Montag, 20. April 2009

Glacier Reconstruction of St. Amarin (1847)


Reconstruction of the glacier that filled the valley of St. Amarin (southern Vosges, France), probably the first tentative reconstruction of an ice age glacier - from COLLOMB (1847): Preuves de l´existence d´anciens glaciers dans les vallées des Vosges.

Sonntag, 19. April 2009

Austrian glaciers still have fever

The measurement of glacier lengths carried out by the Austrian Alps Association (Österreichischer Alpenverein) showed a “strong degrade of the glacier-tongues” in the past years. During the period between 2007 and 2008, 10 of the total 94 controlled glaciers shortened between 33 up to 49m. “These valley glaciers still suffer from the extreme mass lost in the year 2003” explains the author of the study and glacier expert Prof. Dr. Gernot Patzelt.
From the studied glacier, 88 have lost length, 8 remained stationary and only 4 have gained moderate length (ca. 5m), this results in a mean length loss for the Austrian glaciers in the measurement- season 2007-08 of 12,8 meters, slightly inferior to the precedent years (22,2m, where all observed glaciers retreated).
The mean length reduction in the past 10 years resulted to be 14m per year.

The wet and cold weather until July 2008 prevented first the ice melt, but then a pronounced warm period at the beginning of August caused a strong degradation of the snow cover.

Length loss of the glaciers of the Ötztaler Alps (western Austria) in 10m intervals. The valley glaciers with their snouts extending in the valleys showed the strongest retreat and degradation of the studied Austrian glaciers, length gain could only observed by 4 glaciers in the central Tauern Alps (eastern Austria).

Mittwoch, 15. April 2009

IT came from the ice !!!

A bacterial lost world trapped beneath Antarctic ice may help explain how life persisted during the "snowball Earth" period when almost all of the globe's surface was frozen over.

Isolated for at least 1.5 million years from close relatives that live in the ocean, the Antarctic microbes live in a super-salty lake sealed with a 400-metre slab of ice, called Taylor Glacier. But each summer, the temperature warms enough for a trickle of extremely cold water to flow to the surface.

Antarctic explorers and scientists noted the deep red colour left by these flows, created by iron in the water, and called them "blood falls".


Dienstag, 14. April 2009

The Rhône Glacier (1705)

Visiting in the year 1705 the Rhône Glacier, Johann Jakob Scheuchzer (1672-1733, swiss naturalist) publihed his observations of the “true nature of the springs of the river Rhône” in his work “Itinera per Helvetiae alpinas regiones facta annis 1702-1711.”
This engraving shows the “false springs at the mountain Furca” (M, N, O - left and right of the picture) and the “true springs” (J, K, L) coming from the snout of the “great glacier (A-F), surrounded by the “small glacier” (G, H).


Montag, 13. April 2009

The lost continent ... or Wallacea

In 1858 the small island of Gilolo (today known as Halmahera) in the Moluccas archipelago was one of the remotest regions left on the globe.
A letter send on the 9. March 1858 from the nearest post station – on the island of Ternate- had first to be shipped to Singapore. From there a post ship of the British P & O Steamship Company, connecting Hong Kong to Suez, brought it on the African continent. By being transported until Alexandria, the letter where again shipped over the Mediterranean sea to Paris and Rotterdam, and finally London. So after three months finally the letter arrived timely in the morning to Down House, Bromley, Kent – 26 kilometres southeast of London, and 12.000 kilometres east of New Guinea.

This letter contained a 20 page long article with the title “On the Tendency of Varieties to Depart Indefinitely from the Original Type” - containing first concepts to maybe explain the rich biodiversity, the geographical distribution and the development of new species from ol
der ones in Indonesia – to enlarge upon a similar thema of the 35 years old author published in a paper in 1855.
The author of the letter to C. Darwin was Alfred Russel Wallace, an autodidact in natural science born in a poor family on 8. January 1823 in the welsh city of Usk.



A photograph of A.R. Wallace taken in Singapore in 1862 (from Wikipedia)

Working first as a surveyor and then as a teacher, he developed a passion for botany and natural science, finally so strong, that in 1848 he started on an expedition to South America. Only in 1852, after four years of collecting an incredible variety of animal and plant species, he decided to return back to England.
But then the catastrophe – the ship on which he was travelling, the trader “Helen”, cached fire and sunk in the North Atlantic Ocean. Wallace could save only some dra
wings – when he finally arrived to England, 1. October 1852, he virtually had lost everything – his collection, his payment (he made a living by selling collected specimens to museums and collectors) and his hope to get reputation by the prestigious british scientific establishment. Only the insurance sum for his transported collection saved him from financial ruin. But lacking all his collected specimens and data he was able to publish only an “abstract” of his discoveries, denominated “A narrative of Travels on the Amazon and Rio Negro”, a book, poorly considered at this time.
Swearing to never again travel by ship, just one year later the old passion grow so strong, that he embarked on a ship to Indonesia, one of the poorest known regions by the European scientist and naturalists.

The 20. April 1854 he arrived to Singapore. He will remain for 8 years, travelling for more than 22.000 kilometres, collecting and sending back to England more then 125.660 specimens of animals, and discovering 1.500 new species of insects and birds.
This second expedition will be published in 1969 in the book “The Malay Archipelago”, and will establish Wallace as founder of the scientific discipline of biogeography.


The voyage of Wallace between 1854 an 1862 (References).

Ironically it was he’s bad luck that give him the opportunity of an important discovery. 31. January 1856 he missed the ship that should bring him to Sulawesi. For 4 months he was “trapped” in Singapore, until he decided to take a detour by passing on the islands of Bali and Lombok.
On these two islands he noted something important; eve
n if the two islands are separated only by a 30 kilometres broad sea passage, the species of animals found differ considerably, dominated by one side by tigers, rhinoceros, primates and on the other side by kangaroos, koalas and birds of paradise. He will describe these two regions in his paper “On the Zoological Geography of the Malay Archipelago” (1859), separating the west ndio-malayan from the east austro-malayan region.“This islands differ far more from each then another in their birds and quadrupeds then do England and Japan, broths of which features animals common on the Eurasian landmass.”
Even if Wallace couldn’t know about the regional tectonics of Indonesia, nor the changes in sea level, he argued that “Such facts can be only explained by great changes of the earth surface."
The explanation first supposed by Wallace will find confirmation only later.
During the ice age vast amounts of water where trapped in the polar ice caps, the sea level during the maximal expansion of the ice was 180m lower then today, creating a landmass where today is sea, called in the east "Sunda-land" (after the continental shelf) connecting Borneo, Sumatra, Java and Bali with Asia, and in the west "Sahul-land", connecting New Guinea with Australia. The islands of Celebes, Timor and Flores, remaining isolated even with sea level low, are referred as "Wallacea". Only islands or regions surrounded by deeper sea represent barriers that animals coming from the Asian or Australian continents couldn’t reach. This barrier will be become known as Wallace Line.

Bathymetry of Indonesia, showing areas in red within a depth of 200m under sea level.

Samstag, 11. April 2009

Swiss glaciers still have fever

The published results of length variation of Swiss glaciers confirm the general recession trend of glaciers in the Alps observed since 1980. 79 glaciers showed a retreat in 2008, only 5 a small advance (with length gain between 5 and 10m), and 2 remained stationary. Notable the length loss of the Eiger glacier with 225m and Gorner glacier with 290m.

Legend: blue triangle: advancing glacier, yellow: retreating glacier, grey: stationary glacier

Legend: Percentage of advancing Swiss glaciers (blue), stationary glaciers (green) and retreating glaciers (red) in the last 100 years.

References:

Gletscherberichte (1881-2008). "Die Gletscher der Schweizer Alpen", Jahrbücher der Expertenkommission für Kryosphärenmessnetze der Akademie der Naturwissenschaften Schweiz (SCNAT) herausgegegeben seit 1964 durch die Versuchsanstalt für Wasserbau, Hydrologie und Glaziologie (VAW) der ETH Zürich. No. 1-124, (http://glaciology.ethz.ch/swiss-glaciers/).

Mittwoch, 8. April 2009

Do you believe in bad luck?

Do you believe in bad luck? - a black cat on drill cores for a survey on a creeping slope…

Montag, 6. April 2009

Earthquake

At 01h32m39.00s world standard time (03:32 in the morning in Italy) a tragic 20 seconds lasting earthquake with magnitudo 6,9 (followed quite until 12.00 italian time by weaker aftershocks) striked 7km near the city of Aquila (42.33°N, 13.33°) within a depth of 8.8km.

Unfortunately the worst affected townships are more then 21, until now the verified victims are 150 people, thousends injured, and more then 50.000 peoples were forced to leave their houses.

It is a tragedy, and I can only express solidarity with the affected people.

Southern Italy has a long and tragic history of earthquakes. The setting between to larger continental plates (european and african) and various microplates causes highly active tectonics.

In 1783, between 5. february and 28. march the italian region of Calabria was shattered by six successive shocks, causing widespread destruction and 35.000 deaths. The administration in Naples initiated a study, collecting storys of eyewitnesses, and sending experts to evaluate the destruction. Two main items were published, the collection of the eyewitnesses story with 569 pages, and the account of the experts with 372 pages, covering observations in 150 citys and villages.

The first map of seismicity of the mediterranean area, and a extensive research on earthquakes in Italy named „Great Neapolitan Earthquake- The First Principles of Observational Seismology", was published by the irish engineer – and self educated geologist - Robert Mallet in the year 1857. He got caugth by the subject of earthquake exploration in 1830, by a drawing in a natural science book, displaying two columns twisted by an earthquake in Calabria. He decided to study the forces able to do this to human constructions.
He noted that damages on constructions were distributed in „areas, setting out from a point of heaviest havoc. Also this epicenters were not randomly distributed, but found in „seismic belts“, surrounding the entire globe.


Sonntag, 5. April 2009

The mud with the hat

Old legends tell that once a group of pridefully dwarfs were petrified for punishment, and still they can found hidden deep in the forest:



But like many other storys the geological explanation can be also fascinating.

The earth pyramids developed after strong rainfall caused a landslide in 1882, exposing the glacial till to erosion. Larger blocks of gneiss and schist protect the underlying sandy to clayey sediment from outwash by precipitation, forming fragile pillars and stubby columns. When the covering stone (remembers me a pukao) get´s lost, the earth pyramids develop to pinnacles, that over time will shrunk after funally they dissapear. But the regressive erosion will shape new „dwarfs“ from the till, to replace the lost one.

Samstag, 4. April 2009

Mima mounds and hump meadows

Mima mounds (the name derives from the Mima Prairie in Washington state), also known as Hogwallows, are uniformly distributed mounds of soil some 1-3 meters tall that occur in various places in the world, coining the name fort he landscape where they are occurring of „pimpled prairies“. Their age or origin is still unknown. Various theories have been proposed: that they are Amerindian or pre-historic peoples' burial mounds, remnants of glacial or periglacial activity, interactions of the soil with earthquake vibrations, or the cumulative action of gophers or other burrowing animals over a long period of time. But every of this theories deals with different lacks of evidence, traces of gophers or their activity were not found in all areas with hogwallows, also they occur in regions not glaciated or reached by glaciers in the past, and so on.
Excavations made into the Washington mounds show that underneath a blanket of prairie grass lies a mixture of loose sand, fine gravel, and decayed plants up to 2m thick.

Similar geomorphological features – small mounds superimposed on slopes and plains- are known from the austrian Alps and Bavaria. They are called „Buckelwiesen“ – (hump meadows) and prevail on carbonat rich sediments or morain deposits.



Four main theorys to explain their formation were developed since first research attemps between 1940-1960:

- the mounds represent the remanents of a carst-landscape, where different rates of dissolution of carbonatic rocks caused the development of troughs, enhancing the erosion betwen the single „humps“. But this theroy implies a primarly landscape with first differences for disolution processes.

- they formed by melting ice – wedges or / and by cryoturbation, pronounced freeze-thaw cycles can produce mixture of different grain-sized and ice-bearing sediments by difference in the specific weigth and thermal conductivity – producing a pronounced relief. This theory seems also supported by the fact that the forming sediments was deposited during the last glacial, and experience periglacial conditions.

- they rappresent places where once stands trees. The trees protected the underlying soil from erosion, only in the space between trees erosion and dissolution take place, then finally humans cut down the trees to use the resulting meadows for pasture.

- they are primary features of sediment depositon in a particular environment.

Based on new geomorphological and computer aided mapping, dissolution test in the sediments and excavation of some of the mounds, a research team of the Universtity of Vienna now propose a new theory:

The mounds and troughs are disposed more or less paralell, and possess a general oval form, with proportions between length to width of 1,7. Excavations carried out showed in some mounds cavities filled with humus material, interpreted as stump remains, and deep troughs in calcareous material filled with organic rich sediment. Dating showed a young age, of only 720 to 880 years, partly in accordance of older published dates ranging between 1.000 to 7000. This results esclude a direct implications of ice in the formations of the mounds. The new explanation propose that trees, thrown down by wind (this explains the subparalell observed pattern), caused a first mound or deposition of material, and then subsequentely this material and the rotting tree itprotected the underlying calcareous material from precipitation and dissolution. With time, ditches develop between the single trees, where water can even more effectely remove sediments and calcareous sediment.
Finally humans have cut in the last centurys the trees for pasture use, and exposed the "hump meadows".