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African Dust and the Amazon Jungle This photo taken by NASA’s Suomi-NPP orbiting satellite shows a large plume of dust leaving the coast of Africa this week. This dust plume is being blown west out over the Atlantic, and will eventually reach the coast of North America. Plumes of dust like this one play an important role in the ecosystems of the western hemisphere.
Variscite
Often confused with its more common cousin turquoise, this aluminium phosphate mineral is formed by direct precipitation from phosphorous rich waters percolating through aluminium rich country rocks. Usually greener than its cousin, it occurs as nodules, massive infilling in fractures or cavities and crusts. White veins can be an identifying characteristic, as opposed to turquoise's dark ones (though the material from Nevada has dark veining), and it is a little softer, under 5 on Mohs scale, while its cousin (in gem quality at least as opposed to the stabilised muck going around the markets these days) is slightly over. It is very popular for carvings and ornaments thanks to its softness.
Usually opaque to slightly translucent, the common colour is minty green, though many other shades of this hue are known as are violet to reddish specimens when more iron is present in the crystal structure. It was named after the archaic appellation of the Vogtland area of Germany in 1837, but has also been referred to as Utahlite. Found in the USA and Germany, other major localities include Australia, Poland and Brazil. Like its cousin, variscite is porous, and should not be exposed to detergents or chemicals, for example by wearing it while washing up or cleaning your carving. The result can be a permanent and irreversible discolouration.
The sliced Utah nodule in the photo is half a metre across.
Loz
Image credit: J. Stuby
Apatite
We are all intimately familiar with this mineral family, as it is the main inorganic ingredient of our bones and teeth, deposited along with collagen and various cells in a process called biomineralisation. It plays a key part in the global phosphorous cycle, an element so essential to life as we know it that Isaac Asimov referred to it as 'life's bottleneck, since environments impoverished in this element don't support much of an ecosystem.
A calcium phosphate (often incorporating other elements such as chlorine or fluorine, hence the practice of adding fluoride to drinking water and toothpaste), apatite forms in volcanic or metamorphic rocks, using up the phosphorous that doesn't fit into the crystal structure of the more common rock forming minerals. Common colours are green, blue and yellow, large gemmy crystals such as the one in the photo tend to form in pegmatites, the slow cooling remnants of granites that incorporate all the distilled rare elements from the world's depths and crystallise them into a wide variety of beautiful gems. Once the volcanic rocks are eroded, the apatite is deposited in sedimentary environments, micro crystals being the principal constituent of phosphate rich rocks.
Crystals are usually hexagonal prisms, though 12 sided ones are not uncommon. Beryl (emerald, aquamarine) and tourmaline can be confused with it, and the name comes from a Greek word for deceit, as it is often confused with more valuable gems. The Mohs hardness of 5 gives it away, as a steel blade will scratch it, leaving the others unscathed.
It has an important use in geology, since it soaks up Uranium and Thorium, allowing it to be dated, and the tracks left by particles during fission of these elements within the crystal structure are often of use to metamorphic geologists trying to date the events that heated and squished the parent rock (known as the protolith). It is also vital to feeding the world, phosphate rich rocks (essentially fossil phosphorous, just like fossil fuels) are mined globally for use in fertilisers, without which we couldn't sustain the current world population using the currently available sources.
It is also an ore for rare earth elements, and the hand spectroscope often reveals a maze of dark lines in the spectrum due to these impurities. Occasionally faceted for collectors, it is also used by painters who make their own pigments. Major sources of gem apatite include Brazil, Burma and Mexico.
Loz
Image credit: Heritage Auctions
cyborkminerals2018
New thumbnail for my collection...pale blue Wavellite from the lesser known locality Minare Bridge,Cork County/Ireland - NFS
Could Earth’s mantle control the rise of oxygen?
This photo shows peat – high organic carbon material formed today out of plant matter. Every bit of organic carbon on Earth, including the stuff I’m using to type on this keyboard, at some point started out as carbon in the atmosphere. Organic carbon is produced when organisms take CO2 from the atmosphere or ocean, break it apart using energy, and turn it into carbon while releasing oxygen.
The first life forms on Earth had to do this process using chemical energy, but about 3 billion years ago life figured out how to use sunlight as the source of energy that drove this reaction. Single-celled organisms began creating carbon by photosynthesis, releasing oxygen to the atmosphere in the process. By 2.5 billion years ago, oxygen became a regular constituent in the atmosphere, but even though life forms were releasing oxygen, the abundance of that gas didn’t rise anywhere close to the level seen today for nearly 2 billion years. All the ingredients seem to be there, but there just wasn’t enough carbon being buried to push oxygen up in the atmosphere. Why?
A new paper proposes that one possible explanation for why oxygen did not rise in the atmosphere is actually found in the mantle, and connected to the surface through the element phosphorus.
Phosphorus poorly fits in the mantle, it is what we call an incompatible element. When the mantle melts, phosphorus is concentrated into the magma, and eventually it is concentrated in the Earth’s crust. However, when Earth first formed, the planet was so hot that any phosphorus in early magmas was going to be diluted by everything else that melted. Early rocks, therefore, have less phosphorus in them than more recent rocks.
Phosphorus is a nutrient element required for life to flourish. There are areas of the planet today that are phosphorus-limited, meaning that more organisms could live there if there was more phosphorus available, they have every other nutrient they need in abundance.
This paper, led by researchers from The University of Adelaide, suggests that these two topics are connected. Over time, as the planet cools off, phosphorus will go up in rocks coming out of the mantle. As these rocks get more phosphorus in them due to the planet cooling, weathering them releases more phosphorus out to the world, and more organisms are able to grow.
More organisms able to grow means forming more biomass, and more biomass means more oxygen in the atmosphere. Basically, increase the phosphorus in rocks, life gets more phosphorus, more life grows, and the end result is more oxygen in the atmosphere.
There are complications to this idea, of course. As the continental crust was forming, erosion on continents could trap phosphorus in long-lived sedimentary rocks, removing it from the nutrient cycle, and these authors consider some cases where that may have happened during the Precambrian when oxygen contents still remained low.
If this hypothesis is an important one for evolution of the ecosystem on Earth, it will also be important on any other body where life exists. Phosphorus will have the same behavior elsewhere, and if it is a common key nutrient element as is found on Earth, then large planets that remain hot for long periods of time, or planets that do not cool efficiently through plate tectonics, may have a limit to how large of a biosphere they could develop. Oxygen may be easier to detect in the atmosphere of planets like ours – ones that efficiently bring nutrients to the surface and concentrate them through plate tectonics.
-JBB
Image credit: Public Domain Pictures https://bit.ly/2N3jXUz
Original paper: https://bit.ly/2tv1xn8
Another clip in the recent Magic of Chemistry collection shows a number of geologic-type processes, including acid-base reactions, minerals dissolving and reacting with water, and a variety of things burning.
This collection of Envisioning Chemistry includes 5 films: 1. Getting Hot (with Thermal Imaging) 2. Everyday Fire (in Slow Motion) 3. Disappearing Metals (Aluminum, Magnesium, Copper, Lithium, Sodium, Potassium) 4. Elemental Burning (Carbon, Sodium, Phosphorus, Magnesium, Sulfur) 5. Elemental Burning II (Lithium, Hydrogen, Iron, Potassium)
For more films and text descriptions: please visit envisioningchemistry.com
When the bones go blue
Vivianite is a hydrated iron phosphate mineral (Fe2+3(PO4)2 · 8H2O) that can be found in diverse geological environments, including the oxidation zone of metal ore deposits, granite pegmatites that contain phosphate minerals and clays and glauconitic sediments. Vivianite also shows up attached to fossil shells and bones. When vivianite forms, its crystals are colorless or pale green and transparent, but as a result of a quick process of oxidization its color changes to a deep bluish-green or deep blue (http://bit.ly/2uZQXGt).
This mineral has been found several times in partially blue human remains. A good example is Ötzi, the Iceman – a 5,000-year-old man that died and his body remained frozen in the Alps. Another example are the remains of American soldiers who died in an airplane crash in South Vietnam.
The reason why vivianite appears in human remains is related to how phosphate present in bones and teeth interacts with iron and water. When a person dies and the body initiates the decomposing process, the phosphate pours out into the corpse surroundings. If it happens that this environment has presence of water and it is filled with iron, the phosphate will react with these other molecules and vivianite is the result of that interaction.
As mentioned above, when vivianite is formed its crystals are colorless, but due to the presence of oxygen the crystals shift into a different color – in the case of human remains, vivianite’s crystals are deep blue. As you can imagine, this creates an eerie scene for anyone who finds the cadaver.
For archaeologists, vivianite can be both a good and a bad thing. When studying the DNA, this mineral is a big no-no, because vivianite can blunder the molecular process used to access DNA from biological remains – this process is called Polymerase Chain Reaction (PCR).
On the other hand, the presence of vivianite in remains can be quite valuable. For instance, vivianite can bring some light to what happened to a person’s body after their death. Take the example of the American soldiers found in Vietnam: because of the presence of vivianite, scientists could determine that that group of men had been buried in drenched soil filled with iron from the rusting plane. Also, vivianite helps preserve human remains as it slows the natural decaying process. This feature is obviously of great value for archaeologists. This mineral can also help provide information about burial sites as its presence shows evidence of occasional flooding of burial grounds.
Vivianite is not the only mineral that changes the color of corpses: blue-green copper minerals can appear on human cadavers if these were buried with certain items such as jewelry or bullet jackets.
If you are planning on leaving a drop-dead gorgeous corpse behind, you may want to consider to be buried with some jewelry somewhere with lots of water and iron. Besides of keeping you preserved longer, you will give quite a fright to whoever unearths you.
Su
Photo credits: http://bit.ly/2eOr1HE - photo by Terry O'Connor/BoneCommons http://bit.ly/2eO7tn1 - photo by Terry O'Connor/BoneCommons http://bit.ly/2w13tTv - photo by Rob Lavinsky/iRocks.com
Ludlamite
Here we have a rare phosphorous rich mineral that forms in hot fluid rich environments such as the last cooling remnants of granites (called pegmatites) or rocks that have been altered by the ubiquitous hydrothermal fluids of the Earth. These can take many forms, from fluids spat out of lavas to basinal brines expelled as rocks are compressed by the younger rocks above. All of these carry their dissolved components, and frequently mobilise elements from vast volumes of rock to concentrate them elsewhere, forming most of our ore deposits.
This one segregates some of the 'denser' elements, those more common in the Earth's mantle like iron and magnesium. It was first discovered in the pegmatites of the Wheal Jane mine in Cornwall when it was reopened after a period of fallowness. These granites of south west England were a well known source of tin and other metals for thousands of years, and legends say that Jesus may have accompanied Joseph of Arimathea on a tin buying trip there (said legend being the basis of the poem by William Blake later adapted into the well known hymn Jerusalem).
The mineral was named after an English mineralogist in 1877. Ludlamite is a often a secondary mineral made from remobilised phosphorous though it also occurs in the complex polymetallic veins that spat out of those long ago magmas of the Cornish batholith before they froze. Colour is usually green, though colourless and bluey material also exists, iooften as sprays of sheaves. It is too soft (a mere 3.5 on Mohs scale) for faceting.
The original mine has been reopened again, this time uniquely for Ludlamite rather than the ores that were once thought important... with only a few known localities on the planet such a mineral rarity is worth the effort. Other places include La union in Spain, Rapid Creek in the Yukon and a few places in the USA. This 4.5 x 2.7 x 1.6 cm specimen was mined in Brazil.
Loz
Image credit: Rob Lavinsky/iRocks.com
https://www.mindat.org/min-2452.html http://www.galleries.com/Ludlamite http://bit.ly/2n3ZMLo
Mineral Mushroom.
This looks like blobby fungi on the forest floor, but is in fact a hydrated iron aluminium phosphate mineral called Cacoxenite, often found as an inclusion in quartz. It was named after the Greek for bad guest, since it lowers the amount of iron obtained from smelting the ore. Found in pegmatites and iron and phosphorous rich soils, it sometimes displays amazing shapes. It is usually a micromineral, and the field of view of the photo of this specimen from Spain is 3mm.
Loz
Image credit: Christian Rewitzer
http://webmineral.com/data/Cacoxenite.shtml#.Ug10ZG2O64w http://www.mindat.org/min-840.html http://www.galleries.com/Cacoxenite
Enormous algae bloom in China
In this image, residents of the city of Qingdao in Shandong province, China, are walking along a beach. Seriously, this is a beach.
Starting in 2007, this area of China, a province on the coast of the Yellow Sea, has suffered the appearance of massive amounts of green algae. The algae, also known as “sea lettuce” is non-toxic, but it does choke off other marine life and drive away tourism as it begins to rot.
This bloom from 2013 was estimated to be 29,000 square kilometers in area, larger than the state of Connecticut. This bloom is larger than one in 2008 which impacted preparations for the Summer Olympics, but is actually smaller than a monstrous bloom from 2009. These algae blooms are believed to be the largest ones occurring anywhere on Earth today.
Although there are some obvious candidates such as runoff from farming supplying nutrients like phosphorus and seaweed farming taking place farther south along the Chinese coast, there is currently no single explanation for why these large algae blooms are happening or what changed in 2007 causing them to start appearing.
-JBB
Image credit, China Daily via NBC News/Reuters: http://photoblog.nbcnews.com/_news/2013/07/02/19248409-algae-creates-a-giant-green-obstacle-for-chinese-beachgoers
Details, press report: http://www.nytimes.com/2013/07/06/world/asia/huge-algae-bloom-afflicts-qingdao-china.html?_r=0
Other images: http://www.china.org.cn/environment/2013-06/09/content_29078631_4.htm
Odontolite
Also known as Bone turquoise, this beautiful rock is formed in the depths of sedimentary stacks, as bones like this fossil jaw are preserved for the aeons during the process that turns their surrounding sediments into rock. Teeth are the most common part of the skeleton that turn into odontolite, hence its name.
It was long thought to be coloured (like turquoise) by copper, and when analysis failed to reveal its presence, by the iron phosphate mineral vivianite (see http://tinyurl.com/mnvy6vx). Recent research has shown that it usually consists of crystals of blue apatite (see http://tinyurl.com/l5rzpag), coloured by trace impurities of manganese, though some turqouise (copper phosphate) specimens are known, like this sample.
It is formed by heat and copper bearing fluids passing through fossiliferous rocks and is often found near copper deposits in arid areas, part of the same pule of mineralisation that left the ore grade concentrations behind. In the old days it was called occidental turquoise to distinguish it from the oriental version which is a clay rock coloured by copper oxide, and occasionally the former has been erroneously (or fraudulently) sold as the latter. They can be told apart by their hardness, with the oriental version being harder. The most famous locality is in France, especially in the southwestern Languedoc region, where they accumulated in river sediments derived from the erosion of the nearby Pyrenean chain.
They preserve bone structure beautifully and are much sought after by palaeontologists. This kind of mineral replacement is known as pseudomorphing, with the new mineral taking the shape of the previous one, in this case a jawbone. This specimen was mined in the Bolivian altiplano and was once the jawbone of an animal some 20-40,000 years ago. It measures 4.2 x 3.0 x 2.1 cm.
Image credit: Rob Lavinsky/iRocks.com http://bit.ly/2eaZJvb http://www.mindat.org/min-32412.html A paper on how it forms, paywall access: http://bit.ly/2dq03F1
Weekend chemistry fun - 5 elements, carbon, sodium, phosphorus, magnesium, and sulfur, burn and oxidize in the air.
Hydroxylherderite
The apatite group of minerals (see http://bit.ly/2akYWkg) encompasses quite a variety of species, with this variant being a beryllium rich calcium phosphate. Like in the rest of the family, ions of similar size and charge such as OH and fluorine commonly substitute for each other in the crystal lattice alongside the beryllium and calcium, with the final product a result of the composition of the mother fluid from which the piece in question crystallised.
Colour varies from yellow through brown to green, though colourless specimens also turn up. It forms in granitic melts, usually crystallising in pegmatites, the last fluid rich parts of the magma that have concentrated all the rare and unusual elements that do not fit into the more common minerals' lattices. It forms in the late stages of crystallisation, often in cavities as water and steam rage together in the magma's last dying gasps. Another formation method is by alteration of minerals such as beryl, and precipitation from in veins.
It was discovered in Saxony in 1828 and named after a local mining official (a bit like Goethite was named after another better known mining official, this time from Weimar, see http://bit.ly/2aVMCHN for a biopic). The hydroxy was added when this variant was discovered in 1894, and most specimens labelled Herderite are in fact this version.
Locations include Brazil, the Czech Republic, Finland, Germany, Italy, Namibia, Russia, Spain, England and the USA, though this 4.7 x 4.0 x 2.3 cm rare green specimen sitting on a crystal of shorl (black tourmaline) was mined in the Gilgit region of the Hindu Kush in Pakistan. The last photo shows it fluorescing in UV light, whose high energy excite electrons into higher orbits, and when they fall back (since what goes up must come down unless it is held up) they emit lower energy light in the visible range of frequencies.
Loz
Image credit: Rob Lavinsky/iRocks.com http://www.mindat.org/min-1962.html http://bit.ly/2aDZYrQ
Hydroxylherderite
The apatite group of minerals (see http://bit.ly/2akYWkg) encompasses quite a variety of species, with this variant being a beryllium rich calcium phosphate. Like in the rest of the family, ions of similar size and charge such as OH and fluorine commonly substitute for each other in the crystal lattice alongside the beryllium and calcium, with the final product a result of the composition of the mother fluid from which the piece in question crystallised.
Colour varies from yellow through brown to green, though colourless specimens also turn up. It forms in granitic melts, usually crystallising in pegmatites, the last fluid rich parts of the magma that have concentrated all the rare and unusual elements that do not fit into the more common minerals' lattices. It forms in the late stages of crystallisation, often in cavities as water and steam rage together in the magma's last dying gasps. Another formation method is by alteration of minerals such as beryl, and precipitation from in veins.
It was discovered in Saxony in 1828 and named after a local mining official (a bit like Goethite was named after another better known mining official, this time from Weimar, see http://bit.ly/2aVMCHN for a biopic). The hydroxy was added when this variant was discovered in 1894, and most specimens labelled Herderite are in fact this version.
Locations include Brazil, the Czech Republic, Finland, Germany, Italy, Namibia, Russia, Spain, England and the USA, though this 4.7 x 4.0 x 2.3 cm rare green specimen sitting on a crystal of shorl (black tourmaline) was mined in the Gilgit region of the Hindu Kush in Pakistan. The last photo shows it fluorescing in UV light, whose high energy excite electrons into higher orbits, and when they fall back (since what goes up must come down unless it is held up) they emit lower energy light in the visible range of frequencies.
Loz
Image credit: Rob Lavinsky/iRocks.com
http://www.mindat.org/min-1962.html http://bit.ly/2aDZYrQ
Fluorapatite, fluorescing
One of the more eerie seeming properties of some minerals is their ability to glow in the dark when submerged in ultraviolet light, fluorite (after which the phenomenon was named when discovered) being the most obvious example. Atoms within the crystal lattice get excited by the high energy rays, and their electrons jump up with this extra energy to a different shell. They can't hold on to it though, and shed it as they drop back in the form of light at visible wavelengths.
The 5.5 x 4.1 x 1.8 cm example in the photo is a colour zoned fluorine rich apatite (see http://bit.ly/2akYWkg for a detailed discusion) from the Panasqueira Mines of Portugal. As the crystal grew, a pulse of the fluid from which it precipitated was charged with a colour causing impurity which created the green zoning. As you can see, the electrons in this zone of the crystal absorb and shed the energy differently, with higher energy blue wavelengths coming off the white portion of the crystal, and a lovely yellowish green from the coloured portion.
Loz
Image credit: Rob Lavinsky/iRocks.com
Turquoise with pyrite
Only a handful of minerals have given their name to a commonly used color. This is one of them.
This piece of turquoise comes from Arizona. Turquoise commonly forms around larger copper deposits, where the copper is picked up by groundwater percolating through the copper and eventually deposited elsewhere in the sediment. Its main use is as gems/jewelry, so there are a variety of types and textures available from around the world.
This turquoise from Arizona grew with a matrix of pyrite, an iron-sulfur mineral. Iron can fit into the same mineral structure as the copper in turquoise and when present gives the mineral a greenish color (you can see a few faint hints of that here). In this case, the iron picked up by the fluid bonded with sulfur and the copper bonded with phosphorus to make turquoise – there was enough sulfur that the iron went into a different mineral, preserving the blue color of the gem.
-JBB
Image credit: Macroscopic Solutions https://flic.kr/p/nquswQ
References: http://geology.com/minerals/turquoise.shtml http://tucsonturquoise.com/?page_id=28 http://waddelltradingco.com/turquoise-corner/
Eco-Friendly Farming
At first glance, the land pictured here doesn’t appear very impressive. What it is though, is an example of modern, eco-friendly farming.
The farm, a few hours south of Chicago, IL is a portion of a land grant made to my husband’s family around 200 years ago. It is situated a few miles away from the tiny courthouse where Abraham Lincoln once practiced law. Over the years, the land was divided and subdivided, and some sections were sold off. Eventually, when my husband’s part of the family left the area, this parcel was left under the oversight of a local family. Recently, we had an opportunity to see our inheritance for the first time and meet the farm managers. The third and fourth generations of that same family currently work the land in an environmentally-conscious way and they use a remarkable level of technology in doing so.
In the photo, you will see distinct rows of growth. However, the land is never plowed. Strip-farming is a type of no-till agriculture, where crops are planted in strips, as part of a system of crop rotation. In some areas of the world, a crop may be planted with a ground cover in between the rows to help prevent soil erosion, water evaporation, and weeds. On this farm, the crop is planted in strips (in this case, corn), harvested, and the crop residue is left lying in the row, adding nutrients back into the soil as it decays. This is done for 3 consecutive years. Then, a second crop (soybeans are shown here) is planted between the rows of corn stalks.
This pattern of 3 corn crops, followed by one of soybeans has the additional benefit of preventing a parasitic nematode (the soybean cyst nematode) from gaining a foothold. A nematode infestation of this type is not observable until the worm population increases enough to cause above ground symptoms. The 3 successive corn crops give the nematode population time to die off, preventing a serious infestation from ever occurring.
The soil coverage by the crop residue and the fact that the land is never plowed, both help prevent soil erosion. World-wide, over the past 40 years, almost a third of the world’s arable land has become unproductive due to erosion. Erosion causes the soil to lose nutrients, water, soil biota, and organic matter, and allows fertilizer and infectious diseases to wash down into rivers, lakes, and streams.
Planting on the farm is a high-tech event. Each tractor carries six different computers. The fields are mapped using satellite data and computer software directs how far apart and how deep the seeds are planted, insuring that the maximum number of plants survive and thrive. Satellite imagery also determines areas where problems exist (such as retaining too much or too little water), so that the issues can be resolved quickly. Because of the climate of the area, no irrigation is necessary. Chemical fertilizers are seldom used and the farm managers are beginning to look into using beneficial bacteria to release nitrogen and phosphorus that is locked into the land. A newly acquired drone will soon provide us with updated photos of what’s going on with our land. The family who manages the farm presents information about what they do and their increased crop yields to attendants at agricultural conferences, as well as writing articles for agricultural publications. By spreading the word of the increased crop yields they are achieving via their methods, they are helping to improve farming practices across the American Mid-West and hopefully, farther afield (Hah! I inadverdently made a pun!).
CW
Image source: the author
Sources:
http://www.agriinfo.in/?page=topic&superid=1&topicid=443
http://bit.ly/29utPTF
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4008467/
