Marble Monuments Research Articles

Oxalate patinas on ancient monuments: the biological hypothesis

Whewellite and weddellite, calcium oxalate monohydrate and dihydrate respectively, have been found in the form of thin surface layers on limestone and marble monuments and artifacts of various historical periods at different sites. Experimental results indicate that the formation of both minerals must be attributed essentially to the action of oxalic acid secreted by microorganisms (lichens) which live and proliferate on the stone. Oxalic acid attacks the calcium carbonate of the stone surface giving rise to the precipitation of calcium oxalate.

Acidic Deposition and Marble Monuments at Gettysburg National Military Park

Acidic Deposition and Marble Monuments at Gettysburg National Military Park

Deterioration of limestone walls in Jerusalem and marble monuments in Rome caused by cyanobacteria and cyanophilous lichens

Hard limestone walls in Jerusalem and marble monuments in Rome were studied. An attempt was made to classify the principal biodeterioration processes in walls facing the prevailing wind and those which were protected from it. In Jerusalem, those that face the prevailing rain-bearing wind become populated by cyanobacteria and cyanophilous lichens. Within c. 100 years white walls are turned to grey or black colour by these organisms. Rain detaches rock particles from the vicinity of the microorganisms at a rate of 1 mm in 200 years. Dark patches on marble monuments in Rome indicate the presence of cyanobacteria. Such biological activity promotes detachment of particles by rain and accelerates weathering leading to pit formation. The estimated rate of pitting is 1 mm per 40 years in the Forum Traianum. To prevent the biodeterioration of limestone and marble monuments the habitats and ecological demands of the various microorganisms must be considered.

Acidity gradients in the kipda region

Acid precipitation leaves fingerprints upon marble surfaces. Preserved in weathering crusts on dated monuments, these fingerprints serve as guides to identify levels of acidity of a region. We collected scrapings from protected surfaces of tombstones made of Georgia marble whose dates of installation could be determined with reasonable certainty. These scrapings were allowed to equilibrate in 100 ml of deionized water, and the solutions were analyzed for, among other species, sulfates and nitrates. In Louisville, it was found that sulfate is present on tombstones that had been installed as late as 1985. However, to the east, 25 miles away, 1967 is the date of the latest monument with sulfate. An acidity map was produced showing time contours, in other words, the time needed to produce discernible quantities of sulfate. This map reveals that the effect of SO2 on marble diminishes rapidly with increased distance away from the western Louisville industrial area. The use of marble monuments to monitor changes in the acid deposition patterns is suggested.

Microbial calcification of gypsum-rock and sulfated marble

A broth containing the sulfate reducing bacterium Desulfovibrio desulfuricans was used to treat samples of reagent calcium sulfate, gypsum-rock specimens, fragments from a marble monument with a black weathering crust rich in gypsum, and a marble monument with similar crust. Calcite was found to have formed on all treated surfaces suggesting that this microbe has the potential to clean crusted marble monuments whilst also regenerating calcite, the parent mineral of the marble.

Measuring stone weathering in cities: Surface reduction on marble monuments

The purpose of this study was to establish whether measurements of stone weathering recorded by different observers could be aggregated into a single data base for evaluating pollution effects on calcareous building stone. Apparent differences in recorded weathering rates on marble tombstones were here found to be partly a result of lettering size measured, measuring devices used, and individual observers.

The pH of the atmospheric precipitation in Venice, related to both the dynamics of precipitation events and the weathering of monuments

The pH of precipitation in Venice during the 1960s appears to have been slightly above the level of uncontaminated rainfall and very high compared with data generally found in the literature for the rest of Italy and Europe in general. On the contrary, from observations of the weathering of marble monuments in Venice, one would expect aggressive precipitation, i.e. that characterized by lower pH levels. However, the pH level is recognized as an inadequate index for the aggressivity of precipitation and the stone deterioration appears to be closely related to the way rainfall wets the surface of the monuments and activates the dry deposition occurring between two precipitation events. Only rarely does it seem to be due to acid rainfall. On the basis of local dynamic climatology, an analysis has been carried out of present and past data and of the possible hypotheses leading to these unusual values. The analysis indicates some interesting situations as being responsible for many precipitation events and also for a high correlation with wind direction. Particularly interesting is the frontal situation originated aloft by a warm, moist wind (i.e. Scirocco) passing over the Alps and a cold wind below from Dalmatia (i.e. Bora). This situation favours heavy rainfall which is relatively uncontaminated by anthropogenic emissions, but is contaminated, on the other hand, by Saharian dust. From laboratory tests this dust was found to be capable of neutralizing the free acidity in rain. Precipitation events associated with NE wind are very frequent, as shown by the precipitation roses. Therefore, in Venice and its hinterland, precipitation dynamics is often associated with the meeting of air masses which are relatively uncontaminated by anthropogenic activity. The presence of buffering agents, both natural (i.e. Saharian dust, soil particles) and anthropogenic (i.e. agricultural fertilizers) are the main causes of precipitation, with high pH levels in the whole of the region subjected to Bora-type inflows, unlike the rest of the territory, as present measurements appear to confirm.

On Native Ground, and: The Bee Woman, and: Family Reunion, and: Myles Horton Tells The Brier Story, and: The Brier Plans a Mountain Vision Center

^= On Native Ground =J2^_ This wind is blowing me all time's weathers, mingling near and far, pennyrile and woodsmoke, crow's call and carrion. In a jay's harangue saws are singing; the swung ax flashes in a lifting wave;4 twanging still in a white-faced hornet's whine a barbed-wire fence caught in a cuffonce crossing. Seed fallen in flesh rich as woodsdirt, gone days spring up, trees from sown sweat. Now is this green tree's growing bark, this always was and is and forever tree-shading summer was and is and summer will be. A waterbead quivers on my hand: there is a way to enter. Underfoot a mole's nightwork gives way—O doors are everywhere: the spring at the mountain's foot holds the running taste ofchildhood, the barking fox blurts the mountain's riddle. Transparent minnows hanging in green water: windows onto sunken summer days. I enter through a fish's eye to one vast room glowing in cold light. Out of an oilspill on a rainslick road campfires ofa hundred hunts are blazing. A dog's eye caught in headlights on a turn: rose windows warm in his cathedral skull. I travel everywhere on native ground; roads turning into darkness turn me home, plunge me into cool air ofthe mountains. Gray marble monuments bending in a graveyard, \(Q skewed reflections swaying on rolled water, VH 37 straighten to still gray chestnut stumps, a chimney stack among old trees and roses sprawling over tumbled corner stones sprouting second growth. A new house rises. Life grows in rings around a hurt, a tree with barbed wire running through its heart. The Bee Woman She carried the eggs in her straw hat and never reached into a nest with her bare hand. A woman who could conjure warts, who knew charms for drawing fire, spells to make butter come, and mysteries ofbees and hummingbirds, besides, knew to roll eggs from a guinea's nest with a gooseneck hoe. There is a mountain cove and light is leaving. Speckled guineas fly to roose in trees, their potterick and screech drifts far away, becomes the faintest peeping in my dream ofstifling afternoons when we would stand, the old woman and I, by fencerows and cowtrails listening for half-wild guineas screeching as they came off nests they'd stolen away in thickets, briers, scrub pines, and chinquapins. And no matter where I wake—horn's beep, ship's bells, clatter ofgarbage cans, strange tongues spoken on the street below, in a rising falling bunk out at sea,— everywhere I stand on native ground. The bee woman may pass through my dream: running under a cloud ofswarming bees, she beats an empty pie pan with a spoon till the swarm settles, black on a drooping pine bough and guineas regroup pottericking—all moving toward waking's waterfall. Family Reunion Sunlight glints off the chrome of many cars. Cousins chatter like a flock ofguineas. 38 In the shade ofoaks and maples six tables stand filled with good things to eat. Only the jars oficed tea sweat. Here the living and dead mingle like sun and shadow under old trees. For the dead have come too, those dark, stern departed who pose all year in oval picture frames. They are looking out ofthe eyes ofchildren, young sprouts whose laughter blooms fresh as the new flowers in the graveyard. Myles Horton Tells The Brier Story When Bill Moyers came to Highlander Center and interviewed Myles Horton for his Journal (Adventures ofa Radical Hillbilly—in two parts), Myles had to be made up for the cameras. Moyers had hired a local make-up girl, and while she worked, Horton told Moyers all about the history ofthe mountains, where the people came from, all they'd been through, how Appalachia for a hundred years had been the country's guinea pig. Later, when just the two ofthem were together, the make-up girl blurted out to Myles (it turned out she was from up around Lafollette, or Jellico, Tennessee—in that area), just blurted out, and she was close to tears: "That was wonderful—wonderful what you told Some ofthose...

The future of Ancient Rome

Every year, on the traditional anniversary of the founding of Rome, the Mayor reviews the events of the last twelve months and outlines his plans for the future. Last year (the 2,735th anniversary), he began by describing work in progress on conservation and mise-en-valeur in the ancient city. It was wholly appropriate, for the future of classical Rome is a subject which concerns, or should concern, not only the Romans themselves, but all Italian taxpayers (who will foot the bill), town planners and conservation groups throughout Europe—not to mention all readers of ANTIQUITY. The proposals, promoted by the Archaeological Superintendent of Rome, Professor Adriano La Regina, include the creation of an archaeological park extending from the Capitoline to the Appian Way, new museums and—as a matter of extreme urgency—the protection of marble monuments disfigured by pollution. The plans involve both local and national authorities, and in March 1981 Parliament made available over a five-year period the staggering sum of 180,000 million lire (£75 m): 168,000 m for Rome itself, 10,000 m for South Etruria (the area north of Rome) and 2,000 m for Ostia.

THE CONSERVATION OF MARBLE MONUMENTS IN CHURCHES

The processes of deterioration of marble monuments in churches are described together with methods for protecting the monuments from the ambient environment. Methods of cleaning, either in situ or in a laboratory are explained. The use of dowels and resins in repair and reconstruction are dealt with and amplified in a report of work on one monument.