The Earth-shattering Monster of Loch Ness

The first purported photo of Nessie was published in The Daily Mail" on April 21, 1934.  The image, taken by a London surgeon named Kenneth Wilson, was touted for decades as the best evidence for Nessie — until it was admitted as a hoax decades later.

In 2001 Italian geologist Luigi Piccardi presented at the Earth Systems Processes meeting in Edinburgh a hypothesis, explaining the supposed appearance of the lake monster in Loch Ness as a result of the local geology. According to Piccardi, the historical description of the monster - appearing on the surface with great (earth)shakes and waves - could be based on seismic activity along the Great Glen fault. The Great Glen fault is a transcurrent fault where two bits of Earth - the Grampian Highlands, composed of early Paleozoic plutonic rocks, and the Northern Highlands, composed mostly of Neoproterozoic rocks with Palozoic sedimentary covers - are sliding sideways against each other.

 BRETON; COBBOLODY & ZANELLA (2013).

Loch Ness is a 36 km long lake, located just above the fault zone. As the fault moves, earthquakes happen and cause bubbles and waves on the lake's surface. In an interview published in the Italian newspaper "La Repubblica" Piccardi explains:

"There are various effects on the surface of the water that can be related to the activity of the fault ...[]... the beast appears and disappears with great shakes. I think it's an obvious description of what really happened…[] We know that there was a period [1920-1930, a period characterized by many reported sightings of Nessie] with increased activity of the fault, in reality, people have seen the effects of the earthquakes on the water."

According to the biography of St. Columba, the scene described by Piccardi happened in the year 565. Trying to cross the river Ness the missionary is attacked by a beast. However, Columba implores the protection of god and the monster promptly disappears. The original text, however, is very vague and gives no detailed description of the event, stating only that it was an "unknown beast" and it approached with the mouth wide open and a loud roar. In the myth, the supposed lake monster is of much less importance than the ability of St. Columba to tame beasts and demons and doing so to impress the local pagans. It is quite possible that the supposed encounter with the monster was added to make Colomba´s legend bigger than real life. The vague description presented doesn't really support any proposed scenario, neither seismic activity nor a presumed surviving plesiosaur, living in a lake formed by glaciers during the last ice age some 18,000 years ago. Modern sightings in Loch Ness can more reasonably be explained by a combination of hoaxes, misidentification of common animals or waves and the local tourist industry, keeping the myth alive to attract tourists. Research done in the lake has never produced any clue for the possible existence of a population of larger animals in the Loch.

Also, historic seismicity doesn't seem to support the existence of an earth-shaking monster in the Loch. Earthquakes along the Great Glen fault range between a magnitude of 3 to 4, too weak to cause any observable effects on the lake. Stronger events are exceptionally rare and were recorded only in 1816, 1888, 1890 and 1901. These earthquakes don't coincide with the years of supposed increased activity of Nessie, like in the decade around 1933.

The true Geology behind The X-Files: Darkness Falls

Many of the threats encountered on the X-Files are not of this world, but even aliens seem normal when compared to some of our world´s insect species. 

In the episode "Darkness Falls" (season 1, episode 20) special agents Fox Mulder and Dana Scully are called in to investigate the mysterious disappearance of a team of loggers somewhere in the Cascade Range. Initially suspecting bigfoot (Mulder´s suspect) and eco-terrorists (Scully´s favourite), soon the agents find themselves isolated and trapped by a seemingly ancient menace lurking in the dark of the woods. Filming was done in the Seymour Demonstration Forest, north of Vancouver, a difficult to reach location even for the real film-crew.  

Soon it is discovered that an unknown species of insects was freed when the loggers illegally cut down old-grown trees. Mulder speculates that the insects, forming a sort of green-glowing swarm in the night, are a mutation caused by radioactive gases released from the underground, but extinct in the wild. However a swarm of the creatures, in close-up stock-footage of mites was used (mites are not insects, but related to spiders and can´t fly), survived hiding in the pores of a tree-ring, but now the swarm is free, very, very hungry and ready to build a nest. X-Files producer Chris Carter was inspired to write this episode based on his interest in dendrochronology – the study of tree-rings. 

Fig.1. The truth is in the tree-rings of this Douglas-fir - dendrology is used to reconstruct climate change in the past and was used in 1937 by R.H. Finch for the first time to date the activity of the Cinder Cones volcanic field in California.

But what about strange behavior of the supposed insects, are there similar real cases to be found? 

Ants are a common insect group, forming swarms with a complicated social structure and are successfully used as bioindicators - maybe even for gases coming from the underground.

 

 Fig.2. Alien ants...

Faults can be pathways for liquids and gases and some research tries to map faults by measuring the concentration of gases like radon. The permeability of a fault is also influenced by its activity, anomalous gas concentration could be signs of increased tectonic activity. During investigations in 2002 of the structural geology of the Rhenish Massif in Germany, it was noted that anthills of the species Formica rufa, F. polyctena and F. sanguinea display a peculiar linear trend. The locations coincided with active, gas-permeable fault zones. That ants could choose a site for their nest based on the bedrock is not impossible and was noted already 70 years ago, as the bedrock can influence if the soil is wet or dry and ants prefer dry conditions. However no correlation with faults or nests was known. In the 2002 research more than 1000 anthills were mapped, almost 700 of them running parallel to vertical fault lines. It´s not clear what effects the ants, as faults can imply a sudden change of bedrock, topography and gases. The case remains unsolved at the moment...

Fig.3. Ant may take some advantages by building their nests on gas-permeable faults, as the warm gases from the underground can act as sort of natural heating, figure from BERBERICH et al. 2013.

Interested in reading more? Try: 

BERBERICH, G. et al. (2013): Early Results of Three-Year Monitoring of Red Wood Ants’Behavioral Changes and Their Possible Correlation with Earthquake Events. Animals, 3: 63-84

BRENNHOLT, N. (2008): Geologische Störungszonen als Kriterium der Standortwahl Hügel bauender Waldameisen unter Berücksichtigung spezieller mikrobieller Gemeinschaften. Dissertation Universität Duisburg-Essen: 239
SCHREIBER, U.; BRENNHOLT, N. & SIMON, J. (2009): Gas permeable deep reaching fracure zones encourage site selection of ants. Ecological Indicators, 9: 508-517

How The Geology Of Mountains Made America Great

The story of the Appalachians started almost half a billion years ago. The first British colonialists arrived to North America just 400 years ago and yet both events are connected and shaped the history of the United States. Without a series of orogenic cycles 490-300 million years ago, caused by the continental collision assembling the super-continent Pangaea and forming the geological roots of the Appalachians, maybe today there would be the United States of Canada, bordering to the south with the Spanish-American Empire.

The first British colonialists arrived to America in 1607 and were confined by the mountains to the Atlantic coastal plains. The parallel north-south trending ridges of the Appalachians, formed by tilted and folded layers, were a difficult terrain, not suited for permanent settlements and of no use to the first farmers. 

Fig.1. Geological Map of Pennsylvania, published in 1858, showing the north-south trending ridges of the Appalachians mountains (source).

Only the French, settling from the North (territory later to become Canada), claimed the Appalachians, establishing a network of outposts for trading fur in the mountains. In the south Florida and the Great Plains were claimed by the Spanish crown as New Spain. 

It seemed that the British were surrounded by both natural as political opponents. However the isolation soon provided decisive. The plains in the Great Appalachian Valley in eastern Pennsylvania provided fertile ground and the population of the colonies grow over time, unnoticed by the French and Spanish. Soon the British expanded westwards in search of new land. This led to a conflict between England and France above the control of the few gaps and mountain passes in the Appalachians. The English colonists were far more numerous and better supplied than the French, having direct access to the sea. The rugged, poorly accessible terrain of the Appalachians proved difficult to defend by the French and allied Indians and were eventually lost to the expanding British colonies.
 

After the end of the French-American War the English crown wanted to limit the colonization and new settlements to the area of the Appalachians, hoping so to avoid further conflicts with the remaining French and Spanish territories. However the unexpected result was a resentment among the British settlers in America. Colonialists became convinced that the crown didn´t care for the political future of the successful expanding colonies. Among other factors, this resentment will contribute to the later Revolutionary War, where the American colonies will declare their independence, leading in the end to the foundation of the United States of America.
 

Bibliography:
 

ALESHIRE, P. (2008): The Extreme Earth - Mountains. Chelsea House Publishers: 144

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?
 

 

References:

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

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

April 18, 1906: San Francisco´s Wicked Ground

“O, promised land
O, wicked ground
Build a dream
Tear it down

O, promised land
What a wicked ground
Build a dream
Watch it all fall down”
“San Andreas Fault”

Sailors on board of the “Wellington“, just entering the bay of San Francisco, noted something unusual in the early morning hours of April 18, 1906. The captain reported later that the ship “shivered and shook like a springless wagon on a corduroy road” even if the sea was as “smooth as glass.“

Clarence Judson was swimming near Ocean Beach when he suddenly was pulled by a strong current into the sea. He made it back to the shacking shores.

“I tried to run to where I left my shoes, hat and bathrobe ... but I guess I must have described all kinds of figures in the sand.“

In Washington Street, police sergeant Jesse Cook observed a terrifying spectacle:

“The whole street ... It was as if the waves of the ocean were coming towards me,  ...[]... Davis Street split right open in front of me, []… A gaping trench. . . about six feet deep and half full of water. Suddenly ...[]... the walls of the building began to shake. Before I could get into the shelter of the doorway the walls had actually fallen inward.“

George Davidson, professor for Geography, woke up from the tumult coming from the streets. He grabbed his watch on the desk and noted the length of a first quake – 60 seconds – followed by a second – again 20 to 40 seconds long. His observations – 5:12am in the morning – will later be used to determinate the official time of the great earthquake of San Francisco. Many people were still asleep and killed in their beds, those who escaped gathered in the streets. Despite the earthquake, most of the city seemed still intact and surprisingly quiet.
In 1906 San Francisco was already considered a great, but also corrupt, city with more than 400.000 inhabitants. Thanks to the discovery of gold in the rivers of California the city was quickly expanding into its surroundings. It was an important gateway to the Pacific and a modern trade place. The newest technology in film equipment was available in the shops. The earthquake of San Francisco will become the first natural disaster of this magnitude to be so well documented by photographs and film footage (even in color).
However, most buildings in San Francisco were poorly constructed and made of wood. San Francisco had burned to the ground six times in the past century and experienced strong earthquakes in 1865 and 1868, when 30 people were killed.

“Earthquakey Times“, a caricature by Ed Jump of the October 8, 1865 earthquake in San Francisco. While he was working as a newspaper reporter in San Francisco, Mark Twain experienced the earthquake which he describes in his 1872 book “Roughing It.” – “It was just after noon, on a bright October day. I was coming down Third Street. The only objects in motion anywhere . . . were a man in a buggy behind me, and a [horse-drawn] streetcar wending slowly up the cross street. . . . As I turned the corner, around a frame house, there was a great rattle and jar. . . . Before I could turn and seek the door, there came a terrific shock; the ground seemed to roll under me in waves, interrupted by a violent joggling up and down, and there was a heavy grinding noise as of brick houses rubbing together. I fell up against the frame house and hurt my elbow. . . A third and still severer shock came, and as I reeled about on the pavement trying to keep my footing, I saw a sight! The entire front of a tall four-story brick building on Third Street sprung outward like a door and fell sprawling across the street, raising a great dust-like volume of smoke! And here came the buggy-overboard went the man, and in less time than I can tell it the vehicle was distributed in small fragments along three hundred yards of street. . . . The streetcar had stopped, the horses were rearing and plunging, the passengers were pouring out at both ends. . . . Every door, of every house, as far as the eye could reach, was vomiting a stream of human beings; and almost before one could execute a wink and begin another, there was a massed multitude of people stretching in endless procession down every street my position commanded. . . . For some days afterward, groups of eyeing and pointing men stood about many a building, looking at long zig-zag cracks that extended from the eaves to the ground...”

Police sergeant Jesse Cook was the first person to report a fire in a grocery in Clay Street. An hour later there were already fifty fires spotted in the entire city. The firefighters realized horrified that the water pipes in the underground were broken and the hydrants useless. The resulting firestorm will burn three days and will destroy 90 percent of the 28.000 buildings in San Francisco.

Journalist Arnold Genthe will take one of the most famous photos in history. 

“I found that my hand cameras had been so damaged by the falling plaster as to be rendered useless. I went to Montgomery Street to the shop of George Kahn, my dealer, and asked him to lend me a camera. “Take anything you want. This place is going to burn up anyway.” I selected the best small camera, a 3A Kodak Special. I stuffed my pockets with films and started out….”

“Looking Down Sacramento Street, San Francisco, April 18. 1906“, photography by Arnold Genthe.

In Jackson Street, the owner of the “Hotaling´s Whiskey” distillery decides to fight the flames. He pays 80 men to sprinkle 5.000 barrels of whiskey with water pumped out from the sewer system. Later he will mock all those who claim that the earthquake was sent by god by coining a new advertising slogan for his company.

“If, as some say, God spanked the town, for being over frisky – why did He burn the churches down and save Hotaling´s Whiskey?“

Army troops were soon ordered into the city to help the firefighters and prevent panic and looting. Despite the fact that martial law was never proclaimed, the major authorized policeman and soldiers to shoot looting persons – “Obey orders or get shot” was the grim warning on the signboards.
Guion Dewey, a businessman from Virginia, wandering the streets of downtown San Francisco minutes after the quake, experienced the best and worst of human behavior, as he later wrote in a letter to his mother:

“I saw innocent men shot down by the irresponsible militia. I walked four miles to have my jaw set. A stranger tried to make me accept a $10 gold piece. I was threatened with death for trying to help a small girl drag a trunk from a burning house, where her father and mother had been killed. A strange man gave me raw eggs and milk . . . (the first food I had had for twenty-two hours). I saw a soldier shoot a horse because its driver allowed it to drink at a fire hose which had burst. I had a Catholic priest kneel by me in the park as I lay on a bed of alfalfa hay, covered with a piece of carpet, and pray to the Holy Father for relief for my pain. . . . I saw a poor woman, barefoot, told to “Go to Hell and be glad for it” for asking for a glass of milk at a dairyman’s wagon; she had in her arms a baby with its legs broken. I gave her a dollar and walked with her to the hospital. . . .I was pressed into service by an officer, who made me help to strike tents in front of the St. Francis Hotel when the order was issued to dynamite all buildings in the vicinity to save the hotel. I like him and hope to meet him again. When he saw I was hurt, which I had not told him, not yet having been bandaged, he took me to his own tent and gave me water and brandy and a clean handkerchief.“

The earthquake and the firestorms killed an estimated 3.000 to 4.000 people, destroyed 28.000 buildings and the infrastructure of the entire city. However, thanks to a quick rebuilt, just three years later most of San Francisco looked as if the earthquake never happened.

Seismology was still a young scientific discipline at the time of the earthquake in San Francisco. Worldwide there were only 96 seismographs operating, none of these in California. In the aftermath of the disaster, only three days later, the Governor of California announced the formation of the State Earthquake Investigation Commission, led by geologist Andrew C. Lawson of the University of California.
The commission focused on the San Andreas Rift, a nearby valley until then considered of minor interest and mapped geologically only in short sections. For two years Lawson and his team followed the rift, mapping ponds, streams and hills on foot and horseback. They recognized that the rift follows almost the entire coastline of California for more than 1.000 kilometers. During the April 18, earthquake, almost 480 kilometers of this large fault suddenly ruptured, displacing large sections horizontally, not vertically, as geologists had previously believed to be the source of earthquakes. The commission discovered that earthquakes can be generated also along so-called strike-slip faults.
The epicenter of the earthquake was at first located at the point with the largest observed displacement on land. However, today the epicenter is believed to be situated in the Pacific Ocean, in accordance with the seismic waves coming from the sea as observed by the first eyewitnesses.
The results of the scientific investigation of the San Francisco earthquake led Henry Fielding Reid, a geology professor at Johns Hopkins University in Maryland, to propose a new theory regarding the origin of earthquakes, later dubbed the “theory of elastic rebound“. Reid’s hypothesis will have a revolutionary impact on the young science of seismology.

Sources:

SLAVICEK, L.C. (2008): The San Francisco Earthquake and Fire of 1906. Great Historic Disasters. Chelsea House Publishers: 128
STARR, J.D. (1907): The California Earthquake of 1906. A.M. Robertson, San Francisco

Bailey Willis - The Man who made Mountains

U.S.G.S. engineer Bailey Willis († February 19, 1949) was known for his unorthodox approach to geological questions. Puzzled by the geological structures he discovered in mountain ranges, long before computer-models were available, he constructed a machine to simulate the mountain-forming process.

In a box with a moveable piston he folded and crushed layers of beeswax and compared the structures with the large tectonic folds and thrusts he had mapped in the Appalachian Mountains. He realized that folds and nappes could form also by horizontal movements and compressive forces – not, as still many geologists argued, only by vertical movements.

Fig.1. Willis´”Compression Machine for Experiments”  from “The Mechanics of Appalachian Structure” (1891).

Fig.2. Miniature mountains made by the “compression machine” – the strata first form regular folds, however as the shortening continues, shear zones develop and single “tectonic nappes” start to pile up.

Fig.3. Folded strata in the central Appalachian Mountains. In later years Willis proposed a first version of plate tectonics to explain mountain formation processes – the Atlantic Ocean was formed when a “bubble” of magma pushed apart the American and European continents, along the borders the layers of rocks were compressed and folded up – the Appalachian Mountains formed. Unfortunately this mountain range is significantly older than the Atlantic…

Fig.4. Willis subdivided mountain ranges in a central zone, characterized by folds, and an outer zone, characterized by shear zones (geological map of Cleveland in Tennessee). Today we know that the conformation can be much more complicated than that.

January 6, 1912: Happy Birthday Continental Drift!

January 6, 1912 the German meteorologist Alfred Wegener presented in a lecture entitled “Die Heraushebung der Großformen der Erdrinde (Kontinente und Ozeane) auf geophysikalischer Grundlage” (The uprising of large features of earth’s crust (Continents and Oceans) on geophysical basis) for the first time his hypothesis of the ancient supercontinent Pangaea, from which all modern continents split apart.
Three years later he will publish his book “Entstehung der Kontinente und Ozeane“, translated in the third edition and published in 1922 as “The origin of continents and oceans.”
 

Wegener didn’t propose something completely new; as he based his idea on earlier observations and suggestions, but his work started a fierce discussion in the scientific community.

  

In 1889 and 1909 the Italian musician and naturalist Roberto Mantovani published a hypothesis based on his observations on the volcanic island of Réunion: cracks forming during volcanic eruptions could separate even large parts of an island, could it then be possible that entire continents split apart? Mantovani collected various evidence and published maps to show the shape of the hypothetical former continents (Wegener will use these maps to support his idea), however he explained the driving force behind the breakup of former large continents by the slow expansion of the earth.
 

In 1908 the self-educated geologist Frank B. Taylor proposed that the crust of earth was influenced by tidal forces of the moon and the continents were pulled apart in some regions and pushed together in other areas, forming folds like a carpet. However the involved forces were to weak and his explanation wasn’t deemed plausible. The Austrian geologist Otto Ampferer speculated in 1906 that the Alps were formed by folding of the upper crust, as driving force he proposed magma sinking into the mantle and pulling pieces of crust downwards (!). This “Unterströmungstheorie (also Subfluenztheorie)” lacked however a convincing source of energy and couldn’t explain all aspects of the genesis of the Alps, as it implied only pulling and not compressive forces needed to form folds and faults.

Wegener became interested in the idea of a single continent in 1910 by observing an atlas and noting the coasts of the Africa and South American. Some time later he read a paleontological paper discussing the similarities of terrestrial fossils between separated continents.
 
Wegener continued to collect various published evidence to support his theory of a single continent:
- Like a puzzle also the outlines of continents (especially the continental shelves) seem to fit together.
- There are various geomorphologic and geological similarities along the coasts of South America-Africa and Europe-North America.
- Fossil of land vertebrates and plants can be found on different continents, separated today by large oceans.
- Fossil evidence of ancient climates, today without a recognizable pattern, will form climate zones when the continents are put together.

Wegner considered the prevailing explanation for the patterns in the fossil record as impossible: ancient land bridges that connected continents and habitats (like the Isthmus of Panama today) were composed of light continental granitic crust, such pieces of less dense rocks couldn’t simply sink into the much denser oceanic basalts and disappear without trace.

He will explain in 1911 his idea in a letter to his father-in-law, Professor Wladimir Peter Köppen:

“You consider my primordial continent to be a figment of my imagination, but it is only a question of the interpretation of observations. I came to the idea on the grounds of the matching coastlines, but the proof must come from the geological observations.
These compel us to infer, for example, a land connection between South America and Africa. This can be explained in two ways: the sinking of a connecting continent or separation. Previously, because of the unproven concept of permanence, people have considered only the former and have ignored the latter possibility. But the modern teaching of isostasy and more generally our current geophysical ideas oppose the sinking of a continent because it is lighter than the material on which it rests. Thus we are forced to consider the alternative interpretation. And if we now find many surprising simplifications and can begin at last to make real sense of an entire mass of geological data, why should we delay in throwing the old concept overboard?“

 

  

Wegener hypothesis of continental drift (a catchy phrase adopted mainly by the critics, as Wegener talks more general of “displacement theory“) was received with mixed feelings. Most geologists regarded it as cherry-picking of anecdotes from the literature. However some geologist with field experience, especially in Africa and South-America, became soon convinced of this possibility.

Like Taylor also Wegener could not explain the forces necessary to move the continents in the crust. Wegener imagined that continents - like gigantic ice floes - swim on and are surrounded by the much denser oceanic crust.  He proposed gravitational pull, tidal and centrifugal forces, but the English geophysicist Harold Jeffreys demonstrated that these forces are much too weak or if strong enough, had to stop first earth’s rotation.
 
Wegner himself reacted to the critics and tried to respond to them in various editions of his books, however with moderate success. The greatest problem remained the lack of direct evidence for the movements of continents and the needed explanation for the mechanism and also the large amount of energy needed to move and deform rocks. Most importantly Wegener considered his work as starting point and stimulus for other or even future scientists, a message that wasn’t fully understand at his time.

 

Fig.1. – 3. “Eppur si muove!” Reconstruction of the former supercontinent of Pangaea and the subsequent breakup in various smaller continents from the Carboniferous to the Quaternary. From WEGENER, A. (1929): Die Entstehung der Kontinente und Ozeane. 4th ed.

Wegener will die in 1930. His continental drift hypothesis is in many aspects erroneous: not the single continents move but entire plates of the crust and the driving force comes from within the planet, not from outside. However his most important legacy is to have introduced the idea of moving continents to the scientific community and the public (even Lovecraft will became inspired by Wegener’s writings) – decades later this legacy will influence a new kind of theory: Plate Tectonics.

Bibliography:

MILLER, R. & ATWATER, T. (1983): Continents in Collision. Time-life books, Amsterdam: 176
SCALERA, G. (2003): Roberto Mantovani an Italian defender of the continental drift and planetary expansion. From Scalera, G. and Jacob, K.-H. (eds.): Why expanding Earth? – A book in honour of O.C. Hilgenberg. INGV, Rome: 71-74

The Man who made Mountains

U.S.G.S. engineer Bailey Willis († February 19, 1949) was known for his unorthodox approach to geological questions. Puzzled by the geological structures he discovered in mountain ranges, long before computer-models were available, he constructed a machine to simulate the mountain-forming process.

Marie Tharp: The map that changed the world

"The tiny fringe of shallow sunlit waters which has been so frequently treated in books and films is entirely excluded, for in this book we are concerned only with the sunless and little-known abyss which claims over half of the planet."

HEEZEN & HOLLISTER (1971)

Marie Tharp was born July 30, 1920 in Ypsilanti, Michigan. Already at very young age she followed her father, a soil surveyor for the United States Department of Agriculture, into the field. However she also loved to read and decided to study literature at St John's College in Annapolis, but at the time women were not admitted to study there. So she went to Ohio University, where she graduated in 1943. 

The Second World War changed dramatically the situation in the United States - the nation needed highly educated replacement for the men who went into war, women now were encouraged to choose degrees also in science and technology. Marie enrolled in a petroleum geology programme, becoming so a "Petroleum Geology Girl" she graduated in geology in 1944. Afterwards she worked for a short time in the petroleum industry, however she found the work unrewarding and decided to resume her studies at Tulsa University. 

In 1948 she graduated in mathematics and found work at the Lamont Geological Laboratory of Columbia University. The atmosphere there was relaxed and friendly; also in times of Cold War money for geological projects studying the ocean floor, which results promised to be important for the war with submarines, was abundant. 

She began a prolific collaboration with geologist Bruce Charles Heezen (1924 -1977), who was specialized on the gathering of seismic and topographic data from the sea floor. As women Marie was not allowed on board of the research vessels crossing over the sea to collect profiles of the seafloor, so she started to calculate, interpret and visualize the data when Heezen was on the sea. She co-authored with Heezen a book and various papers; however her role was often neglected. Her employment despite continuous remained insecure, in certain moments the bureaucracy and financial troubles forced her to work from home. 

Between 1959 until the death of Heezen in 1977 she worked strenuously on various maps that would depict the still unknown topography of the oceanic basins - and the results were astounding. The ocean floor was not a flat plain of mud, as previously imagined, but displayed mountains, ridges and canyons, sometimes larger and deeper than any feature found on the continents. The most impressive feature however was a chain of mountains cutting in half the large basins of the oceans - Tharp and Heezen had discovered the backbone of earth, the Mid-Ocean Ridges.

Fig.1. "I was so busy making maps I let them argue,...[]" (photography published in HEEZEN & HOLLISTER 1971). Both Heezen and Tharp recognized the Mid-Ocean Ridges as spreading centres of the oceanic crust; both tended to consider this a result of an expanding globe. Marie Tharp´s cartographic accomplishments were exceptional because she overcame educational and employment barriers that limited opportunities for women of her generation. Without doubts she prepared the field for other researchers; however she will not became directly identified with the era's most revolutionary geological theory  - plate tectonics.

Bibliography:

BARTON, C. (2002): Marie Tharp, oceanographic cartographer, and her contributions to the revolution in the Earth sciences. In OLDROYD, D.R. (ed.) The Earth Inside and Out: Some Major Contributions to Geology in the Twentieth Century. Geological Society Special Publications 192, London: 215-228
HEEZEN, B.C. & HOLLISTER, C. D. (1971): The face of the deep. Oxford Univ. Press, New York, London, and Toronto: 659

Humboldt´s Cosmos

"Inside the globe there live mysterious forces, whose effects become apparent on the surface. Outbreaks of vapours, hot slag and new volcanic rocks, as uplifts of islands and mountains"
Alexander von Humboldt

Fig.1. Geologic map and profile of the Pyrenees, after the "Berghaus-Atlas", a supplement to Humboldt's masterpiece "Kosmos" (1845-1862).
In the profile from inside to the outside of the mountains the layers are described as follows "Granitic rocks and general basement" - "transition mountains/rocks" - "secondary mountains". In the map Granite=pink, Basaltic rocks=green, Schist= grey, Clastic rocks/ Limestone= blue, Sandstone= red, Secondary Limestone= yellow, Tertiary rocks= dark-green

The German Alexander von Humboldt (1769-1859) studied finance and also mining engineering and became later a great self-educated explorer and naturalist. Following the tradition prevalent in Germany at the time he was educated to interpret geology with Werner's Neptunism - rocks were formed from liquids and magmatic phenomena are only of local significance.
During his travels in Europe and America he observed also active volcanoes and soon converted to Plutonism - rocks are formed from cooling lava and magmatic forces play a mayor role in shaping earth's surface.
In accordance to the theory of German geologist Leopold von Buch (1774-1835) of "volcanic bubbles" the profile shows the Pyrenees as a result of uplift by a core of magmatic rocks, bending the sedimentary layers of sandstone and limestone formations. According to this hypothesis magmatic rocks are found always as core in mountain ranges. To explain the apparent lack of Grantic rocks (coloured in pink) in the northern areas of the Pyreenes Humboldt apparently suggested selective erosion - explained by the schematic profile at the bottom of the page.

The Pyrenees are a mountain range 1500km long with an average width of 200km, the most western foothills of the Alpine-Himalayan orogenic belt. According to the modern theory of plate tectonics these mountains formed when the Iberian plate was partly subducted under the European plate, in a time period from the late Cretaceous to the Miocene (55-25 Ma).
The profile of the Pyrenees display a fan-shaped structure, with north vergent thrusts in the northern area and south vergent thrusts in the southern part.
In northwest to southeast direction the mountain range can be divided into five structural zones

- The Aquitaine foreland basin with the deformed Cretaceous sediments of the European Plate.
- The North Pyrenean thrust zone with thrust faults developed in the crystalline basement and the Mesozoic to Eocene sediments.
- The Axial zone with three mayor nappes of the crystalline basement
- The South Pyrenean thrust zone with deformed early Eocene to Miocene sediments.
- The Ebro foreland basin molassic, filled with relatively undisturbed sediments.

Fig.2. Axial Zone: Variscan granitoid rocks and Palaeozoic sediments (Humboldt´s granitic rocks); Thrust Zone: Mesozoic to Cainozoic deformed sediments; Foreland basin: Cainozoic undeformed sediments (after SCHELLART 2002).

The asymmetry of the Pyrenees (the estimated shortening is 70km in the south and 32km in the north), recognized already at Humboldt's times, is today explained by rotation due asymmetric mountain roots, where the Iberian plate was partially subducted under the European plate.

Bibliography:

SCHELLART, W.P. 2002: Alpine deformation at the western termination of the Axial Zone, Southern Pyrenees. In: Rosenbaum, G. and Lister, G.S.2002. Reconstruction of the evolution of the Alpine-Himalayan Orogen. Journal of the Virtual Explorer, 8, 35-55

John "Jack" Walter Gregory and the Great Rift Valley

John "Jack" Walter Gregory was born in London in the year 1864. Already in early age his interest in natural sciences and travels emerged - during his later career he will visit Europe, Africa, Australia, India, North- and South America, even the remote island of Spitsbergen.
His interest in geology spawned from the practical need to know where he actually was:

"… my attention was first directed to geology in order to understand the geography of the districts through which I rambled, and the, often, apparently erratic course of the rivers … and to understand local topography'."
Gregory in 1906

He studied natural sciences, working during day as wool merchant and studying at night - he even became accustomed to sleep only 4 hours per day. After graduation he found work at the British Museum for Natural History, where he worked on the collection of rocks, fossil echinoderms and corals.
In October 1892 Gregory was asked if he would take on an expedition to East Africa, comprising the area of today Kenya, Ethiopia and Somalia - regions at the time still poorly known or mapped, but geopolitically important.

Gregory however showed interest in the geology of Africa long before the possibility to join the expedition, impressed by the hypothesis of Austrian geologist Eduard Suess.
The origin of the mountains and depressions of the African continent were fiercely discussed by geologist, Suess summarized in 1891 the results of an expedition leading to Lake Rudolf, carried out by Count Samuel Teleki (de Szek) (1845-1916), and suggested that the depressions starting at the coasts of the Red Sea were the results of periodic tectonic movements.

Fig.1. "The Great Rift Valley: some associated fractions are marked by broken lines." The part of the valley system explored by Gregory in 1892-1893 (located east of Lake Victoria) is today also referred as Gregory Rift (GREGORY 1920).

20, November 1892 the ship of the expedition unloaded 300 tons of equipment in the harbour of Lamu, 110 camels and 40 donkeys were acquired to transport the material and 300 soldiers were hired to protect the caravan - planned destination of the expedition was Lake Rudolf, a destination that they however would never reach.
Despite the 300 tons of equipment soon problems arouse - food went bad and cooking pots and tents were missing or unsuitable. Fever and various diseases spread among the expedition members, Gregory was first plagued by ulcers on the legs that immobilized him for weeks and on 17, January 1893 he fell sick with malaria. He recovered only after days with very high fever - arrived to Mombasa the expedition was officially cancelled.
Gregory, still interested to see for himself the depressions of Central Africa, decided to take advantage of the situation. He was already in Africa and the equipment of the abandoned expedition could still be usefull - with the financial help of his family and the British Museum he organized a new expedition. On 23, March 1893 the expedition comprising this time 41 men left Mombasa. Gregory's old peculiarities emerged; he loved to walk alone for kilometres, collecting specimens of plants, animals and rocks, for most of the time he didn't sleep at night, sneaking trough the camp controlling if the sentries were on duty.

"… the geology was so tempting that I went off alone. By this time the men were accustomed to my going by myself, for I did so whenever the country was safe and the next camping-place easy to find. These solitary rambles were to me the most delightful incidents in the expedition. Free from the bother of the caravan, I could climb a mountain, track a river, visit a neighbouring lake, chase butterflies, and collect plants as careless as a schoolboy."
Gregory 1896

The main geological work was carried out from the village of Njemps on the shores of Lake Baringo, where they mapped the geology of the western wall of the Kamasin Scrap - today recognized as part of the Great Rift Valley. Gregory confirmed Suess interpretation of the tectonic origin of this valley and deduced from the weak erosion seen on the mapped faults that this process must have been very recent. He described his discoveries in an article published in the journal of the Royal Geographical Society in 1920, where he coined also the modern term of Rift Valley and connected it to tectonic movement of the earth (a controversial hypothesis at the time, when most landscapes were regarded as results of erosion).

Fig.2. Geological sketch map of British East Africa (Kenya) showing the locations of Lamu Island, Witu, Mombasa, Lake Baringo and Mount Kenya, all visited by Gregory in 1892 and 1893, plus an outline of the Rift Valley (GREGORY 1896).

Fig.3. Section across the Rift Valley (GREGORY 1896), F=faults, Gregory suggested that the faults, forming the characteristic elements in the section of the rift valley, were due to vertical movements - apparently also Scar from "Lion King" is singing in an area with active tectonic uplift…




"For this type of valley I suggested the term Rift Valley, not implying that the whole valley was formed by the two sides being simply pulled apart, but as a breach due to a subsidence between two series of rents."
GREGORY 1920

Gregory connected the African Rift Valley with the similar Red Sea in the north - the dimensions of this feature surprised him, clearly that was a mayor element of earth's crust, connected to mountain ranges and similar basins found around the globe. He proposed that the magmatic rocks filling the African rift erupted during the Tertiary from the lateral shear zones, evidence of vertical, rather than horizontal movements - before the advent of continental drift a common model for global tectonics.

Gregory visited also Mount Kenya, even if - despite his alpine climbing experience - he was not able to reach the summit. Here he mapped the moraines of the glaciers and noted that they had retreated previously to 1893 to their "actual" position. Mount Kenya was conquered by Sir Halford Mackinder in 1899, who also named one of the glaciers found on the mountain - Gregory Glacier.

Fig.4. Reproduction from his 1896 book of a view of Gregory and an African climbing on Mount Kenya.

Bibliography:

GREGORY, J. W. (1920): The African rift valleys. The Geographical Journal, Vol. 56 (1): 13-41
GREGORY, J. W. (1896): The Great Rift Valley: being the narrative of a journey to Mount Kenya and Lake Baringo : with some account of the geology, natural history, anthropology and future prospects of British East Africa. John Murray, London: 500
LEAKE, B.E. (2011): The Life and Work of Professor J.W. Gregory FRS (1864-1932). Geological Society Memoir, No. 34: 234