Field of Science

How 19th Century Climbing Books Reveal Clues About Climate Change

For the stone from the top for geologists…” answered mountaineer George Mallory once when asked why he’d climb Mount Everest (he and his friend Sandy Irvine perished there on June 6, 1924). 
Geologists nowadays study how climate change weakens the mountains based on observations made by such pioneering mountaineers. Continue reading...

Dante´s Inferno - The Geology of Hell

"Through me the way is to the city dolent;
Through me the way is to eternal dole;
Through me the way among the people lost.
Before me there were no created things,
Only eterne, and I eternal last.
All hope abandon, ye who enter in!
Canto III

"The Gates of Hell", by Jehan Froissart, 15th century.

For a long time the inner earth was a mysterious place, supposedly the reign of demons and place of eternal damnation. Italian poet Dante Alighieri (1265-1321) imagined an especially elaborate version of hell in the “Divine Comedy”. Like later authors he used in part his contemporary knowledge as inspiration and included in the description of the nine circles of hell, with Lucifer residing in the lowest, real landscapes. Dante mentions earthquakes, rivers, the shape of mountains and landslides, a desert of hot sand and some types of rocks (like the marble of Carrara).
The circles gradually become smaller with less circumference, as hell is depicted like an inverted cone in a sphere, protruding towards earth´s core. This image is based on calculations of Greek philosophers (like Eratosthenes of Cyrene, 276-194BC or Claudius Ptolemy, 100-170AD), Dante even gives an exact value of earth´s radius of 3.250 miles (5.230km, actual radius is 6.371km). 

Dante´s Inferno by Jan van der Straet, 1587.

The cone formed when Lucifer, the fallen angel, fell on earth, the impact was so great that it even shaped earth´s surface, with continents formed on the northern hemisphere and the southern hemisphere covered by the sea (Dante didn't know of the existence of the southern continents of Australia and Antarctica). 

"The fallen angels" by Vincent of Beauvais (1463).

In the south we will find only the mountain of Purgatory. Purgatory, together with the holy city of Jerusalem, forms an axis passing earth, with Lucifer´s belly as center of earth. An allegoric image, as Lucifer is damned as far as possible away from the sun and divine light.
Illustration to Dante's "The Divine Comedy" from the "Codice Urbinate Latino 365" (1480) showing the frozen center of earth with Lucifer trapped in eternal ice. Dante imagined this part of hell as frozen wasteland, as it was as farest away from the warm sun as possible in his geocentric universe (earth as center of the cosmos, with sun, moon and stars around it).

Dante when entering hell is guided by the shadow of ancient Roman poet Publius Vergilius Maro (70-19BC), better known as Virgil. During his pilgrimage from hell to purgatory and paradise, the way is obstructed by ruins, destroyed, as one demon reveals to Virgil, by an ancient earthquake.

Like the ruins this side of Trent left by the landslide/
an earthquake or erosion must have caused it/
that hit the Adige on its left bank,/
when, form the mountain’s top where the slide began/
to the plain below, the shattered rocks slipped down,/
shaping a path for a difficult descent/
so was the slope of our ravine’s formation.

Dante describes in these verses the sight of a 3.000 years old landslide near the Italian city of Trento, even arguing that the cause of this ancient landslide was erosion or an earthquake. Dante maybe visited this site, as he lived for a time in the nearby city of Verona. For sure he used German naturalist Albertus Magnus (1200-1280) as reference, who argued that by the river eroding the base of the mountain it collapsed, forming the ruined landscape of the landslide. Dante also experiences an earthquake at the shores of the river Acheron, caused by winds or vapors blowing inside the caverns of earth and igniting from time to time.

It´s curios to note that Dante didn't describe hell filled by fire, despite Mount Etna and Vesuvius were regarded in ancient times as gates to hell and both mountains seem to be filled by the liquid “lava-fire”.... not to mention hellish volcanic eruptions. However Etna is mentioned when referring to the island of Sicily, as site with sulfur vapors. The Phlegethon and some minor rivers are described as rivers of boiling blood with "lithified" margins, like - so Dante writes - the hot springs of Bullicame near the city of Viterbo in the Lazio region.

The Icelandic volcano Hekla as gateway to hell, from "Historiae de gentibus septentrionalibus" by Olaus Magnus (1490-1557), Archbishop of Uppsala.

There is may a simple explanation why Dante didn't include volcanoes more prominent in his work. Both Etna and Vesuvius were at the time relatively calm (Vesuvius erupted only in 1321-1323) and so of no real interest to the poet.

Geology plays even a role in the punishment of the sinners. In the third circle the simonists (people who sold holy artifacts for profit) are driven upside down into the ground and "squeezed tightly in the fissures of the rock".
 The robbers are punished in a circle filled with poisonous snakes. Dante describes looking down into the pit was he sees:

“Within this cruel and bitterest abundance/
people ran terrified and naked, hopeless/
of finding hiding-holes or heliotrope./
Their hands were tied behind their backs with serpents.”

Heliotrope (a chalcedony variety) was since ancient times a gemstone much valued for its magical properties, like to protect from the venom of snakes. 

After Inferno Dante finally reaches the slopes of Mount Purgatory, leaving hell behind:

"The climb had sapped my last strength when I cried:
“Sweet Father, turn to me: unless you pause/
I shall be left here on the mountainside!”/

He pointed to a ledge a little ahead/
that wound around the whole face of the slope./
“Pull yourself that much higher, my son,” he said./

His words so spurred me that I forced myself/
to push on after him on hands and knees/
until at last my feet were on that shelf."

The poets begin their laborious climb up the Mount of Purgatory, illustration by Gustave Doré (1861).

The Divine Comedy is nowadays appreciated for it´s role in the development of literature and Italian language, but it is also valuable source to better understand the natural sciences and the understanding of earth in the 14th century. 

KROONENBERG, S. (2013): Why Hell Stinks of Sulfur: Mythology and Geology of the Underworld. University of Chicago Press: 352
ROMANO, M. (2016): Per tremoto o per sostegno manco”: The Geology of Dante Alighieri’s Inferno. Italian Journal of Geosciences, 135(1): 95-108

Darwin´s first botanizing steps followed the geological ones

I collected every plant, which I could see in flower, & as it was the flowering season I hope my collection may be of some interest to you."
Darwin in a letter to Henslow, 1836
Darwin´s interests in the natural world were widespread. He enjoyed hunting, later also taxidermy. With his cousin William Darwin Fox he hunted for bugs. He collected rocks and minerals and later geologized around the world during the voyage of the Beagle (1831-1836). His mentor and friend John Stevens Henslow was professor of Mineralogy and later for Botany, introducing the student Darwin in both disciplines. Darwin attended Henslow´s botany lectures, labs and field trips each year during his three years at Cambridge, visiting also private science meetings at Henslow´s home. During the geological field trip in summer of 1831 with Adam Sedgwick he also collected and preserved some plant specimens.

Fig.1. Herbarium sheet by J. S. Henslow with three plants collected by Charles Darwin in 1831 at Barmouth, North Wales. This is the earliest-known herbarium specimen collected by Darwin (image source).
During the voyage of the Beagle Darwin collected plants or seeds on the Cape Verde Islands (the first stop of the Beagle), then Argentina, Uruguay, Chile, Brazil, later also on some of the visited islands, like the Falkland, Galápagos and Cocos islands. As Darwin had limited space on the Beagle, most occupied by rocks and animals, he concentrated on remote or less well studied localities.
Darwin had prepared several thousand labels in different colors before the voyage to be applied to every dried plant (the labels including plant name, locality, date and his signature). Wet specimens, conserved in "spirits of wine", were tagged with a metal tag. Henslow, who back in England managed Darwin´s collection, removed however most labels when putting Darwin´s specimens into the herbarium. Unlike the collected rocks and animals Darwin didn´t number the plants, so it seems a bit confusion sneaked into the collection. Another friend of Darwin, botanist Joseph Dalton Hooker, lamented to Darwin that not all notes could be attributed to the preserved plant specimens.
Darwin´s plant collection is especially interesting as it includes many species from the – at the time – less visited islands of Galápagos and Cocos islands. Darwin was intrigued about the relationship of the island species to nearby continents, he will do some experiments with seeds showing that some can survive salt water for months and so be dispersed over the sea. Despite Darwin´s first plans he didn't publish the collected plants in his description of “The Voyage of the Beagle” (published in 1839), as a very busy Henslow didn't meet the deadlines for publication.

Darwin collected 756 different species, subspecies or varieties of vascular plants during his voyage around the world, 220 species were new to science. Darwin was especially surprised by the variability of plants, one collected grass species was divided by Henslow into 15 different groups! This was an intriguing observation, important for his later theory of evolution, as variability is where natural selection acts on. Also the relationship of plant species on islands to nearby continents was an important observation. The plants from the Galápagos islands showed, according to Hooker, a remarkable variability between the single islands, however some even more remarkable similarities to species from North America and Brazil. Would a divine creator not be able to create distinct, unique species on remote islands as he pleased? However if seeds could disperse with marine currents and islands be colonized by plants from nearby continents, couldn't they also evolve there in new species?
PORTER, D.M. (2010): Darwin: the Botanist on the Beagle. Proceedings of the California Academy of Sciences, Vol.61(4): 117-156

Bone and blood is the price of coal - Animals in Mines

"Humanity’s genius is to have always had a sense of its weakness. The physical energy and strength, with which nature insufficiently endowed humans, is found in animals that help them to discover new territories."
From the movie "Home" (2009)
Since prehistoric times humans searched for rocks and minerals hidden deep inside earth. First for silex and quartz, used for stone tools, later for metals and finally for coal and oil to fuel the industrial revolution.
In antiquity the work in mines was done by prisoners or slaves. In the middle ages miners became professional workers. The demand was so high that miners were members of a privileged social class, often freed from direct taxes, living in villages with own independent jurisdiction. The price for the privileges was nevertheless high. The work in the mines was dangerous, rock-fall and sudden flooding of the tunnels, wet and cold conditions for hours, poisoned air and dust causing sickness and death.

But not only humans, also animals had to suffer. In the middle ages animals, like horses, were not yet used directly in the mines, but to move large machines, like pumps, cranes and conveyor belts. Only after 1750 pit ponies were introduced for the first time in coal mines to pull mine tubs.

Fig.1. & 2. A horse as engine, image from Georgius Agricola "De re metallica libri XII" (1556). Apart horses or mules, in alpine regions also dogs were used to help in the transport of the ore, here carrying empty bags up the mountain.

Fig.3. A pit pony in a subterranean railway tunnel.

Apart infrastructure, animals played also a role in the security and hygiene of a mine. To detect poisonous and highly explosive methane-gas, called also grisú, miners relied on canary birds. As birds however have a poorly developed sense of smell they were more useful to detect carbon monoxide, as this gas would suffocate first the birds, warning so the miners.

Fig.4. Miners using a canary.

To control rats and mice in the Yorkshire mines terrier dogs were used, the Yorkshire was breed for size and agility, to catch rats even in the narrowest of tunnels and galleries.
Cats were used as living detectors. Able to see in near darkness and thanks to their keen hearing, entrapped miners could be more quickly found and may rescued in time.
Modern mines nowadays use powerful machinery and sensors have replaced the cats, but it´s still hard work. Also still in many less developed countries, working in small mines, humans and animals risk their health and lives to extract the precious metals, essential to run our modern electronic gadgets.
Famous physician Philippus Theophrastus Aureolus Bombastus von Hohenheim (1493-1541), better known as Paracelsus, interested both in mines and diseases, once wrote:

...nothing good can be acquired without a price.“

The (possible) Geological Origin of the Minotaur Myth

According to myth the Minotaur was a terrible creature, born from an unnatural union between queen Pasiphaë of Crete and a sacred bull, send by the Greek god Poseidon to the island. The monster, half man and half bull, with an appetite for human flesh, was so dangerous that it was imprisoned in a subterranean labyrinth, so complex nobody could escape from it. The poet Callimachus of Cyrene (320-303 BC) describes the angered roars of the Minotaur coming from this prison - and only human sacrifices could calm the beast. 

Fig.1. Wall paintings dating to the 16th century BC from Tell el-Dab (Egypt) showing the bull-leaping ritual, Minoan artists exported their style and skills to other regions around the Mediterranean Sea.

The oldest descriptions of the Minotaur also note that the bull made tremble and shake the earth. It´s also curious to note the relationship between the Minotaur and Poseidon, Greek god of the sea. Poseidon could also generate earthquakes with his trident, as one name describes him as Enosigeo, the earth-shaker. Also the labyrinth is an old symbol of earth´s unknown interior, the womb of the goddess Gea. So the Minotaur myth shows some remarkable connections to earth or earthquakes.

For sure the Greek Minotaur myth was inspired by much older stories from the Minoan Civilization. The antique culture of Crete (3650-1400 BC) did worship the bull, as paintings discovered in the excavated ruins show a strange ritual involving young men leaping over the back of a bull. Bull cults are generally associated to fertility, but possibly on Crete it was also a response to the risk posed by earthquakes.
Weak earthquakes are common on Crete, as the island is located on the border of two important tectonic plates, the African Plate in the South and the Aegean Plate in the North. Stronger events happened in past times (~365 AD) as suggested by a 10m displacement observed along the coasts of the island.

Fig.2. Crete´s location above a subduction zones makes it vulnerable to earthquakes, map from PLATT et al. 2007.

So was the Minotaur – including his associations to earth – a personification of the mysterious, at the time unexplainable, forces of nature?


KAPLAN, M. (2013): The Science of Monsters: The Origins of the Creatures We Love to Fear. Scribner: 256

McINERNEY, J. (2011): Bulls and Bull-leaping in the Minoan World. Expedition. Vol.53(3): 1-13

The Volcano as Crematory - Paolo Gorini´s strange geological-anatomical experiments

Paolo Gorini (1813-1881) was an Italian mathematician and naturalist, interested in medicine and geology, trying to combine in a quite unusual way his two passions. 

Gorini  worked on methods to conserve corpses, in part for medical purposes, in part for more practical reasons  - as he supervised also crematoriums in Italy and in Britain it was sometimes necessary to preserve a body until it could be cremated (in one case, due bureaucratic problems, he had to hold a body for over two years). 

After 1842 Gorini also started to work on a theory to explain the formations of mountains. Gorini believed that rocks and mountains were formed from crystallization of a liquid, or molten substance, following James Hutton´s suggestions. Like in an organism, fluids (which he called plutons) would feed the earth from within and over time a mountain would form or “grow”. Gorini had some evidence from the field, like solidified dikes and veins seen in outcrops or hollow conduits, now empty but once filled with molten magma.
Fig.2. Vein in granite, observed on the Naabranken (a mountain in Bavaria), first depiction of its kind published in 1868 in GÜMBEL, von W.: Geognostische Beschreibung des Königreichs Bayern: II. Abt. Ostbayerisches Grenzgebirge. Such veins form when fluids crystallize, so Gorini was right that some minerals and rocks form in such a way and his theory may also explain (in part) volcanoes, but it can´t explain entire mountain ranges, formed by tectonic deformation of earth´s crust over time.

He designed also some experiments to support his explanations. In public shows he heated liquids until forming bubbles "quite similar to the real ones [volcanoes]”. Gorini hoped that his experiments would prove useful in time. In 1865 Mount Etna erupted,  causing death and devastation, and Gorini criticized that people rely on superstition, offering flowers and prayers to the volcano, instead of science, trying to understand the mechanics behind volcanic eruptions and so may avoid or even prevent them.
He published his theory in 1851 in the book "Sull´Origine delle Montagne e dei Vulcani - Studio Sperimentale" (On the Origin of Mountains and Volcanoes - An Experimental Approach), followed by a series on papers over the years.
Fig.3. Gorini’s first work (1851) concerning mountains and volcanoes.

Despite his success with the public, the “experimental approach” shows were quite popular, his scientific publications were meet with skepticism. Some scholars considered his “experimental geology” an important contribution to better understand volcanoes, other considered Gorini a respectable anatomist, but just a  “geological showman”.
In 1872 Gorini tried to model volcanoes using molten magma. Seeing how insect burst into flames when coming into contact with the incandescent material, he also tried to cremate human corpses, or at least parts, with this artificial lava. However it was difficult to melt and handle enough material to burn an entire human - also lava doesn´t quite work the way as depicted in movies - and Gorini soon abandoned these experiments.  

Fig.4. The dramatic death of Pliny the Elder consumed by fire during the eruption of Vesuvius in 79 AD, from "Histoires prodigieuse" (1560). Contrary to the common myth, the most lethal effects of a volcano are not lava flows and disposing of a corpse in it is quite difficult. Curious side note - there is also no documented case in history where humans were sacrificed in a volcano or volcanoes used to cremate corpses.

Gorini continued his career as respected anatomist and mummification-specialist, however his geological contributions were soon forgotten – a shame, as if even many of his conclusions are wrong (one must also consider the limit knowledge of volcanoes at the time), his ideas and especially his rational approach, using experiments to explain observations in the field, are nevertheless timeless.
LORUSSO, L.; FALCONI, B.; FRANCHINI, F.A. & PORRO, A. (2013): Geology, conservation and dissolution of corpses by Paolo Gorini (1813–1881). In DUFFIN, C. J., MOODY, R. T. J. & GARDNER-THORPE, C. (eds) “A History of Geology and Medicine. Geological Society, London”. Special Publications, 375: 469–474

Geological Prospecting Following The Tales Of Haunted Mines

Myths were already used to reconstruct the geological risk of certain areas and may also be of interest for prospecting geologists. Still many modern localities bear names associated to past mining operations, precious metals or ore. A lateral valley of the South Tyrolean Ahrntal is known as Röttal, “Röt" meaning red and named after the reddish rocks found there. These rocks are ore-rich greenschists, the reddish colors caused by alteration and weathering over time of iron- and sulfur-minerals (often associated with more valuable minerals). Probably this and other geological clues (like rivers poisoned by traces of copper and poor plant growth) helped once to discover the copper deposits deep within the mountain. 
Fig.1. View of a small creek in the "red" valley.

According to a local legend the nearby mine of Prettau was discovered when a wild bull throw some large rocks into the air. The owner of the animal noted some shiny minerals inside the rocks and even if not gold, so he had found a rich deposit of copper- and iron sulfides. Maybe this legend reflects the idea of using such well visible geological clues, like minerals or alteration products, do discover the hidden treasures of a mountain.

Mining for metals in the Alps dates back at least for 4.800 years (a 25m long gallery in North Tyrol was dated to 2.800 B.C.), in South Tyrol slag remains were dated to 1.200-1.000 BC for sure. Slag remains found in Ahrntal possibly date back to the early and middle bronze age (3.300-1.800 BC), even if the provenance of the used copper ore is unknown. The extraction of copper ore in the Ahrntal became important only in medieval times, especially in the 15th century. 

Fig.2. Medieval prospecting pit in ore-bearing greenschists (prasinitic) rocks.

So it´s interesting to note that some galleries found in the Ahrntal are, according to local folklore, associated to the Roman dominion. The galleries excavated in gneiss are not especially deep, the longest recorded is just 40m. It´s for sure only superficial prospecting, soon abandoned.

Fig.3. A supposedly haunted pit, entrance to a short gallery excavated into the weathered grey gneiss, in yellow alteration rim.

In local folklore the galleries are called antrischen Löcher”, "antrisch" an old term to describe something spooky or haunted and "Löcher" simply meaning hole. The antrischen Löcher were inhabited, so the legend tells, by descendants of the first man and women. However as Adam and Eve tried to hide their illegitimate children before god, they now are damned to live in the underground. They are the guardians of underground treasures and eventually will donate the hidden treasures to good people, if they deserve such gifts.

According to historic archives some galleries date back for sure to the year 1530, when a mister Franz Widmair requested permission to prospect for ore in this area. Mines dating back to Roman times are a possibility, even if highly unlikely, as there exists no written record or artifact made of the extracted ore to prove Roman mining operations.

Folklore also tells of silver-veins, even if the petrological composition of the rocks would suggest copper. The found ore is anyway of no economic value nowadays.

Now even if geology contradicts some speculations based solely on local tales (like the galleries dating back 2.000 years and the search for silver), it´s nevertheless interesting to note that without the legends surrounding these artificial galleries and pits these would have probably soon be forgotten. By following and evaluating tales provided by locals a geologist may discover some interesting additional information to include in a geological map, be it abandoned mines, quarries or minerals- and ore-associations.