Sunday, 23 September 2018

South African Directorate for Priority Crime Investigation arrests nine members of Rhinoceros poaching gangs this week.

The South African Directorate for Priority Crime Investigation (or Hawks) have arrested nine people on Rhinoceros poaching related charges this week. On Tuesday 18 September 2018 six people were arrested in Mpumalanga Province, identified as Phenias Lubisi, 56, a police Station Commander, Xolani Lubisi, 33, a former police officer, Thembisile Mhlanga, 30, a serving police officer, Clyde Mnisi, 33, Petrus Mabuza Mshengu, 53, known as 'Mr Big', and Joseph Nyalunga, 54, another former police officer, widely known as 'Big Joe' and thought to be a leading figure in the smuggling syndicate. At the same time a number of luxury vehicles, trucks, motorbikes, animal skins and a large amount of cash were seized. On Thursday 20 September a seventh alleged member of the same gang, Rachel Qwabana, 33, a female police officer working with the Acornhoek Stock Theft Unit, surrendered to authorities voluntarily, having managed to evade arrest for two days. In a separate incident two men were arrested in a house in Standerton, Mpumalanga, while attempting to sell Rhino horns with an estimated value of R7 million (US$489 000), as well as an unlicensed firearm and ammunition. It is unclear if this incident was related to the other arrests.

 Joseph 'Big Joe' Nyalunga, an alleged member of a South African Rhino poaching syndicate arrested on 18 September 2018, at a former court hearing. Lowvelder.

Park authorities and private game reserves across Africa and Asia have been struggling with the problem of Rhino poaching for decades, but the problem has become more acute in recent years, with over a thousand killed in South Africa alone in 2017, and over 5500 in the past five years. The country is home to about 20 000 Rhinos, about 80% of the entire African population. The crime is extremely profitable, and widely believed to be controlled by organised crime syndicates, which are believed to have considerable influence over police and court officials in many areas, which results in suspected poachers often being released before they are brought to trial, often with only nominal bail payments.

The Directorate for Priority Crime Investigation was founded in 2008 to replace the Directorate of Special Operations (or Scorpions) the former South African specialist organise crime unit, which had become mired in controversy over investigations of politicians, which had (probably inevitably) been accused of being politically motivated. The organisation does not have the power to investigate political corruption (a policy which has also been criticised widely), but does have considerable powers to target organised crime and tackle corruption in the police and other government agencies.

Figures published by the Department of Environmental Affairs on Friday 21 September 2018 suggest a 26% drop in Rhinoceros poaching in South Africa compared to last year, with 500 animals killed in the first eight months of 2018, compared to 691 in the first eight months of 2017. This continues a falling trend since 2014, when figures peaked at 1215 Rhinoceros killed in the year, prior to which figures had risen each year since 2007, when only 13 animals were killed. However this drop is not being attributed to successes in in tackling poaching syndicates, with trials of alleged members of syndicates frequently collapsing, so much as a drop in Rhinoceros numbers (down from 9000 in 2014 to 5000 in 2018), combined with better protection technologies on reserves, particularly drones, which has made targeting Rhinos more difficult.

See also...
Follow Sciency Thoughts on Facebook.

Saturday, 22 September 2018

Conglomerate Oilfield discovered in the Junggar Basin of Xinjiang Province, China.

The Junggar Basin of Xinjiang Province is the second largest sedimentary basin in China, covering an area of about 380 000 km². It is bounded by the Altai Mountains in the northeast and the North Tianshan Mountains in the south, with the central part of the basin forming the Guerbantonggute Desert. The basin has a basement of crystaline Precambrian rocks, overlain by folded Devonian to Early-Middle Carboniferous deposits, then a stratified sedimentary sequence that lasts from the Carboniferous to the Quaternary, comprising shallow sea facies limestone, and continental facies, including sandstone, mudstone and conglomerates. The Junggar Basin contains numerous fossil bearing strata, which have produced coal, oil, silicified wood, Dinosaurs, Fish and Shellfish. Oil has been exploited in the basin since 1955, when the Karamay Oilfield was discovered, the first oilfield discovered in China after the revolution, but over sixty years of exploration has failed to find any further significant oil reserves.

In a paper published in the journal Acta Geologica Sinica on 27 February 2018, Hao Ziguo and Fei Hongcai of the Chinese Academy of Geological Sciences and the Geological Society of China, Hao Qingqing of the Institute of Mineral Resources Research of the China Metallurgical Geology Bureau, and Liu Lian, also of the Chinese Academy of Geological Sciences and the Geological Society of China, describe the discovery of a significant oil resevoir in the central part of the Junggar Basin.

The discovery of the reserve was announced by the Xinjiang Oil Field Co, a subsidiary of PetroChina, announced the discovery at the end of 2017, having begun surveys of the basin in 2005. It is located in the Triassic Baikouquan Formation, a shallow water facies fan delta and associated conglomerate deposits, located 4400-6000 m below the surface.

Geological map showing the distribution of conglomerate type oilfields in the Junggar Basin of Xinjiang. (1) Proven reserves; (2) Probable reserves; (3) Possible reserves; (4) Fault; (5) Fan delta plain facies; (6) Fan delta front facies; (7) Shore-shallow lake facies. Hao et al. (2018).

The deposits represent the largest conglomerate is the second largest known conglomerate based oil-reserve in the world, after the Hemlock Oilfield in the United States, with an estimated reserve of over 1.24 billion tons of petroleum.

See also...
Follow Sciency Thoughts on Facebook.

The September Equinox.

The September Equinox will falls on 23 September this year (2018), when the day and night will be of equal length in both of the Earth's hemispheres. The Earth spins on its axis at an angle to the plain of the Solar System. This means that the poles of the Earth do not remain at 90° to the Sun, but rather the northern pole is tilted towards the Sun for six months of the year (the northern summer), and the southern pole for the other six months (the southern summer). This means that twice a year neither pole is inclined towards the Sun, on days known as the equinoxes. 

Simplified diagram showing the tilt of the Earth throughout the year. Not to scale. National Weather Service.

The equinoxes fall each year in March and September, with the March Equinox being the Spring (or Vernal) Equinox in the Northern Hemisphere and the Autumn Equinox in the Southern Hemisphere, while the September Equinox is the Autumn Equinox in the Northern Hemisphere and the Spring Equinox in the Southern Hemisphere. On these two days the day and night are both exactly twelve hours long at every point on the planet, the only days on which this happens.

See also...
Follow Sciency Thoughts on Facebook.

Landslides at limestone quarries kill at least 74 in the Philippines.

Landslides at two limestone quarries have killed at least 74 people in the Philippines this week. At Itogon in Benguet Province on Luzon Island the bodies of 45 people have been recovered and 57 more are missing after a landslide struck an accomodation block where people were sheltering from Typhoon Mangkhut (referred to as Typhoon Ompong in the Philippines) on Saturday 15 September 2018. Despite the large number of people still missing, rescue operations have had to be severly cut back following warnings that the site was still unstable by the Mines and Geosciences Bureau, who raised concenrs that the low probability of finding any further survivors were outweighed by the high probability of further landslips at the site, endangering the lives of rescue workers.

Rescue workers remove a body from the scene of a landslide at a limestone quarry at Itogon in Beguet Province, the Philippines, on Tuesday 18 September 2018. Ted Aljibe/AFP.

At Naga on Cebu Island a second landslide, again associated with a limestone quarry, struck two villages on Thursday 20 September, burrying over 20 homes. Twenty nine bodies have now been recovered following this incident, and it is feared that more than fifty further victims could be burried beneath the rubble. 

Rescue workers at the scene of a landside at Naga on Cebu Island, the Philippines, earlier this week. Bullit Marquez/Associated Press.

Both incidents have been linked to heavy rains associated with Typhoon Mangkhut. Landslides are a common problem after severe weather events, as excess pore water pressure can overcome cohesion in soil and sediments, allowing them to flow like liquids. Approximately 90% of all landslides are caused by heavy rainfall. These events have prompted the Philippine Government to halt mining operations across a large area of the country while safety checks are carried out.

Tropical storms are caused by the warming effect of the Sun over tropical seas. As the air warms it expands, causing a drop in air pressure, and rises, causing air from outside the area to rush in to replace it. If this happens over a sufficiently wide area then the inrushing winds will be affected by centrifugal forces caused by the Earth's rotation (the Coriolis effect). This means that winds will be deflected clockwise in the northern hemisphere and anti-clockwise in the southern hemisphere, eventually creating a large, rotating Tropical Storm. They have different names in different parts of the world, with those in the northwest Pacific being referred to as typhoons.

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 1 cm 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.

Typhoon Mangkhut is considered to be the most severe tropical storm of 2018, and is attributed with the deaths of 81 people in the Philippines, not counting those at the Naga quarry or any unknown deaths at the Itogon quarry, as well as four in Guangdong Province, China and one in Taiwan. It also caused extensive damage in Maccau and Hong Kong,  where over 240 people were injured, but no fatalities have been reported. 

See also...
Follow Sciency Thoughts on Facebook.

Evidence of a late fifth-century massacre at Sandby borg in southern Sweden.

The collapse of the Roman Empire in Western Europe triggered a period of political instability across the region, reaching into areas considerably beyond the extent of the Empire at its peak, known as the Migration Period. During this period southern Scandinavia was dominated by a highly hierarchical Iron Age society in which power had been associated with the control of trade routes to the Roman Empire, but which now became reliant on the ability to manage more complex relationships in a time of famine, war and shifting political alliances across northern Europe. This appears to have led to a drop in population centres in southern Scandinavia, with a number of settlements having been abandoned or even showing signs of deliberate destruction during this period.

In a paper published in the journal Antiquity on 24 April 2018, Clara Alfsdotter of the Department of Archaeology at the Bohusläns Museum, and Ludvig Papmehl-Dufay and Helena Victor of the Department of Museum Archaeology at the Kalmar County Museum, describe the results of a series of excavations at the Sandby borg ringfort, on the island of Öland off the southeast coast of Sweden, which was apparently abandoned following a massacre between 400 and 550 AD.

The Sandby borg ringfort has been subject to a number of surveys and excavations since the discovery of pits apparently dug by looters in 2010. The site is located by the shore on the southeastern part of the island, and comprises an area of about 5000 m² enclosed by an oval stone wall interpreted to have been between between four and five metres high. Within this wall an outer ring of houses were constructed against the outer wall, with an inner block of houses separated from this outer ring by a street, an arrangement typical of ringforts on Öland.

 Plan of Sandby borg with the identified houses numbered. The overview is based on geophysical surveys, excavations and aerial photographs. Alfsdotter et al. (2018).

Initial metal detectors surveys of the site revealed five caches of jewelry in separate houses within the fort. Each of these caches contained a gilded silver relief brooch with decorations in Salins Style I (animal patterns) and spiral patterns, a style which suggests manufacture a date of between 450 and 510 AD, as well as glass beads, finger rings and silver pendants. These broaches are typical of jewelry owned by aristocratic women of the period, and were probably made locally, but some of the other artifacts, such as millefiori glass beads, silver bell pendants and cowrie shell ornaments, are clearly of non-local origin.

The five gilded relief brooches in silver found in five different deposits in 2010. Daniel Lindskog in Alfsdotter et al. (2018).

Subsequent excavations have exposed about 6 % of the site (i.e. 300 m²), including two complete houses, about half of a third house and parts of six more houses. Human remains were discovered in four of these houses, as well as in the street outside. The excavations have also recovered substantial amounts of ceramics, mostly fragmented but complete, bronze, silver, gold and some iron objects, glass and silver beads, a gilded silver sword pendant, a large millefiori glass bead, a Valentinian III solidus (Roman coin manufactured between 425 and 455 AD), and fragments of a sixth glided silver relief broach. Very little military equipment was recovered from the site, which is surprising given the fortified nature of the site, only handful of arrowheads, one lance-head and two or three unique sword details. 

A large millefiori glass sword bead, a Valentinian III solidus and a gilded silver sword pendant found on the floor of house 40. Daniel Lindskog in Alfsdotter et al. (2018).

A great deal of human remains have been found at Sandby borg, which can be attributed to at least 26 individuals (some of the remains are disarticulated), along with the remains of a number of animals.

At least nine individuals were found within one house, 40, five complete skeletons, three of which have been positively identified as adult males, and another two as probably male adolescents, plus the disarticulated remains of at least four more individuals, including a child of 2-5 years and an infant of 18 months-3 years. These disarticulated remains do not appear to have been deliberately dismembered, but rather to have become disarticulated some time after death.

One of the nine human skeletons found on the floor level of house 40. This adolescent was found lying on their side. The white arrow points north. Kalmar County Museum in Alfsdotter et al. (2018).

The four adult male skeletons and one of the adolescents show signs of blunt force trauma immediately before death. Three of these skeletons were lying in extended positions, probably indicting instant death, or at least unconsciousness, two had extended bodies but flexed legs, whole one of the adolescents was lying on one side, probably suggestive of a slower death. The other adolescent was flat on their back with their feet on one of the adults, possibly suggesting having fallen backwards over the prone body of the adult. Two of the skeletons were partially disarticulated ans burned, implying a fire either broke out during the course of events that overrun the settlement, or was deliberately set, but burned out before it could spread.

The skeletal remains of two individuals inside house 40. The remains of the young teenager are stretched out, with the feet on top of the pelvis of an adult man, suggesting that the teenager fell backwards over the dead or dying adult. The adolescent (12–15 years old) displays perimortem blunt force on the skull . The western house wall is at the bottom of the picture. The white arrow points north. Kalmar County Museum in Alfsdotter et al. (2018).

The other houses excavated also contain a number of disarticulated Human remains, as does the street. One house, 52, contains the partially articulated skeleton of an elderly male lying in an extended position face down across the central hearth. This skeleton shows signs of charring, suggesting that the hearth was still lit when he fell onto it. Several other skeletons show signs of violent deaths, including blows to the back and hips (indicative of blows from behind or two one side), but not the facial and forearm injuries typically associated with deaths in battle, suggesting that these individuals were unable to defend themselves for some reason (such as a sudden, overwhelming attack)/

None of the bodies have been identified as female, despite the presence of female jewelry and children in the settlement, both of which indicate women were present, which suggests the women had either left prior to the attack, or were carried of as spoils after it. The presence of so many bodies strongly implies that the settlement was abandoned after the attack, and not subsequently re-entered by survivors of the attack or neighbouring communities, as bodies were typically cremated at the time.

The site also includes a number of articulated and disarticulated animal skeletons, including Dogs, Sheep, Horses and Lambs. The Lambs are particularly interesting, as they are aged 3-6 months, and since all Lambs are born in the spring, can be used to indicate that the attack occured between late spring and early autumn.

See also...
Follow Sciency Thoughts on Facebook.

Sunday, 16 September 2018

Magnitude 5.6 Earthquake in Western Australia.

Geoscience Australia recorded a Magnitude 5.6 Earthquake at a shallow depth close to Lake Muir in southern Western Australia, slightly before 1.00 pm local time (slightly before 5.00 am GMT) on Sunday 16 September 2018. This is one of the largest Earthquakes ever reported in Western Australia, and was felt over a wide area, but there are no reports of any damage or casualties.

The approximate location of the 16 September 2018 Western Australia Earthquake. USGS.
Despite being a long way from any active plate margins, Western Australia is quite prone to Earthquakes, particularly in a zone referred to as the South West Seismic Zone. The cause of these quakes is unclear; the area exists within an area of Archaean Shield known as the Yilgarn Block, which is thought to be between 2.94 and 2.63 billion years old, and which has no internal structures that seem to be related to the quakes.
 The South West Seismic Zone (pink). University of Western Australia.
Witness statements can help geologists to understand Earthquakes and the geological processes that cause them; if you felt this quake (or if you were in the area but did not, which is also useful information) you can report it to Geoscience Australia here.

See also...
Follow Sciency Thoughts on Facebook.

Assessing the potential impact of large-scale wind and solar power generation on the Sahara Desert and surrounding regions.

Reducing global emissions of carbon dioxide has been a major international goal since the 1990s, due to the prospect of significant climate change being brought about by rising levels of the gas in the atmosphere. However since this time little progress has been made in developing energy sources not dependant on burning hydrocarbons (the main source of atmospheric carbon dioxide), while demand for energy has grown across the globe. One possible way to counter this that has been suggested is the development of very large scale wind and solar power generation plants in the world's desert regions, though the likely impact of such plants on the climate is itself unclear.

In a paper published in the journal Science on 7 September 2018, Yan Li of the Department of Atmospheric and Oceanic Science at the University of Maryland, the Department of Natural Resources and Environmental Sciences at the University of Illinois at Urbana-Champaign, and the State Key Laboratory of Earth Surface Processes and Resources Ecology at Beijing Normal University, Eugenia Kalnay, also of the Department of Atmospheric and Oceanic Science, and of the Institute for Physical Science and Technology, at the University of Maryland, Safa Motesharrei, again of the Department of Atmospheric and Oceanic Science, and the Institute for Physical Science and Technology, and the Department of Physics, at the University of Maryland, Jorge Rivas of Rockville in Maryland, Fred Kucharski of the Earth System Physics Section at the Abdus Salam International Centre for Theoretical Physics, Daniel Kirk-Davidoff, again of the Department of Atmospheric and Oceanic Science at the University of Maryland, Eviatar Bach, again of the Department of Atmospheric and Oceanic Science and Institute for Physical Science and Technology, at the University of Maryland, and Ning Zeng, once again of the Department of Atmospheric and Oceanic Science at the University of Maryland, and of the Institute of Atmospheric Physics of the Chinese Academy of Science, publish the results of a study which used computer modelling to try to assess the impact of large scale wind and solar power generation on the the Sahara Desert and its surrounding regions.

The Sahara is the word's largest desert, and is in addition very sparsely populated, so that any future large scale wind or solar power projects would face little competition from other forms of Human land use. Li et al. modelled the potential impact of large scale wind and solar projects on both the Sahara and the more populated Sahel, a transition region between desert and wooded savanna to the south, using a model in which wind farms producing three terawatts of power per year and solar plants producing 79 terawatts of power per year were assessed for their impact.

Li et al. found that the wind farms would result in an average rise in ground temperature of 2.16 K, though this would be mostly due to a rising minimum temperature, which would go up by an average of 2.36 k, with the average maximum temperature rising only by 1.85 K. This is a previously observed phenomenon around wind farms, which mix air layers vertically, bringing down warmer air from above the surface at night. The wind farms also increased average daily precipitation in the Sahara by 0.25 mm per day (more than doubling the amount of rain in the desert, though this would not be in the form of very small amounts of rain each day), and in the Sahel region by 1.12 mm per day, as the increased ground temperature leads to more air rising above the desert (hot air rises), drawing more moisture laden air from elsewhere. This increases precipitation is predicted to lead to an increased vegetative ground cover, leading to a lower albedo (the ability of the ground to reflect heat and light, vegetation tends to absorb, whereas exposed rock and sand, particularly if light in colour, tends to reflect), increased surface air friction (which might reduce average wind speeds by up to 36%), and increased evaporation through transpiration, leading to more cloud cover and more rain. 

 Impacts of wind and solar farms in the Sahara on mean near-surface air temperature (kelvin) and precipitation (millimetres per day). The impacts of wind farms (A) and (B), solar farms (C) and (D), and wind and solar farms together (E) and (F), respectively, are shown. Only areas where changes are significant at the 95% confidence level (t test) are displayed on the map. Gray dots denote the location of wind and/or solar farms. At the bottom of each plot, the number after Δ represents the changes in climate (in either kelvin or millimetres of precipitation per day) averaged over areas covered by wind and solar farms. Li et al (2018).

Solar power projects were found to have a similar effect, raising average ground temperatures and increasing precipitation, though in this case the main driver was a decreasing albedo due to the solar panels themselves, which absorb rather than reflecting sunlight, leading to an average rise in daytime maximum temperatures of 1.28 K, while the minimum nighttime temperature rose by only 0.97 K. These solar projects were predicted to raise precipitation in the Sahara by an average of 0.13 mm per day, and in the Sahel by an average of 0.57 mm per day. This model did not produce a notable drop in average wind speeds.

Combining the wind and solar projects resulted in an average temperature rise of 2.65 K, but an average increae of precipitation of 0.35 mm per day in the Sahara and 1.34 mm per day. This is particularly significant as it results in an increase in average rainfall of almost 500  mm per year, significanlty altering the local climate.

 Relative contributions of roughness change (Rough) and vegetation feedback (Veg) in the climate impacts of wind farms in the Sahara. Contributions in the temperature (A), (C), and (E) and the precipitation (B), (D), and (F) impacts are shown. The wind farm impact is produced by the initial roughness of wind turbines and the subsequent albedo changes due to vegetation feedback. At the bottom of each plot, the number after Δ represents the changes in climate (in either kelvin or millimeters of precipitation per day) averaged over areas covered by wind farms. Li et al (2018).

These predictions were based upon an average energy conversion rate of 15% for the solar panels, roughly what we would expect with today's technology, however Li et al. also note that we should expect solar panels to become more efficient in the future, and that as they do so the amount of ground-level warming they cause should drop, so that once their average efficiency passes 35% they would be predicted to cause a cooling at ground level, combined with a reduction in rainfall, resulting in a rather different impact on the climate of the Sahara.

See also...
Follow Sciency Thoughts on Facebook.