A combination of invasive and non-invasive techniques for the study of the palette and painting structure of a copy of Raphael's Transfiguration of Christ

The main objective of this study is to establish an appropriate method for the characterization of the pigments, materials and structure of the paint layers in a copy of the painting the Transfiguration of Christ by Raffaello Sanzio. A multi-technique approach that combines elemental, molecular and structural analyses and involves optical microscopy (OM), scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM–EDX), μ-Attenuated Total Reflection–Fourier Transform InfraRed (µATR-FTIR), μ-Raman spectrometry (µRS) and non-invasive portable diffractometer (pXRD) was used. Our results revealed that this copy of the Transfiguration was executed with a palette, which includes white lead (cerussite and hydrocerussite), lazurite from lapis lazuli pigment, red and yellow earths (goethite, hematite and lepidocrocite), lead tin yellow, cinnabar, red lake, smalt and bone black, and fillers such as calcite, baryte (an impurity associated to some pigments), and traces of colorless powdered glass. A secondary objective of this research was the application of non-invasive in situ pXRD measurements, which do not require painting sampling and helped to confirm some inconclusive results obtained with other techniques regarding the artist's palette. The results showed the crystalline nature of all the pigments identified, which were known from ancient times and available during the 16th and 17th. Lastly, the used of 14C accelerator mass spectrometry determined that the canvas date was 1451–1633 AD (with a 95% confidence level). Although the main focus of the work was to improve the analytical methodology to better understand the artist’s palette, our results will further help us to explore the authorship of the copy or the school that executed it. Graphical Abstract

Recession curve analysis in function of karst lake hydrogeological regime identification: case study Red Lake, Croatia

<p>Red Lake is an example of a karst phenomenon near the town of Imotski (Croatia), in the central part of Dinaric Karst. It is considered the deepest submerged karst feature in the world, located in an inaccessible area with large slopes of the lakeshore, which makes the research difficult and resource intensive. For this reason, to better understand the hydrogeological functioning of the lake, data on the water level in the lake, collected over a period of five years, were analyzed. The morphometric model of Red Lake was used to determine a relationship between lake volume and depth, furthermore to define integral water inflow and outflow quantities. Recession curves were extracted from the graphical representation of the water influx data series. The calculated recession coefficients were used to identify the dominant hydrogeologic mechanism respective to the water level in the lake and the ratio between recharge components of groundwater and direct runoff. The approach provides a tool for identifying the hydrogeological regime of karst lakes and the stratification of different porosity levels of the surrounding karst massif.</p>

The Miocene Red Lake macroflora of the Deadman River Formation (Chilcotin Group), Interior Plateau, British Columbia, Canada

Despite early interest in Neogene floras, primarily Miocene sites associated with Mio–Pliocene volcanic deposits of the Interior Plateau of British Columbia, few systematic accounts of the Miocene macrofloras of British Columbia – or elsewhere in non-Arctic Canada – have been published since the pioneering studies of J.W. Dawson and his contemporaries in the late 19th century. In this report, the Red Lake macroflora from sediments of the middle Miocene Deadman River Formation exposed in the Red Lake diatomite mine north of Kamloops, British Columbia, is illustrated, and a preliminary assessment presented, along with a brief review of Miocene floras from British Columbia and the U.S. Pacific Northwest. The Red Lake macroflora contains rare Ginkgo leaves, shoots of Cupressaceae (Cupressinocladus, Metasequoia, Taxodium) and shoots and seeds of Pinaceae (Pseudotsuga, Tsuga), maple (Acer) seeds and leaves, Liquidambar (fruit), Trochodendraceae (Zizyphoides auriculata leaves, Nordenskioeldia interglacialis fruits), leaves of 4 species of red and white oaks (Quercus columbiana, Q. prelobata, Q. pseudolyrata, Quercus sp.), leaves of an alder (Alnus harneyana) and birch (Betula thor), chestnut (Castanea spokanensis), beech (Fagus pacifica), sycamore (Platanus dissecta), elm (Ulmus speciosa), leaves of unidentified taxa, fruits of Tilia pedunculata (Malvaceae) and fruits and inflorescences of other unidentified taxa, and leaves of a reed or rush (indet. monocot). The Red Lake middle Miocene climate reconstructed from leaf physiognomy was temperate and mesic, with mean annual temperature ~11–13°C, mild winters (coldest month mean temperature ~3°C), mean annual precipitation 170 −51/+73 cm/yr, and growing season precipitation ~92 cm, with moderate seasonality of precipitation (three wettest months ~51 cm vs. three driest months ~25 cm). The Red Lake flora shows similarities to middle to late Miocene floras from the U.S. Pacific Northwest (i.e., richness in oaks) but is of much lower diversity and lacks key elements common to many of the contemporaneous U.S. Miocene floras (e.g., foliage of Pinaceae esp. Pinus), and is missing taxa detected in the microflora, a pattern likely due to sampling effectiveness at the Red Lake Mine and sampling of different lithofacies for macro- and microfloras.

The human imprint on the unique geological landscape of the Western Caucasus

Human intervention in the geological environment is commonly thought to pose a threat to geoheritage. However, new information from the Western Caucasus where unique geological features are concentrated in Mountainous Adygeya, implies that man-made features in fact add value to geoheritage. Such features include a lengthy artificial niche in the Guama Gorge, accumulations of large artificial clasts along the road leading to the Lagonaki Highland and the Khadzhokh Quarry with the artificial Red Lake. These contribute to the regional uniqueness of geosites and can be classified as geomorphological, sedimentary, economical and hydro(geo)logical geoheritage types. Interestingly, these artificial features have natural analogues in the study area. Such integrity of local geological landscapes urgently require special interpretations for guided excursions and explanatory panels for correct comprehension of the origin of these unique features on the part of unprepared tourists. Generally, the human imprint on geological landscapes of Mountainous Adygeya is significant and occasionally positive, which makes the entire geodiversity hotspot of special, international interest and an object for further investigations.

By the Hand of Angelos? Analytical Investigation of a Remarkable 15th Century Cretan Icon

A 15th century St Theodoros icon of outstanding quality is on display at the Zakynthos Ecclesiastical Art Museum. On the basis of certain stylistic characteristics, this icon has been attributed to the legendary Cretan painter Angelos Akotantos. In order to explore the latter attribution, the icon was subjected to examination via multispectral imaging, while microsamples were investigated through an optical microscope (OM), a scanning electron microscope coupled with an energy dispersive analyzer (SEM-EDX), μ-Raman and X-ray diffraction (XRD). The data were evaluated in the light of the findings of recent analytical studies conducted on several genuine Angelos icons. Identified materials include gypsum, gold leaf, bole, natural ultramarine, lead white, charcoal, green earth, red lake, minium, cinnabar, and red and yellow ochres. The identified materials resemble those employed by Angelos, while the identification of ultramarine is of particular significance, as this extremely expensive and rather rare pigment was very often used by the particular painter. Moreover, multispectral imaging reveals notable painting technique similarities between the icon in consideration and known Angelos icons, while cross sections of corresponding samples exhibit almost identical structures. Overall, the present work considerably strengthens the suggestion that the St Theodoros icon in consideration was painted by Angelos and also widens our knowledge regarding the late Byzantine painting.