Ancient Mining Sites Research Articles

Structural and functional diversity of microbial communities in ancient mining sites from San Luis Potosí, México

AbstractThe purpose of this study was to evaluate the effects of potentially toxic elements (PTEs) on soil microbial community functionality and structure. Charcas and Cedral in San Luis Potosí, Mexico, are sites with ancient mining activity. This activity has generated heavy metals (HMs) polluted soils that provoke deleterious effects on microbial community. Sampling was conducted in sites with and without aged mining activity. The parameters analysed were physicochemical properties and PTE concentrations. Functional diversity was evaluated with a community‐level physiological profiling (CLPP) analysis, diversity was evaluated using the richness (S), and the indices of Shannon's diversity (H), Simpson's dominance (D) and Pielou's evenness (J) were for the structure evaluation, based on relative substrate utilisation. CLPP results of set of soils indicated the following substrate utilisation pattern: carbohydrates > polymers (POL) > carboxylic/ketonic acids > amino acids (AmA) > amine/amides (A/A). In Cedral, the AmA utilisation favoured the increase of J value. In addition, it was observed that the utilisation of these compounds decreases at a higher concentration of Al and organic matter (OM) but increases at a higher concentration of Cu, Pb, Zn, Fe, Mn, and Ni, a phenomenon opposite to that was observed in Charcas. The results of set of soil indicated that AmA utilisation increases the values of S, J, D, and H. These results indicate that the microorganisms in soil are resistant to high PTE concentrations, in that condition they need accessible carbon sources as energy and as nutrients, however, they adapted to use complex carbon sources (POL). Furthermore, it presented low OM mineralisation despite high values of H, or J, then some metabolic processes could be compromised. Therefore, an intervention for soil conservation and monitoring is required.

Trace metals dispersion from 1000 years of mining activity in the northern French Alps

This paper investigates the long-term dispersal of trace metals and their impact on the environment long after mine closure in the French Alps. Three statistical methods derived from modern mining (Exploratory Data Analysis, fractals and Sediment Quality Index) were applied to geochemical analyses of streambed sediments to produce mineral prospectivity maps. About 5% of the samples have a poor or marginal quality and may have an effect on biota. Positive anomalies are either related to the geological background (lithology, major tectonic contacts) or to ancient mining sites. The local impact of former mining was investigated on a medieval Pb–Ag district (Brandes; Pbmax ~8 000 mg kg−1), a small district mined during the 17th–19th c. (Peisey-Nancroix; Pbmax = 583 mg kg−1), and a major modern Pb–Ag mine (Macôt-La Plagne; Pbmax ~ 3 200 mg kg−1).The mining heritage is still traceable in the northern French Alps. The anomalies observed at local scale are related to the volume of extracted ore rather than to the timing and duration of mining, suggesting that old mining sites still release trace metals over centuries and up to a thousand years. The statistical methods used provide a strong tool for archaeological prospection and environmental studies.

Trace-Element Distribution on Sulfide Mineralization in Trento Province, NE Italy

Sulfide mineralization in the province of Trento (northeastern Italy) includes various mineral assemblages that are often silver-rich and have been exploited in different phases from the Middle Ages until the 20th century. This study investigates mineralized rocks from three historically important sites (Calisio mount, Erdemolo lake, and the locality of Cinque Valli), providing new analytical data (Inductively Coupled Plasma-Mass Spectrometry on bulk rocks, and Scanning Electron Microscopy on thin sections) that demonstrate that parageneses do not only include galena, chalcopyrite, and sphalerite but also accessory minerals, such as tetrahedrite, tennantite, acanthite, and sulfosalts (matildite/polybasite). This explains the high content of As (up to 278 ppm), Bi (up to 176 ppm), and Sb (up to 691 ppm) that are associated with Pb–Cu–Zn mineralization. Notably, trace-element ratios indicate that, although closely associated from a geographical point of view, the studied sites are not genetically related and have to be referred to in distinct mineralization events, possibly induced by three diverse magmatic and hydrothermal phases that occurred in the Variscan post-orogenic setting. Besides geological and petrogenetic reconstruction, the new data outline potential geochemical risks, as they reveal a high concentration of elements characterized by marked toxicity that can be transferred into the local soil and water. Therefore, future studies should be devoted to better investigating the metal distribution in the surroundings of ancient mining sites and their geochemical behavior during the weathering processes.

Comparison of mercury distribution and mobility in soils affected by anthropogenic pollution around chloralkali plants and ancient mining sites

A comparative study of total mercury, elemental mercury and mercury fractionation has been performed on particle-size fractions of soils affected by anthropogenic sources of different origins, namely two former chloralkali plants (CAPs) and two historical cinnabar mine sites in Spain. A specifically developed sequential extraction procedure was applied in order to evaluate mercury fractionation, including Labile mercury (F1), mercury bound to humic and fulvic acids (F2), elemental mercury and mercury bound to crystalline iron oxides (F3), and mercury bound to sulfide and refractory species (F4). Markedly higher total mercury concentration were found in ancient mining soils (AMS), with concentration values ranging from 18.6 to 1509 μg·g−1, whereas soils from CAPs exhibited lower total Hg concentrations (1.7–61.6 μg·g−1). Hg(0) was not detected in AMS samples and this indicates the absence of this species in the studied areas. In contrast, very low Hg(0) concentration were found in CAP soils as a consequence of the intense interaction of gaseous Hg deposited along with soil matrix compounds. Sequential extraction analyses revealed different fractionation patterns for both kinds of studied soils: AMS exhibited a clear predominance of Hg bound to sulfide in all particle-size subsamples whereas soils from CAPs mainly contained elemental Hg and Hg bound to crystalline iron oxides in the coarser subsamples. Conversely, Hg bound to sulfide was the major fraction in the finest soils. In summary, the results of the present study indicate a high level of Hg immobilization in CAP soils because of the interaction with soil phases and the prevalence of highly refractory cinnabar in AMS samples. Finally, it is necessary to highlight that, in some cases, compounds with higher reactivity can lead to a lower toxification risk if differences in concentrations are sufficiently marked, as detected in CAPs with respect to AMS.

Trace metals from historical mining sites and past metallurgical activity remain bioavailable to wildlife today

Throughout history, ancient human societies exploited mineral resources all over the world, even in areas that are now protected and considered to be relatively pristine. Here, we show that past mining still has an impact on wildlife in some French protected areas. We measured cadmium, copper, lead, and zinc concentrations in topsoils and wood mouse kidneys from sites located in the Cévennes and the Morvan. The maximum levels of metals in these topsoils are one or two orders of magnitude greater than their commonly reported mean values in European topsoils. The transfer to biota was effective, as the lead concentration (and to a lesser extent, cadmium) in wood mouse kidneys increased with soil concentration, unlike copper and zinc, providing direct evidence that lead emitted in the environment several centuries ago is still bioavailable to free-ranging mammals. The negative correlation between kidney lead concentration and animal body condition suggests that historical mining activity may continue to play a role in the complex relationships between trace metal pollution and body indices. Ancient mining sites could therefore be used to assess the long-term fate of trace metals in soils and the subsequent risks to human health and the environment.

Turquoise Mine and Artefact Correlation for Some Bronze Age Archaeological Sites in Hubei Province, China

In China, there are places that are rich in gem-quality turquoise resources, including north-west Hubei Province and the nearby Baihe County in Shaanxi Province, and many ancient mining sites, although the mining history remains a mystery. Based on the compositional data from reference samples of known deposits, a comparison of the major and trace element contents of archaeological turquoise may help with determination of artefact provenance. This paper discusses new evidence of provenance-tracking of turquoise in this area, obtained from geochemical analyses using REE and other trace elements of 22 turquoises and their surrounding rock samples from six ancient mines and three archaeological sites. The results indicate that the three archaeological turquoises from the tomb of the Middle Spring and Autumn Period (580–560 bc) and the Warring States Period (476–221 bc) in Hubei Province were made of raw material from north-west Hubei Province and the nearby Baihe County in Shaanxi Province. [Correction added on 29 October 2014, after first online publication: In the preceding sentence, the correct dates for the Middle Spring and Autumn Period, and the Warring States Period have been added]

Tracking archaeological and historical mines using mineral prospectivity mapping

The present study proposes a technological transfer from modern mining prospection to the field of archaeology, providing a methodology to facilitate the discovery of ancient mining sites. This method takes advantage of the thousands of geochemical analyses of streambed sediments, performed by national geological surveys to inventory mineral substances. In order to delineate geochemical anomalies, the datasets are treated following two different approaches: Exploratory Data Analysis and a fractal-based method often recognised as more powerful. Mineral prospectivity maps are then obtained by combining the results with a geographical information system. The surroundings of the Celtic oppidum of Bibracte, French Massif Central, known to have been mined at least since the Late Bronze Age until Modern Times, have been chosen to exemplify the method's potential in archaeology. First, an exhaustive record of the mining sites was undertaken over a pilot area by pedestrian prospection. If mineral prospectivity maps had been used as guidelines, ∼70% of these mines would have been discovered by prospecting only ∼15–20% of the whole area whatever the method used to treat the dataset. At least for our specific case, the multifractal approach is as powerful as EDA. Besides saving a significant amount of time and effort, the methods described here may supply clues for determining the nature of mineral substances exploited in the past, when such information cannot be straightforwardly obtained from the field or from textual archives. It should however be noticed that this approach is proposed as a first step before peer archaeological investigation following more conventional methods. Technically, there is no real obstacle to the application of the methodology proposed here, because (i) software and associated packages are freely available from the web, as well as original geochemical datasets (at least in France), and (ii) minimal mathematical skills are required.

Factors that influence mercury concentrations in nestling Eagle Owls (Bubo bubo)

Mercury (Hg) is a global pollutant that bioaccumulates and biomagnifies in food chains, and is associated with adverse effects in both humans and wildlife. The Hg levels detected in blood obtained from Eagle Owl (Bubo bubo) chicks in Southeast Spain (Murcia) can be considered low (mean Hg concentration in blood from 2006 to 2012 was 36.83±145.58μg/l wet weigh, n=600), and it is therefore unlikely that Hg pollution can negatively affect their breeding. Positive correlation (r=0.339, p<0.001, n=229) was found to exist between the Hg concentrations in the blood and back feathers of the chicks. We provide a regression equation that could be helpful to estimate blood Hg levels when analyzing Hg concentrations in back feathers. Blood Hg concentrations in Eagle Owls have shown positive correlations with Hg levels in rabbit muscles, more evident in nests from the Northern area (r=0.600, p=0.014, n=16), where rabbits are the main prey of Eagle Owls. The best Linear Mixed Model to explain variations in blood Hg concentrations in nestling Eagle Owls includes year and location within the mining area as variables. The variable year is assigned the largest value of relative importance, followed by the location in the ancient mining sites and then the zone. Rainfalls may have an effect on the temporal differences in the blood Hg concentrations of nestling Eagle Owls. Although the studied region is not considered Hg polluted, the Hg levels were higher in Eagle Owls and European Rabbits from areas within the ancient mining sites as compared to those in the entire region. This result shows that spatial differences in Hg concentrations in Eagle Owls may be affected by local contamination, and that the role of diet composition may be less significant.

Raman spectroscopic and SEM study of cinnabar from Herod's palace and its likely origin

Mineral samples of cinnabar were obtained from the ancient mining sites of Tarna and Almaden in Spain and from Hunan province in China. A comparison is made using a combination of scanning electron microscopy and Raman spectroscopy with the cinnabar coated on the wall of Herod's palace. Scanning electron microscopy shows that the cinnabar samples from Spain were impure, whereas the sample from the wall of Herod's palace was highly pure. No conclusion can be drawn as to the likely origin of the Herod's palace cinnabar and the mineral is just as likely to have originated in Tuscany or China as Spain.

Ancient quarries

Using a unique set of remote sensing techniques, a team of University of Colorado researchers has detected mining pits dug by Montana Indians 10,000 years ago. The team used satellite images, aerial photographs, and ground tests to locate quarries where ancient North Americans obtained chert for making tools.Anthropology doctoral student Thomas Carr, Mort Turner, of the University of Colorado's Institute of Arctic and Alpine Research, and four undergraduate and graduate students developed 12 “spectral classes” characterizing distinct geologic and vegetation types found in the Horse Prairie Valley study area in southwest Montana. Their data included electromagnetic measurements of soil conductivity from a known Indian quarry in the area, where the altered bedrock contains veins of chert, and an adjacent area of disturbed soil. Using special computer software, the team compared characteristics of nearly one million 30‐m2 pixels from a 1985 regional Landsat satellite image to those of the 12 spectral classes. Twelve possible ancient mining sites in the 800‐square‐mile research area were identified. During a later ground survey using GPS satellite receivers, eight of these were confirmed to be ancient Indian quarries.

STATISTICAL EVALUATION OF THE PRESENTLY ACCUMULATED LEAD ISOTOPE DATA FROM ANATOLIA AND SURROUNDING REGIONS

Several hundred new stable lead isotope ratio determinations of ore and slag specimens from ancient mining sites throughout Anatolia and of samples of artefacts of the Chalcolithic, Bronze Age and Early Iron Age from museum collections in Turkey and the United States have been combined with the accumulated published isotope determinations of such specimens from throughout the eastern Mediterranean and Aegean regions to form a data base of nearly 1000 analyses. It is the purpose of this paper to evaluate the practical effectiveness of using this now extensive data base to discriminate between the many sources of metals throughout this region and to propose methods to enhance this discrimination. By using the full three‐dimensional isotopic data in multivariate statistical treatments and by separating isotopically resolvable source groups within some of the source areas and isolating statistically outlying specimens from them, it has been possible to characterize some ore sources more precisely and compactly and thereby achieve better resolution between ore sources. It has also been possible to isolate isotopically compatible artefact groups which possibly relate to ore sources that, as yet, have not been well defined by isotopic analysis.

Stable lead isotope studies of central taurus ore sources and related artifacts from eastern mediterranean chalcolithic and bronze age sites

This is the first paper in a series presenting stable lead isotope studies of geological and archaelogical specimens obtained in 7 years of archaeometallurgical surveys in Turkey. The geological specimens presented here are ore and slag samples taken from ancient mining sites in the Central Taurus mountain range. The archaelogical specimens are metal objects, dating to the Chalcolithic and Bronze Ages, from Anatolia, Syria, Mesopotamia, Greece and the Aegean. The isotopic measurements on these specimens have been made and statistically analysed as part of a collaborative effort between the Smithsonian Institution Conservation Analytical Laboratory and the United States National Institute of Standards and Technology (NIST). A comprehensive data base of approximately 1000 stable lead isotope measurements on such Eastern Mediterranean specimens has been formed by combining the accumulated measurements at NIST with analyses published in the literature. The overlap between specimens in the overall data bank and the Central Taurus source specimens provides a realistic evaluations of the effectiveness of the use of stable lead isotope measurements for metallic ore source characterization and for the recognition of exchange patterns of metal and metal artifacts in the formative periods of metallurgy.

Ancient gold mines on Thasos

Ancient gold mines on Thasos