Cochise College Student Papers in Geology

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Roger Weller, geology instructor regional geology planetary gems

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Rome and Geology
Elizabeth Stokes
Historical Geology
Spring 2008
Geology in Roman History

Although Roman myth fails to address the creation of the world, the creation of Rome itself is described in many different ways. The three most prevalent creation myths are those of the brothers Remus and Romulus, Virgil’s tale of Aeneas, and the legends of the first Seven Kings. In each tale, one or more protagonists commit violent acts to ensure the creation of Rome.

The geologic story of Rome’s creation is also violent, though the protagonist in this story is not an Epic hero, but an earthen one—plate tectonics.

Two hundred million years ago, as Pangaea ripped itself apart, young ocean floors, still buoyant with warm mantle rock, pushed the waters of the new Atlantic Ocean and the tropical Tethys sea over two-thirds of today’s landmasses (Stewart 41). The presence of shallow shelf seas resulted in thick sedimentary deposits that would later be tectonically resurrected as the Mediterranean landscape. The catalyst for this process was the northward motion of Africa.

Free from its ties to South America, Africa and a host of micro continental minions lurched towards Europe. As it did so, pieces of the continent tore off and joined the growing European plate. The Caucus Mountains, Northern Greece, and parts of Turkey and Iran were formed during this period.

Chunks of seafloor were trapped and metamorphosed between colliding landmasses to form the oil deposits in the Middle East, mountain ranges in Lebanon, and renowned marble deposits in Italy. Enormous mountain ranges were thrust up along the southern edge of the European continent as Africa continued to plough its way north. These mountain ranges would later crumble and collapse, forming the various basins of the Mediterranean sea.

Geological Map of Italy prepared by APAT in 2004.

http://www.apat.gov.it/site/_images/progetto_1250_ingl.jpg

Italy can be roughly divided into eight geographic sections; the Alpine Slope, The Po Valley or North Italian Plain, The Adriatic Plain, the Appine Mountains, Apulia and southeastern Plains, the Western uplands and plains, and the islands of Sicily and Sardinia. The northernmost alps provided Italy with a natural protective barrier. The broad plains of Italy supported agriculture with their fertile soil and temperate climate. The Po and Tiber were both controlled by dikes and levees, though they did not flood frequently.

Rome was located on the Tiber River, on the plain of Latium, surrounded by the famous seven hills. When development of the Roman Empire began to accelerate, the city of Rome could no longer be agriculturally self-sufficient. North Africa and parts of the Italian peninsula became Rome’s granary. Romans began to clear more land for agriculture in the Po valley and throughout Italy. This was an open invitation for erosion to sweep Italy’s fertile soil down the rivers and into costal beach formations.

This forced some port cities out of existence as the marshy delta shores were pushed further out to sea. Both Ostia, the sea-trade outlet for Rome, and Luni, the provider of Rome’s’ exquisite Carraran marble, were virtually abandoned by 500 A.D. By that time, most of Italy’s costal plains had become stagnant, disease-ridden swamps. Malaria became endemic in these areas. The Roman capital was relocated to Ravenna, on the edge of the Po delta, in 402 A.D. in an attempt to escape the malarial marshes that had overtaken Rome and Ostia (Stewart 189).

Location of the restless caldera volcano, Campi Flegri, at Pozzuoli just west of Naples (Napoli).
The impacts of the 79 A.D. eruption of Mt. Vesuvius are shown,
as modified from Fig. 4-3 of J. Boer and D. Saunders, 2002, Volcanoes in Human History. William Hutton 2007.

Italy’s volcanic activity was an influential geologic factor on Rome’s history. In the first century A.D., the cities of Pompeii and Herculaneum were buried by Mt. Vesuvius’ colossal eruption. However, within just a few years, farmers were once again colonizing the volcano’s fertile slopes (Stewart 204). Although the burial of Pompeii was devastating at the time, its subsequent rediscovery has provided tremendous insight into Roman society. Though the volcano remains active, its surrounding area is home to more than 3 million Italians and their agricultural enterprises.

The Campi Flegri, to Vesuvius’ West, may pose a larger threat. Romans believed it was the entrance to Hades. The crater was the site of a massive explosion over 35,000 years ago that spewed more that 200 cubic kilometers of magma onto Earth’s surface. Another eruption in the 8^th century BC gave the Romans a large supply of volcanic tuff, which they used to make pozzolanic cement (Stewart 204). These violent eruptions formed the modern bay at Naples. Campi Flegri’s explosive potential is not its only frightening characteristic.

Near Campi Flegri lies Solfatara, an earthen pressure valve from which toxic fumes are liberated from the earth via groundwater and released into the atmosphere as gas. If the Campi Flegri erupted, it could shake Solfatara and release huge amounts of sulfurous gas into the atmosphere. Such an event, called a dry fog, has severe climactic implications. “These lingering veils of sulphuric acid vapor partially block out sunshine and disrupt weather systems. . . . The cooling that often follows eruptions can result in widespread crop failure . . . widespread famine, then epidemics and possibly pandemics of plague” (Stewart 202). This type of event has happened before in Italy’s geologic history, and it will likely happen again.

Polished Marble – Swirl Pattern. R Weller/Cochise College

Most of us tend to think marble when we imagine Rome; tall, gleaming white buildings, ornamental carvings, and elaborately sculpted fountains. Romans created truly spectacular art and architecture using their native marble deposits. Limestone deposits dating from Tethys’ reign were baked and squeezed as Italy attached itself to Eurasia and during subsequent tectonic events. The heat and pressure exerted on these limestone beds caused them to metamorphose into some of the highest-quality marble in the region. The mines at Carrara are particularly renowned for their pure, snowy marble. W.P. Jarvis describes one of the stunning marble formations at Carrara:

“Two spurs descend from Monte Sagro towards Carrara, suddenly terminating in the slopes above Torano; they enclose a deep narrow ravine . . . The steep sides of this precipitous valley are entirely composed of white marble, and are quarried in their whole extent, according to the caprice of the respective proprietors, who mine here and there, as they consider the quality of the marble likely to be best. This is the valley whence most of the Carrara statuary marble is obtained the names of the principle quarries producing it being in order as follows:– Crestola, Cavetta, Zampone, Poggio Silvestro, Betogli, Mossa, and Polvaccio” (Jervis 3).

Each of the mines mentioned by Jervis produces a unique marble. Some produce pure, white, and easily sculpted marbles, while others produce brilliantly colored or conglomerate marbles. The marble Polvaccio is famous for its use by great sculptors. It’s tight crystalline structure makes Polvaccian marble ideal for sculpture because it can be chisled from almost any angle. Sculptors attribute great value to the natural inclinations of a particular piece of marble. Michelangelo believed he was sculpting forms already inherent in the marble. His chisel was the medium for the marbles’ self-expression, not his own. Due to their high quality, the deposits at Carrara have been mined since Etruscan times for use in sculpture and, most importantly, architecture.

Rome’s architectural achievements remain the most obvious legacy of the empire. They were pioneers in the construction of urban infrastructures such as roads, sewage, and mass entertainment. Buildings like the Pantheon and the Coliseum stand today as testaments to the Romans’ architectural prowess. Roman architecture is more commonly referred to as Greco-Roman due to its prevalent Greek influence. Though the Romans borrowed forms such as Corinthian columns from the Greeks, they utilized marble in revolutionary ways. Moreover, the Romans were the first people to use concrete on a massive scale.

Roman Marble Vase. Photo by Peter John Gates.

As Iain Stewart aptly observes, “the marble splendor of the Roman world is, literally, a façade. . . . the marble is only skin deep” (87). Most marble buildings were, in fact, concrete buildings faced with carved marble cover-stones. Romans created their concrete by mixing ground-up, compacted volcanic ash, or tuff, with dry lime. The silica and aluminum in the two materials combined to form a tough cement, called pozzolanic cement, that could set in water (Stewart 91-93).

The Romans used this cement to build stone harbors, aqueducts, roads, and the cores of large buildings. Buildings like the Coliseum would have been too heavy to support themselves if they had been constructed with solid marble. Walls were instead cast in pozzolanic cement. In different types of construction, triangular or pyramidal blocks would be inserted into the wet cement in order to support the walls. For larger, civic projects, marble cover-stones, sculpted in advance, were affixed to the concrete structure. This made large projects viable; both in terms of logistical engineering and aesthetic appeal.

However, before the marble could be used in construction, it had to be extracted from the ground. Roman mines were notoriously horrible; both for its workers and for the environments in which they operated. Ice cores from Greenland’s immense glaciers reveal that Roman mines affected more than their immediate vicinity; lead concentrations in the ice are almost non-existent in pre-Mesopotamian times. However, they reach an unprecedented concentration during the first centuries before and after Christ. During this period of time, Rome reached their peak in mining and produced over 100,000 tons of lead per year.

This toxic rock was thrust into the atmosphere by mining, construction, and production. More importantly, Romans used it for almost every imaginable purpose. This included cookware, plumbing, jewelry, paint, ornamentation, and a variety of uses. The Roman’s fondness for lead had been partially blamed for the collapse of the Empire. Is it merely coincidence that the empire began to decay and collapse during the same period that lead concentrations in the Greenland ice deposits reached their pre-industrial peak?

The most obvious source of contamination is the pipes Romans used to bring water from into the city: “lead (plumbum) was ideal for the production of water pipes, which were fabricated by plumbarii (plumbers) from fitted rolled sheets” (Grout). But since these pipes were buried in the limestone rocks around Rome, they would have accumulated calcium carbonate deposits. These deposits would have protected the water from contamination. Additionally, the water rushed through these pipes too quickly to pick up dangerous amounts of lead.

Lead, however, is a cumulative poison. Though a single low dose may be harmless, repeated exposure will eventually take its toll. Probably the strongest argument for lead poisoning involves the Romans’ love of food and drink. Sapa was a preservative syrup made by boiling unfermented grape juice to reduce its volume and enhance its sweetness. Sapa was used to preserve fruits, as a cooking additive, and, most importantly, it was added to wine to prevent it from turning into vinegar and enhance its fruity flavor. The problem with sapa was not its use, nor its composition, but it’s preparation.

Native lead sheet partially covering an actinolite schist.

David Barthelmy 2005. Mineralogy Database.

Sapa was generally boiled in copper vessels, but certain connoisseurs suggested that “the vessels . . . should be of lead rather than of brass; for, in the boiling, brazen vessels throw off copper-rust and spoil the flavour of the preservative” (Columella qtd. in Grout). The grape juice, or must, was usually reduced to one-half or one-third of its original volume. If it was reduced in a lead vessel, it would likely contain about 1000 milligrams of lead per liter. The sapa would be mixed with wine for a proportion of one part in 48, resulting in roughly twenty-one milligrams of lead per liter (Grout). This would certainly have been enough to poison the Romans.

At the beginning of the Common Era, the Roman aristocracy began to have problems with infertility. This could have been a symptom of lead poisoning. The upper echelon of Roman society began to shrink with each generation. The emperors of this period also seemed to become increasingly unstable. The ever-apropos Iain Stewart neatly summarizes the reign of these mad emperors:

“Caligula, or Gaius (AD 37-41), a chronic alcoholic who reputedly married his sister, made his horse a consul, turned his palace into a brothel, and killed innocent citizens on a whim. Next was Claudius (AD 41-54), hampered by a limp, trembling and a speech defect [sic] . . . and by continual illness. Finally there was Nero (AD 54-69), who killed his mother and wife and apparently fiddled while the Eternal City burned” (124).

History is affected by Geology, and geology is affected by history. As the Romans delved into the geologic resources of the Italian peninsula, they launched toxic metals into the atmosphere. As we unearth these deposits and learn about previous culture’s use of resources, perhaps we will become wiser in our own use of resources. The problems faced by the Romans—pollution, self-sustainability, and resource management—are all problems we still face today. Romans were fully aware of the harmful nature of lead. Their fondness for it as a useful metal, however, led them to overuse it to the extent that it may have contributed to the downfall of the empire. Will we make the same mistake over different geology?

References

Grout, James. “Lead Poisoning and Rome.” Encyclopaedia Romana. 11 Feb. 2008. 22 April. 2008. http://Penelope.uchicaco.edu/~grout/encyclopaedia_romana/wine/leadpoisoning.html
Jervis, W. P. The Mineral Resources of Central Italy: Including a Description of the Mines and Marble Quarries. London: E. Stanford, 1862.

Stewart, Iain. Journeys from the Centre of the Earth: How Geology Shaped Civilization. London: Century, 2005.

Image Credits

Barthelmy, David. “Native Lead Sheet Partially Covering an Actinolite Schist”. Mineralogy Database. 2005. 27 April 2008 http://webmineral.com/specimens/Lead.jpg

Gates, Peter John. Monumental Roman Marble Vase with Panther-Shaped Handles. Cincinnati Art Museum. Department of Antiquities, Amman, Jordan. 27 April. 2008 http://www.civilization.ca/cmc/petra/images/petra08.jpg

Geological Map of Italy. APAT: Agenzia per la Protezione dell’Ambiente e per i Servizi Tecnici. 2004. 26 Feb. 2007. 27 Apr. 2008 http://www.apat.gov.it/site/_images/ progetto_1250_ingl.jpg

Hutton, William. Naples Map. Hutton Commentaries, Inc. 23 April. 2007. 27 April 2008. http://www.huttoncommentaries.com/subs/ECNews/IndictrVolc/signs_of_PS-EC.htm

Passchier, Cees W. and Wilke D. Schram Lead Pipes. Roman Aqueducts. 2007. 27 April. 2008 http://www.romanaqueducts.info/aquasite/foto/lead_gt_Va.jpg

Weller, R. Polished Marble – Swirl Pattern F. Cochise College Geology Home Pagee. 25 March. 2008. 27 April. 2008 http://skywalker.cochise.edu/wellerr/rocks/mtrx/marble11.htm

Additional Information

“Alpine Geology”. Wikipedia. 29 Feb. 2008. 27 April 2008 http://en.wikipedia.org/ wiki/Geology_of_the_alps

Behncke, Boris. “Campi Flegrei Caldera, Italy.” Italy’s Volcanoes: Cradle of Volcanology. 26 August. 1996. 27 April. 2008 http://boris.vulcanoetna.com/CAMPIFLEGREI.html

“Carrara Marble”. Web Minerals. 27 April 2008
http://www.webmineralshop.com/ articoli/carrara_eng.htm

Geary, Judith. “Buildings of Artificial Stone”. About.com. 2006.New York Times. 27 April. 2008
http://ancienthistory.about.com/library/bl/uc_geary_bas.htm

Lewis, Jack. “Lead Poisoning: A Historical Perspective”. EPA Journal. May 1985. United States Environmental Protection Agency. 21 Sep. 2007. 27 April 2008. http://www.epa.gov/ history/topics/perspect/lead.htm