Beyond Beauty. Byzantine steatite icon from Chełm. Archaeology, Petrography and Traceology

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Andrzej Buko ◽  
Tomasz Dzieńkowski ◽  
Stanisław Gołub ◽  
Mirosław P. Kruk ◽  
Marek Michalik ◽  
...  
Keyword(s):  
Chemical Compositions ◽  
National Museum ◽  
Left Wing ◽  
Exchange Reactions ◽  
Fire Event ◽  
Prolonged Contact ◽  
Petrographic Analyses ◽  
Byzantine Icons ◽  
Local Enrichment ◽  
Mechanical Tool

Abstract A fragmentarily preserved Byzantine icon made of steatite was discovered in 2015 during regular excavations in Chełm, eastern Poland. Identified as the left wing of a diptych illustrating the Twelve Great Feasts and created at the close of the 12th century, the find is one of the most important and beautiful Byzantine artefacts to have been found in Poland. The icon was uncovered within the confines of the palace complex which was created by Daniel (Danylo) Romanovych († 1264) in Chełm in the second quarter of 13th century. The icon, even though it was found within the borders of what is now Poland, is material evidence of contact between Byzantium and the social elite of the Galicia-Volhynia lands, rather than with the Polish Piasts. In this paper we concentrated on the presentation of the archaeological context of the find, which made it possible to establish that the icon arrived Chełm before the middle of the 13th century (terminus ante quem 1253), and especially on petrographic and traceological analyses of the icon. Assuming that greenish plaques were indeed the most characteristic steatite icon type, a decision was made to examine, apart from the Chełm artefact made from white rock, a greenish icon from the National Museum in Krakow as well. Petrographic analyses were based on optical microscopy, scanning electron microscopy with energy dispersive spectrometry (SEM-EDS) and X-ray powder diffraction (XRPD). Both icons were carved in steatite i. e. talc rich rock but their chemical compositions indicate the presence of other components. Artifact from Chełm is white. Porous, enriched in potassium (K) and locally blistering outer rim of the icon from Chełm was formed probably during the fire event. Presence of forsterite and subordinate amount of leucite also indicate high temperature influence. Local enrichment in calcium (Ca) is related to exchange reactions with ground compounds. Accumulation of different components on the surface of the icon’s surface was noted. The icon from the National Museum in Krakow is greenish probably because of the presence of chlorite. The results of the traceological analysis (icon from National Museum in Krakow was not analysed) indicate that the icon found in Chełm was created most likely by a skilled and experienced carver with access to the high-quality magnifying glass and specialist tools required for rendering minuscule objects and their details. The production of the icon also involved the use of a “mechanical” tool, probably a kind of a miller with a rotating polishing head, which also seems to point to a specialist workshop. The use-wear traces observed on artefact are limited to polish resulting from prolonged contact with human hands or storing the icon in a leather case. Most of the extant Byzantine icons are unprovenanced objects held in museum collections or church treasuries. Therefore, as the icon presented in this paper was discovered during archaeological excavations, it ranks among the few Byzantine artefacts to have been found outside of this realm. The petrographic and traceological analyses conducted are the first published natural science contributions to the study of Byzantine steatite icons and we hope they will provide the impetus for undertaking such research on other Byzantine finds, helping to develop Byzantine archaeology further.

scholarly journals A conceptual model of solute acquisition by Alpine glacial meltwaters

1993 ◽  
Vol 39 (133) ◽  
pp. 573-581 ◽  
Author(s):  
Martyn Tranter ◽  
Giles Brown ◽  
Robert Raiswell ◽  
Martin Sharp ◽  
Angela Gurnell
Keyword(s):  
Conceptual Model ◽  
Drainage System ◽  
Chemical Compositions ◽  
Atmospheric Gases ◽  
Exchange Reactions ◽  
Surface Exchange ◽  
Suspended Sediment Concentrations ◽  
Slow Transit ◽  
Main Components ◽  
Solute Acquisition

Abstract Solute acquisition by Alpine glacial meltwaters is the result of the coupling of different pairs of reactions, one of which usually involves dissolved gases. Hence, the availability of atmospheric gases to solution is an important control on the composition of glacial meltwaters. The chemical compositions of the two main components of the bulk meltwater, quick flow and delayed flow, are dominated by different geochemical processes. Delayed flow waters are solute-rich and exhibit high p(CO2) characteristics. The slow transit of these waters through a distributed drainage system and the predominance of relatively rapid reactions, such as sulphide oxidation and carbonate dissolution, in this environment maximize solute acquisition. Quick-flow waters are dilute, both because of their rapid transit through ice-walled conduits and open channels, and because the weathering reactions are fuelled by relatively slow gaseous diffusion of (CO2) into solution, despite solute acquisition being dominated by rapid surface exchange reactions. As a consequence, quick flow usually bears a low or open-system p(CO2) signature. Bulk meltwaters are more likely to exhibit low p(CO2) values when suspended-sediment concentrations are high, which promotes post-mixing reactions. This conceptual model suggests that the composition of both quick flow and delayed flow is likely to be temporally variable, since kinetic, rather than equilibrium, factors determine the composition.

scholarly journals A conceptual model of solute acquisition by Alpine glacial meltwaters

1993 ◽  
Vol 39 (133) ◽  
pp. 573-581 ◽  
Author(s):  
Martyn Tranter ◽  
Giles Brown ◽  
Robert Raiswell ◽  
Martin Sharp ◽  
Angela Gurnell
Keyword(s):  
Conceptual Model ◽  
Drainage System ◽  
Chemical Compositions ◽  
Atmospheric Gases ◽  
Exchange Reactions ◽  
Surface Exchange ◽  
Suspended Sediment Concentrations ◽  
Slow Transit ◽  
Main Components ◽  
Solute Acquisition

AbstractSolute acquisition by Alpine glacial meltwaters is the result of the coupling of different pairs of reactions, one of which usually involves dissolved gases. Hence, the availability of atmospheric gases to solution is an important control on the composition of glacial meltwaters. The chemical compositions of the two main components of the bulk meltwater, quick flow and delayed flow, are dominated by different geochemical processes. Delayed flow waters are solute-rich and exhibit high p(CO2) characteristics. The slow transit of these waters through a distributed drainage system and the predominance of relatively rapid reactions, such as sulphide oxidation and carbonate dissolution, in this environment maximize solute acquisition. Quick-flow waters are dilute, both because of their rapid transit through ice-walled conduits and open channels, and because the weathering reactions are fuelled by relatively slow gaseous diffusion of (CO2) into solution, despite solute acquisition being dominated by rapid surface exchange reactions. As a consequence, quick flow usually bears a low or open-system p(CO2) signature. Bulk meltwaters are more likely to exhibit low p(CO2) values when suspended-sediment concentrations are high, which promotes post-mixing reactions. This conceptual model suggests that the composition of both quick flow and delayed flow is likely to be temporally variable, since kinetic, rather than equilibrium, factors determine the composition.

scholarly journals High chloride, sulphate and fluoride concentrations in clay-rich aquitard porewater, the North China Plain: evidence of geochemical behavior

2019 ◽  
Vol 98 ◽  
pp. 01019
Author(s):  
Dongmei Han ◽  
Guoliang Cao ◽  
Andrew J. Love
Keyword(s):  
North China Plain ◽  
North China ◽  
Pyrite Oxidation ◽  
Extraction Procedure ◽  
Fine Sand ◽  
Chemical Compositions ◽  
Exchange Reactions ◽  
The North ◽  
The North China Plain ◽  
Ion Profiles

The focus of this investigation was to constrain the porewater chemistry from tracer and ion profiles in a 128 m thick clay-rich sequence of Quaternary sediments comprising the clay, silt and fine sand formation in the North China Plain. Porewater are much more saline (1.1-71.0 g/L) than the lower confined groundwaters (0.3-1.3g/L). Chloride profiles from aqueous extraction (AE) (ranging from 117 to 3260 mg/L) generally keep good consistent with that obtained from squeezing test (ST). However, the sulphate and fluoride concentrations by AE (ranging from 340 to 48,700 mg/L and from 8.8 to 144 mg/L, respectively) are far greater than that by ST. Dissolution of evaporites may be responsible for the high Cl/Br ratios greater than 1000, probably indicating recharge occurred during much wetter periods. The original stable isotopic and chemical compositions in the aquitard porewater have been modified by transpiration and evaporation processes concentrating Cl and causing isotopic enrichment during their formation periods. Dissolution of fluorite, hieratite, and cryolite caused by weathering behavior and ion-exchange reactions should be responsible for the high fluoride concentrations in the aquitard porewater. High sulphate levels found in aqueous samples may arise from pyrite oxidation during sampling, storage and/or porewater extraction procedure.

P-T-fluid conditions of mineral equilibria in garnet-biotite crustal xenoliths from the Yubileinaya and Sytykanskaya kimberlite pipes, Yakutian kimberlite province.

2021 ◽  
Author(s):  
Natalia Seliutina ◽  
Oleg Safonov ◽  
Vasiliy Yapaskurt ◽  
Dmitry Varlamov ◽  
Igor Sharygin ◽  
...  
Keyword(s):  
Water Activity ◽  
Siberian Craton ◽  
Database Systems ◽  
Potassium Feldspar ◽  
Coarse Grained ◽  
Chemical Compositions ◽  
Exchange Reactions ◽  
Russian Science ◽  
Isotopic Evidence ◽  
Crustal Xenoliths

<p>This study provides the results of research of the garnet-biotite crustal xenoliths from the Yubileinaya (372±4.8 Ma) and Sytykanskaya (363±13 Ma) kimberlite pipes of the Alakit-Markhinsky field (Siberian craton). Isotopic evidence on zircons from similar crustal xenoliths (Grt+Bt+Pl+Kfs+Qtz±Scp) showed Archean Hf model ages (TDM = 3.13-2.5 Ga) and thus indicated that most of the lower and middle crust beneath the Markha terrane was produced in the Archean time (Shatsky et al., 2016).</p><p>The xenoliths are represented by the assemblage Grt+Bt+Pl+Kfs±Opx. Quartz is present only as rare inclusions in garnets. The rocks are coarse-grained, slightly foliated with garnets porphyroblasts of up to 5 cm in size. A spectacular feature of the rocks is an abundance of K-feldspar. Garnet grains are almost compositionally homogeneous, although they show a rimward decrease of the Mg and Ca contents indicating exchange reactions during cooling. Biotites are characterized by high F increasing from 1.5 wt.% in cores up to 2.2 wt.% in rims, as well as TiO<sub>2</sub> up to 7.8 wt.%, which is typical for high-grade rocks. Orthopyroxene (up to 5.5 wt. % Al<sub>2</sub>O<sub>3</sub>) relics are preserved both as inclusions in garnet and as individual grains in the rock matrix. Plagioclase occurs both as separate grains and as lamellae in potassium feldspar.</p><p>The bulk chemical compositions correspond to a metagraywacke. The REE spectra in these rocks are rather flat with slight enrichment in LREE. All the studied rocks are characterized by a distinct negative Eu anomaly (Eu/Eu* = 0.31-0.45).</p><p>Calculations using the PERPLEX software version 6.7.6 (Connolly, 2005) for Mg and Ca in Grt, Mg in Bt, and Ca in Pl indicated temperatures 630-730°C and pressures 5.8-7.2 kbar for the rocks. However, equilibria involving Al<sub>2</sub>O<sub>3</sub> in orthopyroxene corresponds to temperatures of 750-800<sup>o</sup>С at a similar pressure. It indicates that metamorphism of the garnet-biotite rocks reached higher temperatures, but they were actively modified later during cooling and insignificant decompression (by about 1 kbar). Calculations using the TWQ software version 2.3 (Berman, 2007) indicate consistent temperatures 610-680°C for the garnet-orthopyroxene and 640-690<sup>o</sup>C for garnet-biotite Mg-Fe exchange equilibria. Calculations using the Grs+2Prp+Kfs+H<sub>2</sub>O=Phl+3En+3An equilibrium demonstrated water activity below 0.1. Such low water activity could indicate an influence of highly concentrated alkaline Cl-F-bearing brines. This assumption is confirmed by extensive development of potassium feldspar, absence of quartz in the matrix, and elevated Cl contents of biotite, 0.1-0.3 wt. % at high #Mg (>0.7) and F content.</p><p><em>The study is supported by the Russian Science Foundation project 18-17-00206.</em></p><p><strong> </strong><strong>References </strong></p><p>Berman, R. G. (2007). winTWQ (version 2.3): a software package for performing internally-consistent thermobarometric calculations. Geological survey of Canada, open file, 5462, 41.</p><p>Connolly, T. M., & Begg, C. E. (2005). Database systems: a practical approach to design, implementation, and management. Pearson Education.</p><p>Shatsky, V. S., Malkovets, V. G., Belousova, E. A., ... & O’Reilly, S. Y. (2016). Tectonothermal evolution of the continental crust beneath the Yakutian diamondiferous province (Siberian craton): U–Pb and Hf isotopic evidence on zircons from crustal xenoliths of kimberlite pipes. Precambrian Research, 282, 1-20.</p>

scholarly journals Controls on the Radiocarbon Reservoir Ages in the Modern Dead Sea Drainage System and in the Last Glacial Lake Lisan

Radiocarbon ◽  
2007 ◽  
Vol 49 (2) ◽  
pp. 969-982 ◽  
Author(s):  
Reuven Belmaker ◽  
Mordechai Stein ◽  
Yoseph Yechieli ◽  
Boaz Lazar
Keyword(s):  
Mass Balance ◽  
Sea Water ◽  
Dissolved Inorganic Carbon ◽  
Dead Sea ◽  
Glacial Lake ◽  
Chemical Compositions ◽  
Exchange Reactions ◽  
Last Glacial ◽  
The Dead ◽  
The Last Glacial

Carbon isotopic and chemical compositions of freshwaters feeding the Dead Sea and the Sea of Galilee (i.e. perennial streams and floods along their stream profiles) were used to constrain the factors that dictate the reservoir ages (RA) of these lakes and the last glacial Lake Lisan. Runoff waters are characterized by high Ca2+, Mg2+, alkalinity, and radiocarbon contents (67–108 pMC), suggesting a major role for 14C atmospheric exchange reactions (carbonate rock dissolution alone will result in lower pMC values). These exchange processes were corroborated by dissolved inorganic carbon (DIC) and δ13C trends throughout the flood profile. During the evolution from rain to incipient runoff, the 14CDIC of the water increases and is accompanied by a DIC increase and δ13CDIC decrease, suggesting an addition of soil CO2, which is characterized by light δ13C and high 14C content. When incipient runoffs evolve to floods, the opposite trends are observed.It appears that the Sea of Galilee, the Dead Sea, and its last glacial precursor, Lake Lisan, maintained uniform but specific RAs of 0.8 ± 0.1, 2.3 ± 0.1, and 1.6 ± 0.3 kyr, respectively. However, applying the 14C contents of modern Dead Sea water sources to the water mass balance of Lake Lisan reveals that the RA of Lake Lisan is higher than that predicted by the mass balance. This discrepancy may reflect enhanced dissolution of carbonatic dust, changes in the amount of 14C exchanged in Judean Desert floods, or variations in the contribution of brine and saline springs. Furthermore, the small fluctuations in the Lisan RA (1.6 ± 0.3 kyr) may reflect small, short-term changes in the relative contributions of these sources.

Chemistry and phase petrology of amphiboles and orthoamphibole–cordierite rocks, Old Woman Mountains, SE California, USA

1990 ◽  
Vol 54 (376) ◽  
pp. 393-406 ◽  
Author(s):  
Edward F. Stoddard ◽  
Calvin F. Miller
Keyword(s):  
Thin Section ◽  
Large Range ◽  
Chemical Compositions ◽  
Exchange Reactions ◽  
Ionic Substitution ◽  
Mineral Assemblages ◽  
Rapid Uplift

AbstractProterozoic amphibolites from Sweetwater Wash, in the Old Woman Mountains of southeastern California, contain a variety of mineral assemblages dominated by the low-Ca amphiboles anthophyllite, gedrite, and cummingtonite. Their Mg- and Al-rich, Ca-poor bulk compositions suggest that the amphibolites represent basalts that were altered prior to metamorphism. In addition to amphiboles, mineral assemblages include cordierite, biotite, garnet, Ca-rich plagioclase, and ilmenite ± rutile. Corundum, staurolite, and spinel occur locally in Al-rich enclaves associated with cordierite. Orthoamphiboles commonly exhibit complex microstructures, including twinning, intergrowths, and apparent exsolution; spot analyses show an unusually large range of chemical compositions, even within a single thin section, in several cases extending across the crest of the solvus in the orthoamphibole system. Ionic substitution within the orthoamphibole series was dominated by the Mg-tschermakitic and edenitic exchange reactions. The amphibolites are thought to have been subjected to metamorphic temperatures above the orthoamphibole solvus during both the Proterozoic and the Cretaceous. Cretaceous metamorphism was followed closely by rapid uplift and denudation, which may be responsible for the exsolution and range of compositions of the orthoamphiboles.

scholarly journals Sustainable Use of Nanomaterials in Textiles and Their Environmental Impact

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5134 ◽  
Author(s):  
Haleema Saleem ◽  
Syed Zaidi
Keyword(s):  
Health Risks ◽  
Textile Industry ◽  
Sustainable Use ◽  
Financial Impact ◽  
Chemical Compositions ◽  
Toxic Substances ◽  
Textile Materials ◽  
Functional Textiles ◽  
Prolonged Contact ◽  
Advanced Applications

At present, nanotechnology is a priority in research in several nations due to its massive capability and financial impact. However, due to the uncertainties and abnormalities in shape, size, and chemical compositions, the existence of certain nanomaterials may lead to dangerous effects on the human health and environment. The present review includes the different advanced applications of nanomaterials in textiles industries, as well as their associated environmental and health risks. The four main textile industry fields using nanomaterials, nanofinishing, nanocoatings, nanofibers, and nanocomposites, are analyzed. Different functional textiles with nanomaterials are also briefly reviewed. Most textile materials are in direct and prolonged contact with our skin. Hence, the influence of carcinogenic and toxic substances that are available in textiles must be comprehensively examined. Proper recognition of the conceivable benefits and accidental hazards of nanomaterials to our surroundings is significant for pursuing its development in the forthcoming years. The conclusions of the current paper are anticipated to increase awareness on the possible influence of nanomaterial-containing textile wastes and the significance of better regulations in regards to the ultimate disposal of these wastes.

EVALUATION OF GLAZE AND BODY COMPOSITION IN ANCIENT IRANIAN POTTERY

2002 ◽  
Vol 12 (03n04) ◽  
pp. 245-251 ◽  
Author(s):  
P. OLIAIY ◽  
F. SHOKOUHI ◽  
J. RAHIGHI ◽  
M. LAMEHI-RACHTI ◽  
N. GOLABI
Keyword(s):  
Body Composition ◽  
Proton Beam ◽  
Iron Content ◽  
Elemental Concentration ◽  
Chemical Compositions ◽  
National Museum ◽  
Temperature Oxidation ◽  
Pottery Sherds ◽  
Pixe Method ◽  
Qualitative Analyses

Several samples of pottery sherds owned by the Islamic Arts section of the National museum of Iran excavated in Ray, Neishabur and Kahn – the area around northeast and the central part of Iran – were analyzed in order to establish their chemical compositions. In Van de Graaff Laboratory at the AEOI, qualitative analyses of the sherds were performed using a 2 MeV proton beam. The fragments which dated back to the period between the 9th and the 13th centuries, were analyzed using the PIXE method. The results of the concentrations of the component elements such as Ti , Mn , Fe , Co , Ni , Cu , Zn , Ba and Pb are presented and discussed. The results confirm the effect of the iron content of clay, it's firing conditions such as firing temperature, oxidation and reduction on the color of clay. In addition the dependence of glaze color with the various elemental concentration is established.

The Genesis and Internal Dynamics of El Salvador's People's Revolutionary Army, 1970–1976

2014 ◽  
Vol 38 (01) ◽  
pp. 102-129
Author(s):  
ALBERTO MARTÍN ÁLVAREZ ◽  
EUDALD CORTINA ORERO
Keyword(s):  
Latin America ◽  
El Salvador ◽  
Early Years ◽  
Left Wing ◽  
Internal Dynamics ◽  
Internal Coherence ◽  
The 1960S

AbstractUsing interviews with former militants and previously unpublished documents, this article traces the genesis and internal dynamics of the Ejército Revolucionario del Pueblo (People's Revolutionary Army, ERP) in El Salvador during the early years of its existence (1970–6). This period was marked by the inability of the ERP to maintain internal coherence or any consensus on revolutionary strategy, which led to a series of splits and internal fights over control of the organisation. The evidence marshalled in this case study sheds new light on the origins of the armed Salvadorean Left and thus contributes to a wider understanding of the processes of formation and internal dynamics of armed left-wing groups that emerged from the 1960s onwards in Latin America.

Sign in / Sign up

Export Citation Format

Share Document