January 6, 1912: 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 curst (Continents and Oceans) on geophysical basis) for the first time his hypothesis of the ancient supercontinent Pangaea, from which all modern continents split apart.

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How to celebrate New Year's Eve in style: Fun in a Fossil

To promote the international exhibition in the Crystal Palace (Sydenham , London) for New Year's Eve 1853 twenty-one distinguished guests were invited to a banquet inside the unfinished model of an Iguanodon, sculpture made by artist Benjamin Waterhouse Hawkins under severe examination of leading anatomist Richard Owen to celebrate the new discovered proudly-prehistoric monsters [...]

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The End of the Mayan World

According to the popcorn-movie "2012" (2009) the end of the world will come due increased solar activity that will overheat earth and cause catastrophic volcanic and tectonic storms on December 21, 2012. This premise is so dumb that even NASA declared "2012" as the most "absurd science-fiction movie" of all times, not only because the science is so bad, but the movie exploits also the fear mongering story of the supposed end of the Mayan calendar, first proposed by artist and author José Argüelles in 1987. Almost all of the supposed end of the world tale is nonsense, the various proposed mechanism to explain the destruction of the planet, like solar eruptions, pole shift or the impact of an invisible planet, are unrealistic, as it is unrealistic to claim that the end of a arbitrary time period has any significance for earth.

Fig.1. The goddess Chakchell, with her terrifying snake headdress, is flooding earth with the waters coming from the jar of the gods. She is helped in this task by the dark god of the underworld, with an owl as symbol of his power, and the divine crocodile - even the holy hieroglyphs are crying and the world will soon drown (after the "Codex Dresdensis", ca. 1200-1250, plate 47 "The flood").

However in the last years the Maya Civilization arouse the interest not only of crackpots, but also serious historians and even climate scientists. This ancient society possessed advanced knowledge of astronomy, mathematics and architecture, but 1.200 years ago (750-950 A.D.) the various city-states on the Yucatan peninsula suffered a sudden collapse. Various hypotheses tried to explain this demise: internal warfare, foreign invasions, diseases, overpopulation in combination with environmental degradation and climate change.
The Yucatan peninsula is characterized by a heterogenic spatial distribution of precipitation and seasonal droughts, especially during the beginning of the year (January- May). The climate is influenced by the position of the Intertropical Convergence Zone (ITCZ), wind systems that shift position due the seasons and bring moisture to the land. The Maya had to deal with these variations and in response build large artificial reservoirs. The limestone of the Yucatan peninsula is highly permeable and the groundwater is almost inaccessible, if not by naturally occurring caves or cenotes, and there are virtually no rivers.
It was in these cenotes that geologists of the University of Florida collected sediment cores and discovered in the isotope variations of shells a pronounced drought period between 800 and 1000 A.D., coincident with the collapse of Classic Maya civilization. A even more detailed reconstruction of the climate of the region was possibly by the research done on sediments from the Cariaco Basin, a basin with limited deep water mixing and anoxic conditions on the ground (and therefore perfect sedimentation conditions) offshore Venezuela. Depending from the position of the ITCZ fossil-rich or clastic-rich layers are deposited, so by studying and counting these layers the former variation of the ITCZ and the amount of precipitation can be estimated.
Also this record shows a climate shift and cyclic multi-year droughts from 910 to 760 A.D.

According to the proposed scenario a population at the margin of environmental sustainability experienced repeated droughts and a demise of agricultural production. The various city-states, chronically involved in wars for power and sacrifice victims, consumed the last reserves in a desperate struggle for survive.

However like in the case of Easter Island considering both evidence from natural sciences and historical and cultural circumstances the scenario could become more complicated. The Mayan Civilization was characterized by religious violence and war was less aimed to destroy the enemy than to catch (and sacrifice) the political elite. This society had also survived previous droughts or phases of increased soil erosion, when in A.D. 550-830 the population reached high densities. The power became concentrated in few city-states, which struggled for power and replaced small military expeditions with great wars. The crumbling central government could no longer guarantee the safety of peasants, when the society was further weakened by climate changes.

In the end the city-states were replaced by a most decentralized kind of society, whit the descendants still living today.

Bibliography:

ANSELMETTI, F.S.; HODELL, D.A.; ARIZTEGUI, D.; BRENNER, M. & ROSENMEIER, M.F. (2007): Quantification of soil erosion rates related to ancient Maya deforestation. Geology Vol. 35(10): 915-918
GILL, R.B. (2000): The Great Maya Droughts - Water, Life, and Death. Univ. New Mexico Press: 464
PETERON, L.C. & HAUG, G.H. (2005): Climate and the Collapse of Maya Civilization. American Scientist, Vol. 93: 322-329

Dear Leaders and a Volcano

Eternal President Kim Il-sung (1912-∞) and Dear Leader Kim Jong Il (1941-2011). In the background Tianchi or "Lake of Heavenly Peace", a crater lake inside the volcano Baitoushan or Paektusan ("white headed mountain"). Tianchi Lake has a diameter of more than three kilometres and is 373 meter deep. The volcanic complex is more than 2 million years old, however the caldera formed only during a large eruption about 965 A.D. Since then at least 3 to 5 eruptions of small to moderate size occurred, the last in 1703. 

Curiously the lake is not only the mythical birthplace of Dear Leader but hosts also a Lake Monster.

Bibliography:

SCHMINCKE, H.-U. (2004): Volcanism. Springer, Berlin-Heidelberg: 324

At the Mountains of Madness

December 14, was the 100 years anniversary of the first expedition to reach the geographic South Pole in the middle of the continent of Antarctica. Until then only segments of the coasts were known and partially mapped.  

Fig.1. The dog Chris inspecting a grammophone during the Scott Expedition in Antarctica  (photo by Herbert George Ponting, 1911).

It is no wonder that such an unknown land influenced the imagination of many writers and later film directors. 

"At the Mountains of Madness" is a science-fiction/horror story by the American writer H. P. Lovecraft (1890-1937), written in February/March 1931 and originally published in three parts in the February, March and April 1936 issues of the pulp-magazine "Astounding Stories" (also one of the first pulp- and horror fiction magazines ever to be published).
The story is written in a first-person perspective by geologist William Dyer, a professor from Miskatonic University, which led a geological expedition to Antarctica in "1930".
The expedition discovers first strange fossils, eons of years older then all other signs of life on our planet, and finally a mountain range, much higher and darker then ever imagined. But after a carefully investigation along the borders of the mountains and the discovery of even more strange fossils, contact get lost with a part of the team and the narrator makes his way to discover what happened at the Mountains of Madness.
Lovecraft incorporates in his story many scientific observations made at the time, especially the discovery of fossils. Little was known about the geology of Antarctica; rock exposures comprise only 1-3% of the land area and are limited to isolated coastal regions and to the peaks of the Transantarctic Mountains, crossed for the first time by the Ernest Shackleton-expedition in 1908. Only in 1928-1930 the Richard Evelyn Byrd-expedition collected the first fossils.
Still today sites with fossils are rare spots; from Antarctica we know some dinosaur species, synapsid species, a plesiosaur, Eocene mammals and a terror bird - however plant remains are by far the most common fossils and especially these plants proofed that Antarctica was once a tropical paradise.
Lovecraft describes the fictional discovery of a cave that acted as sediment trap for millions of years:

"Washed down from unknown jungles of Mesozoic tree ferns and fungi, and forests of Tertiary cycads, fan palms, and primitive angiosperms, this osseous medley contained representatives of more Cretaceous, Eocene, and other animal species than the greatest paleontologist could have counted or classified in a year."

Also other authors located a tropical Lost World near the Antarctic continent. Edgar Rice Burroughs (1875-1950) published in 1918 the first part of a science-fiction book in the "Blue Book Magazine": "The Land That Time Forgot". Here a primordial world populated by tropical forests and of course dinosaurs is located on the island of Caprona, a land mass near Antarctica, first reported by the (fictitious) Italian explorer Caproni in 1721. The tale inspired two movies: "The Land That Time Forgot"(1975) and "The People That Time Forgot"(1977).

Fig.3. Cover art for first combined edition (1924) of The Land That Time Forgot.

Si-C

In the science-fiction/monster movie "Monolith-Monster" (1957) fragments of a meteorite are discovered in the desert of California. The strange mineral from outer space starts to grow to gigantic crystals when it comes into contact to water and a heavy rainfall is occurring in the mountains where the fragments are scattered around (the movie is also worth to watch for the geo-babble as noted by Jessica Ball in her Geological Frigthfest review on Magma cum Laude; and you can see here for yourself).  The idea of growing minerals was later adapted in the computer game "Command & Conquer: Tiberium", where an extraterrestrial meteorite brings the unknown mineral Tiberium to earth, that grows by extracting nutrients from all other life-forms.
Every single fragment of these crystals can grow, similar to real crystals; however they are not considered life-forms as they lack the ability to actively self-replicate or even evolve.

 
On earth the dominant life-forms are based on the element carbon (C) - excluding the case of the presumed arsenic bacteria -  but already early science-fiction writers speculated on alternative forms of life, based on other elements like silicon, nitrogen, phosphorus, boron and even metals like titanium, aluminium, magnesium and iron.

In 1891 the German astrophysicist Julius Schreiner was one of the first to propose silicon (Si) life-forms, the  idea was taken seriously by British chemist Emerson Reynolds who speculated about the habitats that such a creature could be inhabit.
Later H.G. Wells wrote

"One is startled towards fantastic imaginings by such a suggestion: visions of silicon-aluminium organisms - why not silicon-aluminium men at once? - wandering through an atmosphere of gaseous sulphur, let us say, by the shores of a sea of liquid iron some thousand degrees or so above the temperature of a blast furnace."

Silicon was chosen because its similarities to carbon - it is common in the universe and it can form log and stable polymers, it also reacts with hydrogen (forming the instable gas silane) and oxygen (forming stable silicones) to form stable molecules. Oxidation is used by terrestrial life forms to gain energy and the waste product is the gas carbon dioxide. A silicon creature would however produce a solid mineral composed of silicon dioxide. According to some authors the respiratory system of a silicon life-form therefore must produces sand or even bricks.
The idea became popular in the short story "A Martian Odyssey", published in 1934 by Stanley Weisbaum (1902-1935):

"Those bricks were its waste matter... We're carbon, and our waste is carbon dioxide, and this thing is silicon, and its waste is silicon dioxide-silica. But silica is a solid, hence the bricks. And it builds itself in, and when it is covered, it moves over to a fresh place to start over."

Aliens as silicon life-forms became very popular in TV-productions and movies also after the Monolith-Monster. The "Island of Terror" (1966) is inhabited by artificial "silicates" life-form that feed on calcium of human bones.

As a matter of fact the very incarnation of the extraterrestrial xenomorph -H.R. Giger´s "Alien" - possesses a shell of Si-compounds to protect it from environmental factors. This resistant shell is also very useful to contain the acid blood of the creature.

In the TV series "Star Trek" the crew discovers a silicon-based life-form during mining activities on the planet Janus VI (episode "Devil in the Dark"), however this creature is less hostile than other xenomorphs:

Spock: "Life as we know it, is universally based on some combination of carbon compounds. But what if life exists based on other element. For instance silicon."

In "Star Trek: The Next Generation" some episodes feature living crystals or the dangerous "Crystalline Entity".
In the X-file episode "Firewalker" a mushroom like parasitic life-form (however terrestrial in origin and the result of a parallel evolution process) produces as waste simple sand (that fills the lungs of its host). The parasite is discovered as spores coming from inside an active volcano start spreading. It is interesting to note that geneticist Haldane, J. B. S. proposed that silicon life-forms could survive inside a planet feeding on partially molten rocks.

Despite these promising visions, the structure of silicates is limited mostly on long chains or sheets (minerals). Silicon doesn't form complex molecules, like enzymes in carbon based life forms, and it would be difficult to achieve a metabolism with such a simple chemistry.

Bibliography:

REYNOLDS, J.E. (1893): Address to the British Association for the Advancement of Science. Nature 48(477)
WELLS, H.G. (1894): Another Basis for Life. Saturday Review: 676

Gaia

"Surface conditions on Earth, have been for most of geological time regulated by life…[]…This new link between Geology and Biology originated in the Gaia hypothesis''
NASA geologist Paul Lowman (2002)

The concept of a living planet is a rare but intriguing vision of pop-art and science-fiction. In the Italian movie "Planet on the Prowl" (1966) the gravitational pull of a planet is causing havoc on earth. A team is send into space to destroy the planet, but here they discover that the celestial body is a living (!) cybernetic organism (however artificial in origin) that will not simply surrender without fight. A very similar plot was already used by director Antonio Margheriti in "Battle of the Worlds" (1961), where the mainframe of an alien spaceship is mimicking a planet.
A classic approach to a planet as life form is found in comics in the shape of the evil characters of Ego the living planet ("Thor" Sept. 1966) and Mogo the living planet ("Green Lantern" May 1985). Both planets are self-concious and selfish entities that feed on other worlds.

In 1965 the independent scientist James Lovelock, inspired by research on the possible habitability  of planet Mars, proposed in a Nature-article to see the various spheres of earth (lithosphere, hydrosphere, biosphere and atmosphere) as an interconnected and self-regulating system. He followed the suggestions by novelist William Golding and called this idea the Gaia-hypothesis, after the ancient mythological titan Gaia - personification of earth (this unintentionally, but supposed religious connection caused most concern in the scientific community). However the general notion that the Gaia-hypothesis states that "earth as a living planet" or a "life form" in the sense of entity or even individual is incorrect.

 

Fig.1. "SimEarth" is a simulator for life-supporting planets, 1990-1992 by Maxis.

Lovelock argued that both biotic and abiotic processes limit the possible amplitude of changes in the salinity of the oceans, the surface temperature of earth and the atmospheric chemistry - therefore forcing earth into a life-supporting disequilibrium between two stable extremes like the frozen wasteland of Mars or a hellish world as Venus.

In 1971 microbiologist Lynn Margulis (1938-2011) joined Lovelock (here an interview with both scientists in 2011), emphasizing the significance of microbial life and activity for the Gaia-theory and arguing how natural selection, acting on single individuals, could account for the development of (apparently) stable systems. Egoistic organism do not manipulate deliberately the system so it can support them; however if an organisms harms his environment (and the life-supporting properties) it will be naturally selected and be removed from the system. Environments are also not static systems that will not react to biotic changes, but can oscillate around "set points" without loosing their life-supporting properties.

"Some 30 million types of extant organisms have descended with modification from common ancestors; that is, all have evolved. All of them-ultimately bacteria or products of symbioses of bacteria - produce reactive gases to and remove them from the atmosphere, the soil, and the fresh and saline waters. All directly or indirectly interact with each other and with the chemical constituents of their environment, including organic compounds, metal ions, salts, gases, and water. Taken together, the flora, fauna, and the microbiota (microbial biomass), confined to the lower troposphere and the upper lithosphere, is called the biota. The metabolism, growth, and multiple interactions of the biota modulate the temperature, acidity-alkalinity, and, with respect to chemically reactive gases, atmospheric composition at the Earth's surface."

Margulis also emphasized the link between geology and biology - for example:
Plate tectonics is like life (as we at the moment know) a unique feature of the planet Earth. Apart of the size, density and petrological composition, plate tectonics seems to depend from the existence of liquid water on a planet. Without an atmosphere, earth would be to cold to maintain water in liquid form; however the chemistry of the atmosphere is influenced both by the lithosphere (by volcanic eruptions) and controlled by the carbon-circle of the biosphere. Finally plate tectonics modified (and modifies) the surface of earth and the environments, forcing life forms to adapt and evolve - probably even with no plate tectonics life would be still possible on earth, but it surely would be much more monotonous.
So every subsystem is connected to the others and influence them, being at the same moment influenced by all other subsystems.

Today´s legacy of Lovelock and Margulis is the consideration to see geology as part of the Earth System Sciences and appropriately to understand the Earth as a system.

Bibliography:

MARGULIS, L. (2004): Gaia by Any Other Name. In (ed.) Schneider S.H. "Scientists Debate Gaia - The Next Century": 7 - 12