Researchers study water cycle and cloud formation and design computer algorithm models to understand impact

May 30, 2014

Single oak pollen grain, SEM image. Credit: Allison Steiner (UM) and Michael Pendleton (Texas A&M)

In the past, many atmospheric scientists believed that pollen particles probably had a negligible effect on climate because they were so big. In recent years, however, as they began to realize that pollen particles were not as sturdy as they once thought, they have been rethinking their old assumptions.
“Pollen can rupture and generate a lot of small, tiny particles,” says Allison Steiner, an associate professor of atmospheric, oceanic and space sciences at the University of Michigan. “They can break pretty easily.”

Moreover, pollen, the same airborne material that wreaks misery during certain seasons in the form of drippy noses and itchy eyes, apparently can have an influence on weather. When big pollen particles break into fine ones, they can take up water vapor in the air to promote the formation of clouds, potentially altering weather systems as a result. Unlike greenhouse gases, which contribute to warming, these fine particles can have a cooling effect.

This is a process that Steiner wants to learn more about, particularly now, when much of the scientific community is devoting considerable attention to the anthropogenic—or human—causes of climate change.

“The impact of pollen in the atmosphere may change weather and it could change our understanding of the climate system,” says the National Science Foundation (NSF)-funded scientist.

“How much is nature contributing?” she adds. “How important will that be in understanding what we will see in the absence of human influences? It’s easier to understand the human causes, but these natural aerosols like pollen are something we don’t understand very well.”

Prior research indicates that when pollen becomes wet, it easily ruptures into very small particles. She wondered whether these small, pollen fragments could, “seed” the creation of clouds.

“If you have water vapor in the atmosphere, it’s hard to form droplets all by itself,” she explains. “But if you have a little particle already there, it’s easy for water to condense on it and grow into a droplet, which enables the formation of cloud droplets.

“Most people think of pollen as being pretty inert in the atmosphere, and it’s not,” she adds. “It’s interacting with the water cycle, and can influence clouds in ways that people hadn’t realized before.”

She and her team are using ground based observation data obtained from across the nation to design a computer algorithm emissions model. The model includes the different types of pollen, and takes into account various conditions that can have an effect on pollen when it enters the atmosphere, for example, rain.

Furthermore, tiny pollen particles can react with radiation. “The models simulate the ability of pollen particles to interact with incoming solar radiation to understand how these particles will affect climate,” she says. By using computer models, she can estimate the effect these particles have on regional climate.

She also has been working in the laboratory of Sarah Brooks, a professor of atmospheric sciences at Texas A&M University, to demonstrate pollen’s effect on cloud formation. Using a cloud condensation nuclei chamber, an instrument that can reproduce the atmospheric conditions that form clouds, they were able to demonstrate that pollen can in fact grow and act as cloud droplets.

“This means that pollen could have an impact on climate,” says Steiner, who conducted the experiments at Texas A & M in the spring. “One thing we are still trying to figure out is how big that effect actually is.”

Steiner is conducting her research under an NSF Faculty Early Career Development (CAREER) award, which she received in 2010. The award supports junior faculty who exemplify the role of teacher-scholars through outstanding research, excellent education, and the integration of education and research within the context of the mission of their organization. NSF is funding her work with $599,940 over five years.

As part of the grant’s educational component, she has worked with middle schools and high schools in Detroit and Ypsilanti. Using the sites and numerous hands-on activities will introduce students to hypothesis development, data collection and analysis, and interpretation, and also will help the pollen emissions model development.

She also plans to integrate elements of the pollen project with University of Michigan undergraduate and graduate programs, as well as form a partnership with the International Centre for Theoretical Physics in Trieste, Italy to train scientists from developing nations on the role of biosphere-atmosphere interactions.

Steiner says she is especially gratified by the response of the young middle school students “who find it a real change to have a college professor come into their classroom on a regular basis,” she says, adding: “It can be a real challenge to make our research relevant for middle-school students. But the students have asked great questions, and we’ve developed some novel hands-on activities that have really helped the students to see how fun and exciting scientific research can be.”

Note : The above story is based on materials provided by National Science Foundation

Margarite

May 30, 2014

Chemical Formula: CaAl₂(Al₂Si₂O₁₀)(OH)₂
Locality: Corundum mines at Ekaterinurg Distict, Ural Mountains, Russia.
Name Origin: From the Greek margaritos – “pearl.”

Margarite is a calcium rich member of the mica group of the phyllosilicates with formula: CaAl₂(Al₂Si₂O₁₀)(OH)₂. It forms white to pinkish or yellowish gray masses or thin laminae. It crystallizes in the monoclinic crystal system. It typically has a specific gravity of around 3 and a Mohs hardness of 4. It is translucent with perfect 010 cleavage and exhibits crystal twinning.

It occurs commonly as an alteration product of corundum, andalusite and other aluminous minerals. It has been reported as forming alteration pseudomorphs of chiastolite along with muscovite and paragonite. The margarite in this occurrence forms preferentially along the dark graphite rich inclusions with the chiastolite crystals.

Table of Contents

History

Discovery date : 1823
Town of Origin: MT. GREINER, STERZING, TYROL
Country of Origin : AUTRICHE

Optical properties

Optical and misc. Properties : Translucent to subtranslucent
Refractive Index: from 1,63 to 1,65
Axial angle 2V : 40-67°

Physical Properties

Cleavage: {001} Good
Color: White, Gray, Pinkish gray, Yellowish gray.
Density: 2.99 – 3.08, Average = 3.03
Diaphaneity: Translucent to subtranslucent
Fracture: Brittle – Generally displayed by glasses and most non-metallic minerals.
Hardness: 4 – Fluorite
Luminescence: Fluorescent, Short UV=sky blue, Long UV=strong sky blue.
Luster: Pearly
Streak: white

Photo:

Chester Emery Mines, Chester, Hampden Co., Massachusetts, USA © Rob Lavinsky

Margarite Location: Long Hill/Old Tungsten Mine in Trumbull, Connecticut, USA. Scale: 10 x 5 cm. Copyright: © Walter Mroch / Gem and Mineral Exploration Company

Margarite Locality: Wright Mine, Chester Emery Mines, Chester, Hampden Co., Massachusetts, USA Dimensions: 4.8 cm x 3.4 cm x 2.6 cm Photo Copyright © Rob Lavinsky & irocks

Kimberley rocks tell first mass extinction of complex life

May 30, 2014

Basalt rocks formed from cooled lava, in Marella Gorge, north-east Kimberley. Credit: Lena Evins

Volcanic eruptions across a vast area of what is now Western Australian and the Northern Territory 510 million years ago caused the first known mass extinction of complex life forms.

Curtin University’s Dr Fred Jourdan says it is widely documented that the Early-Middle Cambrian extinction of complex multicellular life was related to changes in climate and depletion of oxygen in the oceans but the exact cause has been unknown until now.

He is part of an international team of scientists that calculated a near perfect chronological correlation between large volcanic eruptions, climate changes and mass extinction over the history of life during the last 550 million years.

The eruptions produced rapid fluctuations in climate making it difficult for species to survive.

The research team’s findings High-precision dating of the Kalkarindji large igneous province, Australia, and synchrony with the early–Middle Cambrian (Stage 4–5) extinction, have been reported in the journal Geology.

The paper concludes the likely factors responsible for the Early–Middle Cambrian extinction are rapid climate shifts triggered by volcanic eruptions emitting mantle gases sulphur dioxide and greenhouse gases methane and carbon dioxide, either dissolved in the magma or generated by the interaction between magma and evaporite layers and/or oil-rich rocks.

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Primative ocean life

Since there was no existing fauna or flora on land during the period, the extinction mechanism must have acted on the oceans.

Life at that time would have included the reef building sponge-like organism Archaeocyathids and Trilobites, the most primitive groups.

Dating techniques

The team used high-precision 40Ar/39Ar and U-Pb mineral dating to measure the age of eruptions in the Kalkarindji volcanic province in the Northern Territory and Western Australia where lavas covered more than two million square kilometres.

Both techniques are based on completely different elements and give the same age for the lavas, which is a strong validation that the age is correct.

Insights into gas emission effect

Dr Jourdan says the research is vital to understanding the long term implications that modern-day massive gas emission into the atmosphere can have on the climate and life.

“I’m talking about greenhouses gases like methane and carbon dioxide which warm the climate and sulphur dioxide which can cool the climate for short periods of time but more relevant to now, can cause acid rains which can wreck ecosystem and massive toxic pollution; part of the irritant pollutants in Beijing come from sulphur dioxide.

“…we can see the effect of those gases on nature by studying the rock record, and we are injecting a massive amount of those into the atmosphere, mostly by burning fossil fuels like coal and oil.”

More information: F. Jourdan, K. Hodges, B. Sell, U. Schaltegger, M.T.D. Wingate, L.Z. Evins, U. Söderlund, P.W. Haines, D. Phillips, and T. Blenkinsop. “High-precision dating of the Kalkarindji large igneous province, Australia, and synchrony with the Early–Middle Cambrian (Stage 4–5) extinction.” Geology, G35434.1, first published on April 24, 2014, DOI: 10.1130/G35434.1

Note : The above story is based on materials provided by Science Network WA

Protein test for fossil identity extended by 950,000 years

May 30, 2014

Scientists have found a way to extend the length of time they can use protein molecules to identify tissues like bone and teeth.
Every animal has thousands of proteins in its bones containing information on its species. These proteins make up an almost unique fingerprint that survives long after the animal’s DNA has decomposed.

Scientists can take advantage of this long survival time and use the proteins to try to identify fossils and other ancient tissues like hair and skin. But over time these proteins also begin to break down, which makes it hard to extract the genetic information they hold.

Last year Dr Mike Buckley of the University of Manchester showed that collagen, which contains almost 90 per cent of the proteins in bone, could be used to identify extremely old fossils when his collagen-fingerprinting technique identified a 1.5 million-year-old camel fossil from the high Arctic.

But proteins that aren’t found in collagen have only ever been used to test the genetic information of fossils up to 50,000 years old.

Now Buckley and his PhD student Caroline Wadsworth have managed to use these non-collagenous proteins to test fossils over one million years old.

They found that thousands of non-collagenous proteins – with the potential to be even more informative than collagen – also survive the burial process, and hope to use these in the future to test many older fossils.

Note : The above story is based on materials provided by Harriet Jarlett for © Natural Environment Research Council

Marcasite

May 29, 2014

Chemical Formula: FeS₂
Locality: Common world wide.
Name Origin: Arabic or Moorish name for pyrites and similar material of uncertain origin.
The mineral marcasite, sometimes called white iron pyrite, is iron sulfide (FeS₂) with orthorhombic crystal structure. It is physically and crystallographically distinct from pyrite, which is iron sulfide with cubic crystal structure. Both structures do have in common that they contain the disulfide S₂^2- ion having a short bonding distance between the sulfur atoms.

The structures differ in how these di-anions are arranged around the Fe²⁺ cations. Marcasite is lighter and more brittle than pyrite. Specimens of marcasite often crumble and break up due to the unstable crystal structure.

On fresh surfaces it is pale yellow to almost white and has a bright metallic luster. It tarnishes to a yellowish or brownish color and gives a black streak. It is a brittle material that cannot be scratched with a knife. The thin, flat, tabular crystals, when joined in groups, are called “cockscombs.”

In marcasite jewellery, pyrite used as a gemstone is termed “marcasite”. That is, marcasite jewellery is made from pyrite not from marcasite. In the late medieval and early modern eras the word “marcasite” meant both pyrite and marcasite (and iron sulfides in general). The narrower, modern scientific definition for marcasite as orthorhombic iron sulfide dates from 1845. The jewellery sense for the word pre-dates this 1845 scientific redefinition. Marcasite in the scientific sense is not used as a gem due to its brittleness.

Table of Contents

Occurrence

Marcasite can be formed as both a primary or a secondary mineral. It typically forms under low-temperature highly acidic conditions. It occurs in sedimentary rocks (shales, limestones and low grade coals) as well as in low temperature hydrothermal veins. Commonly associated minerals include pyrite, pyrrhotite, galena, sphalerite, fluorite, dolomite and calcite.

As a primary mineral it forms nodules, concretions and crystals in a variety of sedimentary rock, such as at Dover, Kent, England, where it forms as sharp individual crystals and crystal groups, and nodules (similar to those shown here) in chalk.

As a secondary mineral it forms by chemical alteration of a primary mineral such as pyrrhotite or chalcopyrite.

History

Discovery date : 1845

Optical properties

Optical and misc. Properties : Opaque
Reflective Power : 49,1-54,1% (580)

Physical Properties

Cleavage: {010} Indistinct
Color: Bronze, Light brass yellow, Tin white.
Density: 4.89
Diaphaneity: Opaque
Fracture: Uneven – Flat surfaces (not cleavage) fractured in an uneven pattern.
Hardness: 6-6.5 – Orthoclase-Pyrite
Luminescence: Non-fluorescent.
Luster: Metallic
Magnetism: Magnetic after heating
Streak: gray brownish black

Photos :

Marcasite over fluorite Moscona mine – Solís – Corvera de Asturias – Villabona mining area – Asturias – Spain Specimen weight:1080 gr. Crystal size:mm. 8 Overall size: 130mm x 105 mm x 30 mm © minservice

Marcasite Panasqueira, Portugal Small Cabinet, 6.2 x 4.3 x 4.1 cm © irocks

MARCASITE Locality: Vintirov, Cechy (formerly in Bohemia), Czech Republic Mined: 1974 Specimen Size: 10.5 x 7.5 x 9 cm (cabinet) © minclassics

Limites quarry, Ave-et-Auffe, Rochefort, Namur Province, Belgium © Harjo

Marcasite Dalen-Kjørholt mine – Kjørholt – Brevik – Porsgrunn – Telemark – Norway Specimen weight:100 gr. Crystal size:mm. 20 Overall size: 45mm x 30 mm x 50 mm © minservice

Age-old relationship between birds and flowers: World’s oldest fossil of a nectarivorous bird

May 29, 2014

The fossil bird from Messel with its revealing stomach contents (insert) Credit: © Senckenberg

Scientists of the Senckenberg Research Institute in Frankfurt have described the oldest known fossil of a pollinating bird. The well-preserved stomach contents contained pollen from various flowering plants. This indicates that the relationship between birds and flowers dates back at least 47 million years. The fossil comes from the well-known fossil site “Messel Pit.” The study was published today in the scientific journal Biology Letters.
They fly from flower to flower, and with their long, slender bills they transfer the pollen required for the plants’ reproduction. Particularly in the tropics and subtropics, birds, besides insects, serve as the most important pollinators.

“While this process is well known and understood in the present, geological history has offered very little evidence of pollination through birds,” says Dr. Gerald Mayr, head of the Ornithological Section at the Senckenberg Research Institute in Frankfurt. He adds, “there have been occasional hints, such as characteristic bill shapes, that nectarivorous birds occurred in the past, but, so far, there existed no conclusive evidence.”

Now, however, the ornithologist from Frankfurt and his colleague, paleobotanist Dr. Volker Wilde, have found this evidence. In the well-preserved stomach contents of a fossil bird unearthed in the Messel Pit, the scientists discovered fossilized pollen grains.

“This is another discovery that underlines the unique significance of the Messel fossil site,” exclaims a delighted Dr. Wilde. “Not only does the presence of pollen offer direct evidence of the bird’s feeding habits, but it shows that birds already visited flowers as long as 47 million years ago!”

Fossil evidence for the existence of pollinating insects dates back to the Cretaceous period. Until now, however, there had been no information at what time pollination through vertebrates, and birds in particular, came into existence. To date, the oldest indication of an avian pollinator came from the early Oligocene, about 30 million years ago. “But this hummingbird fossil only offers indirect evidence of the existence of nectarivorous birds,” explains Mayr. “Thanks to the excellent state of preservation of the Messel bird, we were able to identify two different types of pollen, which is the first conclusive proof of nectarivory.”

Large numbers of differently sized pollen grains were found in the stomach contents of the completely preserved avian fossil. “Along with the bird’s skeletal anatomy, this indicates that we indeed have the fossil of a nectarivorous bird” explains Wilde.

And the spectacular discovery also suggests another conclusion: If a pollinating bird lived as much as 47 million years ago, it must be assumed that some representatives of the flora at that time had already adapted to this mode of pollination.

“To date, there are no fossil plants from this geological era that offer proof of the existence of ornithophily — i.e., the pollination of flowers through birds,” adds paleobotanist Wilde.

“However, the characteristic traits of bird-pollinated plants, such as red flowers or a lack of scent, do not fossilize,” elaborates Mayr. This lends an even greater importance to discoveries such as the Messel bird to understand the interactions between birds and flowers through geological time.

Note : The above story is based on materials provided by Senckenberg Research Institute and Natural History Museum.

Delving into the spread of marine life: Understanding deep-sea limpets

May 29, 2014

One of Deep-sea limpets, Lepetodrilus nux. Credit: Image courtesy of OIST

A paper by Dr. Masako Nakamura of the OIST Marine Biophysics Unit on the ecology of one of deep-sea limpets called Lepetodrilus nux has been published in the Marine Ecology Progress Series. These deep-sea limpets are conches with shells about 1 cm long. They have been confirmed to live in the long, narrow seabed known as the Okinawa Trough, located at an average of depth of 1000 meters and northwest of the Nansei and Ryukyu Islands. In this paper, three major findings are reported: new limpet habitats in the Okinawa Trough, the process of limpet population formation surmised from their shell length, and limpet reproduction patterns. This is the first study of the life history of limpets living in the Okinawa Trough, including their reproduction and spread, and Dr. Nakamura’s work provides insights into their ecological mechanisms.

In order to understand the spread of marine life, Dr. Nakamura studies benthos, which are animals that are sessile or hardly move in the adult stage. They include deep-sea limpets, reef-building corals, and coral predator crown-of-thorns starfish. In autumn 2011, she boarded a deep-sea research vessel of the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) to collect samples of deep-sea benthos from hydrothermal vents in the Okinawa Trough. Hydrothermal vents, where heated, mineral-laden seawater spews from cracks in the ocean crust, are home to various diverse organisms. From the collected samples, Nakamura took some deep-sea limpets back to her laboratory to study their population formation and colonization patterns. She did this by examining two characteristics: shell length and distribution pattern. Each sample was carefully measured to examine the time the sample has lived in a colony. The longer the shell length, the longer the inhabitance.

To understand the distribution patterns, Nakamura studies the fertilization process of limpets. Through microscopic observation of tissue sections from limpet gonads, she confirmed the stages of egg and sperm development. While limpets have distinct male and female sexes, the female has a bag-like organ called a spermatheca to store sperms for internal fertilization. Nakamura also discovered that eggs and sperms in various stages of maturity coexist simultaneously within the limpet’s genital glands. The limpets undergo a continual fertilization process in which each egg is spawned when it reaches maturity. This is different from coral fertilization, in which numerous mature eggs and sperms are released simultaneously and fertilized in the water. Fertilized limpet eggs released into the sea drift through the larval stage of growth, eventually finding home and adhering to the seabed to join a benthos community. The OIST Marine Biophysics Unit to which Dr. Nakamura belongs also studies ocean currents, which have considerable impact on the spread of benthic larvae. The team is trying to understand life history traits of benthos at the initial stage and the influence of ocean currents in order to find out how these organisms expand their habitat and respond to environmental changes.

Dr. Nakamura goes out on the water and observes marine organisms first hand. This approach is rooted in her belief that certain things can only be understood through observation of their natural state, and that the information obtained through these observations should be valued. “I would like to pass along to the next generation of researchers a diligent field research approach to understand ecosystems,” Dr. Nakamura said. By accumulating the understanding of the ecology of small marine organisms, she hopes to deepen an understanding of the spread of life in the entire ocean.

Note : The above story is based on materials provided by Okinawa Institute of Science and Technology – OIST.

Manganite

May 29, 2014

Chemical Formula: MnO(OH)
Locality: Ilfeld, Harz, Germany
Name Origin: Named after its chemical composition.

Manganite is a mineral. Its composition is manganese oxide-hydroxide, MnO(OH), crystallizing in the monoclinic system (pseudo-orthorhombic). Crystals of manganite are prismatic and deeply striated parallel to their length; they are often grouped together in bundles. The color is dark steel-grey to iron-black, and the luster brilliant and submetallic. The streak is dark reddish-brown. The hardness is 4, and the specific gravity is 4.3. There is a perfect cleavage parallel to the brachypinacoid, and less-perfect cleavage parallel to the prism faces. Twinned crystals are not infrequent.

The mineral contains 89.7% manganese sesquioxide; it dissolves in hydrochloric acid with evolution of chlorine.

Table of Contents

Occurrence

Manganite occurs with other manganese oxides in deposits formed by circulating meteoric water in the weathering environment in clay deposits and laterites. It forms by low temperature hydrothermal action in veins in association with calcite, barite, and siderite. Often associated with pyrolusite, braunite, hausmannite and goethite.

Manganite occurs in specimens exhibiting good crystal form at Ilfeld in the Harz Mountains of Germany, where the mineral occurs with calcite and barite in veins traversing porphyry. Crystals have also been found at Ilmenau in Thuringia, Neukirch near Sélestat in Alsace (newkirkite), Granam near Towie in Aberdeenshire, and in Upton Pyne near Exeter, UK and Negaunee, Michigan, United States, and in the Pilbarra of Western Australia. Good crystals have also been found at Atikokan, Ontario and Nova Scotia, Canada. As an ore of manganese it is much less abundant than pyrolusite or psilomelane.

Although described with various other names as early as 1772, the name manganite was first applied in a publication by W. Haidinger in 1827.

History

Discovery date : 1827
Town of Origin : ILFELD,HARZ
Country of Origin: ALLEMAGNE

Optical properties

Optical and misc. Properties : Opaque
Reflective Power : ~17%

Physical Properties

Cleavage: {010} Perfect
Color: Black, Gray, Grayish black.
Density: 4.3 – 4.4, Average = 4.34
Diaphaneity: Opaque
Fracture: Brittle – Generally displayed by glasses and most non-metallic minerals.
Hardness: 4 – Fluorite
Luminescence: Non-fluorescent.
Luster: Sub Metallic
Magnetism: Nonmagnetic
Streak: dark brown

Photos:

Manganite Ilfeld, Harz Mountains, Germany Miniature, 4.8 x 1.3 x 1 cm © irocks

Manganite 8.0×5.0x2.8 cm Caland Ore Properties Atikokan Ontario, Canada Copyright © David K. Joyce Minerals

Manganite Ilfeld, Nordhausen, Harz Mts, Thuringia, Germany Size: 4.0 x 3.0 x 1.5 cm (miniature) © danweinrich

N’Chwaning II Mine, N’Chwaning Mines, Kuruman, Kalahari manganese field, Northern Cape Province, South Africa

Four-billion-year-old rocks yield clues about Earth’s earliest crust

May 29, 2014

A sample of ancient rock from the Acasta Gneiss Complex in the Northwest Territories. Credit: Image courtesy of University of Alberta

It looks like just another rock, but what Jesse Reimink holds in his hands is a four-billion-year-old chunk of an ancient protocontinent that holds clues about how Earth’s first continents formed.
The University of Alberta geochemistry student spent the better part of three years collecting and studying ancient rock samples from the Acasta Gneiss Complex in the Northwest Territories, part of his PhD research to understand the environment in which they formed.

“The timing and mode of continental crust formation throughout Earth’s history is a controversial topic in early Earth sciences,” says Reimink, lead author of a new study in Nature Geoscience that points to Iceland as a solid comparison for how the earliest continents formed.

Continents today form when one tectonic plate shifts beneath another into Earth’s mantle and cause magma to rise to the surface, a process called subduction. It’s unclear whether plate tectonics existed 2.5 billion to four billion years ago or if another process was at play, says Reimink.

One theory is the first continents formed in the ocean as liquid magma rose from Earth’s mantle before cooling and solidifying into a crust.

Iceland’s crust formed when magma from the mantle rises to shallow levels, incorporating previously formed volcanic rocks. For this reason, Reimink says Iceland is considered a theoretical analogue on early Earth continental crust formation.

Ancient rocks 3.6 to four billion years old

A sample of ancient rock from the Acasta Gneiss Complex in the Northwest Territories

Working under the supervision of co-author Tom Chacko, Reimink spent his summers in the field collecting rock samples from the Acasta Gneiss Complex, which was discovered in the 1980s and found to contain some of Earth’s oldest rocks, between 3.6 and four billion years old. Due to their extreme age, the rocks have undergone multiple metamorphic events, making it difficult to understand their geochemistry, Reimink says.

Fortunately, a few rocks — which the research team dubbed “Idiwhaa” meaning “ancient” in the local Tlicho dialect — were better preserved. This provided a “window” to see the samples’ geochemical characteristics, which Reimink says showed crust-forming processes that are very similar to those occurring in present-day Iceland.

“This provides the first physical evidence that a setting similar to modern Iceland was present on the early Earth.”

These ancient rocks are among the oldest samples of protocontinental crust that we have, he adds, and may have helped jump-start the formation of the rest of the continental crust.

Reimink, who came to the U of A to work with Chacko, says the university’s lab resources are “second to none,” particularly the Ion Microprobe facility within the Canadian Centre for Isotopic Microanalysis run by co-author Richard Stern, which was instrumental to the discovery.

“That lab is producing some of the best data of its kind in the world. That was very key to this project.”

Note : The above story is based on materials provided by University of Alberta.

NASA missions let scientists see moon’s dancing tide from orbit

May 29, 2014

Illustration of Earth as seen from the moon. The gravitational tug-of-war between Earth and the moon raises a small bulge on the moon. The position of this bulge shifts slightly over time. Credit: NASA’s Goddard Space Flight Center

Scientists combined observations from two NASA missions to check out the moon’s lopsided shape and how it changes under Earth’s sway — a response not seen from orbit before.
The team drew on studies by NASA’s Lunar Reconnaissance Orbiter, which has been investigating the moon since 2009, and by NASA’s Gravity Recovery and Interior Laboratory, or GRAIL, mission. Because orbiting spacecraft gathered the data, the scientists were able to take the entire moon into account, not just the side that can be observed from Earth.

“The deformation of the moon due to Earth’s pull is very challenging to measure, but learning more about it gives us clues about the interior of the moon,” said Erwan Mazarico, a scientist with the Massachusetts Institute of Technology in Cambridge, Mass., who works at NASA’s Goddard Space Flight Center in Greenbelt, Md.

The lopsided shape of the moon is one result of its gravitational tug-of-war with Earth. The mutual pulling of the two bodies is powerful enough to stretch them both, so they wind up shaped a little like two eggs with their ends pointing toward one another. On Earth, the tension has an especially strong effect on the oceans, because water moves so freely, and is the driving force behind tides.

Earth’s distorting effect on the moon, called the lunar body tide, is more difficult to detect, because the moon is solid except for its small core. Even so, there is enough force to raise a bulge about 20 inches (51 centimeters) high on the near side of the moon and similar one on the far side.

The position of the bulge actually shifts a few inches over time. Although the same side of the moon constantly faces Earth, because of the tilt and shape of the moon’s orbit, the side facing Earth appears to wobble. From the moon’s viewpoint, Earth doesn’t sit motionless but moves around within a small patch of sky. The bulge responds to Earth’s movements like a dance partner, following wherever the lead goes.

“If nothing changed on the moon — if there were no lunar body tide or if its tide were completely static — then every time scientists measured the surface height at a particular location, they would get the same value,” said Mike Barker, a Sigma Space Corporation scientist based at Goddard and co-author of the new study, which is available online in Geophysical Research Letters.

A few studies of these subtle changes were conducted previously from Earth. But not until LRO and GRAIL did satellites provide enough resolution to see the lunar tide from orbit.

To search for the tide’s signature, the scientists turned to data taken by LRO’s Lunar Orbiter Laser Altimeter, or LOLA, which is mapping the height of features on the moon’s surface. The team chose spots that the spacecraft has passed over more than once, each time approaching along a different flight path. More than 350,000 locations were selected, covering areas on the near and far sides of the moon.

The researchers precisely matched measurements taken at the same spot and calculated whether the height had risen or fallen from one satellite pass to the next; a change indicated a shift in the location of the bulge.

A crucial step in the process was to pinpoint exactly how far above the surface LRO was located for each measurement. To reconstruct the spacecraft’s orbit with sufficient accuracy, the researchers needed the detailed map of the moon’s gravity field provided by the GRAIL mission.

“This study provides a more direct measurement of the lunar body tide and much more comprehensive coverage than has been achieved before,” said John Keller, LRO project scientist at Goddard.

The good news for lunar scientists is that the new results are consistent with earlier findings. The estimated size of the tide confirmed the previous measurement of the bulge. The other value of great interest to researchers is the overall stiffness of the moon, known as the Love number h2, and this was also similar to prior results.

Having confirmation of the previous values — with significantly smaller errors than before — will make the lunar body tide a more useful piece of information for scientists.

“This research shows the power of bringing together the capabilities of two missions. The extraction of the tide from the LOLA data would have been impossible without the gravity model of the moon provided by the GRAIL mission,” said David Smith, the principal investigator for LRO’s LOLA instrument and the deputy principal investigator for the GRAIL mission. Smith is affiliated with Goddard and the Massachusetts Institute of Technology.

Note : The above story is based on materials provided by NASA/Goddard Space Flight Center.

Magnetite

May 28, 2014

Chemical Formula: Fe²⁺Fe³⁺₂O₄
Locality: Many localities and environments world wide.
Name Origin: Named for Magnes, a Geek shepherd, who discovered the mineral on Mt, Ida, He noted that the nails of his shoe and the iron ferrule of his staff clung to a rock.

Magnetite is a mineral, one of the three common naturally occurring iron oxides (chemical formula Fe₃O₄) and a member of the spinel group. Magnetite is the most magnetic of all the naturally occurring minerals on Earth. Naturally magnetized pieces of magnetite, called lodestone, will attract small pieces of iron, and this was how ancient people first noticed the property of magnetism.

Small grains of magnetite occur in almost all igneous and metamorphic rocks. Magnetite is black or brownish-black with a metallic luster, has a Mohs hardness of 5–6 and a black streak.

The chemical IUPAC name is iron(II,III) oxide and the common chemical name is ferrous-ferric oxide.

Table of Contents

History

Discovery date : 1845
Town of Origin : MAGNESIA, THESSALIE
Country of Origin : GRECE

Optical properties

Optical and misc. Properties : Opaque
Reflective Power : ~21%

Physical Properties

Cleavage: None
Color: Grayish black, Iron black.
Density: 5.1 – 5.2, Average = 5.15
Diaphaneity: Opaque
Fracture: Sub Conchoidal – Fractures developed in brittle materials characterized by semi-curving surfaces.
Hardness: 5.5-6 – Knife Blade-Orthoclase
Luminescence: Non-fluorescent.
Luster: Metallic
Magnetism: Naturally strong
Streak: black

Photos :

Magnetite 5.6×5.6×3.8 cm Bentley Lake Faraday Mine Property Ontario, Canada Copyright © David K. Joyce Minerals

Magnetite ZCA Mine No. 4, Balmat, St Lawrence Co., New York, USA Cabinet, 11.9 x 11.0 x 9.5 cm © irocks

Magnetite ZCA Mine, Balmat, St Lawrence County, New York, USA Cabinet, 11.5 x 4.6 x 4.5 cm © irocks

Rio Varbore, Manubiola Valley, Berceto, Parma Province, Emilia-Romagna, Italy © Chinellato Matteo

High-resolution images shed light on dinosaur bone healing

May 28, 2014

Scientists have used a highly sensitive, high-resolution X-ray scanning technique to detect minute quantities of chemicals associated with bone healing in 150-million-year-old dinosaur bones.

They looked in cracks, fractures and breaks in the ancient remains, and found traces of copper, zinc and strontium, which are essential for enzymes involved with bone maintenance, repair and healing.
As well as shedding light on the differences between normal and healed bone, the findings give the first chemical clues to how the dinosaurs’ bones may have healed when they were injured.

They also suggest that many predatory dinosaurs may have recovered from the impact of massive trauma, which would likely kill you or me.

The findings are published in Journal of the Royal Society Interface.

‘It seems dinosaurs evolved a splendid suite of defence mechanisms to help regulate the healing and repair of injuries. Not a lot is known about the biochemistry of healing in extinct animals. So, the ability to diagnose such processes some 150 million years later might well shed light on how we can use Jurassic chemistry in the 21st century,’ says Dr Phil Manning of the University of Manchester, one of the study’s co-authors.

Fossilised bones sometimes show evidence of trauma, sickness and subsequent signs healing. Working out what happened to them usually relies on scientists slicing through ancient, valuable specimens to analyse them.

Manning and colleagues from UK and US universities realised that looking at so-called chemical signatures in the bones could uncover details about how they healed.

‘This is because the body uses a distinct suite of trace-metal co-ordinated enzymes to repair bones,’ explains Manning.

‘Copper-based enzymes are associated with forming calluses. The second stage of bone repair involves zinc-containing enzymes, which promotes bone growth. And the final stage to check all the work done is good involves an enzyme that contains strontium,’ he adds.

‘So if you’re imaging a healed fracture, you’ll find trace amounts of strontium evenly distributed along the healed bone. But if it’s still healing, there’ll be higher concentrations of zinc.’

These elements make up much less than one per cent of our entire bodies, which means trying to find them in 150-million-year-old fossils is a big ask.

The interdisciplinary team based at the University of Manchester used both the Stanford Synchrotron Radiation Light Source and Diamond Light Source to analyse a bone from a theropod dinosaur called Allosaurus fragilis.

The predatory Allosaurus, which means ‘different lizard’, lived 155 to 150 million years ago during the late Jurassic Period. It was a member of a group of vertebrates called the archosaurs, whose modern members include the crocodiles and birds.

The researchers also used the Stanford synchrotron to analyse a bone from a living archosaur, the turkey vulture.

‘Theropods are a logical study group as they are more closely related to the most diverse group of extant archosaurs, the birds,’ explain the authors.

Synchrotron particle accelerators act like a giant microscope, harnessing the power of electrons to produce light brighter than a billion suns to study anything from jet engines to viruses and vaccines.

The team used extremely bright light produced by the two particle accelerators to find minute traces of zinc, copper and strontium in the bones.

‘You can only detect such chemistry using a synchrotron, because this technique permits you to exactly image the relationship of each atom to its surrounding elements. This allows you to identify if the element was part of the bone-healing process, or if it came from the environment in which the bone became fossilised,’ says Manning.

When they compared the chemical signatures in the dinosaur and turkey vulture specimens, they expected them to be fairly similar.

But they found that the dinosaur bone revealed signs of fracture healing that are more reminiscent of that of modern reptiles like crocodiles or alligators.

‘It is quite possible you’ve got a reptilian-style repair mechanism combined with elevated metabolism, like that you’d find in alligators and birds respectively. So you’ve got a double whammy in a good way. If you suffer massive trauma, you’ve got the perfect set-up to survive it,’ says Manning.

‘Bones doesn’t form scar tissue, like a scratch to your skin, so the body has to completely reform new bone following the same stages that occurred at the skeleton grew in the first place. The means we are able to tease out the chemistry of bone development through such pathological studies,’ says Jennifer Anné, PhD student at the University of Manchester, first author of the study.

‘You’re basically seeing a biological process preserved in the sands of time,’ adds Manning.

More Information :
Jennifer Anné, Nicholas P. Edwards, Roy A. Wogelius, Allison R. Tumarkin-Deratzian, William I. Sellers, Arjen van Veelen, Uwe Bergmann, Dimosthensis Sokaras, Roberto Alonso-Mori, Konstantin Ignatyev, Victoria M. Egerton and Phillip L. Manning, Synchrotron imaging reveals bone healing and remodelling strategies in extinct and extant vertebrates, Journal of the Royal Society Interface, published 7th May 2014, http://dx.doi.org/10.1098/rsif.2014.0277

Note : The above story is based on materials provided by © Natural Environment Research Council

Antarctic Ice Sheet unstable at end of last ice age, new study finds

May 28, 2014

This is one of many icebergs that sheared off the continent and ended up in the Scotia Sea. Credit: Michael Weber, University of Cologne

A new study has found that the Antarctic Ice Sheet began melting about 5,000 years earlier than previously thought coming out of the last ice age – and that shrinkage of the vast ice sheet accelerated during eight distinct episodes, causing rapid sea level rise.
The international study, funded in part by the National Science Foundation, is particularly important coming on the heels of recent studies that suggest destabilization of part of the West Antarctic Ice Sheet has begun.

Results of this latest study are being published this week in the journal Nature. It was conducted by researchers at University of Cologne, Oregon State University, the Alfred-Wegener-Institute, University of Hawaii at Manoa, University of Lapland, University of New South Wales, and University of Bonn.

The researchers examined two sediment cores from the Scotia Sea between Antarctica and South America that contained “iceberg-rafted debris” that had been scraped off Antarctica by moving ice and deposited via icebergs into the sea. As the icebergs melted, they dropped the minerals into the seafloor sediments, giving scientists a glimpse at the past behavior of the Antarctic Ice Sheet.

Periods of rapid increases in iceberg-rafted debris suggest that more icebergs were being released by the Antarctic Ice Sheet. The researchers discovered increased amounts of debris during eight separate episodes beginning as early as 20,000 years ago, and continuing until 9,000 years ago.

The melting of the Antarctic Ice Sheet wasn’t thought to have started, however, until 14,000 years ago.

“Conventional thinking based on past research is that the Antarctic Ice Sheet has been relatively stable since the last ice age, that it began to melt relatively late during the deglaciation process, and that its decline was slow and steady until it reached its present size,” said lead author Michael Weber, a scientist from the University of Cologne in Germany.

“The sediment record suggests a different pattern – one that is more episodic and suggests that parts of the ice sheet repeatedly became unstable during the last deglaciation,” Weber added.

The research also provides the first solid evidence that the Antarctic Ice Sheet contributed to what is known as meltwater pulse 1A, a period of very rapid sea level rise that began some 14,500 years ago, according to Peter Clark, an Oregon State University paleoclimatologist and co-author on the study.

The largest of the eight episodic pulses outlined in the new Nature study coincides with meltwater pulse 1A.

“During that time, the sea level on a global basis rose about 50 feet in just 350 years – or about 20 times faster than sea level rise over the last century,” noted Clark, a professor in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences. “We don’t yet know what triggered these eight episodes or pulses, but it appears that once the melting of the ice sheet began it was amplified by physical processes.”

The researchers suspect that a feedback mechanism may have accelerated the melting, possibly by changing ocean circulation that brought warmer water to the Antarctic subsurface, according to co-author Axel Timmermann, a climate researcher at the University of Hawaii at Manoa.

“This positive feedback is a perfect recipe for rapid sea level rise,” Timmermann said.

Some 9,000 years ago, the episodic pulses of melting stopped, the researchers say.

“Just as we are unsure of what triggered these eight pulses,” Clark said, “we don’t know why they stopped. Perhaps the sheet ran out of ice that was vulnerable to the physical changes that were taking place. However, our new results suggest that the Antarctic Ice Sheet is more unstable than previously considered.”

Today, the annual calving of icebergs from Antarctic represents more than half of the annual loss of mass of the Antarctic Ice Sheet – an estimated 1,300 to 2,000 gigatons (a gigaton is a billion tons). Some of these giant icebergs are longer than 18 kilometers.

More information: Paper: Millennial-scale variability in Antarctic ice-sheet discharge during the last deglaciation, dx.doi.org/10.1038/nature13397

Note : The above story is based on materials provided by Oregon State University

Magnesite

May 28, 2014

Chemical Formula: MgCO₃
Locality: Magnisía (Magnesia) Prefecture, Thessalia (Thessaly) Department, Greece
Name Origin: Named after its chemical composition.

Magnesite is a mineral with the chemical formula MgCO₃ (magnesium carbonate). Mixed crystals of iron II carbonate and magnesite (mixed crystals known as ankerite) possess a layered structure: monolayers of carbonate groups alternate with magnesium monolayers as well as iron II carbonate monolayers. Manganese, cobalt and nickel may also occur in small amounts.

Table of Contents

Occurrence

Magnesite occurs as veins in and an alteration product of ultramafic rocks, serpentinite and other magnesium rich rock types in both contact and regional metamorphic terrains. These magnesites often are cryptocrystalline and contain silica in the form of opal or chert.

Magnesite is also present within the regolith above ultramafic rocks as a secondary carbonate within soil and subsoil, where it is deposited as a consequence of dissolution of magnesium-bearing minerals by carbon dioxide within groundwaters.

History

Discovery date : 1808
Town of Origin : MAGNESIA, THESSALIE
Country of Origin : GRECE

Optical properties

Optical and misc. Properties : Transparent to translucent to opaque
Refractive Index : from 1,50 to 1,70

Physical Properties

Cleavage: {1011} Perfect, {1011} Perfect, {1011} Perfect
Color: Colorless, White, Grayish white, Yellowish white, Brownish white.
Density: 3
Diaphaneity: Transparent to translucent to opaque
Fracture: Brittle – Conchoidal – Very brittle fracture producing small, conchoidal fragments.
Hardness: 4 – Fluorite
Luminescence: Fluorescent, Short UV=blue white, Long UV=bright blue white.
Luster: Vitreous (Glassy)
Streak: white

Photos :

Uvite with Magnesite Brumado, Bahia, Brazil Size: 7.0 x 6.0 x 6.0 cm (small cabinet) © danweinrich

Uvite with Magnesite Brumado, Bahia, Brazil Size: 2.5 x 2.0 x 1.3 cm (thumbnail) © danweinrich

Magnesite Bahia, Brazil Thumbnail, 12.7 x 8.0 mm ; 3.52 carats © irocks

Beryl var. Emerald with Magnesite Brumado, Bahia, Brazil Size: 6.3 x 2.0 x 1.8 cm (miniature) © danweinrich

Pomba pit, Serra das Éguas, Brumado (Bom Jesus dos Meiras), Bahia, Brazil © Rob Lavinsky

Where have all the craters gone?

May 28, 2014

Impact craters reveal one of the most spectacular geologic process known to man. During the past 3.5 billion years, it is estimated that more than 80 bodies, larger than the dinosaur-killing asteroid that struck the Yucatan Peninsula 66 million years ago, have bombarded Earth. However, tectonic processes, weathering, and burial quickly obscure or destroy craters. For example, if Earth weren’t so dynamic, its surface would be heavily cratered like the Moon or Mercury.

Work by B.C. Johnson and T.J. Bowling predicts that only about four of the craters produced by these impacts could persist until today, and geologists have already found three such craters (larger than 170 km in diameter). Their study, published online for Geology on 22 May 2014, indicates that craters on Earth cannot be used to understand Earth’s bombardment history.

Johnson and Bowling write, however, that layers of molten rock blasted out early in the impact process may act as better records of impacts—even after the active Earth has destroyed the source craters. The authors suggest that searches for these impact ejecta layers will be more fruitful for determining how many times Earth was hit by big asteroids than searches for large craters.

Reference:
B.C. Johnson and T.J. Bowling. Where have all the craters gone? “Earth’s bombardment history and the expected terrestrial cratering record.” Geology, G35754.1, first published on May 22, 2014, DOI: 10.1130/G35754.1

Note : The above story is based on materials provided by Geological Society of America

Slave River

May 28, 2014

The Slave River is a Canadian river that flows from Lake Athabasca in northeastern Alberta and empties into Great Slave Lake in the Northwest Territories. The river’s name is thought to derive from the name for the Slavey group of the Dene First Nations, Deh Gah Got’ine, in the Athabaskan language, and has nothing to do with slavery. The Chipewyan had displaced other native people from this region.

Table of Contents

Course

The Slave River originates in the Peace-Athabasca Delta, at the forks of Peace River and Riviere Des Roches, which drains the Athabasca River and Lake Athabasca. The Slave River flows north into the Northwest Territories and into the Great Slave Lake north of Fort Resolution. From there the water reaches the Arctic Ocean through the Mackenzie River.The river is 434 km in length and has a cumulative drainage area of 616,400 km².

Portage and Navigation

Prior to the extension of railway service to Hay River, Northwest Territories, a river port on Great Slave Lake, cargo shipment on the Slave River was an important transport route. Locally built wooden vessels were navigating the river into the late 19th Century. The rapids required a portage of 16 miles (26 km). Tractors were imported from Germany to assist in hauling goods around the rapids. Tugs and barges of the Northern Transportation Company’s “Radium Line” were constructed in the south and disassembled. The parts were then shipped by rail to Waterways, Alberta, shipped by barge to the portage, and portaged to the lower river for reassembly, where they could navigate most of the rest of the extensive Mackenzie River basin.

Tributaries

Peace-Athabasca Delta
- Athabasca River
- Lake Athabasca
- Riviere Des Roches
- Chilloneys Creek
- Revillon Coupe
- Dempsey Creek
- Peace River
- Scow Channel
- Murdock Creek
- Darough Creek

Powder Creek
La Butte Creek
Hornaday River
Salt River
Little Buffalo River

Note : The above story is based on materials provided by Wikipedia

Ludlockite

May 27, 2014

Chemical Formula: PbFe³⁺₄As³⁺₁₀O₂₂
Locality: In a boulder of ore found at Tsumeb, Namibia.
Name Origin: Named for mineral dealers Ludlow Smith and Locke Key, who discovered the mineral.

Table of Contents

History

Discovery date : 1970
Town of Origin : TSUMEB
Country of Origin : NAMIBIE

Optical properties

Refractive Index: from 1,96 to 2,12

Physical Properties

Cleavage: {011} Perfect, {021} Perfect
Color: Reddish brown.
Density: 4.37 – 4.4, Average = 4.38
Hardness: 1.5-2 – Talc-Gypsum
Luster: Subadamantine
Streak: pale brown

Photos :

Ludlockite, Philipsbornite $85.00 2.1×1.7×1.7 cm Tsumeb Namibia Copyright © David K. Joyce Minerals

Ludlockite with Leiteite and yellow unknown Tsumeb Mine, Tsumeb, Otjikoto Region, Namibia Size: 4.0 x 3.0 x 2.0 cm (miniature) © danweinrich

Ludlockite Tsumeb Mine, Tsumeb, Otjikoto Region, Namibia Miniature, 3.9 x 2.3 x 1.5 cm © irocks

Tsumeb Mine (Tsumcorp Mine), Tsumeb, Otjikoto Region (Oshikoto), Namibia © Paul De Bondt

Seafloor experts publish new view of zone where Malaysia Airlines flight 370 might lie

May 27, 2014

Seafloor topography in the Malaysia Airlines flight MH370 search area. Dashed lines approximate the search zone for sonar pings emitted by the flight data recorder and cockpit voice recorder popularly called black boxes. The first sonar contact (black circle) was reportedly made by a Chinese vessel on the east flank of Batavia Plateau (B), where the shallowest point in the area (S) is at an estimated depth of 1637 meters. The next reported sonar contact (red circle) was made by an Australian vessel on the north flank of Zenith Plateau (Z). The deepest point in the area (D) lies in the Wallaby-Zenith Fracture Zone at an estimated depth of 7883 meters. The Wallaby Plateau (W) lies to the east of the Zenith Plateau. The shallowest point in the entire area shown here is on Broken Ridge (BR). Deep Sea Drilling Project (DSDP) site 256 is marked by a gray dot. The inset in the top left shows the area’s location to the west of Australia. Seafloor depths are from the General Bathymetric Chart of the Oceans [2010]. Credit: Walter H.F. Smith and Karen M. Marks

A new illustration of the seafloor, created by two of the world’s leading ocean floor mapping experts that details underwater terrain where the missing Malaysia Airlines flight might be located, could shed additional light on what type of underwater vehicles might be used to find the missing airplane and where any debris from the crash might lie.
The seafloor topography map illustrates jagged plateaus, ridges and other underwater features of a large area underneath the Indian Ocean where search efforts have focused since contact with Malaysia Airlines flight MH370 was lost on March 8. The image was published today in Eos, the weekly newspaper of the Earth and space sciences, published by the American Geophysical Union.

The new illustration of a 2,000 kilometer by 1,400 kilometer (1,243 miles by 870 miles) area where the plane might be shows locations on the seafloor corresponding to where acoustic signals from the airplane’s black boxes were reportedly detected at the surface by two vessels in the area. It also shows the two plateaus near where these “pings” were heard.

It points out the deepest point in the area: 7,883 meters (about five miles) underneath the sea in the Wallaby-Zenith Fracture Zone — about as deep as 20 Empire State buildings stacked top to bottom. Undersea mountains and plateaus rise nearly 5,000 meters (about three miles) above the deep seafloor, according to the map.

The illustration, designated as Figure 1 of the Eos article, was created by Walter H.F. Smith and Karen M. Marks, both of the National Oceanic and Atmospheric Administration’s Laboratory for Satellite Altimetry in College Park, Maryland, and the former and current chairs, respectively, of the Technical Sub-Committee on Ocean Mapping of the General Bathymetric Chart of the Oceans, or GEBCO. GEBCO is an international organization that aims to provide the most authoritative publicly available maps of the depths and shapes of the terrain underneath the world’s oceans.

Satellite altimetry has made it possible to depict the topography of vast regions of the seafloor that would otherwise have remained unmapped, Smith said. To illustrate the topography of the search area, Smith and Marks used publicly available data from GEBCO and other bathymetric models and data banks, along with information culled from news reports.

Smith said the terrain and depths shown in the map could help searchers choose the appropriate underwater robotic vehicles they might use to look for the missing plane. Knowing the roughness and shape of the ocean floor could also help inform models predicting where floating debris from the airplane might turn up.

Smith cautions that the new illustration is not a roadmap to find the missing airplane. Nor does the map define the official search area for the aircraft, he added.

“It is not ‘x marks the spot’,” Smith said of their map. “We are painting with a very, very broad brush.”

Search efforts for the missing airplane have focused on an area of the southern Indian Ocean west of Australia where officials suspect that the plane crashed after it veered off course. After an initial air and underwater search failed to find any trace of the airplane, authorities announced this month that they will expand the search area and also map the seabed in the area.

Smith pointed out that the search for the missing plane is made more difficult because so little is understood about the seafloor in this part of the Indian Ocean. In the southeast Indian Ocean, only 5 percent of the ocean bottom has been measured by ships with echo soundings. Knowledge of the rest of the area comes from satellite altimetry, which provides relatively low-resolution mapping compared to ship-borne methods.

“It is a very complex part of the world that is very poorly known,” Smith said.

A lack of good data about Earth’s seafloors not only hinders search efforts, it also makes it harder for scientists to accurately model the world’s environment and climate, Smith noted. Today, our knowledge of our planet’s undersea topography is “vastly poorer than our knowledge of the topographies of Earth’s Moon, Mars and Venus,” Smith and Marks write in Eos. This is because these other planetary bodies have no oceans, making their surfaces relatively easy to sense from space.

Smith said he hoped that “the data collected during the search for MH370 will be contributed to public data banks and will be a start of greater efforts to map Earth’s ocean floor.”

Note : The above story is based on materials provided by American Geophysical Union.

Research suggests more silicon in Earth’s lower mantle than thought

May 27, 2014

For many years geophysicists have argued over the perplexing mystery regarding the amount of silicon in the Earth’s mantle that is thought to have arrived there via impacts with asteroids.
The problem is that tests done to determine the composition of the mantel have found that there appears to be less silicon in it proportionally, than there is in asteroids. Now new research by a Japanese team suggests that the lowest section of the Earth’s mantle has more silicon in it than does the upper parts, perhaps solving the mystery. They have described their work in their paper published in the journal Nature.

To help clarify what lies far beneath our feet, geophysicists have subdivided the Earth’s mantle into three broad sections: the upper, middle and lower mantle. The upper mantle describes the crust and approximately 400 km below. The middle is about 250 km thick and the lower goes to about 2,900 km in depth.

The upper mantle is far easier to study of course, due to its proximity and thus the proportion of silicon in it is well understood. Not so well understood has been the composition of the middle and lower mantles. To study them, researches generally use seismic data recorded by sending shockwaves into the ground, but doing so thus far, has led more often to speculation than good science.

To get a better handle on what is happening so far beneath the Earth’s surface the Japanese team took a different approach; instead of trying to measure the lower mantle itself, they sought to recreate it in a lab where it could be measured much more easily. To do that, they mixed the ingredients (mainly silicate perovskite and ferropericlase) they believe exist in the lower mantel and placed them in a pressure chamber. There the sample was subjected to different pressure levels consistent with current theories describing the differing degrees of pressure at different levels of the mantle. They then applied the same seismic tests normally done on the real mantle. In so doing, they have come to believe that the lower mantle has a volume that is approximately 93% silicate perovskite, which when compared with data describing the upper crust gives an average amount of silicon for the entire mantle that is very nearly equal to that found in asteroids. Thus, the mystery, they say is solved.

More information: Nature 485, 90–94 (03 May 2012) doi:10.1038/nature11004

Ludlamite

May 27, 2014

Chemical Formula: (Fe,Mn,Mg)₃(PO₄)₂·4H₂O
Locality: Wheal Jane, Kea, near Truro, Cornwall, England, UK.
Name Origin: Named for Henry Ludlam (1824-1880), English mineralogist and collector.

Ludlamite is a rare phosphate mineral with formula: (Fe,Mn,Mg)₃(PO₄)₂·4H₂O

It was first described in 1877 for an occurrence in Wheal Jane mine in Cornwall, England and named for English mineralogist Henry Ludlam (1824–1880).

Table of Contents

History

Discovery date : 1877
Town of Origin : WHEAL JANE (MINE), TRURO, CORNOUAILLES
Country of Origin: ANGLETERRE

Optical properties

Optical and misc. Properties : Transparent to Translucent
Refractive Index: from 1,65 to 1,69
Axial angle 2V : 82°

Physical Properties

Cleavage: {001} Perfect, {100} Indistinct
Color: Apple green, Colorless, Green, Greenish white, Light green.
Density: 3.15
Diaphaneity: Transparent to Translucent
Hardness: 3.5 – Copper Penny
Luster: Vitreous (Glassy)
Streak: white

History

Optical properties

Physical Properties

Photo:

Primative ocean life

Dating techniques

Insights into gas emission effect

Occurrence

History

Optical properties

Physical Properties

Photos :

Occurrence

History

Optical properties

Physical Properties

Photos:

Ancient rocks 3.6 to four billion years old

History

Optical properties

Physical Properties

Photos :

Occurrence

History

Optical properties

Physical Properties

Photos :

Course

Portage and Navigation

Tributaries

History

Optical properties

Physical Properties

Photos :

History

Optical properties

Physical Properties

Photos :

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