit (Middle Urals)

LITOSFERA ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 884-893
Author(s):  
M. E. Prytchin ◽  
E. I. Soroka ◽  
V. N. Puchkov
Keyword(s):  
Middle Devonian ◽  
Volcanic Rocks ◽  
Middle Urals ◽  
Structural Formation ◽  
Secondary Ions ◽  
Formation Zone ◽  
Upper Silurian ◽  
Western Side ◽  
Number Of Publications ◽  
First Time

Research subject. Zircons from the Saf’yanovskoe Cu-Zn deposit rhyolite (Middle Urals). For the first time, zircon U-Pb dating for the rhyolite of the ore-bearing volcanic-sedimentary rocks of the Saf’yanovskoe deposit was performed. The volcanites are characterized by an andesite-rhyodacite composition and are localized at the southern edge of the Rezhevskaya structural-formation zone (SFZ) of the Eastern Ural megazone. A number of publications assign these rocks either to the basalt-rhyolite formation of the Middle Devonian, or to the basalt-andesite-dacite-rhyolite formation of the Lower-Middle Devonian.Aim. To estimate the age of the ore-bearing volcanic rocks under study using the U-Pb SHRIMP-II isotop ic system of zircon from the rhyolite of the eastern side of the Saf’yanovskoe deposit. By its chemical composition, the rhyolite belongs to the silicic varieties of subvolcanic rocks. Methods and results. The U-Pb isotopic system of zircon was studied by 5-collector mass-spectrometer of high precision and emission of the secondary ions SHRIMP-II (ASI, Australia)  in the VSЕGEI Institute. U-Pb relations were investigated by a procedure developed by I.S. Williams. The U-Pb data obtained based on 13 zircon grains showed the age of 422.8 ± 3.7 Ma. Conclusions. The U-Pb dating of zircon obtained previously from the lens-shaped andesite bodies of the western side of the Safyanovskoe deposit gave the age of 422.8 Ma, which corresponds to the Przydoli series epoch of the Upper Silurian. We established that, among the volcanic rocks of the Saf’yanovskoe deposit, the effusive formations of the Upper Silurian are present.

scholarly journals Radiocarbon Chronology of the Shigir and Gorbunovo Archaeological Bog Sites, Middle Urals, Russia

Radiocarbon ◽  
2012 ◽  
Vol 54 (3-4) ◽  
pp. 783-794 ◽  
Author(s):  
Natalia E Zaretskaya ◽  
Sönke Hartz ◽  
Thomas Terberger ◽  
Svetlana N Savchenko ◽  
Mikhail G Zhilin
Keyword(s):  
Mass Spectrometry ◽  
Central And Eastern Europe ◽  
Archaeological Sites ◽  
Peat Bogs ◽  
Middle Urals ◽  
Early Neolithic ◽  
Radiocarbon Chronology ◽  
First Time ◽  
Late Mesolithic ◽  
Ams Dates

Two well-known archaeological sites, the peat bogs of Shigir and Gorbunovo (Middle Urals, Russia), have been radiocarbon dated (61 conventional and accelerator mass spectrometry [AMS] dates from various natural and artifact samples). For the first time, a detailed chronology of Early to Late Mesolithic and Early Neolithic occupation for this region has been obtained, and a paleoenvironmental history reconstructed. Based on these results, we propose that the Mesolithic settlement of the Middle Urals region started in the early Holocene, at the same time as in central and eastern Europe.

Two newly identified cheiracanthid acanthodians from the Mey Flagstone Formation (Givetian, Middle Devonian) of the Orcadian Basin, Scotland

2020 ◽  
Vol 57 (1) ◽  
pp. sjg2020-009
Author(s):  
Michael J. Newman ◽  
Jan L. den Blaauwen ◽  
Carole J. Burrow
Keyword(s):  
Middle Devonian ◽  
Leading Edge ◽  
Baltic Region ◽  
Head Region ◽  
Longitudinal Ridge ◽  
Orcadian Basin ◽  
First Time ◽  
Fin Spines

Articulated cheiracanthid acanthodians are relatively rare above the Dickosteus thrieplandi biostratigraphic zone in the Orcadian Basin, with Cheiracanthus peachi den Blaauwen, Newman & Burrow the only species identified to date. Here we describe two other taxa Fallodentus davidsoni nov. gen. et sp. and Markacanthus costulatus Valiukevičius from the Mey Flagstone Formation. F. davidsoni occurs at the base of the formation, in the Osteolepis panderi biostratigraphic zone, and is readily identified by its robust fin spines which have a wide longitudinal ridge on each side below the groove separating the leading edge from the side of the spine. The taxon is most similar to Homalacanthus concinnus (Whiteaves) from the younger (Frasnian) Escuminac Formation in Quebec, Canada. The unique specimen of Markacanthus costulatus is from the top of the Mey Flagstone Formation. This taxon was previously only known from isolated scales from the upper Narva and Aruküla Regional Stages of the east Baltic region. The dorsoventral preservation of the head region in the F. davidsoni specimens reveals clearly the position of the ceratohyal cartilages in a cheiracanthid, as well as showing for the first time that there is a basihyal cartilage anterior to the ceratohyals.

scholarly journals New data on the ecological peculiarities and the distribution in Bulgaria of the vulnerable habitat F3.1d Balkan-Anatolian submontane genistoid scrub from the European Red List of Habitats

Hacquetia ◽  
2019 ◽  
Vol 18 (2) ◽  
pp. 271-287
Author(s):  
Georgi Kunev ◽  
Rossen Tzonev
Keyword(s):  
Vegetation Type ◽  
Volcanic Rocks ◽  
Habitat Type ◽  
Life Forms ◽  
Plant Life Forms ◽  
Area Of Occupancy ◽  
Floristic Elements ◽  
First Time ◽  
Floristic Structure ◽  
East Mediterranean Region

Abstract The study presents new data on the habitat dominated by the species complex of Genista lydia/G. rumelica in Bulgaria. It is based on 129 phytocoenological relevés and provides information on the chorology, ecology and floristic structure of these communities. This habitat type occupies substrates composed by different volcanic rocks. The floristic structure is very rich in species. The phytogeographical relationships with the East Mediterranean region are considerable, which is proved by the high occurrence of floristic elements with Mediterranean or sub-Mediterranean origin. The plant life-forms analysis demonstrates that the therophytes, geophytes and chamephytes prevail in their floristic structure, which is also typical for the shrub communities in this region. During the field study this vegetation type has been mapped and its total area of occupancy has been calculated. For a first time it is proposed this habitat to be divided into three habitat sub-types due to the established differences in the environmental factors. Some recommendations have been proposed on the conservation management and also complements on the habitat‘s descriptions in EUNIS habitat classification.

Printers to Hendrik Niclaes: Plantin and Augustijn van Hasselt

Quaerendo ◽  
1984 ◽  
Vol 14 (4) ◽  
pp. 247-272 ◽  
Author(s):  
Paul Valkema Blouw
Keyword(s):  
The Other ◽  
Literary Sources ◽  
The Family ◽  
Religious Sect ◽  
Set Up ◽  
Number Of Publications ◽  
First Time ◽  
New Evidence ◽  
Publishing Business

AbstractFrom the chronicles of the Family of Love we know that, besides printers in Deventer and later in Cologne, both Plantin and Augustijn van Hasselt printed for this religious sect. On the basis of this information quite a large number of publications have hitherto been attributed to Plantin, while only one single edition in Latin was reckoned to be the work of Augustijn. An analysis of the typography, however, shows that apart from Hendrik Niclaes's chief work, Den Spegel der Gherechticheyt, Plantin only printed two of his minor writings and that all the other ascriptions to Plantin must be revised in favour of Augustijn van Hasselt. In 1561-2 Augustijn was running a printing shop in the Dutch town of Kampen, specially set up by HN for the purpose of publishing those of his works that had not previously been printed. Plantin, who was partly involved in this enterprise, took the opportunity to have a book printed on this press for his publishing business. The analysis providing the typographical evidence of this collaboration proves for the first time the accuracy of the literary sources as regards Plantin's involvement in the publication of the works of Hendrik Niclaes. In the presentation of the new evidence it was necessary to establish more clearly the date of Plantin's '[1561]' inventory and which roman and German types he owned at what times. The article ends with some notes regarding the end of the 'Bohmbargen' press at Cologne.

scholarly journals The First Find of Cr2O3 Eskolaite Associated with Marble-Hosted Ruby in the Southern Urals and the Problem of Al and Cr Sources

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 101
Author(s):  
Aleksander Kissin ◽  
Irina Gottman ◽  
Sergei Sustavov ◽  
Valery Murzin ◽  
Daria Kiseleva
Keyword(s):  
Granite Gneiss ◽  
Southern Urals ◽  
X Ray Diffraction ◽  
The Southern Urals ◽  
Near Surface ◽  
X Ray ◽  
Gneiss Domes ◽  
Electron Probe Microanalyzer ◽  
Formation Zone ◽  
First Time

The results of the study of eskolaite associated with marble-hosted ruby found for the first time in the Kuchinskoe occurrence (Southern Urals) are presented. Here, eskolaite was located on the surface and near-surface regions of ruby crystals. Eskolaite diagnostics was confirmed by powder X-ray diffraction (URS-55). The morphology and chemical composition of eskolaite and associated ruby was studied using a JSM-6390LV scanning electron microscope and a Cameca SX 100 electron probe microanalyzer. The eskolaite crystals were hexagonal and tabular, up to 0.2 mm in size. Ruby mineralization was formed during prograde and retrograde dynamothermal metamorphism. The eskolaite associated with the prograde stage ruby contained Al2O3 (9.1–23.62 wt %), TiO2 (0.52–9.66 wt %), V2O3 (0.53–1.54 wt %), FeO (0.03–0.1 wt %), MgO (0.05–0.24 wt %), and SiO2 (0.1–0.21 wt %). The eskolaite associated with the retrograde stage ruby was distinguished by a sharp depletion in Ti and contained Al2O3 (12.25–21.2 wt %), TiO2 (0.01–0.07 wt %), V2O3 (0.32–1.62 wt %), FeO (0.01–0.08 wt %), MgO (0.0–0.48 wt %), and SiO2 (0.01–0.1 wt %). The associated rubies contained almost equal amounts of Cr2O3 (2.36–2.69 wt %) and were almost free from admixtures. The identification of the eskolaite associated with the marble-hosted rubies from the Kuchinskoe occurrence is a new argument in favor of introduction of Al and Cr into the mineral formation zone. The mineralization was localized in the metamorphic frame of the granite gneiss domes and was formed synchronously with them.

The Lower Ordovician Brachiopod Syntrophla sp., cf. S. arethusa (Billings 1862) from South Catcher Pond, Northeastern Newfoundland

1973 ◽  
Vol 10 (3) ◽  
pp. 427-430 ◽  
Author(s):  
A. J. Boucot
Keyword(s):  
North American ◽  
Volcanic Rocks ◽  
Lower Ordovician ◽  
First Time

The Lower Ordovician North American Province brachiopod genus Syntrophia is recognized for the first time from northern Newfoundland. It occurs together with other Lower Ordovician fossils (trilobites and conodonts) in a limestone lens interbedded with volcanic rocks that may belong to the Lush's Bight Group.

Arachnoxylon from the Middle Devonian of southwestern Virginia

1983 ◽  
Vol 61 (4) ◽  
pp. 1283-1299 ◽  
Author(s):  
William E. Stein Jr. ◽  
David C. Wight ◽  
Charles B. Beck
Keyword(s):  
Middle Devonian ◽  
Main Axis ◽  
Supplementary Information ◽  
Monotypic Genus ◽  
Primary Xylem ◽  
New Material ◽  
Shale Formation ◽  
Definition Of ◽  
A Minor ◽  
First Time

Eight specimens from the Middle Devonian Purcell Member of the Millboro Shale Formation in southwestern Virginia conform to a recent definition of the previously monotypic genus Arachnoxylon. The new material provides supplementary information on several tissue regions of the main axis, including evidence on variability in the structure of the protoxylem, and on departure of the large, or "major" traces. In addition, evidence is provided here for the first time on a discrete region, immediately adjacent to the primary xylem, containing probable conducting elements of the primary phloem, on the structure of the epidermis, and on the presence of multicellular superficial emergences. Although clearly assignable to Arachnoxylon, all but one of our specimens vary significantly from previous specimens in the genus in several features which may be interpreted as relating directly or indirectly to size. It is possible that all specimens in Arachnoxylon represent portions of a single kind of plant. However, organic connection between the large and small forms has not been demonstrated. We elect, therefore, to establish A. minor sp. n. for the smaller specimens.

Pyroclastic rocks from Kanchanaburi and Uthai Thani Province, Inthanon Zone, Western Thailand

2020 ◽  
Author(s):  
Suwijai Jatupohnkhongchai ◽  
Sirot Salyapongse ◽  
Burapha Phajuy ◽  
Daniela Gallhofer ◽  
Christoph Hauzenberger
Keyword(s):  
Volcanic Rocks ◽  
Potassium Feldspar ◽  
Geochronological Data ◽  
Rock Composition ◽  
Pyroclastic Rocks ◽  
Eu Anomaly ◽  
Geologic Map ◽  
Ree Patterns ◽  
First Time ◽  
Strong Depletion

<p>A series of pyroclastic rocks are mapped as a Silurian-Devonian unit in the Kanchanaburi-Uthai Thani area, Western Thailand, which belongs to the Inthanon Zone. These pyroclastic rocks were discovered and described for the first time in 1977 and mentioned in the 1:250,000 Suphanburi geologic map sheet and report. Since then these rocks were poorly investigated and their formation and geotectonic setting is unclear. As a result, we report petrographic, geochemical and geochronological data of these pyroclastic rocks. Petrographically, the pyroclastic rocks can be described as a meta-quartz-K-feldspar crystal tuff, a meta-quartz crystal tuff, and a meta-lithic tuff. They are made up of mm sized clasts in a finely grained matrix. The clasts consist of potassium feldspar, rounded quartz, embayed quartz, trachytic and metasedimentary rock clasts embedded in a highly altered devitrified fine-ash matrix containing sericite.</p><p>The whole-rock composition shows enrichments in SiO<sub>2</sub> and K<sub>2</sub>O and a strong depletion in CaO and Na<sub>2</sub>O which is related to late alteration of the volcanoclastic rocks. Based on the immobile element classification plot of Pearce 1996, the tuffs can be classified as trachyandesite, trachyte, dacite and rhyolite. Their chondrite-normalized REE patterns display light REE enrichment with nearly flat heavy REE and a negative Eu anomaly, typical for calcalkaline volcanic rocks. Most samples fall in the volcanic arc granites field in the granite discrimination diagrams of Pearce 1984.</p><p>Zircons extracted from the tuffs will be used to constrain their crystallization age by U-Pb LA-MCICPMS dating. This allows us to constrain the age of formation and to place this in context with the closure of the Paleotethys.</p>

Investigations of electrical properties of weathered layers in the Yala area, western Kenya, using resistivity soundings

Geophysics ◽  
1991 ◽  
Vol 56 (1) ◽  
pp. 133-138 ◽  
Author(s):  
J. O. Barongo ◽  
G. J. Palacky
Keyword(s):  
Electrical Properties ◽  
Volcanic Rocks ◽  
Silica Content ◽  
Data Sets ◽  
Geologic Mapping ◽  
Weathering Profile ◽  
Western Kenya ◽  
Tropical Regions ◽  
Weathered Layer ◽  
First Time

Investigation in many parts of the world have indicated that resistivity of saprolite (a chloritization zone at the base of the weathering profile) depends uniquely on the underlying rock type. A study of electrical properties of the weathered layer was undertaken near Yala in the Nyanzian‐Kavirondian greenstone belt in western Kenya. Resistivity soundings were systematically carried out in a 24 × 40 km area. Saprolite formed over basalt had the lowest resistivity (14 Ω•m), followed by andesite (27 Ω•m) and rhyolite (67 Ω•m). Statistically meaningful data sets conclusively show, for the first time, that saprolite resistivity increases with the silica content of parent volcanic rocks. Plutonic and sedimentary rocks had higher average resistivities (granite 135 Ω•m, mudstone 79 Ω•m, grit 213 Ω•m). Thickness of the weathered layer varied between 10 and 40 m, with the largest values observed over grit (sandstone). Compared with other tropical regions, the saprolite layer in western Kenya appears relatively thin, possibly because of the relatively rapid tectonic uplift of the area which leads to fast erosion. As observed in earlier studies, resistivity and electromagnetic surveys can increase the speed and reliability of geologic mapping in tropical terrains.

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