A 3,000 Year Old Geological Map

According to ancient historians, gold in the kingdom of Egypt was as common as is sand in the desert. It´s true that Egypt exported for centuries large quantities, and even the Romans mined gold in Egypt (last attempts for gold mining were done in the 1950s). However, where the ancient mines were once located became forgotten over time.
 

Archaeologist Rosemarie and Dietrich Klemm discovered in the 1980s the lost mines following an ancient "geological" map. Discovered near modern Luxor (ancient Thebes) between 1814 and 1821, the papyrus/map was brought to Italy and is today hosted in the collection of the Museum of Egyptian History in Turin. The Turin papyrus dates back to 1,150 BC and  was prepared for an expedition led by Ramesses IV.

Reconstructed map of the Turin papyrus, image source. Pinkish-red= gold-bearing rocks, dark-green= rocks for construction.

Modern interpretation of geology , red=Hammamat-fm sandstone and volcanics, blue= Atalla-Serpentinite, yellow & green= Fawakhir-Granite.

The map shows the landscape around an unknown oasis. Inscriptions describe the "Mountain of the Gold”, the “Mountain of the Silver”, but also the location of the “Village of the Miners”, the "Temple of Amun", the streets to the (Red-) Sea and a street to Ta-menti (an unknown locality). The different colors of the map are inspired by the real colors of the rocks, reddish feldspar-granite (Fawakhir-Granite), dark Atalla-Serpentinite and Hammamat-Formation, and yellow for the sand of the desert. A dry river runs down the entire valley, eroding and transprting the rocks, as shown by the pebbles in different colors. A quarry of bekhen stone, a blue-green sandstone used to carve statues, is shown, as are many mines for gold. The most important indication was the location of a well near the village. Thanks to this well, archaeologists identified the area shown on the map. The ancient mountains of gold and silver are situated in the Wadi Hammamat, near Bir-Um-Fawakhir, an ancient miner settlement, almost 100km east of Luxor. Following the indications of the map into the field, the archaeologist discovered ancient signs of mining, like 50m long tunnels following quartz veins. The important veins are shown as lines in the Turin map. The gold is found as tiny fragments in the massive quartz, almost invisible to the naked eye. That ancient Egyptians found it, is a impressive evidence for their (emprical) geological knowledge. Already in 3,200 BC professional geological prospectors, called “sementi“, searched for deposits and veins of gold, to meet the demand of the divine pharao. Tutankhamun’s tomb alone was filled with more than 500 items, many made of pure gold. Following the veins into the mountain, the miners extracted the rock, crushing it, and washing the heavy gold out. Large deposits of quartz sand, the remains of the crushed rocks, still today testimony the hard work done by the ancient miners.

Will democracy survive climate change? - A lesson from the past

Allegory of volcanism as bringer of fortune (fertile soils) and destruction, by artist Alexandre-Évariste Fragonard (1780-1850) after a draft by French naturalist Joseph Nicolas Nicollet (1786-1843).

In June 1783 a volcano in Iceland erupted. Volcanoes are nothing unusual in Iceland, but this eruption, later referred as Laki,  was different. For eight months volcanic ash and gases poisoned the atmosphere over Europe changing the climate for years to come. In Europe the exceptionally hot summer of 1783 was followed by long and harsh winters until 1788. Crop harvests were poor and bread, essential for the large and poor population on the continent, experienced a massive price increase.

Map showing the lava flows of Lakagigar, from Magnus Stephensen "Kort Beskrivelse: Vester-Skaptefields-Syssel paa Island" (1785). The lava from the fissures ended up covering an estimated 2,500 km² (965 sq mi) of land.
 

At the time France was characterized by a great inequality between the poor peasants and the upper class. The rich aristocracy and the corrupted clergy lived in an own world, distant from daily problems. The lower and middle class had no political power despite its important role in economy and the king was to weak to control the aristocracy. Poor harvests and war expenditures resulted in an economic crisis and famine spread. In human history hunger was always a powerful agent of change. Italian officials noted in 1648 during a widespread famine that “it was always better to die by the sword than to die of hunger.” Women revolted on the streets demanding bread. July 14, 1789 5,000 citizens of Paris stormed the Bastille. Years of chaos followed. French lawyer Maximilien Robespierre instituted an authoritarian regime, culminating in 1793 with the execution of king Ludwig XVI. followed by 16.000 other people only in Paris. In 1799 Napoleon Bonaparte promised to bring order in those chaotic times and in the end declared himself emperor - celebrated by the same people that just some years earlier battled an absolute monarch. Even if the French Revolution is often seen as starting point for the modern Europe, democracy was predated by tyranny.

Georg Heinrich Sieveking’s “Execution of Louis XVI” in 1793.
 

Today we observe similar tumultuous times and a changing climate. However this time the changing climate is not the result of a short-lived volcanic aftermath. The warming caused by the anthropogenic carbon-dioxide emissions  into earth´s atmosphere will continue for the next centuries. Some research has suggested that a warmer climate will fuel future conflicts. Droughts can cause water and food shortages in less industrialized nations. In 2010 drought in Russia and too wet weather in Europa caused a 20% loss of crops harvest, prices in response were raised on the international market by 40 to 70%, also due speculations. China, also suffering from a poor harvest, stocked crop, causing ulterior shortages.

The increased costs, widespread unemployment and misery lead to riots and demonstrations in many North African countries. The chaos lead in part to installments of  governments controlled by the military and in Syria (hit also by a drought from 2006 to 2010) the civil war is still going on. The civil wars in Africa and Near East caused mass migrations of refugees to the first world countries, Europe was not ready for the onrush, causing a political chaos. In response many right-winged parties, promising simple solutions like walls or travel bans, gained support in many European countries (U.K., France, Germany, Austria, Italy). Right-wing politics promised also simple solutions in the United States. The poor and middle class fears migration as this implies to share already limited resources. The rich class supports such fears as it distracts from the real causes (less than 3% of the population controls more than 50% of the global wealth).
Travel bans and suppressing research about climate change doesn´t solve problems but simply hides the truth. Already authoritarian systems like Russia or China seem also best fitted to deal with future climate change. Such systems can suppress disadvantageous news about climate change effects but also react faster to impending disasters. China, dealing with severe environmental problems due its rapid industrialization, planted millions of trees in governmental controlled projects or simply limited traffic in cities. Such projects would need more effort, time and especially support by citizens in democratic systems.
In times of supposed chaos, overwhelmed by the problems (real or faked), we demand for simple solutions, as authoritarian systems can quickly promise (if they really will hold the promise is another problem), but simple is not necessary the right way.

Non Sequitur by Wiley Miller

Charles Darwin in Rio de Janeiro and the Geology Of Sugarloaf Mountain

The Sugarloaf Mountain (aka: Pão de Açúcar) rising almost 400m above Rio de Janeiro is composed of granitoid rock – a plutonic rock formed by the slow cooling from magma and composed mostly of the minerals quartz, feldspar and mica.
 

Charles Darwin, visiting Rio de Janeiro in 1832, describes in details this rock “- This whole district is almost exclusively formed of gneiss, abounding with garnets, and porphyritic with large crystals, even three and four inches in length, of orthoclase feldspar: in these crystals, mica and garnets are often enclosed.”
 

Fig.1. View of Rio de Janeiro with Sugarloaf Mountain as seen from the Corcovado by HMS Beagle artist Augustus Earle. 

Granite shows commonly no preferred orientation of the minerals, however Darwin noted that the granite of Rio de Janeiro seems to be more of a gneiss with a weak developed “stratification and foliation” of minerals, as he continues “The mountains of gneiss-granite are to a remarkable degree abruptly conical, which seems caused by the rock tending to exfoliate in thick, conically concentric layers: ...”
 

Indeed the Sugarloaf is, as correctly described by Darwin, composed mostly of augen-gneiss, a metamorphic rock with single large, often elongated, crystals, resembling eyes in a finer matrix of smaller crystals, therefore the name as auge means eye in German.

Fig.2. Simplified geological map of the Sugarloaf and surrounding bornhardts, from MIGON 2010.

The Sugorloaf is also evidence for plate tectonics. 560 million years ago, when the ancient supercontinent of Gondwana started slowly to break apart, large magmatic bodies intruded into the weakened crust, feed from below by the Tristan da Cunha hotspot. 

Fig.3. Large Igneous Provinces (LIP) and correlated hotspots. Magmatic rocks of the same type can be found on both sides of the Atlantic Ocean, showing that South America and Africa once were one single continent.

Slowly cooling in the upper crust these magmatic bodies formed a large granitic pluton. During the movement of the continents parts of the pluton broke apart, as we find the same type of rock along the coasts of South-America and of Africa, also some metamorphism and deformation of the rocks occurred and the cleavage of the gneiss formed. Later finally the metamorphic pluton was pushed upwards and erosion started to form the modern landscape of Rio with the hard augen-gneiss towering above weaker and more erodible rocks.

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

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

In search of Punt: The Lost Land of Gold

"Suddenly I heard a noise as of thunder, which I thought to be that of a wave of the sea. The trees shook, and the earth was moved. I uncovered my face, and I saw that a serpent drew near…[]…his body was as overlaid with gold, and his colour as that of true lazuli….[]… it was the prince of the land of Punt…"
"The Shipwrecked Sailor", 2200 B.C.



May 9, 1871 the German geologist Karl Mauch finally spotted after one year of strenuously search was he had hoped for: the impressive ruins of gigantic stone buildings - the remains of a long lost city, at least for the European explorers. The local people of the tribe of the Shona know the ruins well - in their language the buildings were called "dzimba woye" - the venerated houses, build by an ancient African civilization. Mauch however, following the racial ideas of the time, was sure that the buildings "could not possibly being built by Negroes." * He thought that he had discovered the ruins of the mythical city of Ophir, known in legends for the immeasurable wealth treasured there, and of course founded by Asian immigrants. 

The bible cites Ophir as unidentified place from which King Salomon received a cargo of gold, silver, sandalwood, precious stones, ivory, apes and peacocks - and all this every three years. Various scholars puzzled about the exact location of this rich land, the African continent seemed to be supported by the tales of exotic animals found in Ophir, but in 1857 the German archaeologist Heinrich Ferdinand Karl Brugsch collocated Ophir on the Arabian Peninsula.
Other scientists associated Ophir with another legendary place - "Ta netjer" the land of the gods, also known by the ancient Egyptians as the land of gold - the mythical Punt.
But Punt was more than a legend - long before 2000 B.C. Egyptian Pharaohs send expeditions to Punt to recover precious metals - gold, silver and electrum, gemstones - like malachite, wood and resin. The successful expeditions were so important, such great achievements, that the Egyptians immortalized them on their temples.
In the temple of Athribis, commissioned by Ptolemaios XII, a relief shows the various and precious trees growing in Punt - apparently Punt was a lush, tropical land.
In 1858 the French archaeologist Auguste Ferdinand François Mariette interpreted a relief in the temple of Deir el-Bahari, the mortuary temple of Queen Hatshepsut, as realistic depiction of an expedition to the remote and fabled land of Punt. 

Fig.1. The expedition to Punt as immortalized in the mortuary temple of Queen Hatshepsut. The ships are loaded with gifts and exotic animals, (large version) image from Institute for Egyptology - University of Bern.

The reliefs show a fleet, the five ships are loaded with gold, trees and exotic animals like leopards, apes and giraffes - species associated with the African continent. In the sea the reliefs sows various fish species, zoologist identified some of them living on the coast of Africa, but also near the Arabian Peninsula. The plants that produce frankincense and Myrrh, Boswellia sp. and Commiphora myrrha, are native to the Arabian Peninsula (Oman, Yemen) and to Africa (Djibouti, Ethiopia, Somalia, Northeast Kenya).

Maybe looking at the geology the place of Punt can be traced back to Africa? Still today in Eritrea gold can be found, associated to the old metamorphic rocks of the interior plateau. The river of Nahr Al-qa-sh is known for its gold bearing sediments. Also in Ethiopia gold is associated with the proterozoic metamorphic rocks, found to the west of the Afar lowlands, where cenozoic volcanic rocks mark the Great Rift System of the African plate. The eastern part of this proterozoic basement is found on the northern coast of Somalia. The overall geology of Saudi-Arabia - especially Yemen and Oman- is characterized instead by phanerozoic sediments mostly lacking gold. 

 Fig.2. Simplified geology of north-eastern Africa and possible localization of Punt, Mersa Gawasis was an ancient Egyptian harbour.

Geology can however give us another ulterior clue to find the lost land of Punt. Along the gifts brought back from Punt were also living exotic animals, so baboons (Papio sp.) - as clearly depicted on the relief of Deir el-Bahari. In 2010 researchers analyzed hair samples from 3.000 years old mummified baboons found in the tombs of the Valley of the Kings. 

Every living organism must drink water and water consists of two elements: hydrogen and oxygen. Both elements exist in various isotopes, atoms who differ in mass and also (slightly) in chemical properties. The oxygen isotopic signature of a particular spring can be unique and is controlled by geology and location of an aquifer. By comparing the results of the ancient hair samples with hair samples of animals living in Eritrea, Ethiopia, Somalia, Yemen, Uganda and Mozambique the research concluded that most isotopic similarity can be found with animals coming from eastern Ethiopia and all of Eritrea.

Mystery solved? Well, the isotopic signature could be identified only from one baboon and the localization is still very vague. The search of a myth continues….

*The British archaeologist Gertrude Caton-Thompson proved in 1929 that Great Zimbadwe and the civilization that build these monuments are of African origin.

Bibliography:

BROWN, D.M. & LYNCH, J. (1995): Africa's Glorious Legacy (Lost Civilizations). Time-Life-Books: 168
FRANZ, A. (2011): Das sagenhafte Goldland Punt. Bild der wissenschaft 9(11): 68-75
HOULIHAN, P.F. (1996): The Animal World of the Pharaohs. Thames & Hudson: 237
SCHLÜTER, T. & TRAUTH, M.H. (2006): Geological Atlas of Africa - With Notes on Stratigraphy, Tectonics, Economic Geology, Geohazards and Geosites of Each Country. Springer-Verlag Berlin Heidelberg: 255

Online Resources:

(2008): Terra X - Weihrauch für den Pharao - Aufbruch nach Punt. (Accessed on 01.10.2011)

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

In search of Lemuria

"Yet if hope has flown away
In a night, or in a day,
In a vision, or in none,
Is it therefore the less gone?
All that we see or seem
Is but a dream within a dream."
"A Dream Within A Dream" by Edgar Allan Poe (1809-1849)

With the census of life forms in the 19th century naturalists realized that many similar animal species were distributed on different continents or remote islands. For short distances this was explainable by (voluntary or involuntarily) migration on water, on islands or in the air, but many distances were too great to overcome by large animals, especially by mammals.
The English lawyer and zoologist Philip Lutley Sclater (1829-1913) noted the particular distribution pattern of a particular group of primates - the Lemurs. Sclater however included in his Lemuridae more species than modern systematic - the Lemurs, the Indri and the Aye-aye (found on Madagascar), the Galagos (found in Africa), the Loris (found in Asia) and the Tarsiers (found in Indonesia). He observed that "while 30 different species of Lemurs are found in Madagascar alone, all of Africa contains some 11 or 12, while the Indian region has only 3." In a short essay of 1864 titled "The Mammals of Madagascar", published in the brand new "The Quarterly Journal of Science", he addressed the possible answer - Madagascar with it's rich diversity of species was the homeland of lemurs which spread all over Asia and Africa by a land bridge connecting once these continents. He named this supposed continent appropriately "Lemuria" and because of similarities with of the lemurs of Madagascar to new world monkeys he speculated even with a connection to America:

"The anomalies of the Mammal fauna of Madagascar can best be explained by supposing that anterior to the existence of Africa in its present shape, a large continent occupied parts of the Atlantic and Indian Oceans stretching out towards (what is now) America to the west, and to India and its islands on the east; that this continent was broken up into islands, of which some have became amalgamated with the present continent of Africa, and some, possibly, with what is now Asia; and that in Madagascar and the Mascarene Islands we have existing relics of this great continent, for which as the original focus of the "Stirps Lemurum," I should propose the name Lemuria!"

In later works he was more cautious:

"This fact would seem to show that the ancient "Lemuria", as the hypothetical continent which was originally the home of the Lemurs has been termed, must have extended across the Indian Ocean and the Indian Peninsula to the further side of the Bay of Bengal and over the great islands of the Indian Archipelago."
Page 236-237, SCLATER & SCLATER (1899): "The Geography of Mammals."

Sclater was not the first to promote ancient land bridges or even a sunken continent in the Indian Ocean, the idea of oceans as drown landmasses was a plausible geological theory at the time. Marine fossils found on land demonstrated that sea level changed over time, land became sea and even if the exact mechanism was unknown, it was not impossible to image that also land would become sea.
The French geologist Etienne Geoffrey Saint-Hilaire had speculated about a connection between Madagascar and India in 1840, the English geologist Searles V. Wood (1830-1884) hypothesized the existence of a giant southern continent during the "secondary era" (modern Mesozoic). Alfred R. Wallace (1823-1913), biogeographer of South America and Indonesia, proposed in 1859 a sunken continent to explain the fauna found on Celebes, but became later one of the most eloquent critic of the theory.
The theory of Lemuria was interesting speculation but even Sclater mention it only as idea and never promoted it too much.

In 1868 the German biologist Ernst Haeckel published his German edition of "Natürliche Schöpfungsgeschichte"(The history of Creation), addressed to a general public where he promoted his view of evolution of life and humans. Haeckel considered the earliest humans descending from Asian primates and placed the cradle of humanity in Asia or in alternative Africa and very cautiously on the hypothetical continent between these landmasses. Lemuria played a major role as possible migration route of humans into Africa and Indonesia (Natürliche Schöpfungsgeschichte, page 515).
In later editions and the English version of the book, translated by Ray Lankester in 1876, the supposed continent is even emphasised and labelled in the map as "Paradise" and displayed as cradle of humanity.

"The primeval home, or the "Centre of Creation", of the Malays must be looked for in the south-eastern part of the Asiatic continent, or possibly in the more extensive continent which existed at the time when further India was directly connected with the Sunda Archipelago and eastern Lemuria."
Page 329, HAECKEL (1876): "The history of Creation."

Fig.2. and 3. Ernst Haeckel, "A hypothetical sketch of the monophyletic origin and extension of the twelve races of Man from Lemuria over Earth." From Haeckel, Natürliche Schöpfungsgeschichte, Plate XV. Note the differences in the German version (1868) without Lemuria and the English version (1876) with Lemuria, after 1870 Haeckel adopted and promoted the idea of a sunken continent in the Indian Ocean.

"The probable primeval home or "Paradise" is here assumed to be Lemuria, a tropical continent at present lying below the level of the Indian Ocean, the former existence of which in the tertiary period seems very probable from numerous facts in animal and vegetable geography. But it is also very possible that the hypothetical "cradle of the human race" lay further to the east (in Hindostan or Further India), or further to the west (in eastern Africa)."
HAECKEL in 1870.

Haeckels work, as vague at is was, however spread the idea of sunken continents to a larger public, still in 1919 the English author Herbert George Wells wrote:

"We do not know yet the region in which the ancestors of the brownish Neolithic peoples worked their way up from the Palaeolithic stage of human development. Probably it was somewhere about south-western Asia, or in some region now submerged beneath the Mediterranean Sea or the Indian Ocean, that, while the Neanderthal men still lived their hard lives in the bleak climate of a glaciated Europe, the ancestors, of the white men developed the rude arts of their Later Palaeolithic period."
WELLS (1919): "Outline of History."

The idea of Lemura as lost cradle of humankind proposed (however not too actively supported) by serious scientists was to fascinating for pseudoscientific and esoteric groups and authors not to be incorporated in their worldview.
In 1888 the Russian esoteric author Elena Petrovna Blavatskaja (1831-1891), strongly influenced by Asian philosophy, published her "The secret doctrine" in which she proposes Lemuria as the cradle of one of the seven root races of humanity. These beings supposedly possessed four arms and eyes and were egg-laying hermaphrodites and shared the continent Lemuria with dinosaurs. The never existed continent of Lemuria became part of popular culture.

Bibliography:

RAMASWAMY, S. (2004): The lost land of Lemuria - Fabulous geographies, catastrophic histories. University of California Press: 334

Online Resources:

FREISTETTER, F. (04.04.2011): Lemuria: wenn Wissenschaft zu Esoterik wird. (Accessed on 07.04.2011)

Mediterranean desiccation and giant evaporates

Outcrops of salt-bearing and gypsum-bearing sediments in the Mediterranean region were already noted by geologists in the late 19th century. In 1849 the Italian chemist J. Usiglio conducted evaporation experiments with seawater along the French Riviera and established the order in which evaporate minerals precipitate. It seemed clear that the salt deposits cold be explained by changes in the distribution of sea and land, but the extent and thickness was impressive.
Karl Mayer-Eymar (1826-1907) a Swiss geologist and palaeontologist, dated the sediments by fossils in the Miocene Epoch and in 1867 named the period the Messinian, for the Italian region of Messina. The formation of these deposits however remained a riddle.

In 1961, seismic surveying of the Mediterranean basin revealed a geological feature some 100-200 metres below the seafloor. This feature, dubbed the M-reflector by its strong property to reflect the seismic signals, closely followed the contours of the present seafloor, suggesting that this presumably compact layer was laid down evenly and consistently at some point in the past. New and high quality seismic data on the M-reflector were acquired in the Mediterranean Basin in 1970, at the same time the M-layer was cored during the Leg 13 (Site 124) of the Deep Sea Drilling Program conducted from the Glomar Challenger under the supervision of co-chief scientists William B.F. Ryan (specialized in geophysics) and Kenneth J. Hsü (specialized in sedimentology). One of the goals of the two young scientists (criticised by some older colleagues as "student and amateur") was to reach the mysterious M-layer.
Only the second attempt in the Balearic Basin off the Spanish coast was (sort of) successful, the drill string begun to vibrate and finally got jammed. Recuperated the drill bit only some loose debris could be collected from the deep underground. Ryan and Hsü along with palaeontologist Maria Bianca Cita begun to study the apparently disappointing sample, but soon they discovered some strange properties.
The debris consisted of basaltic rocks, white limestone, transparent crystals of gypsum and microfossils. Especially the microfossils were interesting; shoal-water foraminifers, but also tiny mollusc shells. According to Cita the organisms were small and underdeveloped, maybe as response to an extreme environmental stress.
Ryan and Hsü soon recognized that the basalt clasts were cobbles and pebbles formed by fluviatile transport, the limestone and gypsum the remains of a sabkha and the micofossils inhabitants of a hypersaline lake.

To form such a succession of lithological facies in situ only one explanation was possible: the entire Mediterranean Sea disappeared some 7 million years ago. This desiccation hypothesis caused mixed reactions by the scientific community, and is still under scrutiny today, especially because this relatively recent event could maybe represent a model to explain large evaporate deposits in the geological past.

Even today the Mediterranean Sea is characterized by a semiarid climate with low precipitation and high evaporation. The amount of fresh water flowing into the sea by rivers is not sufficient to compensate the loss; however the inflow of 2.000 square kilometres per year from the Atlantic Ocean trough the strait of Gibraltar holds the Mediterranean Sea level constant. If this connection would be sealed, in only some thousand of years the Mediterranean Sea would almost evaporate completely.
During the late Miocene - the Messinian Stage (7,2-5,3Ma) - tectonic forces between the European and African plate pushed up the Spanish Sierra Nevada and closed the strait of Gibraltar. By the evaporation of the seawater various evaporitic minerals became deposited like halite, anhydrite, gypsum and others, forming finally a succession of sediments incredible 2.500 meters thick.
Most of these evaporates still lie hidden underground or under the bottom of the sea, however in Italy these sediments became uplifted by tectonic forces during the orogenesis of the Apennines. On the southern coast of Sicily, near the village of Eraclea Minoa, in the Messinian sediments at least six cycles can be observed, from beds of gypsum crystals to fine laminated marls and claystones to crystalline layers of selenite, capped again by sandstone.

Fig.1.

Fig.2.Fig.3.

Fig.1-3. Outcrop of Messinian evaporitic sediments at the Eraclea Minoa site in Sicily. The resistant gypsum beds are less eroded by weathering processes than under- and overlying marls. The upper crystalline selenite domes (in Italian called Gessoso-Solfifera, fig.2.) of cycle 4 were formed in shallow lagoon conditions and are cropped by fine laminated marls and gypsum beds (Balatino, fig.3.) at the base of cycle 5. In the background of the photo cycle 6, characterized by much thicker marls and claystone deposits than the previous cycles, is recognizable, covered by the Pliocene.

The base of the Pliocene (GSSP Messinian-Zanclean 5,332Ma) is formed by the sandstone of the Arenazzolo-Formation, followed by grey marls of the Trubi-Formation.

The base of the succession is formed by reworked debris of basaltic rocks, followed by conglomerates, sandstone, laminated marls and evapoitic layers. In the sediments various cycles of marls and gypsum beds are recognizable, it is not completely clear if this succession is the result of repeated flooding and desiccation of the entire Mediterranean Sea (if so, at least 24 such cycles are recognized) or local events in tectonic active basins.
Fig.4. Example of the Messinian succession of facies from the section North-West of Alba (Tertiary Piedmontese Basin) as drawn by the Italian geologist Sturani in a Seminar in October 1975 (LOZAR et al. 2008). The section starts with silty clays and marls of a normal marine environment, truncated by sand, silts and clays followed by silty clays with stromatolithic limestones. Here we observe a decrease of depth from a intermediate depth facies to a shallow lagoon with first evaporitic phases. In a restricted lagoon clays with lenses of early diagenetic selenite form, changes in water circulation occur as indicated by the fossils and a succession of silts, silty marls and sand beds. Then in an alluvial plain or marsh evenly bedded, massive clays were deposited. The entire section is cropped again by normal marine, Pliocene clays and marls.
 
More than 5 million years ago the sea finally returned to stay. The entire evaporate succession is cropped by marine sediments, first the Arenazzolo-Sandstone of the brackish Lago-Mare-Unit and then deep sea turbiditic marls of the Trubi-Formation.

The following video from the TV-documentation "Europe: A Natural History/Wild Europe" (2005) oversimplifies the story and presents uncritically some inaccuracies, like the reconstruction of a surprisingly narrow dam at Gibraltar and the infill of the Mediterranean Sea directly by the modern strait (there was probably an episodic connection to the Atlantic more to the north), but it gives a graphic and overall idea of the event.

Bibliography:

FISCHER, A.G. & GARRISON, R.E. (2009): The role of the Mediterranean region in the development of sedimentary geology: a historical overview. Sedimentology 56: 3-41
LOZAR, F.; MARTINETTO, E; DELA PIERRE, F., TRENKWALDER, S. & VIOLANTI, D. (ed.) (2008): Messinian Palaeontology - Papers in honour of Carlo Sturani´s outstanding contributions in geology and palaeontology. Bollettino della Societá Paleontologica Italiana Vol. 47(2): 202MORRISON, P. & MORRISON, P. (1988): Das Geheimnis unserer Wahrnehmung - Warum wir wissen, was wir wissen. Droemer Knaur Verlag, München: 320
USIGLIO, J. (1849): Analyse de l´eau de la Mediterranée sur le Cotes de France. Ann. Des Chem.Phys., Third Ser. 27 :92-107