Search results for "MBI"
showing 10 items of 15110 documents
Sr/Ca and Mg/Ca ratios of ontogenetically old, long-lived bivalve shells (Arctica islandica) and their function as paleotemperature proxies
2011
International audience; The Sr/Ca and Mg/Ca ratios of many biogenic skeletons provide useful paleotemperature estimates. As yet however, it has remained largely impossible to obtain such information from bivalve shells. In the present study, metal-to-calcium values in the hinge plate (aragonite, outer shell layer) of four ontogenetically old (85 to 374 year-old) specimens of the long-lived bivalve, Arctica islandica, were measured on a LA-ICP-MS. The shells were collected alive in 1868, 1986 and 2003 from three different localities around Iceland. With increasing ontogenetic age and decreasing growth rate, a distinct trend toward increasing Sr/Ca (max. 5.17 mmol/mol) and Mg/Ca values (max. …
Activity-composition relations for the calculation of partial melting equilibria in metabasic rocks
2020
A set of thermodynamic models is presented that, for the first time, allows partial melting equilibria to be calculated for metabasic rocks. The models consist of new activity–composition relations combined with end-member thermodynamic properties from the Holland & Powell dataset, version 6. They allow for forward modelling in the system Na (Formula presented.) O–CaO–K (Formula presented.) O–FeO–MgO–Al (Formula presented.) O (Formula presented.) –SiO (Formula presented.) –H (Formula presented.) O–TiO (Formula presented.) –Fe (Formula presented.) O (Formula presented.). In particular, new activity–composition relations are presented for silicate melt of broadly trondhjemitic–tonalitic compo…
Stage–Discharge Relationship for an Upstream Inclined Grid with Transversal Bars
2016
AbstractCheck dams with grids upgrading upstream are often used in mountain rivers, where intense sediment transport and steep slopes occur. In some cases, sloping grids are used in the construction of debris flow breakers. In this paper, the outflow process of an upstream-inclined grid with transversal bars is studied by using the dimensional analysis and the incomplete self-similarity theory. Next, the theoretical analysis shows that a power equation can be used for establishing the stage-discharge equation. The coefficient of the power equation depends on both the slope angle and the void ratio, whereas the exponent depends only on the slope angle. Finally, this deduced stage–discharge r…
Biological and microclimatic monitoring for conservation of cultural heritage: a case study at the De Rossi room of the Palatina library in Parma
2019
Biological particles in heritage-related indoor environments (museums, libraries, archives) represent a hazard to artifacts (biodeteriogenic action), operators and visitors’ health. The aim of the study was to evaluate environmental biological contamination and microclimate conditions in different periods of the year in De Rossi room of the historical Palatina Library in Parma. Microclimatic measurements were recorded continuously for a period ranging from 11 to 17 days in: January–February, May and September 2017. Monitoring of bacterial and fungal contamination was performed for air by active and passive sampling and by nitrocellulose membranes on shelves and manuscripts. Microorganisms w…
Un assemblage inhabituel d’insectivores au Miocène inférieur du Sud-Ouest de l’Europe : les talpidés et les dimylidés du bassin de Ribesalbes–Alcora …
2019
The Miocene record of talpids and dimylids in south-western Europe is very scarce. In the present work, we study for the first time the talpids and complete the description of the dimylids, already started with a new species of the genus Plesiodimylus from the Ribesalbes–Alcora Basin (MN4, lower Aragonian, early Miocene) by Crespo et al. (2018). The talpids recovered inRibesalbes–Alcora comprise themost common Desmanodon daamsi and Desmanella fejfari, for which the last known occurrence is recorded here. The dimylids comprise the species Plesiodimylus ilercavonicus, which expands the biostratigraphic record of the genus and species and has been found in a new site. On the other hand, we dis…
First discovery of orichalcum ingots from the remains of a 6th century BC shipwreck near Gela (Sicily) seabed
2017
Ingots recently recovered from the seabed near Gela, a major harbour of Sicily, reveal an unexpected side of ancient metallurgy. The ingots were found near remains of a ship and earthenware dated around the end of the VI century BC and probably coming from the eastern Mediterranean and the Aegean sea. The ingots were analysed by means of X-Ray Fluorescence spectroscopy via a portable spectrometer. Results indicate that they are mostly consist of copper and zinc although many of them have a significant amount of lead. This alloy is nowday called brass, but in ancient time it was know as orichalcum, one of the rarest and most precious alloy along with gold and silver. Only small items of oric…
New results in ancient Maya rituals researches: The study of human painted bones fragments from Calakmul archaeological site (Mexico)
2020
Abstract The funeral chambers of the ancient city of Calakmul (Mexico) and the individuals who were buried in them have brought in recent decades new knowledge about the beliefs and funeral customs of the pre-Hispanic Maya. Tombs and bodies were prepared as part of the rituals that should favor the return of ch'ulel to the Underworld, known as Xibalba by the ancient Maya. The ch'ulel is one of the two anemic entities that inhabit the individual, equivalent to our concept of the soul. Bodies preparation included coloured scented body ointments application, with a deep symbolic connotation and probably also a conservative purpose. The aim of this research was to characterize pigments and bind…
The production of traditional building materials in Oristano (Sardinia, Italy)
2016
The study of ceramic-making communities which employ traditional practices can provide insights into the raw materials and techniques used over the centuries in a particular territory. The archaeometric study of ceramic products and of the raw materials used in their production is an effective complement to the existing ethnographic information. This paper focuses on the brick and tile making tradition of Oristano, a town in Central-Western Sardinia (Italy). Applying a combination of techniques, it includes an extensive analysis of traditional handmade and early industrial bricks and tiles, and a study of the local clays that may have been used as raw materials. Although we were unable to s…
Consolidation of earthen building materials: a comparative study
2019
The consolidation and protection of mud bricks are a challenge in the field of conservation of archeological sites. One of the solutions is represented by the coverage of the entire excavation that assures a protection against mud dissolution. Unfortunately, this is not always feasible, both for economical and practical issues. For these reasons, alternative solutions are needed. In this work, laboratory experimentation has been carried out in order to test the efficacy of some products to slow down the dissolution process and increase the brick toughness. Three typologies of raw materials taken from different outcrops (one from the Republic of Azerbaijan and two from Calabria region, Italy…
Climbing into the past—first Himalayan mummies discovered in Nepal
2003
In a cave system in Mebrak (Mustang District, Western Nepal), a team of archaeologists investigating extensive abandoned settlements in the high Himalayas made an extraordinary discovery in 1995. One of the caves had been used as a community burial chamber from ca. 400 BC to 50 AD. Inside, approximately 30 naturally mummified bodies rested in bed-like wooden coffins exhibiting ornamental carving and elaborate painting. The dead had been furnished with a rich store of grave goods consisting of both personal ornaments and objects of daily life as well as the remains of domestic animals. Due to the favourable climatic conditions, all of the artefacts, which also include fur and textile garment…