Tuesday, 30 April 2019

Collapse at Myanmar ruby mine kills two.

Two people have reportedly died following a wall collapse at a disused ruby mine in Baw Lone Gyi near Mogok in the Mandalay Region of Myanmar on Tuesday 23 April 2019. The two were reportedly killed shortly after entering the mine, which was closed last year after the licence to work it held by the Hay Paing mining company expired. The mine has been the scene of several incidents since that time, most of them involving clashes between company officials, who have reportedly tried to retain control of the mine, and local people seeking to extract rubies informally.

Rubies are a form of the mineral corundum (a crystalline form of aluminium oxide) with a high aluminium content, which gives them their deep red colour (high iron corundum is green in colour, with the gemstones being known as saphires); rubies from the Mogok Stone Tract are particularly high in aluminium, making them a very deep red colour, and causing them to fluoresce under ultra-violet light, making them highly sought after. These rubies are traded as ‘Burmese Rubies’, although rubies from other parts of Myanmar are often traded under the name as well, and these are generally considered inferior by gem-dealers.

Rubies and sapphires are found at several localities throughout the immediate area surrounding Mogok in the Mandalay District of Myanmar (Burma). Peridot is mined only in the Pyaung Ganng Hills, north-northwest of the Mogok Township. This map shows the approximate locations of all Myanmar Gems Enterprise (MGE) mines and several joint-venture mines in the Mogok Stone Tract. Indicated here are the major gems mined, with red and blue used together to show both ruby and sapphire. Note that significant quantities of spinel are found at virtually all of the corundum mines, as are limited quantities of other gem materials. Unauthorized mining sites are not shown. Robert Kane in Kane & Kammerling (1992).

Corundum is typically formed within metamorphic rocks that are subjected to high levels of heat and pressure, usually along tectonic suture zones. The majority of the world’s rubies come from the Himalayan Suture, caused by the impact of the Indian Plate into the Eurasian, with a band of ruby-producing rocks that stretches from Afghanistan to Thailand, though the Burmese Rubies of Mogok are considered the finest rubies from this zone. Elsewhere in the world rubies are also mined in Macedonia, Montana and Mozambique.

The Mogok rubies originally formed as inclusions within marble beds (metamorphosed crystalline limestone), but are found in such deposits at a very low density, with most extraction being undertaken of reworked rubies from alluvial deposits (old river beds). This makes the industry particularly dangerous, as the deposits from which the rubies are extracted are poorly consolidated and highly unstable, making them difficult to work with modern mining machinery, with miners often using traditional methods that have poor safety records.

The majority of rubies from the Mogok Stone Tract are principally extracted using three forms of traditional mining.

Hmyawdwins are long, deep trenches which cut down through the sediments overlying the ruby-baring layers, through which water is then flushed to loosen the sediments, enabling rubies to be sieved from the deposits.

Ruby miners in a Hmyawdwin trench in the Mogok Stone Tract. The Myanmar Times.

Secondly, twinlons and lebins are deep-pit mines in which a narrow shaft is cut down through the overlying layers to reach the ruby-baring deposits; twinlons being simple round tunnels and lebins are square tunnels reinforced with timber. In both cases miners are lowered into the pit on a winch and pully, which is also used to extract sediment from the mine, which is sieved above ground for rubies. These mines are typically lit using a mirror above, and were formerly kept drying using locally made hand pumps, though modern diesel pumps are widely used today.

(Left) A variation of the classic twinlon mining method, a lebin is a square pit reinforced with timber and large leaves. Note the use of aluminium foil to reflect light into the mine and of a hand-cranked winch to hoist dirt and gem gravel to the surface in tightly woven bamboo buckets. (Right) At the bottom of a 100-m-deep shaft at Than Ta Yar, workers use a hand winch to haul out buckets of waste material. The wide plastic tube to their left carries water and gem-bearing gravels to the surface for processing. Holly & Robert Kane in Kane & Kammerling (1992). 

Finally, loodwins are mining operations in which the miners enter natural caves in the limestone, formed by water percolating through the slightly soluble rock, searching for rubies that accumulated in sediments within the cave system, deposits in which the gemstones cab be highly concentrated.

Miners emerging from a loodwin mine in the Mogok Stone Tract. Getty Images.

The mines of the Mogok Stone Tract have long had a poor reputation for Human Rights, with prisoners being sent to the region as forced labour since at least the seventeenth century, until a rebellion in the early nineteenth century led to a cessation of (officially sanctioned) mining in the area. The area was annexed by the British in 1866, who granted sole rights to mine the area to Burma Ruby Mines Ltd. The company initially tried to prevent local artisanal mining in the area, but found this impossible, then tried to impose a tax on any rubies extracted, again with limited success as the area proved to have excellent smuggling networks, then eventually settled for charging a small license fee to mine, combined with trying to buy up the best gemstones on the open market that emerged.

Myanmar gained independence from Britain in 1948, with large scale mining in the area having been sporadic since then, hampered by the country’s poor Human Rights record. All mining in the area was nationalised in 1960, and remained in state hands until 1990 when foreign companies were invited to invest in the area. However, concerns about the behaviour of the ruling Military Council led to trade embargoes of Myanmar gemstones by the European Union, Canada, Australia, Switzerland, Norway, and the United States being introduced by 2008. The holding of elections in Myanmar and the replacement of the Military Council with an elected government led to the majority of these country’s lifting these bans between 2012 and 2016, but the resumption of hostilities by the Myanmar Military against member of the Rohinga ethnic group and other minorities has led to many country’s re-imposing embargoes, as well as a public outcry which led to leading jewellery companies, such as Cartier, stating that they would no longer handle gemstones from Myanmar.

Whilst these problems have hampered official exports from Myanmar, the economic stagnation that resulted has led to a thriving black market, with gemstones being smuggled across the country’s often porous borders, principally to Thailand, which hosts one of the world’s largest gem-cutting industries, and buyers are often unconcerned about the origin of stones. This has led to a proliferation of informal mineworkings, which provide an income for local people, but typically pay little-or-no attention to even Myanmar’s scant safety regulations.

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Saturday, 27 April 2019

Khurendukhosaurus sp.: New material sheds light on an enigmatic Choristodere.

The Choristoderes were a group of semi-aquatic Diapsids that appeared in the Middle Jurassic, or possibly earlier, and persisted until the Miocene. Their exact relationships to other Diapsid groups is unclear, with suggestions that they might be Lepidosaurs (members of the group that includes Lizards), Archosauromorphs (members of the group that includes Turtles, Crocodiles, Pterosaurs and Dinosaurs) or a separate group, possibly more closely related to the Archosauromorphs than to the Lepidosaurs. The Choristoderes had three different and distinct body shapes, which may represent taxonomic groups or ecological morphs that repeatedly evolved, these being short-necked, short-snouted forms, long-snouted, short-necked forms, and short-snouted, long-necked forms. The genus Khurendukhosaurus was first described from fragmentary material from the Early Cretaceous of Mongolia, and has subsequently been described from Russia; there are currently two described species, Khurendukhosaurus orlovi and Khurendukhosaurus bajkalensis, though these are both described from fragmemtary material, with no real distinguishing features, so the validity of the second described species (Khurendukhosaurus bajkalensis) is unclear. Due to the limited material available, it has been impossibly to place Khurendukhosaurus in one of the three Choristodere morphogroups, though it has been suggested that it is related to the long-necked Chinese Hyphalosaurus and Japanese Shokawa.

In a paper published in the journal Acta Palaeontologica Polonica on 21 March 2019, Ryoko Matsumoto of the Kanagawa Prefectural Museum of Natural History, Khishigjav Tsogtbaatar of the Institute of Paleontology and Geology of the Mongolian Academy of Sciences, Shinobu Ishigaki of the Okayama University of Science, Chinzorig Tsogtbaatar and Zorig Enkhtaivan, also of the Institute of Paleontology and Geology of the Mongolian Academy of Sciences, and Susan Evans of the Department of Cell and Developmental Biology at University College London, describe a new specimen of Khurendukhosaurus from the Early Cretaceous Khuren-Dukh Formation of eastern Mongolia (the same deposits that produced the first described specimen, and which give their name to the genus ('Khurendukhosaurus' meaning 'Khuren-Dukh Lizard').

The new specimen is a much more complete post-cranianl skeleton, comprising seven cervical vertebrae; eight dorsal vertebrae; six caudal vertebrae; a cervical rib; nineteen dorsal ribs; several gastralia; the right and left humeri and radii; a scapulocoracoid and interclavicle; the right and left ilia, pubes, and ischia; the right and left femora, right tibia, and left fibula. 

All elements of the newly discovered specimen of the Choristoderan  Khurendukhosaurus sp. from middle–late Albian (Early Cretaceous), Khuren-Dukh, Mongolia. The bones are disarticulated but preserved in close association. This image shows the elements arranged in anatomical position. Matsumoto et al. (2019).

These remains clearly show that Khurendukhosaurus was a long-necked Choristodere, and allowed the performing of a proper phylogenetic analysis, to determine the relationship of this genus to other Choristoderes. This in turn suggests that all long-necked Choristoderes are in fact members of a single clade (i.e. they all share a common ancestor, and that all the common descendants of that ancestor can be placed within the group). Furthermore this group has a rather limited range, with all known species being from the Early Cretaceous of East Asia, with the group apparently not persisting into the Middle Cretaceous or spreading to other parts of the globe.

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Seven confirmed deaths as Cyclone Kenneth hits Comoros Mozambique.

Seven people have been confirmed dead as Cyclone Kenneth swept over parts of the Comoros Islands and northern Mozambique this week. The storm passed to the north of the Comoros Islands on Wednesday 24 April 2019, bringing sustained wind speeds (wind speeds maintained for a minute or more) of up to 140 km per hour and extensive flooding to the island of Anjouan, as well as the northern part of Grande Comore, with local authorities reporting three deaths and a number of injuries. The following day the storm hit the coast of Mozambique, passing over the island of Ibo where it killed two more people and destroyed around 90% of all housing, then hitting mainland coast in Cabo Delgado Province, where it caused two further known fatalities, one in the city of Pemba and one in Macomia District. The storm is reported to have caused four ships to sink off the coast of Mozambique, though all crew members have now been reported safe.

Damage caused by Cyclone Kenneth in Moroni, the capitol of the Comoros, following the passage of Cyclone Kenneth to the north of the Islands this week. Anziza M'Changama/AP.

Cyclone Kenneth hit the coast of Mozambique only weeks after Cyclone Idai, which brought extensive flooding to the south of the country, and caused over 700 deaths in Mozambique, Zimbabwe and Malawi. Kenneth is considered to have been the larger of the two storms, in terms of energy released, which translates into higher winds, more rain and larger storm surges, and indeed is one of the largest storms to hit East Africa since records began, however the region where it made landfall is much less densely populated, so it is unlikely to have caused a similar number of fatalities, though many thousands are thought to have been made homeless by the storm.

Damage caused by Cyclone Kenneth in the city of Pemba in northern Mozambique. Neidi de Carvalho/UNICEF.
Tropical storms (referred to as Cyclones in the Indian Ocean) are caused by solar energy heating the air above the oceans, which causes the air to rise leading to an inrush of air. If this happens over a large enough area the inrushing air will start to circulate, as the rotation of the Earth causes the winds closer to the equator to move eastwards compared to those further away (the Coriolis Effect). This leads to tropical storms rotating clockwise in the southern hemisphere and anticlockwise in the northern hemisphere.These storms tend to grow in strength as they move across the ocean and lose it as they pass over land (this is not completely true: many tropical storms peter out without reaching land due to wider atmospheric patterns), since the land tends to absorb solar energy while the sea reflects it.

 Damaged cars in Moroni following the passage of Cyclone Kenneth. Anziza M'Changama/AP.

Despite the obvious danger of winds of this speed, which can physically blow people, and other large objects, away as well as damaging buildings and uprooting trees, the real danger from these storms comes from the flooding they bring. Each drop millibar drop in air-pressure leads to an approximate one centimetre rise in sea level, with big tropical storms capable of causing a storm surge of several meters. This is always accompanied by heavy rainfall, since warm air over the ocean leads to evaporation of sea water, which is then carried with the storm. These combined often lead to catastrophic flooding in areas hit by tropical storms.

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Thaumetopoea processionea: Warnings issued as Oak Processionary Moth invades Milton Keynes.

The public has been warned to be wary after colonies of Oak Processionary Moth caterpillars, Thaumetopoea processionea, have been sighted in several parts of Milton Keynes this week. Forestry England issued the warning about the caterpillars, which are native to southern Europe, after large colonies were spotted in gardens and parks in the Buckinghamshire town. The caterpillars are covered in a dense coat of tiny hairs, which are covered in toxins that can cause skin complaints and respiratory problems, particulalrly in children, and which can achieve very high population densities in countries, such as the UK, where they have no natural predators.

 Oak Processionary Moth caterpillars, Thaumetopoea processionea, on a tree trunk. Henry Kuppen/Forest Research.

Oak Processionary Moths are native to parts of Southern and Central Europe, where they have a number of natural predators. However a combination of a warming climate and accidental transplantation by Humans has led to the species becoming established in a number of countries in Northern Europe, where, in the absence of predators, they can form very large colonies, presenting problems for public health. They were first introduced to England by accident in 2005, and have spread across much of the southeast of the country.

As well as the obvious problems caused by detect contact with the caterpillars, the detached hairs, which can remain toxic for up to a decade, can present problems in themselves. Each individual hair has very little toxin, and does not present any danger to Humans, but they hairs can become concentrated in places such as the surfaces of still ponds, or in the hoppers of lawnmowers, resulting in unexpected contact with sufficient hairs to cause problems in places where the caterpillars are not present, which is particularly hazardous as the cause of the health problems triggered will not be clear, delaying appropriate treatment.

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Magnitude 4.7 Earthquake in Kathmandu District, Nepal.

The United States Geological Survey recorded a Magnitude 4.7 Earthquake at a depth of 28.7 km, roughly 27 km to the northwest of the city of Kirtipur in Kathmandu District, Nepal slightly before 6.30 am local time, (slightly before 0.45 am GMT) on Wednesday 24 April 2019. The event was felt across central Nepal, but no major damage or casualties have been reported.

The approximate location of the 24 April 2019 Kirtipur Earthquake. USGS.

Earthquake activity in the area is caused by the uplift of the Tibetan Plateau, due to the impact of India into Eurasia to the south. he Indian Plate is moving northwards at a rate of 5 cm per year, causing it to impact into Eurasia, which is also moving northward, but only at a rate of 2 cm per year. The collision of the Indian and Eurasian plates has lead to the formation of the Himalayan Mountains, the Tibetan Plateau, and the mountains of southwest China, Central Asia and the Hindu Kush.

Block diagram showing how the impact of the Indian Plate into Eurasia is causing uplift on the Tibetan Plateau. Jayne Doucette/Woods Hole Oceanographic Institution.

Much of northern India and neighbouring areas of Central Asia and the Himalayas, are prone to Earthquakes caused by the impact of the Indian Plate into Eurasia from the south. When two tectonic plates collide in this way and one or both are oceanic then one will be subducted beneath the other (if one of the plates is continental then the other will be subducted), but if both plates are continental then subduction will not fully occur, but instead the plates will crumple, leading to folding and uplift (and quite a lot of Earthquakes). The collision of the Indian and Eurasian plates has lead to the formation of the Himalayan Mountains, the Tibetan Plateau, and the mountains of southwest China, Central Asia and the Hindu Kush.

 The movement of India into Eurasia over the last 71 million years. USGS.

Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. The international non-profit organisation Earthquake Report is interested in hearing from people who may have felt this event; if you felt this quake then you can report it to Earthquake Report here.
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Friday, 26 April 2019

Asteroid 2019 GC6 passes the Earth.

Asteroid 2019 G6 passed by the Earth at a distance of about 219 200 km (0.57 times the average distance between the Earth and the Moon, or 0.15% of the distance between the Earth and the Sun), slightly after 6.40 am GMT on Thursday 18 April 2019. There was no danger of the asteroid hitting us, though were it to do so it would not have presented a significant threat. 2019 GC6 has an estimated equivalent diameter of 9-30 m (i.e. it is estimated that a spherical object with the same volume would be 9-30 m in diameter), and an object of this size would be expected to explode in an airburst (an explosion caused by superheating from friction with the Earth's atmosphere, which is greater than that caused by simply falling, due to the orbital momentum of the asteroid) in the atmosphere between 30 and 16 km above the ground, with only fragmentary material reaching the Earth's surface.

The calculated orbit of 2019 GC6. Minor Planet Center.

2019 GC6 was discovered on 9 April 2019 (nine days before its closest approach to the Earth) by the University of Arizona's Catalina Sky Survey, which is located in the Catalina Mountains north of Tucson. The designation 2019 GC6 implies that it was the 147th asteroid (asteroid G6 - in numbering asteroids the letters A-Y, excluding I, are assigned numbers from 1 to 24, with a number added to the end each time the alphabet is ended, so that A = 1, A1 = 25, A2 = 49, etc., which means that C6 = 3 + (24 X 6) = 147) discovered in the first half of April 2019 (period 2019 G).

2019 GC6 is calculated to have an 424 day orbital period and an eccentric orbit tilted at an angle of 1.26° to the plane of the Solar System, which takes it from 0.91 AU from the Sun (i.e. 91% of the the average distance at which the Earth orbits the Sun) to 1.30 AU from the Sun (i.e. 130% of the average distance at which the Earth orbits the Sun). It is therefore classed as an Apollo Group Asteroid (an asteroid that is on average further from the Sun than the Earth, but which does get closer). This means that close encounters between the asteroid and the Earth are quite common, with the last calculated to have happened in October 2012 and the next predicted for November this year.  

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Thursday, 25 April 2019

Anthoscytina daidaleos: A new species of Froghopper from the Middle Jurassic Daohugou Lagerstätte of Inner Mongolia.

Froghoppers, Cercopoidea are small members of the True Bug order (Hemiptera), related to Cicadas, Cicadoidea, Leafhoppers and Treehoppers, Membracoidea. They resemble Leafhoppers, but are smaller and more robust. Over 3000 species of Froghoppers have been described to date, they are found throughout the world and most numerous in the tropics, although tropical Froghoppers have not been extensively studied to date. Modern Froghoppers are divided into five families, the Cercopidae, Aphrophoridae, Clastopteridae, Machaerotidae, and Epipygidae, with another three, extinct, families represented in the Mesozoic fossil record, the Procercopidae, Sinoalidae, and Cercopionidae. The Procercopidae are the oldest of these groups, first appearing in the fossil record in the Early Jurassic in Eurasia and Australia, and persisting at least until the Early Cretaceous. 

In a paper published in the journal Palaeoentomology on 28 December 2018, Yanzhe Fu of the State Key Laboratory of Palaeobiology and Stratigraphy at the Nanjing Institute of Geology and Palaeontology, and the University of Science and Technology of China, Diying Huang, also of the State Key Laboratory of Palaeobiology and Stratigraphy at the Nanjing Institute of Geology and Palaeontology, and Michael Engel of the Division of Entomology at the Natural History Museum of the University of Kansas, and the Department of Ecology and Evolutionary Biology at the University of Kansas, describe a new species of Procercopid Froghopper from the Middle Jurassic Haifanggou Formation, part of the Daohugou Lagerstätte of Inner Mongolia.

The Haifanggou Formation outcrops around Daohugou Village, and has produced a large number of exceptionally well preserved Insects, which along with similar fossils from the associated Jiulongshan Formation form what is commonly known as the Daohugou Lagerstätte, part of the Yanliao Biota. The fossils are thought to be late Middle Jurassic in origin, from the boundary between the Bathonian and Callovian eras, making them about 165 million years old. This provides a valuable insight into insect diversity in the Jurassic, before the appearance and rapid rise to dominance of Angiosperms (Flowering Plants), an event which radically reshaped Insect faunas. The Daohugou beds are interpreted as a lake environment, with largely still waters.

The new species is placed in the genus long-lived genus Anthoscytina, which currently contains eleven species from the Early Jurassic to Early Cretaceous of northern Asia, and given the specific name 'daidaleos', meaning 'spotted' or 'dappled' in reference to the pattern on the hind wings. The species is described from four female specimens and a fifth of indeterminate sex, ranging in length from 12.6 to 13.5 mm, and differentiated from other members of the genus by the pattern of veins in the wings (commonly used as a way to differentiate Insect species).

Specimen of Anthoscytina daidaleos from the Middle to Upper Jurassic Haifanggou Formation
at Daohugou. Scale Bar is 2 mm. Fu et al. (2019).

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