Wednesday, July 4, 2012 1:46:32 PM
Dinosaurs, geology, Palaeontology, fossils
A newly found fossil of
Sciurumimus albersdoerferi, which lived about 150 million years ago, provides the first evidence of feathered theropod dinosaurs that are not closely related to birds. The fossil is described in a paper published online on 2 July in the Proceedings of the National Academy of Sciences (PNAS). Because the new species sits deep within the evolutionary tree of theropods, the findings suggest that all predatory dinosaurs might have had feathers. In other words feathered dinosaurs might have been much more common than we thought. Down may also have been a special way of protecting baby dinosaurs. This may explain why they have not been found on adults.
This baby
Sciurumimus, just about 70 cm long, was found in the limestones of northern Bavaria and preserves remains of a filamentous plumage, indicating that the whole body was covered with feathers. The genus name of Sciurumimus albersdoerferi refers to the scientific name of the tree squirrels, Sciurus, and means “squirrel-mimic”—referring to the especially bushy tail of the animal. The species name honors the two private collectors who made the specimen available for scientific study, Raimund og Birgit Albersdörfer.
The specimen of Sciurumimus is the most complete megalosauroid yet discovered and helps clarify significant anatomical details of this important basal theropod clade, such as the complete absence of the fourth finger.
Reference:
O. Rauhut et al. (2012)
Exceptionally preserved juvenile megalosauroid theropod dinosaur with filamentous integument from the Late Jurassic of Germany.PNAS, published online 2 July 2012 (see
abstract)
DOI:10.1073/pnas.1203238109
In
Norwegian:
http://www.forskning.no/artikler/2012/juli/327055 
Monday, July 2, 2012 10:13:01 AM
mining, geology, rare earths
In the Pacific seabed near the island of Minamitorishima (nick-named
Marcus Island) about 2000 km east of Tokyo a large deposit of rare earth minerals has been found, believed to be close to 6.8 million tons, which could supply Japan for almost 227 years worth of its consumer electronics, windmills, and hybrid car engine needs.
For the time being Japan is buying about 60% of the whole Chinese production of rare earth minerals. Japan will probably work together with Vietnam, where there is also believed to be large deposits of these metals. Japan has the financing and technology needed in order to process the minerals. This would lessen these two countries dependence on Chinese supplies. Other countries in the world would of course also benefit from a larger world supply of rare earth minerals.
In
Danish:
http://ing.dk/artikel/130509-megafund-af-sjaeldne-jordarter-kan-daekke-japans-behov-i-227-aar
Saturday, June 30, 2012 8:36:00 AM
Greenland, mining, geology, impact craters
On a Nordic geological winter meeting in Oslo in January 2010 Adam Garde told about a possible impact structure in Greenland (see my
post). He and co-authors have now published further findings in a paper in Earth and Planetary Science Letters of 1 July 2012.
The so far oldest (i.e. 2975 million years) impact crater on Earth was found near Maniitsoq (in “my days” - and in Danish - known as
Sukkertoppen) in West Greenland. It is the fourth multi-ring crater discovered on Earth, besides Chicxulub, Sudbury, and Vredefort. It is a 100 km-scale, circular structure in the Archaean North Atlantic Craton centred at 65°15′N, 51°50′W near the Maniitsoq town in the Qeqqata municipality in West Greenland. The structure comprises a set of highly unusual geological features that were created during a single event involving intense crushing and heating and are incompatible with crustal orogenic processes. The presently exposed features of the Maniitsoq structure were buried 20–25 km below the surface when this event occurred at about 3000 million years ago, during waning convergent orogeny. These features include: a large aeromagnetic anomaly; a central 35×50 km
2 large area of comminuted quartzo-feldspathic material; regional-scale circular deformation; widespread random fractures with featherlike textures; intense fracture cleavage; amphibolite–granite-matrix breccias unrelated to faulting or intrusions; formation and common fluidisation of microbreccias; abundant evidence of direct K-feldspar and plagioclase melting superimposed on already migmatised rocks; deformation of quartz by <c> slip; formation of planar elements in quartz and plagioclase; and, emplacement of crustally contaminated ultramafic intrusions and regional scale hydrothermal alteration under amphibolite-facies conditions. The diagnostic tools employed to identify impacting in the upper crust are inadequate for structures preserved deep within the continental crust. Nevertheless, the inferred scale, strain rates and temperatures necessary to create the Maniitsoq structure rule out a terrestrial origin of the structure.
Finding sufficient evidence was extremely hard because there is no obvious bowl-shaped crater left to find. Over the 3 billion years since the impact, the land has been eroded down to expose deeper crust 25 km below the original surface. All external parts of the impact structure have been removed, but the effects of the intense impact shock wave penetrated deep into the crust -- far deeper than at any other known crater -- and these remain visible. Because the effects of impact at these depths have never been observed before it has taken nearly three years of painstaking work to assemble all the key evidence. Only around 180 impact craters have ever been discovered on Earth and around 30% of them contain important natural resources of minerals or oil and gas. The largest and oldest known crater prior to this study, the 300 kilometre wide Vredefort crater in South Africa, is 2 billion years in age and heavily eroded. It has taken Adam Garde and his co-workers nearly three years to convince their peers in the scientific community that this is an impact structure, while the mining industry was far more receptive. A Canadian exploration company has been using the impact model to explore for deposits of nickel and platinum metals at Maniitsoq since the autumn of 2011.
Reference:
Adam A. Garde et al.
Searching for giant, ancient impact structures on Earth: The Mesoarchaean Maniitsoq structure, West GreenlandEarth and Planetary Science Letters
Volumes 337–338, 1 July 2012, Pages 197–210
http://dx.doi.org/10.1016/j.epsl.2012.04.026
Tuesday, June 19, 2012 7:28:12 PM
geology, microbial activity, dolomite
I cannot say that I am surprised, maybe rather relieved, that there is increasing evidence that bacteria play a key role in the formation of dolomite. For many years the formation of dolomite was a puzzle as dolomitization just didn’t work in the laboratory - well until somebody began to play around with bacteria. A new study presented in the journal Geology seems in fact to confirm the idea that sulphur-reducing bacteria are a key player.
A research team examined globally distributed marine bacteria that use sulphur compounds instead of oxygen to generate energy (i.e. sulphate respiration). They discovered that primary dolomite crystals are formed under conditions that are currently found in marine sediments. The dolomite precipitates exclusively within a mucus matrix, secreted by the bacteria to form biofilms. Different chemical conditions prevail within the biofilm compared to the surrounding water. In particular, the alteration of the magnesium to calcium ratio plays an important role. (The dolomitization principle is to take some limestone, which consists of calcite (CaCO
3) and add some Magnesium (Mg) to get dolomite CaMg(CO
3)
2)). The magnesium to calcium ratio changes allow for the formation of dolomite crystals. The team was able to show that the ratio of different isotopes of calcium between the ambient water, the biofilm and dolomite crystals is different. This ratio is an important tool to reconstruct past environmental conditions. The fact that bacteria are involved in this process allows more precise interpretations of climate signals that are stored in sediments.
A strong possibility is that massive primary dolomite can form particularly during times when large quantities of organic matter in the seabed are degraded by sulphate-respiring bacteria. Such conditions exist when the sea water above the seafloor is free of oxygen. In Earth's history, several such oxygen-free periods have occurred, partly consistent with time periods of intensified dolomite deposition.
Over 90% of (sedimentary) dolomite is made up of the mineral dolomite. Researchers became aware of large deposits of primary dolomite as old as 600 million years. Dolomite was first scientifically described in 1791 as a rock by Dolomieu from exposures in what are now known as the Dolomite Alps of northern Italy. Experts say the process of recent primary dolomite formation is restricted to extreme ecosystems, including bacterial mats in highly saline lakes and lagoons. As these systems are very limited in space, there is an explanation gap for geologists for the widespread presence of fossil dolomite.
See also my post on Microbial Dolomite in Abu Dhabi [
http://my.opera.com/nielsol/blog/2010/10/08/microbial-dolomite-in-abu-dhabi]
Wednesday, June 13, 2012 12:46:04 PM
Dinosaurs, geology, Palaeontology
The finds of a new saurolophine dinosaur,
Kundurosaurus nagornyi, are described in
PlosOne. The new dinosaur was found in the Udurchukan Formation (Maastrichtian) of Kundur (at the Amur plateau in Eastern Russia), and represented by disarticulated cranial and postcranial material. All Kundurosaurus specimens were collected in the Kundur locality, hence the name.
The Kundur locality was discovered in 1990 and Large-scale excavations started at Kundur in 1999. In four sites dinosaur bone of different species form large bonebeds extending over several hundreds of m
2.
I gather you can guess why these types of dinosaurs are called Duck-Billed dinosaurs when you look at the following illustration from the new paper.
Notice the similarity of the head to that of modern ducks.
Reference:
Godefroit P, Bolotsky YL, Lauters P (2012)
A New Saurolophine Dinosaur from the Latest Cretaceous of Far Eastern Russia.
PLoS ONE 7(5): e36849.
doi:10.1371/journal.pone.0036849
Wednesday, April 11, 2012 8:02:31 PM
geology, tsunamis
A thorough study of old reports, newspapers, and other sources provided useful hints that a tsunami occurred in the North Sea Basin on 5 June 1858, with run-up values of up to 6 m along the west coast of Denmark. In a study published in the
Journal of Coastal Research the German geographers Jürgen Newig and Dieter Kelletat from the university of Kiel, Germany, concludes that this tsunami was triggered by an underwater landslide in the Atlantic Ocean.
The Danish Meteorological institute (DMI) has recently released a report that suggested that the risk of a tsunami off Danish coasts was very low. DMI predicted that a tsunami was likely to occur once every 1,000 years and that it would most likely be catalysed by a seabed shift in an area north of Scotland.
Actually there is a comprehensive tsunami warning system being put in place throughout Europe. In Denmark, DMI has been assigned the responsibility of being the tsunami watchdog and will convey any dangers of tsunamis the same way they do major storm systems, utilising the media, police and other emergency crews. The tsunami warning system is scheduled to be ready and fully implemented sometime 2013.
While a storm in the North Sea can be predicted days ahead of time, with a tsunami there is only about a five to six hour window before the water masses hit the Danish coast.
In
Danish:
In
German:
Tuesday, April 10, 2012 8:53:21 AM
geology, Deserts
We seem to have different views on what a desert really is, although I suppose it is generally accepted that they are dry with extremely little vegetation and rather desolate. But a general conception that they are always hot and sandy is not true. Sand covers only about 20% of Earth's deserts, and the desert I am going to write about today is a cold winter desert. Actually it got a 14-cm deposit of snow due to consecutive snowing in December 2002. In January 2008 the whole desert was
covered by snow and the temperature got as low as minus 32 degrees Celsius.
Apart from that Taklimakan Desert is however a true sand desert. It is reputed to be the world's second largest shifting sand desert with about 85% made up of shifting sand dunes. It is the largest desert in China covering an area of 327,000 km
2.
The Taklimakan Desert is hemmed in to the north by the snow-covered Tian Shan Mountain range and to the south by the rugged Kunlun Mountains. It is sitting in a depression in between called the Tarim Basin. Although the map above shows rivers crossing the basin they are relatively dry as precipitation in the Tarim Basin is extremely scanty due to the surrounding high mountains (“rain shadow”), and in some years it is nonexistent.
The NASA Earth Observatory image below shows the Taklimakan Desert as a vast region of sand desert.
Another more recent NASA Earth Observatory image (of 5 April 2012) shows dust storms in the Taklimakan Desert. Dust was thickest along the desert’s southern margin. Dust storms are common in the Taklimakan Desert. Marching sand dunes, some reaching a height of 200 m, cover most of the desert floor. The dunes are virtually devoid of vegetation, but plants survive along the desert perimeter, and experience distinct seasonal variations.
Deserts take up about one third (33%) of the Earth's land surface.
Friday, April 6, 2012 10:01:02 AM
Geopolitics, geology, drought, oil
The Taoudenni Basin covers large parts of the West African craton in Mauritania and Mali. It is of considerable interest due to its possible reserves of oil. The remote location and hostile environment of the Sahara desert would make extraction expensive, but ….
On 6 April 2012 the Tuaregs declared "irrevocably" the independence of Azawad from Mali. The National Movement for the Liberation of Azawad (MNLA) made the statement on its website, adding that it would respect other states' borders.
As far as I can make out the area proclaimed independent covers roughly speaking the northern part of Mali that I have marked on the map of Mali.
Compared with a map of the areas where significant numbers of Tuareg live I find it “interesting” to notice that the Mali part of the Taoudenni Basin seems to be part of the new “state” of Azawad. My guess is that troubles in this area, also suffering from drought and distressed by several thousands of refugees isn’t over yet.
The place of Taoudenni itself, by the way, is a remote salt mining center in the desert region of northern Mali, 664 km north of Timbuktu. The salt is dug by hand from the bed of an ancient salt lake, cut into slabs and transported either by truck or by camel to Timbuktu. The camel caravans from Taoudenni are some of the last that still operate in the Sahara.
In
Danish:
http://www.dr.dk/Nyheder/Udland/2012/04/06/080349.htm
Monday, March 5, 2012 8:10:58 AM
geology, Deserts
Most sand deserts consist of quartz sand, but White Sands has got its name because its main constituent is (white) gypsum. Normally desert sand becomes extremely hot when the sun is shining, but the white gypsum in White Sands reflect most of the sun radiation back into the atmosphere (albedo effect) so that the desert remains relatively cool.
The White Sands in New Mexico is the world’s largest gypsum dune field, stretching over 710 km
2. Gypsum is rarely found in the form of sand because it is water-soluble. Normally, rain would dissolve the gypsum and carry it to the sea. The basin, in which the White sands lie, is enclosed and has no outlet to the sea, so that rain that dissolves gypsum from the surrounding mountains is trapped within the basin. Thus water either sinks into the ground or forms shallow pools which subsequently dry out and leave gypsum in a crystalline form, called selenite, on the surface. During the last ice age, a lake covered much of the basin. When it dried out, it left a large flat area of selenite crystals. Another lake is a dry lake bed, at one of the lowest points of the basin, which occasionally fills with water. Much of the ground is covered with selenite crystals which reach lengths of up to 1 m. Weathering and erosion eventually breaks the crystals into sand-size grains that are carried away by the prevailing winds from the southwest, forming white dunes. Winds occasionally lift the gypsum sands into the air. A gypsum dust storm emerged from the dunes in late February 2012.
The dust blowing out of White Sands National Monument was part of a larger pattern of dust storms in the region, including dust in Mexico, Kansas, and Oklahoma.
In
Danish:
Note:
Albedo is the fraction of solar energy (shortwave radiation) reflected from the Earth back into space. It is a measure of the reflectivity of the earth's surface.
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