The Early Exploration and Geology of the Chamois Mountains

„Su le dentate scintillanti vette, 
salta il camoscio, 
tuona la valanga da' ghiacci immani
rotolando per le selve scroscianti; 
ma da i silenzi de l'effuso azzurro esce nel sole l'aquila,
e distende in tarde ruote digradanti il nero volo solenne.“
Giosuè Carducci (1835-1907)

In medieval times the Alps, especially the alpine regions above the tree line, were simply referred as Gamsgebirg - the chamois mountains.

Fig.1. The Livre de chasse is a medieval book on hunting, written between 1387 and 1391 by Gaston III, Count of Foix and dedicated to Philip the Bold, Duke of Burgundy. One figure shows an alpine hunt with ibex and chamois hiding between the peaks.

Only, as a guide from 1917 describes, fools would venture there. However the Alps since ancient times were a traveled region. Shepherds, merchants, collectors of plants and minerals and hunters populated the valleys, high-altitude pastures and maybe sometimes also climbed a peak.
The first person to climb a mountain just "because it´s there" was supposedly Italian poet Francesco Petrarca (1304-1374), as he describes an ascent on Mount Ventoux in France. 

Italian author Valerius Faventies in 1561 publishes “De montium origine”, wherein he collects all the contemporary theories explaining the formation of mountains. An important role was given to celestial influences. But only later authors like cartographer Sebastian Münster (1489-1552), cartographer Johannes Stumpf (1500-1566),  naturalist Konrad Gessner (1516-1565)  and especially naturalist Johann Jakob Scheuchzer (1672-1733) describe mountains in great details, including plants, animals and the geology.

Fig.2. The chamois in Konrad Gessner´s „Allgemeines Thierbuch“ (1565).

Scheuchzer used examples of large-scale folds observed in the Swiss Alps as evidence for the veracity of the Biblical account of a flood in remote times. Only a large flood, a deluge, could twist, break and fold the sedimentary rocks.

Fig.3. "Views of Chamonix, as seen [during the expedition] in 1742", apart glaciers the drawing shows also typical animals, like the ibex, the chamois and the marmot. Figure from a report to the Royal Society in London by William Windham.

Also English theologian and naturalist Thomas Burnet in his book “The Sacred Theory of the Earth“, published in 1684, tries to explain the mountains and shapes of the continents by the biblical flood. The homogenous primordial crust of earth was shattered, releasing water from the underground. The water covers the entire planet and finally flows back in the fissures, leaving behind fragments of the crust that now forms the modern islands and continents. Mountains, so Burnet, were fragments of the primordial crust of earth stacked atop, ruins of the former perfect paradisic world.

Fig.4. The chamois hunter's hunting ground, by Johann Baptist Zwecker (1814–1876).

Still for a long time the Alps were seen as haunted, dangerous and most important unholy territory. One there was "in company of the devil,..." as Swiss naturalist Horace-Bénédict de Saussure (1740-1799) refers to the chamois when writing about the Alps. De Saussure was also the first naturalist to describe the geology of one of the highest peaks in the Alps (mostly composed of granite), the 4,808.73m high Mont Blanc, climbed by his expedition in July 1789.

Interested in reading more? Try: 

BEATTIE, A. (2006): The Alps: A Cultural History. Oxford University Press: 246
BRIDLE, B. (2011): Mountaineers. Royal Geographical Society,The Alpine Club: 359
MacFARLANE, R. (2003): Mountains of the Mind - Adevntures in Reaching the Summit. Random House Publishing, New York: 324

An advice for the prospecting geologist from 1731 - observe the water

“The miner needs in his art to have the most experience, so that he knows the place, the mountain or the hill, the valley or the field, that can be mined with success, and to avoid to dig were nothing can be gained.”
from Agricola, "Zwölf Bücher vom Berg- und Hüttenwesen", I. Buch (1549)

Georg Grandtegger was a mine inspector in the Prettauer mine (Tyrol) who published in 1731 a field guide to find ore. Some of his suggestions may be useful even today, so he writes:
 

"The water of a spring must be tasted for the dissolved substances in it"
 

It is true that minerals like salt, sulfur and some metallic ores are water-soluble and can alter the taste and smell of water. Water saturated with metals can also precipitate new minerals (mostly oxides and hydroxides) in a river, like reddish-brown sediments when saturated with iron or greenish crusts when saturated with copper.
 

So Grandtegger continues:

"The brand [a term referring to color-alteration of the rock] comes from an ore along the creek. Follow it as long as you see it, then you will find the ore.”
"If you find in fountains [read springs], feed by the mountain, many reddish, bluish or black stones, or even colored green, even if the rocks itself have no ore, so flows the water out from veins of ore."
 

Fig.1. A spring, the mud around is colored by iron-oxides and -hydroxides, a clue that in the underground there is ore-rich schist to be found.

Grandtegger correctly suggest that a prospecting geologist should observe carefully if rocks are colored by precipitations of metals in a river. If so the geologist can follow the river until the spring. The source of the dissolved metals will likely to be found here in the underground. 

Fig.2. The reddish colors of the pebbles in this creek suggest the presence of iron and copper. Sometimes even the name of certain localities can help the prospecting geologist, like here, as this small creek is found in the “red valley”.

A last important observation, as dissolved copper is poisonous for animals and plants, rivers flowing in copper-rich rocks will likely show a diminished presence of insects and fish – so it may be a good idea to ask local fishermen about spots were they don´t get to catch anything, it may be the right spot for the geologist.

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. 

Damned Souls and Fiery Oceans - Early Views Of Earth`s Core

"We know more about the stars high above our heads, than about earth just below our feet."
Leonardo da Vinci
 

There is some truth in da Vinci´s words, as for a long time the interior of earth was a mysterious place, supposedly the reign of demons and place of eternal damnation. Italian poet Dante Alighieri (1265-1321) imagined a core of ice, an allegoric image, far away from the sun and divine light where the damned souls are entrapped in eternal ice. 

German Jesuit Athanasius Kircher (1602–1680) imagined earth´s section in his "Mundus Subterraneus" (1664-1665) as crossed by veins of water and fire. The water would feed springs and rivers, the fire the volcanic mountains – but apart practical observations Kircher´s worldview was influenced also by religious-philosophical considerations, the two opposite elements water and fire united in a perfect creation.
 

Fig.1. from "Mundus Subterraneus", first edition published in 1664-1665.

Leonardo da Vinci´s (1452-1519) approach was more rational, even if inspired by the idea that earth worked a bit like a human body, just blood replaced by water. Water, so da Vinci, eroded, transported and deposited sediments, connecting mountains with the sea. He imagined earth filled by an immense underground ocean, sections of the superficial crust sinking into it would explain the formation of mountains.
 

Fig.2. Leonardo da Vinci´s speculative section of planet earth, from his private notes (Codex Leicester, 1510).
 

James Hutton (1726-1797) recognized the importance of magmatic rocks on earth. To explain the large quantities of volcanic rocks on earth´s surface and the energy needed to melt rocks, Plutonists proposed a molten interior, even if it is was not clear if molten rocks form most of earth or were to be found in only large magmatic chambers, distributed in the upper layers of earth.
 

Fig.3. Section of earth from Erasmus Darwin´s poetic-naturalistic work (1791), note the "unknown region supposed to consist of Lava kept in semifluid state by heat...[]".

French science-fiction author Jules Gabriel Verne (1828 - 1905) based his novel "A Journey to the Center of the Earth" (1864) on the science of his time. In his novel Verne uses the hollow conduit of the Icelandic volcano Snæfellsjökull to venture inside earth, an idea supported by the geologic models of volcanoes proposed at the time - a single or a series of magma chamber(s) with conduits connecting them to the surface. Geologists assumed that during an eruption the magma reservoir becomes empty and large voids and caverns were left behind.
 

Fig.4. Geological section, published in the book "Einführung in die Erdbeben- und Vulkankunde Süditaliens" (1914), shows the anatomy of a stratovolcano, with a main conduit, various lateral dikes and a large sill connected to the magma reservoir. 

The Spanish adaptation of Verne´s novel "The Fabulous Journey to the Center of the Earth"/ Where Time Began" (1976) summarizes best the problems geologists faced all this time:

"-Gentleman, the truth is that all our theories are just that, theories. None of us has the least idea of how the earth was really formed. Because the distance between the earths crust and its core is over 6.500 kilometres, and no men has ever descended to a depth of more than 3 miles. So it's obvious, we will never have a glimmer of true knowledge, until we are able to reach a depth of at least a 100 leagues.
 

- What's your opinion Professor Lindenbrook?
 

- Well gentlemen, at one point at least I agree with Professor Christophe, the materials of the geologists are not charts, chalk and chatter, but the earth itself. We should never know the truth, until we are able to make that journey, and see for ourselves."

To be continued...

Bibliography:
 

PARCELL, W.C. (2009): Signs and symbols in Kircher’s Mundus Subterraneus. In Rosenberg, G.D., ed., The Revolution in Geology from the Renaissance to the Enlightenment: Geological Society of America Memoir 203: 63-74

A History of Geological Maps: I. From Outcrop to the first Map

March 23, 1769 marks the birthday of pioneering stratigrapher William Smith, who is also credited as author of the first modern geological map, however like many other great accomplishments also Smith’s idea of depicting the distribution of rocks on a topographic map didn’t materialize out of nowhere.

The German mining engineer Georgius Agricola (1494-1555) dedicated in his “De re metallica” (1556) -  an early  textbook on mining technologies – an entire chapter to the distribution of valuable rocks in earth’s crust. The written description is correlated with various figures, showing in a sort of combined landscape – section the distribution, thickness and direction inside the mountain of the mineralized veins.

 

Fig.1. Veins and mineral seams, figure from “De re metallica”, not a real map, however directions are given on the borders.

The idea of a real map of rock-distribution was proposed first in 1684 by the British physician and naturalist Martin Lister (1639-1712). Lister suggested that the distribution of the different soil types of the British landscape could accurately be represented on a topographic map.

“The Soil might either be coloured, by variety of Lines, or Etchings; but the great care must be, very exactly to note upon the Map, where such and such Soiles are bounded…Now if it were noted, how far these extended, and the limits of each Soil appeared on a Map, something more might be comprehended from the whole, and from every part, then I can possibly foresee, which would make such a labour very well worth the pains.“
 

As – so Lister continues – the soil types correlate with the underlying bedrock, by mapping the soils one could also map the rocks hidden in the underground.

However Lister never realized a real map based on this theoretical premise. It was the Italian Count Luigi Ferdinando Marsili (1658-1730) who made the next important step. As military engineer Marsigli traveled widely in Italy, France, Germany, the Balkans and Turkey, creating topographic maps for military use of the visited countries. An exact representation of the landscape was essential to plan movements of an army or identify the best locations for fortifications. Marsigli became a keen observer and a skilled cartographer of the landscape, sketching rock outcrops or  prominent features of the landscape. After an unfortunate military campaign in Germany, Marsigli was accused of cowardice, his military career ruined he used his acquired skills to create maps for more peaceful applications.

 

Fig.2. Section combined with a map of a silvermine, published in - "Mappa metalographica…[]" by Luigi Ferdinando Marsili, he added also some geological information (lower right corner) with a detailed rock-section - "Upper rock", "Vein" with mined "Ore" and "Lower Quartz".

In 1726 he published a map of the mining districts in Hungary and sketched the distribution of gypsum and sulfur deposits near his hometown Bologna (1717). In his sketch he connected the single gypsum quarries and outcrops along rivers with a shaded area, delimiting so the folded gypsum-bearing rocks. This map is important as it displays a first approach to the problem all geologists must face – not only documenting the visible outcrop of a rock or the position of a mine or quarry (such maps existed already), but interpolating the distribution of the not accessible part of  a geological formation.

 

Fig.3. The map from “Atlas et Description Minéralogiques de la France” (1780), by French pharmacist and botanist Jean-Étienne Guettard, shows the distribution of outcrops with minerals, fossils or rocks. Such mineralogical maps predate true geological maps, showing sites of geological interest, however lacking the interpolation between the single “data points” (image in public domain, originally posted by BibliOdyssey).

It may surprises that despite many naturalist had already produced very detailed descriptions and maps of single outcrops, almost nobody made a connection between sites with similar rocks. But not only was the unequivocal identification of geologic formations at the time still very difficult, many naturalists considered connecting single outcrops by a presumed (not visible at the surface) extension of the rocks as unscientific speculation. This aversion of early geognosts to geological maps is exemplified by the strange behavior of naturalist Jean-Étienne Guettard (1715-1786), famous for his detailed mineralogical and volcanological maps. Guettard in 1777, after eleven years of  hard work, abandoned the prestigious project by the French minister of Mining to produce a series of geological maps of France. He simply couldn’t overcome the idea that a map should represent only facts (in this case outcrops) – but a blank map with just some isolated spots of color wasn’t exactly what the French authorities wanted.

Maybe the first true geological map was drawn by an anonymous naval cartographer in 1757. In the outlines of the German island of Heligoland he added boundaries between four different rock types: Kreide (chalk), Muschelkalkstein (limestone), Bunter Sandstein (sandstone) and Kohle (coal beds). The map depicts the boundaries of the various geological formations even below the sea.

As the author, also the intended use of this map is unknown. The historian of geology  – David. R. Oldroyd – speculates that the map maybe could be used as aid to navigation, as sailors could determine their position by evaluating the rocks and sediments dredged from the seafloor.

To be continued…

Bibliography:

FRANCESCHELLI, C. & MARABINI, S. (2006): Luigi Ferdinando Marsili (1658-1730): A pioneer in geomorphological and archaeological surveying. In VAI, G.B. ed, The origins of geology in Italy: Geological Society of America Special Paper 411: 129-139
OLDROYD, D. (2013): Maps as pictures or diagrams: The early development of geological maps. In BAKER, V.R. ed, Rethinking the fabric of geology: Geological Society of America Special Paper 502: 41-101

A History of the Use of Illustrations in the Geosciences: I. Seeing is Believing...

The progress made in understanding realistic landscape-views and the rediscovery of ancient encyclopedias (like the works by Pliny the Elder) inspired Renaissance naturalists to adopt an exact and systematic approach to describe the curiosities found in the natural world. As most information as possible should be associated to every studied object – compiled from the works of ancient authors, own observations, may also supposed medical and magical properties, a good description should also include a detailed figure showing the described specimen (at the time a very expensive approach, as artists and engravers had to be hired).
 

One of the most extraordinary examples of this new approach to nature is the work by Italian naturalist Ulisse Aldrovandi (1522-1605) – his motto was “to understand plants and animals there is no better way than to depict them from life“. The commissioned figures for his encyclopedia on animals and freaks of nature are indeed of exquisite quality, even more if compared to the at the time still very popular bestiaries with their fanciful illustrations of mythical monsters. 

Aldrovandi included also some drawings of fossils in his work, not of such high quality as the depicted animals, however good enough to still identify the real fossil models.

The first book to depict in a systematic order fossils was published in 1565 by naturalist Conrad Gesner (1516- 1565). In "De Rerum fossilium, Lapidum et Gemmarum maxime, figuris et similitudinis Liber” (On Fossil Objects), Gesner compares fossil sea urchins with living specimens, arguing that some fossils are lithified organisms. However Gesner observed and shows also differences between living organisms and fossils, arguing that those differences are evidence that other fossils are of inorganic origin. The figures play an important role to support his observations, theories and make them accessible also to other scholars. Also Danish anatomist and naturalist Niels Stensen uses in 1667 a similar approach when showing the organic nature of fossil shark teeth.
 

Fig.1. Shark teeth depicted in C. Gesner´s "De Rerum fossilium...[]”. Such figures made it possible for other naturalists to compare their fossils with specimens of other collectors or hosted in private, non easily accessible, collections. However the quality of the used wood cuts was still poor and were soon replaced by copper engravings, with a higher reproduction quality.
 

Naturalist Federico Angelo Cesi (1585–1630) founded in 1603 the Accademia dei Lincei (Academy of Lynx, as a tribute to the sharpness of vision of this animal). This Italian association of scholars was devoted to study and classify all of nature, one member, Fabio Collona, predated even Steno in the interpretation of fossil shark teeth. The Accademia supported the use of drawings in the member´s publications and in the end it possessed more than 7.000 drawings and paintings in its collection. Cesi was interested in the classification and origin of what appeared to be fossil wood, emerging from Pliocene sediments of Umbria. In his posthumously (1637) published work, according to the principles of the association, he not only features drawings of the collected and studied specimens, but also – for the very first time – drawings from the field. In Cesi´s field drawings he documents the landscape of the fossil sites, the horizon of the wood samples, also the work done, like the excavation of large logs. Some drawings are accompanied by descriptions of the samples, with measurements and notes on color, shape and weight of specimens. Only 200 years later geological works will equal Cesi´s notes.
 

Fig.2. Drawing of field site showing a gully with accumulation of fossil wood.

 

Fig.3. Published plate (1637) of a fossil log as found and excavated in situ.

Fig.4. Fossil wood shown in a classic manner, as collection of specimens.

Bibliography:

MARRA, A,C, (2004): Iconografia dei fossili tra scienza, filosofia e istificazione. PaleoItalia, No.10: 3-8
SCOTT, A.C. (2001): Federico Cesi and his field study on the origin of fossils between 1610 and 1630. Endeavour, Vol.25(3): 93-103

Eppur non si muove - Galileo Galilei and the impossible biomechanics of giants

Until the 17th century the discovery of skeletons of giants was a quite common event. In January 1546 and then in the years 1564, 1580 and 1613 bones were unearthed near the castle of Chaumont (France). The bones were identified as the bones of the giant Teutobochus, king of the barbarians, and exhibited in many French cities. Jesuit Jacques Tissot describes the discovery as follows:

“The real story of the life and the bones of the giant Teutobochus, king of the Teutons, Cimbrians and Ambrones, defeated in the year 105 before Christ. He was defeated along with his army of 100.000 men by Mario, the Roman consul, and then he was killed and buried near the castle once known as Chaumont and now as Langon, near the Roman town of Daulphiné. On this site his tomb was discovered, thirty feet long, with his name written in Roman letters. The bones in the grave exceeded 25 feet and one tooth was heavier than 11 pounds, all bones were monstrous in size and shape, as you will see in display“

Fig.1. Generations of giants, image from “Mundus subterraneus” by Athanasius Kircher (1678). The biggest giant is based on the bones discovered in Sicily, from left to right follows a common man, the legendary Goliath, the giant of Lucerne and the giant of Mauritania.

Today the supposed bones of giants are identified as fossils of extinct large ice-age mammals and gigantic reptiles known as dinosaurs. 

However already in 1638 the Italian physicist Galileo Galilei (1564-1642) realized that the basic principles of biomechanics refute the existence of human giants. In his book “Discorsi e Dimostrazioni Matematiche intorno a due nuove Scienze Attenenti alla Meccanica & i Movimenti Locali” (Discourses and Mathematical Demonstrations Relating to the Two New Sciences of Mechanics and Movements) he describes how the bones of large and small animals must differ in their proportions as a result of physical laws. A larger bone is not simply a larger copy of a small bone, but its thickness increases much faster than the length to support the increased weight of a larger body. A human giant would never show human proportions, but be a shapeless monster, unable even to move .... Eppur non si muove!

Fig.2. Figure from “Discorsi e Dimostrazioni Matematiche…” showing how thickness of a column (and bone) must increase much faster than lenght to support increased forces.

Bibliography:

Prothero, D. (2003): Bringing Fossils To Life: An Introduction To Paleobiology. McGraw-Hill Science: 512

From the Contracting Earth to early Supercontinents

“What are they? Creations of mind?- 
The mind can make Substance, and people planets of its own  
With beings brighter than have been, and give  
A breath to forms which can outlive all flesh.”
“The Dream“, Lord Byron (1788-1824)

Already when the first maps of America were published (1507 and after), geographers and naturalists alike noted the similar shape of the west-coast of Africa and the east-coast of South America.

In 1620 the English philosopher Francis Bacon claimed in his “Novum Organum” that “it’s more then a curiosity”. In 1658 the cleric Francois Placet published a small booklet entitled “The break up of large and small world’s, as being demonstrated that America was connected before the flood with the other parts of the world.” He argued that the two continents were once connected by the continent of “Atlantis”, submerged and lost forever during the biblical flood.

The idea of a flood to explain the shape of continents will remain very popular for the next 250 years.

Fig.1. Illustration from Thomas Burnet´s book “The Sacred Theory of the Earth“, published in 1684, where he tries to explain the shapes of the continents by the biblical flood. The homogenous primordial crust of earth is shattered (first drawing) releasing water from the underground. This water covers the entire planet (second drawing) and finally flows back in the fissures, leaving behind fragments of the crust that now forms the modern islands and continents (last drawing).

The great French palaeontologist Buffon in his “Les Epoques de la Nature” (1717) not only addresses the age of earth, but also speculates about a former land bridge connecting Ireland and America to explain the distribution of fossil shells found on both sides of the Atlantic Ocean.

The American president (of the Academy and College of Philadelphia) and naturalist Benjamin Franklin explained marine fossils found on mountains in a letter to French geologist Abbé J. L. Giraud-Soulavie in 1782 as follows:

“Such changes in the superficial parts of the globe seemed to me unlikely to happen if the earth were solid to the center. I therefore imagined that the internal parts might be a fluid more dense, and of greater specific gravity than any of the solids we are acquainted with, which therefore might swim in or upon that fluid. Thus the surface of the earth would be a shell, capable of being broken and disordered by the violent movements of the fluid on which it rested.“

The great German naturalist and geographer Alexander von Humboldt explored South America in 1799-1804 and observed that the similitudes between the two coastlines were not only restricted to a morphological pattern, but also to the geological features: mountain ranges that seemed to end on one continent continued on the other, the Brazilian highland is similar to the landscape of the Congo, the Amazonian basin has it’s counterpart in the lowlands of Guinea, the mountain ranges of North America are – geologically – very similar to the old European mountains and rocks in Mexico resemble those found in Ireland.

Fig.2. Columnar Jointing in the basalts of Regla, Mexico, as depicted in Alexander von Humboldts (1810) “Pittoreske Ansichten der Cordilleren und Monumente amerikanischer Völker.” (image in public domain), the accompanying text explains: “The basalts of Regla, which are presented on this copper plate, are an incontrovertible proof of this identity of forms, which is noted on the rocks of different climates. Travelled mineralogist need only to look at this drawing to recognize the basalt forms in Vivarais, in the Euganean Mountains or in the foothills of Antrim, in Ireland. The smallest coincidences observed in the European rock-pillars are also found in this group of Mexican basalts. Such a great analogy let us assume a similar principle of formation acting under all climates in various temporal epochs, the basalts covered by compact limestone and clay-slate must be of different age than those who are resting on layers of coal and boulders.”

But even Humboldt still argued that the Atlantic Ocean represents a large and ancient river bed, flooded subsequently by the biblical catastrophe.

The French zoologist Jean-Baptiste Lamarck developed a surprisingly new hypothesis. To explain the discovery of fossil marine animals on dry land he proposed that the continents “move” slowly around the globe in a very peculiar manner. The eastern coastlines of the single continents are eroded by the sea, but in the same time new sediments were deposited on the western coasts, so the continents apparently move around the globe and the sea becomes land.
Unfortunately, also for the lack of evidence for his theory, Lamarck was not able to find a publisher for his “Hydrogéologie” and printed in 1802 on his own behalf 1.025 copies, but only a small number of books were sold.

In the early 19th century another hypothesis was proposed to explain the shape of Earth: the Contracting Earth theory formulated by the American geologist James Dwigth Dana explained mountains and continents as products of a cooling and subsequently shrinking earth. Like an old and dry apple the shrinking surface of earth would develop fissures (basins) and wrinkles (mountains).

Austrian Geologist Eduard Suess published in his multi-volume work “Das Antlitz der Erde” (1883-1909) this hand coloured map, showing the supposed remains of the primordial continents – preserved “cores of crust” surrounded by younger basins today filled with oceans. Curiously he suggested also that the deep-sea trenches, found along the borders of the Pacific, are zones where the ocean floor was pushed under the continents (!).

Fig.3. Hand coloured map showing the primordial continent -”cores” according to the Austrian geologist Eduard Suess, published in “Das Antlitz der Erde” (The Face of the Earth) 1883 to 1909 (image in public domain).

But the Contracting Earth theory couldn’t explain the irregular distribution of mountains on earth and why there are regions with strong tectonic movements and earthquakes and also “quiet” areas. According to this theory, such features and events should to be distributed randomly on the surface of a homogenous cooling and shrinking planet.

Already in 1858 the French naturalist Antonio Snider-Pellegrini (1802–1885) published a reconstruction of America and Africa forming a single continent on a planet with a fixed volume. But Snider-Pellegrini couldn’t propose a convincing mechanism, apart the great flood described in the Bible, to explain the forces needed to move entire continents.

Fig.4. This 1858 reconstruction by Antonio Snider-Pellegrini is the first map showing a former supercontinent.

Bibliography:

FRISCH, W.; MESCHEDE, M. & BLAKEY, R. (2011): Plate Tectonics – Continental Drift and Mountain Building. Springer-Publisher: 212
MILLER, R. & ATWATER, T. (1983): Continents in Collision. Time-life books, Amsterdam: 176

Vitruvian Geology – Leonardo da Vinci and the Realistic Depiction of the Earth’s Surface

Leonardo da Vinci studied rocks and landscapes not only to improve the realism of his paintings, but also in an attempt to understand how the earth works. Leonardo was obsessed with water, which he considered a vector to erode ancient rocks and to deposit new sedimentary rocks, reshaping so over time the “living” earth. The running water is for earth what blood is for the human body – it flows from the mountains to the sea, then – so Leonardo – in subterranean veins returns to the mountains, a circulatory system like found in humans.

October 23, 4004: The Creation of the World

October 23, has become famous by (non)geologists as earth's birthday - largely due the brief mention in textbooks of the Irish Archbishop James Ussher's (1581-1656) work published in 1650 as the "Annales veteris testamenti, a prima mundi origine deducti" (Annals of the Old Testament, deduced from the earliest beginning of the world). Ussher presents a possible chronology of the 6.000 years old history of earth and humankind based on references in the bible and research of others scholars of the time (most influential was John Lightfoot - 1602-1675 - who published his calculations in 1644). 
For Ussher and other scholars it was important to know the age of the earth to possibly infer the time of the rapture. As for god a day is like thousand days and he needed 6 days to create the universe, the world would was created 4.000 years before Christ and last for 2.000 years after.
The exact date given by the Ussher-Lightfoot-Chronology - October 23*, 4004 B.C., at nine o'clock in the morning - has become ridiculed by scientists as the futile attempt to determinate natural facts only based on the interpretation of Bronze Age myths [* or 6 p.m. October 22, 4004 B.C. according to the Jewish calendar].

However considering the time and the purpose of the work, Ussher's attempts were not too farfetched - his conclusions were based on the information that was available at the time and served well the theological questions that they should help clarify.

Also this age was not universally and uncritically accepted- there were many earlier attempts to determinate the age of the earth and many concluded that earth was significantly older than known human history. Also during and shortly after Ussher there were serious doubts on the veracity of the 6.000 years time interval, manly due the observation in nature and outcrops.
For example in the book "A Tour through Sicily and Malta" the stratigraphic research by the Sicilian Canon Giuseppe Recupero (1720-1778) on the slopes of Mount Etna is mentioned. Recupero discovered a succession of seven lava flows, he dated the youngest to the second Punic War (218 to 201 B.C.) and therefore the oldest could be 7x2.000 years =14.000 years old.

Finally on March 17, 1785 a man will propose a new modern approach - "we find no vestige of a beginning, no prospect of an end."

Fig.1. llustration from Thomas Burnet´s book "The Sacred Theory of the Earth", published in 1684.

Accretionary Wedge #35: Giologia-Geognosie-Geology

"Broadly speaking, the short words are the best, and the old words best of all."
Sir Winston Churchill, British politician (1874 - 1965)

Evelyn is asking on her Georneys for everyone favourite Geology Word - what better word there is than the term that describes the knowledge of the anatomy of earth itself - the Geognosie, evolved today in the better known term Geology.

It was in the 18th and 19th century that common and noble men begun to gather natural curiosities in their cabinets or museum. The displayed natural oddities and specimen were collected mostly by lucky discoverers, paid assistants or conscripted students, only in later times also noble men started to go in the field by themselves, even is such activity was considered more a necessity to gather more specimen than to explore and understand nature.
The Swiss professor of philosophy Horace-Bénédict de Saussure (1740-1799) was one of the first to propose to the savants of the time the necessity to gain observations and exact measurements in the field. Savants was a general term adopted simply to well educated people interested in various abilities - philosophy, art and medicine, which often encompassed natural studies. People interested and dedicated to the new emerging fields of "Natural history" and "Natural philosophy" - fields trying to describe natural phenomena and infer their (mathematical) rules -were more specifically referred as "naturalists" and "natural philosophers".
Natural philosophy encompassed all observable phenomena in nature, from the physiological reaction of the body on the summit of Mount Blanc to the rocks composing the mountain. At the time it was very roughly divided in three sub-disciplines- zoology, botany and mineralogy, still the specimen (animals, plants and mineral) approach to nature is evident.

Fig.1. James Hutton (left) and Joseph Black portrayed as "philosophers" or early "geognosts": caricature publsihed in 1787 by John Kay (Edinburgh) (From RUDWICK 2005).

A much larger approach, to the structure of earth itself, was tried by a new science emerging from geography adapted to the necessities of the mining industries to understand the underground and the position of ore-bearing rocks

In Germany the science called "Geognosie" (earth knowledge) encompassed the description and representation of the surface of earth, like geography, but widened it approach to the third dimension, hidden in the underground. This science was referred also as "mineralogical geography" or "géographie souterraine", its goals are best understandable in the Italian name "anatomia della terra" - anatomy of earth.

Fig.2. Luigi Ferdinando Marsili "On the Structures of Mountains" (1705), early geognosts mapped and developed a classification scheme for the various landscapes observed in nature, however still a theorizing part was missing (from BATTISTA 2003).

However it was an applied, descriptive art, not a science in modern sense dedicated to formulate rules or hypothesis and test them. Geognosts went in the field to map the rocks of the countryside, theirs maps and profiles were a major input to create a new, a real science researching also theories.

Fig.3. John Clerk of Eldin (1728-1812) "Whinstone Dykes´by Fairlie, Firth of Clyde", a drawing of a Cliff in Scotland made in 1786. Eldin, a passionate amateur geologist tries in this wonderful depiction to sketch the position and direction of the basaltic dykes in the underground, merging a two-dimensional map with the third dimension, the profile (found in THÜSEN 2008).

Already Georges-Louis Leclerc de Buffon (1707-1788) stressed in his "Nature's Epochs" (1778) the need to create an own geotheory to understand the structure, the sediments, the fossils and in the end the history of earth. In fact Saussure tried to adopt this approach in his natural studies. In the same year of Buffon's "Epochs" the term geology was introduced (hesitant) in the literature by the Swiss naturalist Jean-Andre de Luc in his opus "Letters on Mountains".

"I mean here by cosmology only the knowledge of the earth, and not that of the universe. In this sense, "geology" would have been the correct word, but I dare not adopt it, because it is not in common use."

Fig.4. "I a geologist", from the Notebook M, 1838, page 39 of Charles Darwin, the full phrase as follows: "I a geologist have illdefined notion of land covered with ocean, former animals, slow force cracking surface &c truly poetical."

Geology became synonymous with the "Theory of the Earth" - a part of cosmology dedicated to the description of the character of earth and maybe more important it relationships with animals, plants and finally humans.

"In now addressing my brother -geologists - and under this term I would comprehend all who take an interest in the progress of a science whose problems are inseparably interwoven with the whole study of nature - I have been influenced by the conviction that it is good for us, as workers in the same field, occasionally to pause and question ourselves as to the ultimate bearing of our investigations."
David Page (1863): "The Philosophy of Geology."

However the word geology itself has older roots, even if other meaning - in his testament and legacy written in 1603 the Italian Renaissance- naturalist Ulisse Aldrovandi (1522-1605) introduces the term "Giologia" to refer to the study of "fossilia" - the things unearthed.
Aldrovandi had tried his whole life to classify nature - to separate rocks and fossils from the animals and plants the already existing term mineralogy was not sufficient - giologia would encompass all stones, all minerals and especially the petrified organisms (he recognized some fossils as once living beings) and also rocks nobody at the time could explain found on the surface of earth, but also excavated - again an tentative approach to consider the three-dimensional structure of earth.

Fig.5. The word "La giologia" in the official version of Aldrovandi´s will (from BATTISTA 2003).

200 years later the term, theory and principles of Geology will become largely known by the work of many fulltime geologists, like for example Sir Charles Lyell.

Bibliography:

ROSENBERG, G.D. (2009): The measure of man and landscape in the Renaissance and Scientific Revolution. In Rosenberg, G.D. (ed.): The Revolution in Geology from the Renaissance to the Enlightenment: Geological Society of America Memoir 203: 13-40
RUDWICK, M.J.S (2005): Bursting the limits of time - The reconstruction of Geohistory in the Age of Revolution. The University of Chicago Press, Chicago, London: 708
THÜSEN, J.v.d. (2008) : Schönheit und Schrecken der Vulkane - Zur Kulturgeschichte des Vulkanismus. Wissenschaftliche Buchgesellschaft, Darmstadt: 239
VAI, B. (2003): Aldrovandi´s Will: introducing the term "Geology" in 1603. In BATTISTA, G. & CAVAZZA, W. (2003): Four Centuries of the Word geology - Ulisse Aldrovandi 1603 in Bologna. Minerva Edizioni: 327