Freitag, 31. Oktober 2008

Mammoth Mummies Mystery

To honour the host of this month Boneyard XXV, who is dedicated to debunk creationist claims – a look on Mammoths, C. Heston and Pseudoscience:

"No such hypothesis is sufficient to explain either the cataclysms or the glacial phenomena; and we need not hesitate to confess our ignorance of this strange, this mysterious, episode in the history of the globe...."

BRISTOW, H.G. (1872) p.435

Some representative animals of the Pleistocene fauna are well known, in fact, extraordinary well known, because we are able not only to study bones, like happening with so many other extinct animals, but to study entire corpses – trough “mummies” found in the frozen soil of the far north. Still, much about these animals is poorly understand, questions remain about their environment, and how they died and get preserved so perfectly.
Lacking of knowledge or presumed unexplainable situations often give rise to controversial hypothesis, or in the worst case to lies and pseudoscientific claims.

The extraordinary conservation of some carcasses of Mammoth, apparently only explainable by a rapid death and a rapid burial, brought to some speculation and wild guesses. Even more puzzling, elephants are seen as typical animals of warm climates and regions, such animal surviving in a cold, empty Tundra, seemed impossible.
During the 18 and 19th century, it seemed plausible, that Mammoths once lived in warm regions, and were killed and transported north by a great flood, where the corpses were deposited on ground, and became frozen. Even Charles Lyell, one of the founding father of geology, supported this “floater” theory.

This theory was still debated in 1848 by the arctic explorer Middendorf, even if already in 1825 the French anatomist Georges Cuvier observed the adaptations from the Mammoth to cold environments (long, dense pelage, subcutaneous fat, small ears, etc.). These controversies helped fund many expeditions, in first line organized by the Russian Academy of Sciences. They reported extraordinarily good preserved animals, but also poorly preserved, not supporting a “sudden fall in temperature”.

Fig. The most important Mammoth discoveries in Siberia.

Even in the last years pseudoscientific writers and creationists use the frozen bodies as supporting fact of their claims, and the flood hypothesis is still not dead and buried.

The American historian and writer Charles H. Hapgood (1904-1982) used Mammoths to support his Pole Shift Theory or Earth Crust Displacement Theory.
He based his idea primarily on ancient maps (the most important the so called Piri Reis Map, after admiral of the Turkish fleet), that seems to show the Antarctic continent without ice (explained by a different position of the continent, presumably more to nord), and biblical verses, that describe that the sun changed motion direction in the sky (explained by the change of the earth axis tilting).

As scientific support he cited mammoths and other Pleistocene animals, which seemed to show a rapid and catastrophic climatic change, explainable only by a catastrophic shift of the earth crust. After this theory, through the weight of the polar caps ice masses, or an enigmatic planet or asteroid, the relative position of the poles changed so suddenly, that the animals travelling on the continent, where transported from a temperate, or tropic climate so suddenly to a cold region, that they were literally shock frozen.
This, so Hapgood, happened not once, but often, and cyclic:

He reconstructed the timing and the locations of the catastrophic shifts of the polar ice capes:

90.000 B.C. Alaska
50.000 B.C. Norway
12.000 B.C: Hudson Bay
0 B.C. North Pole

Modern glaciological survey and analysis of ice cores show that the ice masses on the South Pole are at minimum 2 to 3 million years old, they on Greenland at least 120.000 years, they surely changed extensions, but they never disappeared completely. So one of the strongest arguments by Hapgood, is not supported by scientific measurements. From the geological view, he also fails to explain how it should be possible, that the entire crust of the earth can flip on the (heterogenic) mantle so easily.

Ice masses (and here I will introduce a special guest - Mr. C.Heston !) are not heavy enough to tilt the axis as supposed, and a bypassing planet large enough to influence the earth should be discovered at least, not to mention that a cyclic event had the earth thrown out of the orbit.

We also have to relativities the claim, that the bodies were frozen. The found Mammoths are never found in ice, especially not in glacier ice, a common misconception. Mummies occur in frozen silt, which contains local ice lenses or wedges, of secondary genesis. This ice maybe plays an important role in the desiccation and preservation of the carcass, as moisture, migrated from the body and frozen outside.

A different approach to support their claims is used by creationists. They see Mammoths as scientific prove of a flood, presumably Noah’s flood.
The most naive approach is to pretend the enormous number of found carcass and fossils are due a mass kill of a single (flood) event. Dating showed that ages of the carcasses reach at least from 29.000 to 4000 y B.P. (but you can still pretend that radiocarbon dating doesn´t work).
As we have seen also the affirmation, the mammoth needed a rapid burial (a common creationistic claim) is not necessary. Small carcasses, like from the mammoth calf “Dima” (discovered 1977) could cool quickly. This specimen most probably drowned in a small pound, and the cold mud cooled the carcass and prevented entirely decomposition.

Fig. Dima , a 4-6 month old Mammoth calf, considered the best preserved specimen

Animals died at the end of the summer, could become frozen during winter, and then subsequently buried during spring. It’s important to note, that sediment erosion and deposition during Ice ages differed considerably from modern sedimentation processes.

Fig. Watersatured mud "flowing" down hillside. The lack of a continues vegetation cover in the Mammoth steppe maybe caused strong redeposition of glacial sediments during snowmelt in spring.

But unfortunately, for most of the reported (historic) mammoth-discoveries, despite description, surrounding sediments or other paleontological hinds are not or only poorly mentioned – in fact the causes of death of most specimen are unknown, and the taphonomy of large carcass in Permafrost is still poorly understand.

A chapter for it’s own is the climate and the vegetation in Siberia during glacial periods. It is a misconception to compare the modern Tundra or Taiga with the Mammoth steppe, and claim that the productivity of this landscape was to poor to sustain large herbivores. The Mammoth steppe was a vegetation type that mixed cold tolerant with dry tolerant plant species, with resulting high species richness. The dry climate and the lack of precipitation prevented a long snow cover, enabling longer periods of photosynthesis. Also it is highly probable that herbivores migrated between summer and winter.

References:

GUTHRIE (1990): Frozen Fauna of the Mammoth Steppe – The story of Blue Babe.

Montag, 27. Oktober 2008

World Wide Water


96% of one of the most important resources on earth can be found underground - potable water. For thousand of years, wells and natural springs have supplied clean and abundant groundwater to human communities’ throughout the world.
Even if groundwater was and is so important, until now there was no map or data about the global distribution of it in the underground. But now the first results of the in the year 2000 initiated International Hydrologic Program (IHP), coordinated by the UNESCO, are presented – the "World-wide Hydrological Mapping and Assessment Programme" (WHYMAP). In the databank were mapped all aquifers extending about country borders - in total 273.
68 aquifers can be found in North- and South America, 38 in Africa, 65 in Europe, and 12 in Asia. The maps also show the water quality and the amount that the reservoirs contain.
65% of the global Groundwater were used as drink water, Europe covers 70% of it need, some countries, especially in dry regions, cover 100% of their water-need with groundwater.


It’s interesting to note that the African continent possesses aquifers, which contain vast amounts of water. Once precipitation, that felt 10.000 to 6.000 years ago, when the climatic shift brought wet air masses were today you can find the saharian desert.

Samstag, 25. Oktober 2008

Tree-rings

Tree-rings of Picea, showing the annual growth rings with the brigth, and wider earlywood, and the darker latewood.

Dendrochronology deals with the dating and the study of the annual growth layers in woody trees and shrubs - appropriately claimed tree-rings. In temperate climates, with a growth period (spring-summer, the produced wood is the so called earlywood) and a rest phase (autumn-winter, the so called latewood) with no or very low growth, trees produce annual rings. Counting this annual rings, the age of the studied plant can be determinate.

Comparing the wide of the rings, claims about annual growth factors affecting the plant can be argued, like temperature, precipitations or competition. In the early fifteenth century, Leonardo da Vinci noted tree rings as annual patterns, and recognized a relationship between tree ring widths and precipitation.
In the following centuries the anatomy and ecology of tree rings were studied in detail. In 1904, the American astronomer Andrew Ellicott Douglass (he later founded the Laboratory of Tree Ring Research, University of Arizona), developed a tree ring chronology for the south-western United States, using the narrow tree rings found in Ponderosa pine trees, caused by droughts, to corelating different, individual trees. By 1914, he showed in a 500-year record a positive correlation between ring width and precipitation. He then used this chronology to date wood samples found in the Indian pueblo sites, affirming dendrology as dating method.
Joined in his studies by Edmund Schulman, they tried to improve and lengthened the tree ring record, discovering the (until then) oldest known trees of the world, the over 4.000 year old bristlecone pines in the Californian White Mountains. The bristlecone pine chronology, and so the climatic reconstruction, now dates back to 8.500 years. This methusalems were also used to calibrate the 14C curve (influenced by the atmospheric relationships of the carbon-isotopes).

Bristlecone pine (Pinus longaeva)



References:

SMITH & LEWIS (2007): Dendrochronology. in ELIAS (ed.) (2007): Encyclopedia of Quaternary science: 459-465

Freitag, 17. Oktober 2008

Arctic getting hot


The now published annual report by the american National Oceanic and Atmospheric Administration (NOAA) claims that the average air-temperature this autumn in the Arctic is 5° higher then the long-term average. The vanishing ice cover provides less reflection and isolation, and the darker seawater adsorbs more radiation. The actually measured ice cover is lesser by 34% to the average from 1979-2003, only 2007 showed a higher value, with 43%.

Sonntag, 12. Oktober 2008

Lichenometry

Lichens are a symbiotic live community between algae and fungi. The alga furnishes nutrients for the fungus, the fungus provide moisture and shelter for the alga. This partnership enables the two partners to colonize habitats, which a single organism couldn’t colonize by itself, and they colonize an extraordinary variety of habitats and surfaces.

Lichens can be found in the death zone of mountains (up to 7400m a.s.l. in the Himalayan), in rainforests, deserts, temperate regions and on the coast of the sea.

The body of lichen that is visible is formed by the fungus, and is called “thallus”. Lichens can divided into three broad groups based on the shape of the thallus: the fruiticose type consists of small tubules and branches, the foliose type which have a leaf-like plant body, and the flattened crustose type. This last group comprises the most common members of the lichen family, and can be found extensively on hard surfaces, including rock outcrops, boulders, tree bark, buildings and gravestones.


Lichens after HAECKEL 1904 "Kunstformen der Natur"

The first study related to Lichenometry, the dating method that use the growth rate of lichens for dating the surface that they colonize, was carried out by the Austrian scientist Roland Beschel in 1950.
Given similar rocks and climatic conditions, the larger the lichen colony, the longer will be the time passed since the growth surface becomes exposed.
Estimating the absolute age of a material from the lichen growing on its exposed surface first requires the determination of the growth rate of the area. After measuring lichen on surfaces of known age (for example by comparing lichens on historic buildings or geomorphic features with known age) it is possible to plot a growth curve that relates lichen diameters to time.
Then is it possible to compare lichen on a surface of unknown age, within the same area, with the grow curve to determinate the surface’s age.
The growth of a lichen proceeds in three different phases:
1) rapid, logarithmic growth
2) linear growth
3) slow growth phase, where lichen growth gradually declines until death.
Only lichen species with a gradual and progressive growth can be used for dating purpose. In a study only the same lichen species can be used. The growth is influenced by local, and regional environmental factors, such as temperature, day length and snow cover.


The photosynthetic productivity is compared to high plants low, only ca. 25% comparing same areas with lichens and plants. This low productivity implies a low growth rate and a great longevity. Some lichen species (like Rhizocarpon geographicum) are estimated to reach (under favourable conditions like in the cold and dry conditions of western Greenland) 5.000 to 9.000 years.

Rhizocarpon geographicum


But because lichens colonies eventually grow together, and can no longer be measured individually, lichenometry as dating tool is used in a range less than 500 years. Under optimal circumstances lichenometry can provide a dating tool accurate to +-5 years over the last 200 years. So these organisms provide accurate dates for young glacial deposits, rockfalls and mudflows – all events that expose new rock surfaces on which lichen can grow.


Brodoa intestiniformis

References

BENEDICT (1990): Experiments on lichen growth. 1 Seasonal patterns and environmental controls. Arctic and Alpine Research 22:244-253

BESCHEL (1961): Dating rock surfaces by lichen growth and its application to glaciology and physiography (lichenometry). In Raasch (ed.) Geology of the Arctic vol.2. Univ. of Toronto Press: 1044-62

BESCHEL (1973): Lichens as a measure of the age of recent moraines. Arctic and Alpine Research 5:303-309

INNES (1982): Lichenometric use of an aggregated Rhizocarpon “species”. Boreas 11:53-57

INNES (1983): Use of an aggregated Rhizocarpon “species” in lichenometry an evolution. Boreas 12:183-190

INNES (1983): Size frequency distributions as a lichenometric technique: an assessment. Arctic and Alpine Research 15:285-294

INNES (1985): An examination of some factors affecting the largest lichens on a substrate. Arctic and Alpine Research 17:99-106

HEUBERGER (1966): Gletschergeschichte. Untersuchungen in den Zentralalpen zwischen Sellrain- und Ötztal. Wissenschaftliche Alpenvereinshefte 20:125


KONRAD & CLARK (1998): Evidence for an early Neoglacial glacier advance from rockglaciers and lake sediments in the Sierra Nevada, California USA. Arctic and Alpine Research 30:272-284

MATTHEWS (1992): The ecology of recently deglaciated terrain. Cambridge University Press

O´NEAL & SCHOENENBERGER (2003): A Rhizocarpon geographicum growth curve for the Cascade Range of Washington and Northern Oregon, USA. Quaternary Research 60:233-241

WALKER (2005): Quaternary dating methods. Wiley Press

Mittwoch, 8. Oktober 2008

Boneyard XIV

Who dares to enter the BONEYARD !!!



Samstag, 4. Oktober 2008

The active rockglacier at Hohe Gaisl - implications on genesis

Active rockglaciers are less common in the mountain ranges composed of carbonatic rocks, such as the Northern Cretaceous Alps ort he Dolomites, even if here more than lithology probably the minor mean elevation plays a role.
Although few active rockglaciers are present in the Dolomites, they have never been studied in detail.
One studied rockglacier is located in the “Gletscherkar (glacier cirque)” on the north-eastern side of the Hohe Gaisl (3146m). The rockglacier lies in a deeply incised cirque, surrounded by steep walls composed of upper Triassic dolomite and limestone.

Fig.1. Air photos and digital terrain modell of the Hohe Gaisl mountain group with two active rockglaciers in the north-eastern cirques (Autonomous Province of Bozen/Bolzano - South Tyrol)
Fig.2. View to west on the Hohe Gaisl mountain group with two active rockglaciers in the north-eastern exposed, deeply incised cirques. The visited rockglacier can be found in the right cirque (north).

Debris of the rockglacier is mainly derived from a prominent, NW-SE-trending fault, along which the bedrock is intensively deformed. The rockglacier is 850m long, 300-550m wide and covers an area of 0,3 square kilometres. The rockglacier extends from an altitude of 2340m at the front to about 2500m. The eastern lobe shows well developed surface topography of transverse ridges and furrows. The surface is coarse grained and varies from place to place, manly constituted of poorly sorted gravel and sand, huge boulders are missing, great blocks exceeding 1m are rare.

Fig.3. View to west on front of the "Gletscherkar" rockglacier.

In the upper part massive ice is exposed during the summer months at several places below a less than 1m thick debris layer. The ice is coarse-grained, banded, and contains thin, fine-grained debris layers parallel to the banding. Rarely larger clasts occur within the ice.
During the melting season small thermokarst lakes may be developed on the upper part of the rockglacier.

Fig.4a. Ice-exposure on the rockglacier (15.09.2007).
Fig.4b. Fine-grained debris layers parallel to the banding in the ice (15.09.2007).

Georadar measurements provided information on the internal structure and thickness of the rockglacier. The data indicate that the rockglacier has a total thickness of approximately 25m. In the lower and middle part the debris layer is 3-5m thick. Below the debris layer numerous, well developed reflectors are visible indicating the presence of shear planes in the frozen body of the rockglacier, which according to ice exposure in the upper part is composed of coarse (glacier) ice with numerous thin debris layers parallel to the banding. A thin sediment layer (?lodgement till) may be present at the base of the rockglacier.

Internal structure and ice exposure clearly indicate that the rockglacier in the Gletscherkar developed from a debris-covered cirque glacier. It is suggested that the glacier has developed from a small cirque glacier during retreat trough inefficiency of sediment transfer from the glacier ice to the meltwater. The presence of a cirque glacier at Gletscherkar is documented in the older literature and on older maps, for example on a topographic map published in 1902 (FREYTAG 1902).

References:


KRAINER, K. & LANG, K. (2007): Active rock glaciers at Hohe Gaisl (eastern Dolomites). Geo.Alp 4, 127-131
LANG, K. (2006): Geologie des Hohe Gaisl Massivs (Pragser- und Ampezzaner Dolomiten) unter besonderer Berücksichtigung der aktiven Blockgletscher. Unveröff. Diplomarbeit, Institut für Geologie und Paläontologie Leopold-Franzens-Universität Innsbruck, 170S.
SHRODER, J.F.; BISHOP, M.P.; COPLAND, L. & SLOAN, V.F. (2000): Debris-covered glaciers
and rock glaciers in the Nanga Parbat Himalya, Pakistan. Geografiska Annaler 82(A):
17 - 31

Mittwoch, 1. Oktober 2008

William Smith

Writing some notes on the history of geology and glaciology, I “noted” how fascinating this theme is – so in future I will try to spend some time and place on the blog to present extraordinary personalities in geology or related sciences. Hope you enjoy the idea, and find some new or primary unknown facts behind the names that we can so often read in textbooks.

I will begin with a man that I admire much, a pioneer in an even today young science:


Fossils have been long studied as great curiosities, collected with great pains, treasured with great care and at a great expense, and shown and admired with as much pleasure as a child's hobby-horse is shown and admired by himself and his playfellows, because it is pretty; and this has been done by thousands who have never paid the least regard to that wonderful order and regularity with which nature has disposed of these singular productions, and assigned to each class its peculiar stratum.


William Smith, notes written January 5, 1796

In the morning of the 31 of August 1819 the doors of the King´s Bench prison in London release some debtors, and a man - stubby, approximately fifty years old – hurry up to leave the place.
Ten weeks earlier the bailiff had taken him directly from home – Buckingham Street no. 15, one of the better places in London – after he missed to pay a debt of 300 pounds to Mr. Charles Cornally.
But the doors of his house are barred, valuables, papers and maps – all his work- pawned. The very same day he will leave London.
For over 20 years he travelled thousand of kilometres trough the entire Kingdom, noted outcrops, mapped them, trying to ensure a vision. A vision of an unseen, an unknown world, and he would be the first to draw a map, a unique map, a never before seen map, of this mysterious world. A world so near, directly under our feet’s, but still poorly understand and ignored.

His passion for outcrops, stones and fossils had a huge cost; he has been laughed at his ideas by the noble academic gentlemen’s, and he is misunderstood by his contemporary.
The call him “Strata Smith” because his interest to explore mines and other artificial outcrops, like canals or stone quarries.

William Smith was born on March 23 1769 in the village of Churchill, in the county of Oxfordshire, into a respectable farming family. His father died when he was seven, so his mother brought him to the farm of his uncle.
And just here the young William makes an encounter that will change everything. In these parts of Oxfordshire, for the “long pound”, a weight measure used to weigh butter –ca. 600g- are used non the common iron weights, but rounded stones, flat on the one side, with a diameter of 10 centimeters. They are commonly found in the nearby quarries. Smith is fascinated of this stones, why they resemble the sea urchins, that he has seen in the books or on the coast of the sea, distant more then 160 kilometers from the place where they are now found. If these are remnants of animals, why are they petrified, and why some of them resemble animals, that no scientist has ever seen? Commonly this fossils are attributed to the great flood, in a time, where still the age of the earth is debated, ranging form 4004 years to a maximal amount of incredible 1 million years.

Puzzled by this mystery, he starts to seek and collect minerals and fossils. He is an enthusiastic autodidact; he studies the landscape, learns geometry, surveying, and mapping, and is interested in hydraulics and hydrology.

At the age of eighteen he became an assistant surveyor, learning his trade from the master surveyor Edward Webb. Surveying required Smith to travel all over England; in 1794 and following years he toured the entire country. In an England of land reforms and industrialisations, detailed maps were essential to plan and construct streets and canals, and good surveyor were requested.
Here Smith can his apply his knowledge, the job of surveying canal routes requires detailed knowledge of the rocks through which the canal was to be dug. Most of his work time he walks, up to 80 kilometres per day are nothing extraordinary, and he continues to note his observations in his diary.
In 1792 he works for the rich coalmine owner Elisabeth Jones in Somerset. In this time he lives in a property of the lady – Rugbourne Farm, that he will later call – the birthplace of geology, because of his habitude here to sit in a niche and study his rocks.
While studying the technical problems of the mine (high water groundtable) he notes that the coal-bearing layers are over- and underline by a characteristic succession of sandstones and marls. Always is the coal formation overlain by marine, and then non-marine depositions. Always is the coal stratum underline by a grey clay – the ancient soil on which the coal forming giant ferns and horsetails grown, millions of years ago.
Smith, like so oft before, examines the local rocks very carefully. While doing this, Smith observed that the fossils found in a section of sedimentary rock were always in a certain order from the bottom to the top of the section. This order of appearance could also be seen in other rock sections, even those on the other side of England, maybe on the entire world there is a order, and whoever can read and understand it, can much easily find the coal – the black gold of the 18th century.


. . . each stratum contained organized fossils peculiar to itself, and might, in cases otherwise doubtful, be recognised and discriminated from others like it, but in a different part of the series, by examination of them.



This is a statement of the "principle of faunal succession." The layers of sedimentary rocks in any given location contain fossils of a definite age in a definite sequence; the same sequence can be found in rocks elsewhere, and hence the strata with the same age and biocenosis can be correlated between locations. The principle of deposition, a stratum that lays deeply in a succession is older, and vice versa, was not new. But Smith was the first to proof this hypothesis by using fossils, as guide fossils. Geological maps before Smith mapped and catalogued rocks by their inorganic characteristics, sandstones, marls and chalks. Still further differentiation was only possible maybe by colour or other minor properties. This classification was very restricted, it showed no apparent pattern, only to many colours, or to less colours.


Smith has discovered a ulterior classification scheme, a scheme that can differ rocks with no doubt, even if they look very similar.


Ammonites, characteristic fossils for the Mesozoic, and the most appreciated fossils by Smith.

In the summer of 1795 he supervises the excavating of a more than 40 kilometres long canal between Camerton and Limpley Stoke. The salary is excellent, Smith can verify his hypothesis, and finally he is accepted by literate gentlemen’s, which admire his knowledge on fossil determination.
In 1796, after been fired because of a technical debate, Smith was elected to the agricultural society at Bath, and began to discuss his ideas with others who were interested in rocks and fossils. His friends forced him to public his idea, but only hesitating he began to write notes and draw up local geologic maps.

In 1816 he publishes his observations, describing for ever strata of the United Kingdom the characteristic fossils:

Strata - Identified by organized Fossils.

Unfortunately, Smith's map was overlooked at first by the scientific community of the time; his humble origins and limited education were an obstacle to success in learned, God-given society. His financial problems grow, and in 1816 (sigh!) he was forced to sell his greatest achievement, his 2657 exemplars counting fossil collection. Finally he was arrested and his property confiscated. The papers and his maps were acquired by a friend, which at least returned him his work.

The man and his fossils can be imprisoned, but not his idea.

A diagram of 1888, showing the sequence of strata and their characteristic fossils. Notice that at this date, the recently proposed Ordovician (1878) System had not yet been accepted, nor the Paleocene (1874) or Oligocene (1854) as epochs of the Cenozoic. Instead of “Precambrian” or “Primary” this scale uses the term “Laurentian”, since the studies of Precambrian rocks had made the most progress in the Laurentian region of the Canadian Shield.


The modern application of fossils in stratigraphy – without which geology doesn’t exist- is virtually unlimited. Without correlation between outcrops, sections and wells there is no possibility to reconstruct the extension of layers, which possibly contain resources like coal, oil and many minerals or rocks.
Furthermore, until the rocks are dated, there is no possibility to reconstruct the depositional and structural development of the area. Through much of the Phanerozoic, and in general ways at least the upper part of the Proterozoic, fossils offer the most precise means of correlation available. Today there are supplementary methods for (absolute) dating and correlating rocks, but still fossils are the most precise and cheap method in the field.




A Blues in honor of Smith...

It´s all there locked in the stone

the truth is told in fossilized bone.



References:


SMITH, W. (1816-1819). Strata identified by organized fossils, containing prints on coloured paper of the most characteristic specimens in each stratum. London: W. Arding.

WINCHESTER, W. (2001). The Map that Changed the World: William Smith and the Birth of Modern Geology. New York: Harper Collins.