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The latest Research, Reviews, News and information about Geology / Earth Science from around the web. GEOLOGY INFO
The relic of King Albert I of Belgium, bought at an auction by VTM journalist Reinout Goddyn: blood-stained tree leaves collected by people living near the forest at the foot of the rocks of Marche-les-Dames. The DNA analysis has confirmed that the blood really belonged to the monarch. Credit: Copyright KU Leuven - Maarten Larmuseau
The relic of King Albert I of Belgium, bought at an auction by VTM journalist Reinout Goddyn: blood-stained tree leaves collected by people living near the forest at the foot of the rocks of Marche-les-Dames. The DNA analysis has confirmed that the blood really belonged to the monarch. Credit: Copyright KU Leuven - Maarten Larmuseau
The death of King Albert I of Belgium in 1934 -- officially a climbing accident -- still fuels speculation. Forensic geneticist Maarten Larmuseau and his colleagues at KU Leuven (University of Leuven, Belgium), have now compared DNA from blood found on the scene in 1934 to that of two distant relatives. Their analysis confirms that the blood really is that of Albert I. This conclusion is at odds with several conspiracy theories about the king's death.

On 17 February 1934, King Albert I -- the third King of the Belgians -- died after a fall from the rocks in Marche-les-Dames, in the Ardennes region of Belgium near Namur. Albert I was popular and world famous due to his role during the First World War. The fact that there were no witnesses to his death soon fuelled speculations about the king's 'real' cause of death.

Conspiracy theories are circulating to this very day, ranging from a political murder to a crime of passion: the king is said to have been murdered elsewhere, his dead body allegedly never was in Marche-les-Dames, or his fall is believed to have been staged only later. Evidence for these theories, however, has never been found.

After the death of Albert I, Marche-les-Dames virtually became a place of pilgrimage, and relics turned up with the king's trails of blood, said to have been collected during the night of 17 to 18 February by people living in the neighbourhood.

VTM journalist Reinout Goddyn, who works for the Flemish television programme Royalty, bought one of these relics: blood-stained tree leaves. He wanted to know if this could really be the blood of Albert I, given the conspiracy theories. In 2014, UGent Professor Dieter Deforce had already confirmed that the blood was definitely human.

Forensic geneticist Maarten Larmuseau and his colleagues from KU Leuven (University of Leuven, Belgium) continued the investigation and found two living relatives of Albert I: "King Simeon II of Saxe-Coburg and Gotha, the last tsar and former prime minister of Bulgaria who is related to Albert I on his father's side, and Anna Maria Freifrau von Haxthausen, a German baroness who is related to Albert I on her mother's side, were willing to cooperate. They gave up DNA samples that we compared with the DNA of the trails of blood. We found that the blood is indeed that of Albert I."

This confirmation has historical importance. "80 years after the fact, everyone involved has passed away, and most material is gone; we will probably never be able to dismiss all speculations concerning this 'cold case'. This study was one of the last possibilities to gather additional data. The authenticity of the trails of blood confirms the official account of the death of Albert I. The story that the dead body of the king has never been in Marche-les-Dames or was only placed there at night has now become very improbable. Furthermore, the results show that conducting a perfect legal investigation at the time was impossible right from the start, because souvenir hunters had disturbed the scene."

This type of genetic family-tree research confronts researchers with quite a few ethical questions, adds bioethicist Pascal Borry from the KU Leuven Interfaculty Centre for Biomedical Ethics and Law: "We have to take into account the consequences of this study for living relatives. After all, in addition to the actual identification, a genetic profile can reveal quite a bit of sensitive information, in the context of a kinship analysis or in terms of hereditary conditions. This particular case concerns someone who's deceased and has obviously never given permission for a genetic profile."

"We only focused on the identification of the trails of blood and deliberately avoided deducing unexpected results from the DNA," Larmuseau continues. "The latter was the most difficult aspect of this study. We also want to protect the privacy of everyone involved and of living relatives, and avoid commercialization of the genetic information, following international guidelines for biomedical research. Therefore, the genetic profiles have not been published, but they were double-checked by independent experts. The DNA samples of our study have been destroyed. What is left of the relic will be entrusted to an institution for cultural heritage or a scientific institution."
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Source:
The above post is reprinted from materials provided by KU Leuven. Note: Materials may be edited for content and length.

Reference:
Maarten H.D. Larmuseau, Bram Bekaert, Maarten Baumers, Tom Wenseleers, Pieter Deforce, Pascal Borry, and Ronny Decorte. Biohistorical materials and contemporary privacy concerns -- The forensic case of King Albert I. Forensic Science International: Genetics, 2016 DOI: 10.1016/j.fsigen.2016.07.008
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The latest Research, Reviews, News and information about Geology / Earth Science from around the web. GEOLOGY INFO
The Chao volcano in northern Chile with a lava coulée approx. 14.5 km long (centre of picture). The composition of the lava matches that of deposits of adjacent supervolcanic calderas. Chao erupted about 75,000 years ago, but zircon crystals in the lava were already forming in a subterranean magma reservoir for nearly three million years. Credit: Landsat 8, U.S. Geological Survey
The Chao volcano in northern Chile with a lava coulée approx. 14.5 km long (centre of picture). The composition of the lava matches that of deposits of adjacent supervolcanic calderas. Chao erupted about 75,000 years ago, but zircon crystals in the lava were already forming in a subterranean magma reservoir for nearly three million years. Credit: Landsat 8, U.S. Geological Survey
Geoscientists from Heidelberg University have discovered accumulations of magma in the Andes sufficient to have set off a super-eruption but which, in fact, did not. Such eruptions, which expel enormous quantities of magma, are the largest volcanic events on earth. Together with colleagues from the USA, researchers from the Institute of Earth Sciences discovered that magma volumes of supervolcanic proportions have been continuously accumulating in the Altiplano-Puna region since the last super-eruption nearly 2.9 million years ago. These magmas, however, did not reach the surface to trigger a catastrophic eruption but instead slowly cooled at depth and hardened into plutonic rock. The results of the research were published in the journal Geology.

"A supervolcanic eruption spews out more than 1,000 cubic kilometres of magma, which accumulated over time in reservoirs close the earth's surface," explains Prof. Dr Axel Schmitt of the Institute of Earth Sciences. "In turn, these reservoirs are fed from deeper layers in the earth's crust and the underlying mantle. During an eruption, the overlying rock layers collapse into the empty magma chamber and form depressions, known as calderas, of up to 100 kilometres in diameter." Axel Schmitt indicates that there have been at least seven super-eruptions in the Altiplano-Puna region within the last ten million years, the most recent one about 2.9 million years ago. What remains unclear is why no further major eruptions have occurred since then and whether the region can now be considered inactive for such events.

Using samples from five comparatively small lava domes in northern Chile and southeast Bolivia, the Heidelberg researchers and their American colleagues investigated the most recent eruptions whose chemical composition matches the supervolcanic magmas from the region. They determined the age of very small zircon crystals from these lava flows with the aid of a high-spatial-resolution mass spectrometer. "The mineral zircon forms almost exclusively in magmas, so its age revealss when those magmas were present under the volcano," explains Axel Schmitt. "The astonishing result was that the ages of the zircons measured from all five of the smaller volcanoes extended continuously from the time of the eruption 75,000 years ago back to the last supervolcanic eruption."

Prof. Schmitt reports that model calculations demonstrated that zircon formation is only possible over such protracted durations if the inflow of magma amounted to approx. one cubic kilometre over 1,000 years, which is unusually high for a relatively small volcano. "This means that over a long period of time a magma volume of supervolcanic proportions must have accumulated under the five lava domes, which then solidified into plutonic rock at depth." The volcanologist explains that the lack of a major volcanic eruption does not necessarily indicate that magmatic activity has come to a complete halt. Perhaps the rise in magma from deeper regions merely slowed during the last 2.9 million years, forming an enormous body of rock known as a pluton.

"However, our results also show that a relatively small increase in the long-term magma recharge from about one to five cubic kilometres in 1,000 years would recreate conditions favouring a catastrophic supervolcanic eruption. A new super-eruption in the Altiplano-Puna region would be possible, but only after a long lead time," explains Prof. Schmitt.

Researchers from Oregon State University and the University of California in Los Angeles also contributed to the research.
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Source:
The above post is reprinted from materials provided by Heidelberg University.

Reference:
Casey R. Tierney, Axel K. Schmitt, Oscar M. Lovera, Shanaka L. de Silva. Voluminous plutonism during volcanic quiescence revealed by thermochemical modeling of zircon. Geology, 2016; 44 (8): 683 DOI: 10.1130/G37968.1
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The latest Research, Reviews, News and information about Geology / Earth Science from around the web. GEOLOGY INFO
Schematic diagram of a subduction zone with sediments structure. Credit: C. Kersten GEOMAR
Schematic diagram of a subduction zone with sediments structure. Credit: C. Kersten GEOMAR
Where a tectonic plate dives under another, in the so-called subduction zones at ocean margins, many strong earthquakes occur. Especially the earthquakes at shallow depths often cause tsunamis. How exactly are such earthquakes initiated? Which rock composition favours a break in the earth's interior that can lead to such natural disasters? Scientists at GEOMAR Helmholtz Centre for Ocean Research Kiel and the University of Utrecht (NL) published a study in the scientific journal Nature Geoscience which points to earthquake nucleation in calcareous sediments.

The effects of earthquakes are often severe and highly visible. They can destroy homes, induce slope failures and trigger tsunamis. The main cause for earthquakes are the stresses that occur in the Earth's interior, when two tectonic plates pass each other and interlock during this process. But even the worst earthquake starts with a very small first crack in the rock from which a large fracture can develop. So far it was assumed that initial cracks for earthquakes mainly occur in clay-rich sediments. Scientists at GEOMAR Helmholtz Centre for Ocean Research Kiel and the University of Utrecht (NL) were now able to prove that under certain conditions calcareous sediments are the most likely candidates for the first breakage of an earthquake. The study is published today in the international journal Nature Geoscience.

For their investigations the scientists used samples obtained during two expeditions in 2011 and 2012 with the US drillship JOIDES RESOLUTION off the coast of Costa Rica. There the Pacific Cocos plate is subducted beneath the Caribbean plate. In the past this has repeatedly led to severe earthquakes in this region. "The aim of the Costa Rica Seismogenesis Project (CRISP) was to obtain information about the structure of the subducting and the overriding plate using drill cores" Dr. Michael Stipp from GEOMAR, initiator and second author of the current research study, explains.

During subduction the Cocos Plate carries its overlying sediments downwards, which are thus sandwiched between the plates. "Off the coast of Costa Rica, the seismogenic zone that is the zone where earthquakes are generated along the plate boundary, starts already in an exceptionally shallow depth of about five to six kilometres. This is right in these subducted sediments," Robert Kurzawski states, PhD student at GEOMAR and first author of the study.

However, the sediments usually show variable compositions. Off the coast of Costa Rica and in most subduction zones in the tropical and subtropical area both clayey and calcareous sediment layers are found. Due to the drill cores obtained from JOIDES RESOLUTION the scientist could investigate samples exactly from these sediment layers. In the "Rock Mechanics Laboratory" of the University of Utrecht they brought the samples to conditions that prevail at depth, where shallow earthquakes occur. "These conditions include an increased pressure, temperatures of about 100 degrees Celsius and finally shear movements," Dr. Stipp explains.

Since the clay sediments are considered mechanically weak, it was assumed that the first cracks would be formed in these when the subsurface stresses are large enough. In the experiments, it became clear that the clay-rich sediments from Costa Rica in contrast to the calcareous sediments react less sensitive to changes in stress, temperature and especially pore pressure. The calcareous sediments, however, change their frictional properties significantly during the increase in temperature and pore pressure. "Exactly at the conditions which are expected for shallow earthquakes the chalks suddenly got unstable and weaker than the clayey material. With these properties the calcareous sediments form the predetermined breaking point in the rock sequence, " Robert Kurzawski explains.

These results are particular interesting, because calcareous sediments are typical and widespread especially for tropical and subtropical oceans and thus occur at many subduction zones around the Pacific, but also in the Caribbean and Mediterranean Sea. "Of course we still do not know all the processes that can trigger earthquakes. But we have demonstrated by this study that material properties cannot simply be extrapolated from surface conditions to those at greater depth. Therefore, further drilling, especially in the framework of the International Ocean Discovery Program (IODP), is required to learn more about the earthquake processes at depth, " Michael Stipp concludes.
***
Source:
The above post is reprinted from materials provided by Helmholtz Centre for Ocean Research Kiel (GEOMAR).

Reference:
Kurzawski, R. M., M. Stipp, A. R. Niemeijer, C. J. Spiers, J. H. Behrmann. Earthquake nu-cleation in weak subducted carbonates. Nature Geoscience, 2016 DOI: 10.1038/ngeo2774
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