29, May 2006 : Birth of the mud volcano of Sidoarjo

Five years ago, at 5 o'clock in the morning of May 29, the inhabitants of the village of Sidoarjo in East Java witnessed the beginning of the eruption of a mud volcano - and still today every day nearly 30.000 cubic metre of gasses, water and mud emerge from the underground.

Already in 1778 the Italian physicist Alessandro Volta examined the methane gas outpouring from the mud volcanoes of Pietramala near Florence, from time to time this gas ignited producing up to 2 meter high natural torches.
The German explorer Alexander von Humboldt described mud volcanoes he encountered near the Columbian village of Turbaco during his expedition to South America in the years 1799 to 1804 - even if he exaggerated the height with three to four meters (the mounds are approximately one meter high).

Fig.1. The mud volcanoes near the Columbian city of Turbaco, after HUMBOLDT & BONPLAND (1804): Personal Narrative of Travels to the Equinoctial Regions of America, During the Years 1799-1804.

Today worldwide more than 1.100 mud volcanoes are recognized, located on continental shelves but also on continents.
There are various mechanisms that can cause the eruption of mud from the underground, whereby only the last two are regarded as true mud volcanoes, the rest as mud pots.

- Through magmatic activity heated gas or groundwater, that circulating carries with it loose or reworked sediments

- Liquefaction effects during an earthquake.

- Overpressured groundwater, fluids, gas and sediments in sedimentary basins, like a cap impermeable rocks can prevent underlying sediments to escape, as soon as this cap is damaged or removed water begins to rise to the surface.

- Cold methane gas or other fluids escaping from the underground and transporting sediments.

However the mud volcano of Lumpur Sidoarjo ("mud of Sidoarjo"), abbreviated to Lusi, is unique as probably the only artificial mud volcano in history. It erupted up to 180.000 cubic metres mud per day but until 2011 this amount decreased to 30.000 cubic metres per day, however only the construction of dams limited the extant of the mud flow to 7 square kilometres in 2008 - 30.000 people had to be evacuated and 11 people were killed in the explosion of a submerged gas-pipeline.



The cause of the Lumpur Sidoarjo is still controversial. In March 2006 the Indonesian oil company Lapindo Bantas started a drilling campaign 200 meter distant to the future eruption site. The company denies a direct connection to the drill operations and the eruption and affirms that an earthquake and reactivation of an underground fault system triggered the flow of overpressured gases and groundwater from a reservoir in carbonate rocks into the overlying clays.
Some independent research (DAVIES et al. 2007) blames the company to have not adequately coated the borehole. It collapsed in a depth of 1.100 meters after encountering the carbonate reservoir, the growing pressure crashed the surrounding impermeable clay rocks, therefore enabling gas and water to reach the surface and feed the mud volcano.

Fig.2. Schematic three-dimensional model of the Lusi mud volcano according to DAVIES et al. 2007, the research team proposed that an inadequate coating of the bore hole caused fractures in the surrounding rocks, causing overpressured fluids to push to the surface. A legal investigation concluded however that the drill operations were carried out according to standard procedure, the charge of negligence by oil company Lapindo Bantas was therefore rejected.
According to the spokesman the company states that the drill operations were carried out according to standard procedure, the legal case and especially the payments of compensation proceed very slowly and since 2010 legal actions against the company have stalled.

Bibliography:

DAVIES, R.J.; SWARBRICK, R.E.; EVANS, R.J. & HUUSE, M. (2007): Birth of a mud volcano: East Java, 29 May 2006. GSA Today Vol. 17(2): 4-9
HUMBOLDT, von A. & BONPLAND, A. (1804): Personal Narrative of Travels to the Equinoctial Regions of America, During the Years 1799-1804.

A geologist riddle #18

Less a riddle than a preview of the subject of the posts to come:

Five million years of terror: Quatermass and the Pit (1967)

In many science-fiction films the adversary or monster is inspired by prehistoric creatures, dinosaurs are the most popular, but sometimes also mammals and their "derivatives" play a role. The classic monster movie has a quite predictable storyline: men enter and find a place not intended to be explored, awaken so the monster, the scientist explains what it is (even to those who are watching the film) and in the end the hero and we discover how to kill it ...
The animal, and especially a "primitive" creature, is used in movies as a powerful symbol for our subconscious emotions and irrational behaviour, it represents the most primitive instincts of survival - nourishment and sexual reproduction - that are in modern men controlled (maybe even suppressed) by rationality and society.

"Quatermass and the Pit" was in origin a black and white science-fiction/horror TV-serial broadcasted in 1958 and 1959. The story based on a script by Nigel Kneale was later adapted by the British Hammer Film Productions (a company notoriously known for its B-movies) to a movie with same title (1967). Curiously in the U.S. the film was released under the title "Five Million Years to Earth" and in Germany "Das grüne Blut der Dämonen" ("The green blood of the demons", probably influenced by one autopsy scene).
The movie story follows on a first glance only loosely the classic monster story and uses an intriguing variation of the monster as symbol of primitive behaviour.



During construction works in London bones and skulls were uncovered, the anthropologist Dr. Roney discovers the fossils are of a particular breed of primate, much older than all the genera previously known to science.
Meanwhile the archaeological survey is interrupted by what appears to be the discovery of an unknown bomb-rocket of World War II, strangely embedded in the same geological strata as the fossils. The army is informed and General Breen seeks the aid of rocket scientist professor Quatermass. He will soon discover the terrible truth: the supposed rocket is an alien spacecraft. The hypothesis presented by the scientists: 5 millions of years ago a superior race of Martian insects tried to create a race of slaves from primitive monkeys, bursting the evolution of mankind. But before the aliens succeeded in their plan they annihilated themselves in a terrible eugenic war in a distant past.
In fact the reconstruction, based on the fossils and modelled in an extraordinary short time interval by Dr. Roney, shows a giant monkey with a big head, the classic missing link between man and animal (even Piltdown man is mentioned in the technobabble of some scenes of the TV-serial) in accordance to the classic "ladder of evolution" of man. The reconstruction with a large brain resembles also a bit to much modern humans, according to the real fossil record five million years the genus Australopithecus would be a more realistic approach, a bipedal primate with not to unusual characteristics in cranial volume.

In contrast to a classic monster movie in Quatermass and the Pit the discovered fossils remain however dead - there is no physical reanimation and a rampage of classic ape-men trough London. But the discovery of the ancient spaceship has started by telepathic influence also a self-destruction program in the genes of the descendants of the first ape-men - We are the monsters! By following the most primitive instinct and survival of the strongest humans begin to kill each other, like the Martian million years ago.
The movie also cites and shows in form of the war that destroyed the aliens the dangers of a worldwide nuclear threat and armament - a common topic in monster movies of the sixties and seventies. Interesting the decision to gave the Martian the aspect of locusts (but the comparison of the sorcerer of Les Trois Frères is farfetched), maybe to represent the human behaviour of colonizing and overexploiting new land ?

Quatermass and the Pit is not the classic monster movie of the sixties. The first half builds up suspense and then it develops from a science-fiction story to a ghost-horror movie, even with the classic demonic possession scene. The Martian technology is capable to control human minds, taking from us our personality transforming us in a single mob - also the attacks comes from the most unsuspected side, the common people on the street.
It's surely one of the better and more serious Hammer films.
The idea that life on earth, especially the rise of man, can be explained by the intervention of aliens is still used in science fiction today (a recent example is the film "Mission to Mars" in 2000) - ironically that some authors copied this idea even for their pseudo-serious books about Paleoseti in recent years.

Permian Pyroclastic Flow Facies

The German geologist Christian Leopold Freiherr von Buch (1774-1853) was one of the most known geologists of the first half of the 19th century. Educated as a Neptunist, he became quickly interested in volcanoes and their deposits and therefore decided to visit the nearest active volcanoes. So in 1800 he travelled by feet from Germany to Italy, taking with him only one dress, a note book, a barometer and his hammer.
He was the first to study in detail the outcrops of reddish rocks surrounding the South Tyrolean city of Bozen and recognized them as volcanic products and named them appropriately: Bozner Quarzporphyr - quartz porphyry of Bozen.

Fig.1. Example of typical "Bozner Quarzporphyr", this term encompassed very different volcanic facies, like ignimbrite rich in feldspar crystals and flattened clasts (in the photo) deposits, lava flows and even clastic fluvial sediments, only in the last decades a more specific approach and distinction was adopted.

This complex reaches an incredible maximal thickness of 4.000 meters The precise age, origin and geotectonic significance of the Permian magmatism in the Southern Alps is still controversial, one (classic) model propose that the intense volcanism was triggered by the extension of the lithosphere during the break-up of the supercontinent of Pangaea, a second model interprets the volcanic rocks as the magmatic arc of a nearby (today not preserved anymore) subduction zone. Early interpretations suggested that the Bozner Quarzporphyr is mainly a homogenous infill of a gigantic volcanic caldera.
However the Athesian Volcanic Group (the modern term) is a complex succession of both plutonic, magmatic and sedimentary rocks, it consists of volcanic episodes with pyroclastic density currents, ash- and tuff-layers, lava flows, clastic and limnic sediments of erosion phases during volcanic resting phases and intrusion of plutonic rocks, that became uncovered by tectonic movements and erosion.

Fig.2. Geological map of the eastern part of the Athesian Volcanic Group with supposed borders (stripped line) of former caldera, after BARGOSSI et al. 2004.

Fig.3. Example of intruded plutonic rock in the volcanic rocks of the Athesian Volcanic Group, feldspar-porphyry of the Terlano sub-volcanic body.

Many of the various volcanic rocks were and still are used in construction and especially as paving stone.
The Nalles-Formation consists of a sequence of events which produced an aesthetic volcanic breccia. This tuff-breccia is organized in very thick parallel beds, made by variable portion of volcanic, angular to poorly rounded, large clasts swimming in a matrix of crystal fragments and ashes. Some of the larger fragments show a coloured rim as results of thermic alteration. This facies was obviously deposited still quite hot, in a high energy regime capable to transport at the same moment fine particles but also large boulders - this suggest that these are deposits of repeated pyroclastic flows (which even maybe killed at least one poor reptile).

Fig.4. Nalles-formation with large clasts swimming in a matrix of crystal fragments and ashes.

Fig.5. Detail of larger clasts with thermic reaction rim.

Bibliography:

MORELLI, C.; BARGOSSI, G.M.; MAIR, V.; MAROCCHI, M. & MORETTI, A. (2007): The lower Permian volcanics along the Etsch Valley from Meran to Auer (Bozen). Mitt. Österr. Minera. Ges. 153: 1-25

A geologist riddle #17

Hurry up to solve this georiddle before the end or the world is here! The following photographs show the same, the second in greater detail - what is this particular rock and what connection has it to the posts of this (last earthly) week (note the boot on the left corner of the first picture for scale) ?

Volcanoes - myths: North America

The Cascade Range on the west coast of the U.S. is not only characterized by earthquakes and their stories, but especially by volcanoes and them too became incorporated in local legends.

Many mountains and areas were feared by local tribes. The Canadian artist Paul Kane who visited Mount St. Helens, in a phase of activity since 1847, wanted to approach the mountain, but was unable to find any local guide

"this mountain has never been visited by either whites or Indians; the latter assert that it is inhabited by a race of beings of a different species, who are cannibals, and whom they hold in great dread."

Other stories recorded by ethnologists tell of displacing encounters "Sometimes people would hear three whistles, and soon stones would begin to hit their lodges. Then they knew that the giants were coming."
Also Spirit Lake was named after an old tradition involving evil spirits and therefore a place to avoid - according to this myth the salmons found in the lake are the transformed ghosts of evil people.

Fig.1. Cascade Range Volcanoes from the U.S.G.S.

This caution was maybe influenced by the experience of eruptions of the Cascade volcanoes in prehistoric times.
The Klamath people of Oregon tell of the time when the chief of Above World - called Skell- and the chief of Below World - called Llao- decided to settle the dispute which of them was stronger. For many days the fight raged over the land, the two adversaries' hurled rocks and flames at each other and soon darkness covered the land. To better see his adversary Llao decided to climb on the highest mountain he could find - the ancient volcano Mount Mazama - but as soon he reached the peak the mountain collapsed with terrible thunders and hurled him back into his underworld domain. The large hole that remained was then filled up with water and became known as Crater Lake.

An eruption in 1800 at Mount St. Helens, known by the locals as Tah-one-lat-clah - "the Fire-Mountain" caused most concern, the Spokane Indians of eastern Washington thought that "the world was falling to pieces" and the Kalispel of northern Idaho, who remember a rain of "cinders and fire", supposed "that the sun had burnt up, and that there was an end of all things."

Other mountains were also regarded as dangerous or inhabited by malevolent spirits. According to one legend once Mount Baker, known previously as Komo Kulshan, one day got so mad that a big piece fell off and slid way down the mountain, causing a big fire and lots of noise.
Mount Rainier, or Tacobud, also one day take a breath so deep that she burst her blood vessels. All over her body, rivers of blood gushed forth and flowed down her sides. Additionally Mount Tacobud was even inhabited by a terrible flood causing monster, which however was finally defeated by some mighty warriors.
Mount Hood, or Wyeast, was also a mountain haunted by evil spirits who "became so angry that they threw out fire and smoke and streams of hot rocks..[] and caused "rivers of liquid rock [that] ran toward the sea, killing all growing things and forcing the Indians to move far away." Unfortunately this time the great chief, that battled the spirits, by scarifying his life was only capable to entrap them, so it is still possible that they will return.

Even if some stories resemble the description of an eruption followed by pyroclastic flows and ash clouds, caution must be adopted to ascribe every myth to a specific and real eruption. Many volcanoes erupted thousand of years ago (like Mount Baker-6.000 years, Mount Rainier- 2.000 years or Mount Mazama- 6.000 years) and it is hard to imagine that oral traditions were passed unmodified trough so many generations and changing cultures in such vast time periods.
Still it is possible that some legends were really inspired by relatively recent eruption like on Mount Hood or Mount St. Helens and that these myths were subsequently adopted to other, maybe similar looking, mountains or regions.

Fig.2. Cascades Eruptions During the Past 4000 Years, from the U.S.G.S.

Not only active or dormant volcanoes, also extinct volcanoes and their landscape influenced the mythology of North America.

The Devils Tower is the eroded neck of a volcano located in north-eastern Wyoming. The name assigned to the monolith by several of the local tribes mention surprisingly often the bear - like Bear's House (Cheyenne, Crow), Bear's Lair (Cheyenne, Crow), Bear's Lodge (Cheyenne, Lakota), Bear's Lodge Butte (Lakota), Bear's Tipi (Arapaho, Cheyenne) and Grizzly Bear Lodge (Lakota).
Two Indian tribes living in the vicinity have slightly different stories accounting for its unique shape, but both involve a group of people being pursued by a giant and angry bear. Exhausted the Indians appealed to their deity for help, suddenly the ground on which they stood raised to the sky, forming a smooth pillar. The bear tried to climb the pillar; the claw marks (a classic example of columnar jointing) made by the bear as he tried to reach them are still visible today.

In California the outcrops of volcanic obsidian glass were an important resource for tool making and considered a gift by spirits or ancient heroes. According to one myth an enormous eagle or condor, the spirit Milili, once scattered all around over California pieces of obsidian, which shattered on impact on the ground. Maybe this could explain the chaotic appearance of some of the ancient lava flows from which obsidian was gathered.

The Wintu Indians of northern California once didn't possess obsidian and therefore their weapons were not much useful to hunt deer. One day the great hunter Adder arrived, who possessed such an extraordinary weapon made of this particular volcanic rock that he managed to kill many deers in just one day. The Wintu hunters became envious, and so they asked Ground squirrel to steal one of the arrows of Adder. Ground squirrel managed to extract a piece of obsidian from one of the hunted deer and run away, but Adder soon noticed the thievery and set the world in fire. Ground squirrel escaped and dropped his load where today is located Glass Mountain near Mount Shasta- however the piece of obsidian carried on his back burned his skin so bad that still today his descends display a black mark on their back.

References:

CASHMAN, K.V. & CRONIN, S.J. (2008): Welcoming a monster to the world: Myths, oral tradition, and modern societal response to volcanic disasters. Journal of Volcanology and Geothermal Research 176: 407-418
VITALIANO, D.B. (2007): Geomythology: geological origins of myths and legends. In Piccardi, L. & Masse, W.B: (eds): Myth and Geology. Geological Society, London, Special Publications, 273: 1-7

May 18, 1980: Tah-one-lat-clah or St. Helens

In the years 1792 to 1794 the crew of the "H.M.S. Discovery" under the command of captain George Vancouver was surveying the western coast of the North American continent, when they in October 1792 spotted a mountain and named it after the British diplomat Alleyne FitzHerbert, 1st Baron St. Helens (1753-1839).
The origin of Saint Helens was however discovered by naturalists only in 1835, when a minor eruption revealed its volcanic nature. First geologic studies were carried out since 1841, when an expedition of the U.S. Army lead by Charles Wilkes reached the volcano; the summit was finally conquered in 1853 by newspaper editor Thomas J. Dryer. In November 1842 the missionary Josiah Parrish experienced an ash rain and earthquakes generated probably by the 130km distant St. Helens. This phase of activity lasted until 1857.

Fig.1. Painting by Canadian painter Paul Kane Mount St. Helens erupting at night after his 1847 visit to the area.

However the local tribes know well the character of these volcanoes, St. Helens was called by the Klickitats the Loo-Wit Lat-kla - "Keeper of the Fire" or Louwala-Clough - "One from Whom Smoke Comes" and also Tah-one-lat-clah - "the Fire- or Smoking-Mountain". According to their legends, the mountain was once the beautiful princess Loo-Wit, who was disputed by two warriors in a battle of fire and smoke which buried entire villages and forests. To end the battle all three were transformed in mountains: the beautiful and shy princess became the symmetrical, ice covered St. Helens; the two angry warriors became the clunky Mount Hood in the south and Mount Adams in the west. This myth was possibly inspired by the observation of a prehistoric eruption of one of the mentioned volcanoes, but there are also direct eyewitnesses' reports: in 1800 the Sanpoil and Spokan Indians told to the first missionaries and traders visiting the area of an eruption occurring on St. Helens.

"The people called it snow… The ashes fell several inches deep all along the Columbia and far on both sides. Everybody was so badly scared that the whole summer was spent in praying. The people even danced — something they never did except in winter.
They didn't gather any food but what they had to have to live on. That winter many people starved to death."
(Oral traditions originally recorded by anthropologist Verne F. Ray in the late 1920s from the Sanpoil and Nespelem Indians of northeast Washington)

Minor eruptions with small explosions and lava flows occurred again in 1898, 1903 and 1921. It was this apparent tranquillity that lead until 1980 to believe that many of the volcanoes of the Cascades were dormant and not threatening, especially one of the youngest and smallest of them - like St. Helens.
In 1969 geologists Dwigth Crandell warned during a congress in San Francisco that the continental volcanoes of North America were still poorly studied and monitored, and much more active than previously assumed. Based on dated deposits of past eruptions, Crandell published with Donal Mullineaux a paper in which he warned that "the scheme of activity of St. Helens led to the assumption that it is possible to postulate an eruption in the next 100 years and maybe even before the end of this century".
In March 1980 finally a monitoring system was installed on St. Helens, also in response to increased interest of the volcanoes located along subduction zones, as is the Cascade Range, after a surprising destructive eruption in the sixties of the Arenal in Central America.
The system registered from the very beginning onwards an increased seismic activity, until end of March earthquakes with a magnitude of 4 happened periodically, on March 27, an explosion occurred - it was now clear that St. Helens had entered a new eruption phase. The volcano became intensively monitored, in April the northern flank begun to rise, probably by intruding magma inside the mountain, an eruption was impending and therefore the area around the volcano was closed to the public.

On Sunday May 18, at 8:32 an earthquake of magnitude 5.1 triggered one of the largest landslide-avalanche ever to be recorded (estimated 2.8 cubic kilometres of rocks and ice) on the northern slope of the mountain, followed by a gigantic explosion. In just 60 seconds the mountain shrinked from 2.950m to 2.549m, 600 square kilometres were devastated by a 600°C hot pyroclastic density current and the burst of the explosion. The melting glacier ice and the overspill of Spirit Lake caused lahars that devastated the valley of the Toutle Rivers.



Despite the delimitated danger zone, 57 people were killed, many of them scientists studying the active volcano inside the zone - nobody expected that the eruption would occur so fast and so furious. Notable the story of David Johnston, U.S.G.S. geologist. Johnston was well aware of the risk of being with his observation station so close to the mountain, but he stayed on there right up to the moment of the eruption - his last recorded words and the first mention of the eruption:

"Vancouver, Vancouver, this is it!".

It is thanks to his work and many others that the eruption of St. Helens is one of the best documented in history. Two geologists, Dorothy and Keith Stoffel, were overflying St. Helens when it erupted:

"The whole north side of the summit crater began to move as one gigantic mass,…[] The entire mass began to ripple and churn without moving laterally. Then the whole north side of the summit began sliding to the north along a deep-seated slide plane."

Also many reporters, hikers and volcano enthusiast, located outside the danger zone, documented the eruption with photographs or descriptions.

This video created with photographs taken by Gary Rosenquist, stationed at 18km northeast of St. Helens in the morning of May 18, shows the dynamics of the slope collapse and the pyroclastic explosion. The first photo was taken at 8:27, in the next 6 minutes he take a dozen photos before he escaped the approaching pyroclastic current. The landslide previous the eruption is well visible as the block moves downward, followed by the pyroclastic flow projecting first upward, then sideward and surpassing the landslide.



The eruption at St. Helens was only a single event in the long history of the Fire Mountains of the Cascade Range, like in the fossil forest of Yellowstone many times the landscape was destroyed, reborn and modified by volcanic eruptions. Today St. Helens is monitored and the area protected to understand the colonization by animals and plants of a devastated landscape - a new chapter to be written in the geologic record.



Bibliography:

DAVIS, L. (2008): Natural Disasters. Facts on File Science Library. Infobase Publishing: 464
CRANDELL, D. R. & MULLINEAUX D, R., (1978): Potential hazards from future eruptions of Mount St. Helens, Washington: U.S. Geological Survey Bulletin 1383-C: 26
GUNN, A.M. (2008): Encyclopedia of Disasters - Environmental Catastrophes and Human Tragedies. Vol.1. Greenwood Press, London: 733
LEWIS, T.A.(ed) (1985): Volcano (Planet Earth). Time-Life Books: 176

Online Resources:

TOPINKA, L. (03.01.2011): Volcanoes and History. Cascades Volcano Observatory, Vancouver, Washington. (Accessed 17.05.2011)
WATSON, J. (25.06.1997): Mount St. Helens Volcano. (Accessed 17.05.2011)

12, May 1931 : Alfred Lothar Wegener

"We stand against [the earth] like the judge stands against a defendant who refused to give any information, and we have the task to reveal the truth by circumstantial evidence."
"Die Entstehung der Kontinente und Ozeane." 4th ed by Alfred L. Wegener (1929)

Fig.1. 12, May 1931 the body of Alfred Wegener is found on the ice of Greenland, the remaining members of the expedition led by Kurt Wegener, Alfred´s brother, use a drill pipe to mark the grave with a cross. They respected Wegener´s love to the Arctic and buried him in the ice he had studied for many years and on various expeditions (photography by the Alfred Wegener Institute).
Today, all signs of Wegener’s last resting place are vanished beneath the ice.

The fossil forests of Amethyst Mountain

The fossil forests of Specimen Ridge and Amethyst Mountain, both situated in the Yellowstone National Park, are peculiar because of many preserved trees still found as upright trunks and stumps emerging from the sediments.
The geologist, anthropologist and artist Dr. William H. Holmes was the first to study the outcrop of Amethyst Mountain and published his observations in 1878:

"As we ride up the trail that meanders the smooth river bottom [the Lamar River] we have but to turn our attention to the cliffs on the right hand to discover a multitude of the bleached trunks of the ancient forests. In the steeper middle portion of the mountain face, rows of upright trunks stand out on the ledges like the columns of a ruined temple. On the more gentle slopes farther down, but where it is still too steep to support vegetation, save a few pines, the petrified trunks fairly cover the surface, and were at first supposed by us to be shattered remains of a recent forest."

Fig.1. Pencil drawing ca. 1879 by Holmes of the outcrop of Amethyst Mountain, National Archives.

Fig.2. Two fine specimens of fossil tree trunks of Pilyoxylon aldersoni in the fossil forest on a steep hillside of Specimen Ridge, exposed by erosion of the basic breccia in which the stumps and roots are firmly embedded. Nearby a hoodoo, showing the character of the breccia and the manner in which it has been deposited. Circa 1890. Figure 2, U.S. Geological Survey Folio 30, USGS Photo Library.

Holmes studying the outcrops realized that the silicified stumps are distributed in various levels (more than fifty are today recognized) and embedded in volcanic deposits like ash, mud flows and breccias. These deposits provided also an explanation of the remarkable well preserved structure of the wood: from the rocks the silica was solved by the percolating water and substituted the organic matter of the wood. Inside of some hollows trunks even geods with crystals of amethyst formed and the name of the mineral was adopted previous of 1870 to the entire site, unfortunately most of these specimens were removed by collectors already in the late 19th century.
The upright position and the well preserved roots are a sign that the trees became embedded in situ, covered by ashes, mudstone, breccias and conglomerates during a volcanic eruption. There are also signs of fluvial reworking of the deposits, many trees rooted in tuffaceous sandstones, interpretated as paleosoils, and conglomerates deposited by a braided river system.

Fig.3. Schematic profile of Amethyst Mountain as imagined by Holmes and published in "Fossil forests of the volcanic tertiary formations of the Yellowstone National Park. Bull U.S. Geological and Geographical Survey of the Territories Vol.5.(1), 1879-1880"

A modern example possibly resembling the environment of formation of the petrified Yellowstone forests was the landscape after the eruption of Mount St. Helens in 1980. Here a violent eruption razed down large areas of the forest surrounding the mountain, leaving behind stumps that were buried under pyroclastic flows and lahars.
Today, more than 30 years later the effects of the explosion are still visible, even if a new forest has begun to colonize the devastated area. Subsequent research showed that St. Helens experienced many eruptions in the Holocene, repeatedly the area was devastated and repeatedly the area was reconquered by nature.

Also in Yellowstone the buried forest was destroyed, entombed in the volcanic deposits and the new formed landscape colonized again by a new forest. The time period involved in these cycles was however at the time of Holmes unclear, however the perfectly preserved tree rings inspired geologists to try to estimate how much time was involved in the growth phase of the plants and finally in the formation of the entire sedimentary succession:

"Pine trees of the types represented in the fossil trunks require 200 or 300 years to reach maturity, and redwoods may require from 500 to 1,000 years. Twelve or more of these forest levels have been found. By multiplying this number by the minimum age of the trees (200 years) we shall have 2,400 years, and by multiplying it by the maximum age of the redwood (1,000 years) we shall have 12,000 years as the possible time during which these forests flourished. It is possible that the truth lies somewhere between these extremes."
(KNOWLTON 1921)

Glacial erosion on Specimen Ridge and Amethyst Mountain showed that the volcanic activity was older than the ice age and therefore geologist inferred a tertiary age, so Knowlton in 1921 summarizes:

"After the Cretaceous period, there was a time of great volcanic activity, which appears to have lasted until perhaps the beginning of the glacial epoch."

Today the sediments are dated thanks to modern methods into the Eocene. The events at St. Helens provided also a possible time period for the formation of the fossils, well preserved wood was found in centuries old lahars of the volcano with silica beginning to substitute the organic matter, in some cases even after 36.000 years the fossilisation was not completed.

However I have to note that this scenario is only a theory and there is an alternative explanation: the forest was buried in a worldwide flood send by a magic, invisible creature living in the sky that so loved its own creation that it decided to destroy it to punish a single species of upright, naked ape, with the exception of a single family dedicated to inbreed - much more plausible than a series of boring volcanic eruptions...

Online Ressource:

COFFIN, H.G. (1976): Orientation of trees in the Yellowstone Petrified Forests. Journal of Paleontology. Vol.50(3): 539-543. (Accessed 16.05.2011)
KNOWLTON, F.H. (1921): Fossil Forests of the Yellowstone National Park. USGS Monograph 32: 651-791. (Accessed 16.05.2011)
VINEY, M. (2008): The Virtual Petrified Wood Museum. (Accessed 16.05.2011)

Old Man River

Caricature published in the newspaper "Ledger" 03.05.1927 depicting the "Old Man River" affected by a severe case of "floods".
The Secretary of Commerce Herbert Hoover and the Commander of the Engineer Corps Major General Edgar Jadwin of the US-Army endorse the common (snake oil ?-)cure: higher and higher dams as projected for the Mississippi River and Tributaries Project after the great flood of 1927 - despite modern methods like reforestation, flood management and limitation of construction in flood plains, dismissed as new-fashion drugs, are available.

Cabinets of curiosities #5: The Last of Their Kind

"Begin at the beginning and go on till you come to the end; then stop."
Lewis Carroll (1832-1898)

Presumably 99% of all the species that inhabited earth in the geological past went extinct, some during mass extinctions, most however slowly but inescapable, even if some described creatures or monsters and fossils apparently never existed.
A strange flightless bird became an icon of extinction - endemic on Mauritius today only fragments survive in our museums and as cruel aftermath his appearance became soon distorted by humans after his extinction.
The role of human induced extinction during the Pleistocene is still discussed - for example for the strange marsupial lion, for the recent past however it is well documented, especially for species confined on archipelagos or islands like in the Arctic or Japan or Tasmania.
But also species with billions of individuals were hunted down so efficiently that they went extinct in a geological blip.
Today at least we care and try to minimize the impact of our society on the environment and species richness; however it is clear that it is necessary to assign priorities, not only for animal, but also plant species.

A geologist riddle #16

This drawing will be related to a next week anniversary, the most peculiar feature of this outcrop are the small vertical structures as seen in the left sketch - so what phenomena and concept of geology is recognizable here ?

Earthquakes and the rapture

Peter Hadfield debunks again all the religious crap and quacks misusing geologic phenomena to promote their delusions:

Fig.1. Boxplot-diagram showing earthquake magnitude after Richter in the years 1900-2002 - the mean value of every year shows no significant trend 1900-1960, since 1960 the monitoring system incorporates more and weaker earthquakes, therefore the step - but again the mean value of all events per year show no trend, also stronger earthquakes do not surpass the years of the first half of the 20th century…all the self-proclaimed prophets obviously didn´t even bother to control the information aviable on the site of the U.S.G.S.

And now more prophets....

War Geology

In the year 1915 the Great War reached the, at the time, Austrian Dolomites as the neutral Italy declared war to the Austrian-Hungarian Empire. The military high commando feared that bypassing the Alps the Italian army could reach the city of Vienna in just one week, so it was decided to secure the most important routes and mountain passes at the national borders.

The Falzarego pass, connecting the city of Cortina d´Ampezzo with the western valleys, was of strategic significance - this pass is situated at 2.105m a.s.l. and is dominated in the north by the nearly vertical cliff of the small Lagazuoi, a 2.700m high mountain.

Fig.1. The Lagazuoi overlooking the Falzarego pass situated at the left corner of the photography. The Austrian front line followed the crest of the mountain.

There was no experience with war in such an extreme and alpine environment, it was nearly impossible to attack directly the enemy when he hid behind inaccessible rocks or in steep cliffs and soon a position warfare between the Austrian and Italian troops developed.
The strategists of the military tried to resolve this problem with a war technology successfully adopted in the soft shale, cretaceous sediments and quaternary deposits of the low plains of France, Netherlands or Russia: the mine war. Long tunnels were dig until approaching hidden in the underground the enemy front line, then the end of the tunnel is filled with explosives or mines and the enemy simply blasted away.
In mountains by undermining the enemy position or by causing rock-fall on the enemy it was possible to misuse the geology as tactical weapon of mass destruction. However the Triassic rocks of the Dolomites were much harder to excavate than expected and only with great effort in material and men it was possible to extend the military tunnels by 10m every day in the dolostone.

In the years 1915 to 1917, when the war in the Dolomites was finally abandoned, at the entire front line of Tyrol 34 blasting operations were attempted, 20 by the Italian army and the remaining by the Austrian army.
The Austrian army realized the importance to know the geology of the battle fiels and instituted a special division formed by war-geologists - the "Kriegsgeologen". These geologists recorded the geology in the front line and studied the best solutions for engineering problems to construct defensive positions, artificial tunnels and other military infrastructures. Apart their military duties they however enjoyed great liberties and were allowed to move free at the front line and to continue their scientific work by collecting samples, rocks and fossils. Also in the Italian army many professional geologists were engaged, even if the Italians never possessed an own military geologists-division.

Fig.2. A romantic view of the war in the Dolomites as seen by the Austrian artist and alpinist Gustav Jahn (1879-1919), who fought in the first world war. Soon the soldiers realized that this war would last much longer than expected and that the beautiful landscape hid a harsh mountain environment that would cost more lifes than the battle operations.

The Lagazuoi is composed of the Cassian Dolomite-formation, dolostone of a former Triassic reef complex with the massif reef core at its centre and the clinostratification of reef debris interfingering with marls of a sea basin to the east. The dolostone of this formation is hard but brittle and also tectonically weakened, so driving small tunnels into the mountain is still possible, even if a tedious quest.
In 1915, to reach the Italian position situated in middle of the southern rock wall of the Lagazuoi, the Austrian army begun to excavate from the northern slope a tunnel trough the mountain. Adopting a similar strategy the Italian soldiers tried to undermine the peak of the Lagazuoi, where the Austrian soldiers were stationed, so the Italian excavated in five months a more than 1.000m long tunnel to reach a position below the mountain peak.

The Austrian Kaiserjäger Hanz Berger remembers the work in the tunnels:

"In the tunnels I'm afraid to be blasted into the air from below or to become entrapped, the pointers of my clock seem to slow down in this place, a second lasts for two, a minute for 20 minutes, a night can last forever and it seems that the sun is gone forever."

Fig.3. The Austrian front line follows a rock wall on the summit of the Lagazoui - today the huts and the tunnels used by the soldiers are a memorial place.

Fig.4. A simple hut constructed by the soldiers.

Fig.5. Inside the hut, the soldiers lived for months, often the entire winter, in such primitive shelters.

Fig.6. View outside one of the tunnels through a loophole into the valley.

At the Lagazuoi many tunnels were constructed and 5 mines were detonated by the two armies during the war:

Shortly after midnight of the new-year day of 1916 the Austrian army initiated the mine wars at the Dolomites front with the detonation of 300kg of explosives inside of the Lagazoui. A large boulder was blasted off but it caused only minor damage on the huts of the Italian position.

On 11.07.1916 the Italian army blasts off the "Castelletto", a rock ledge on the steep cliff of the Tofana di Roces, a mountain situated in the east to the Lagazuoi, using 35.000kg of explosives hidden in a 400m long gallery inside the mountain. They hope to bury and destroy the underlying Austrian front line, 13 soldiers were killed.

Fig.7. The Tofane di Roces today.

On 14.01.1917 using 16.000kg of explosives a 37m in diameter and 45 deep crater was blasted into the mountain, still today the debris of the explosion is recognizable at the base of the cliff of the Lagazuoi (left debris cone).

22.05.1917 the third Austrian blast operation with 30.400kg explosives tries to destroy the Italian position, 200.000 cubic meters debris fell off from the mountain producing a 200 high and 140m broad scar, 4 Italian soldiers were killed.

In the morning of the 20, June 1917, after the construction of a complex gallery trough the mountain, 33.000kg of explosives deposited under the peak of the Lagazuoi explode, tearing apart the mountain and producing the right debris cone at the base of the Lagazuoi.

Fig.8. The scar in the rock wall and the debris cone produced from the explosion in 1917 is still well visible. The Italian front line was situated in the middle of the rock wall, on the large step visible in the photography, formed by the contact of two stages of the reef-growth during the Triassic.

The Italian soldier Luigi Panicalli recalls this day:

"I realize that in few moments the results of all this months, in which we worked and suffered, will be shown. I'm like petrified. In this last moments my thoughts are by the enemy - poor guys - do they feel that death is approaching, do they anticipate that their enemy is inside the mountain and will hurl them from the summit of the mountain into the grave ?"

In the end the various attempts and operations in all these years didn't change the front line or the progress of the war - and still today the scars of the mountain are visible like silent reminders of the madness of war.



Bibliography:

AVANZINI, M. & ZAMBOTTO, P. (2009): Paleontologi in Guerra. PaleoItalia 20: 17-20
PIERO, G.; AVANZINI, M.; BREDA, A.; KUSTATSCHER, E.; PRETO, N.; ROGHI, G.; FURIN, S.; MASSARI, F. PICOTTI, V. & STEFANI, M. (2010): Dolomites 7th international Triassic Field Workshop Pan-European correlation of the Triassic. Field trip to the world heritage site of the Tethyan Triassic September 5-10, 2010 Dolomites, Southern Alps, Italy: 122

Online Resources:

KNOPP, G. (2009): Der Kampf um Südtirol. (Accessed 11.05.2011)
STRIFFLER, R. (): Die 34 Minensprengungen an der Tiroler Gebirgsfront 1916-1918. (Accessed 11.05.2011)

A geologist riddle #15

There is a tragic connection between the following contrasting photographs, it will give you the location and the connection to geology of what happened here: