Evidence for a Carboniferous glaciation in the Ennedi-Bourkou Mountains of northern Chad.

During the Late Palaeozoic the supercontinent of Gondwana covered the Southern Polar Region, with the Pole itself moving across Africa and Australia. Evidence for an extensive Southern Polar Glaciation has been found in South Australia, Oman, Ethiopia, Brazil, Egypt, Niger, and Libya. The glaciation seen in Niger and Libya seems extremely likely to continue across the northern part of Chad, which separates the the two regions, however, the remote nature and political instability of this region has prevented exploration by geologists to date.

In a paper published in the journal Geology on 29 November 2017, Daniel Le Heron of the Department of Earth Sciences at Royal Holloway, University of London, describes the results of a study of the topography of the Ennedi-Bourkou Mountains of northern Chad, made using satellite data from Google Earth, which shows the presence of an extensive Carboniferous ice-stream system.

The Ennedi-Bourkou Mountains form the southern margin of the Al Kufrah Basin, which has striated surfaces interpreted as glacial in origin around Jabal Azbah on its eastern margin, in southern Libya. However no such structures have previously been described from the less well explored Chaddian portion of the basin. Le Heron found that the Ennedi-Bourkou Mountains show a series of sinuous belts cutting across a sandstone platform dated to the Carboniferous in the early 1960s (when nobody was looking for evidence of glaciation in the Central Sahara).

Lineament analysis of Google Earth imagery, Ennedi-Bourkou region, northern Chad, illustrating suite of curvilinear features interpreted as mega-scale glacial lineations traversing outcrop belts mapped as Devonian and Carboniferous. Sinuous belts of mega-scale glacial lineations are interpreted as paleo–ice stream pathways; neighbouring regions devoid of these are interpreted as inter-stream areas. The “Mousso” structure is a possible impact crater. Le Heron (2017).

Le Heron was able to detect five main sinuous belts, each 5-12 km in width, which, combined with the interstream areas, cover an area of about 6000 km². These belts can be traced for tens of kilometres, and run approximately north to south.

High-resolution view and interpretation of a paleo–ice stream track shown in Figure 2. Note deflection of mega-scale glacial lineations (MSGLs) around hill interpreted as a nunatak. Elevation of nunatak (1100 m) and of paleo–ice stream track to the west (850 m) allows maximum thickness of ice to be estimated (i.e. less than 250 m). La Heron (2017).<250 br="" m="">

The belts are cross-cut by more recent features, such as wadis and faults, supporting the interpretation of them as ancient structures, though it is impossible to tell whether they represent a single extended glacial event or a series of glacial cycles.

Series of snapshots from Google Earth imagery of the Ennedi-Bourkou plateaux (Chad) with accompanying interpretations. (A) Interaction of mega-scale glacial lineations (yellow lines) with dipping strata of presumed pre-glacial origin (orange lines), with interpreted glacial erosion surface indicated. Scale bar applies to immediate foreground only. (B) Low-angle perspective of interpreted palaeo–ice stream pathway shown in (A). Note interpreted inter-stream area which is devoid of mega-scale glacial lineations. (C) Mega-scale glacial lineations with evidence of fault offsets (faults in red), underscoring their antiquity (d—drumlins). (D) Development of mega-scale glacial lineations on two plateau levels. La Heron (2017).

The Chadian linear structures appear to cross cut layers of rock similar to those cross-cut by similar structures in Niger, which have been used to date the Niger structures to the Visean Stage, roughly 346.7 to 330.9 million years ago. This suggests an extensive Carboniferous ice sheet in the Sahara, draining to the north. This appears to correlate with an ancient palaeo-shoreline recorded in parts of northern Chad, and dated to about 350 million years ago. The absence of any known fluvial (river-generated) systems associated with this coastline suggests a significant ice-sheet covering the land and calving at the shore margin. 

Tentative paleogeographic reconstruction of Visean ice sheet in north-central Africa, incorporating ice flow directions in Aïr Massif of northern Niger with newly documented set of paleo–ice stream pathways in northern Chad. Speculated paleo–ice stream tracks are also shown. Coastline position for Tournasian at 350 Ma. Note close association of paleo–ice stream termini and palaeo-shoreline. La Heron (2017).

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Mineworker killed in accident in West Virginia.

A worker has died in an accident at the Revelation Energy operated  Revelation S7 Mine near Mount Hope in Fayette County, West Virginia. Thurman Watts, 34, of Harts in Lincoln County, was driving a bulldozer when it went over the side of the open pit at about 1.00 am local time on Friday 29 December 2017. The cause of the incident is being investigated by the West Virginia Office of Miners’ Health, Safety and Training.

The approximate location of the S7 Surface Mine. Google Maps.

This is the eighth death in the mining industry in West Virginia this year, and the fifteenth in the US. This is up from 2016, when there were only eight mining fatalities in the US, and marks the worst year in the West Virginian mining industry since 2010, when there were 35 fatalities in the state, 29 of them in a single incident, an underground explosion at the Upper Big Branch Mine in Raleigh County. There has been a steady decline in mining accidents in the US over the past decade, which has generally been ascribed to a tightening of mining regulations by the Obama Government. The Trump administration has promised to undo many of these regulations, but has not yet done so, preventing a direct correlation between the change in administrations and the rise in fatalities in the US mining industry.

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Magnitude 1.7 Earthquake on the Isle of Mull, Scotland.

The British Geological Survey recorded a Magnitude 1.7 Earthquake at a depth of about 8 km on the eastern part of the Isle of Mull, in Argyll and Bute, Scotland, at about 10.40 pm GMT on Tuesday 26 December 2017. This was not a major event, and presented no threat to human life or property, but was felt on the islands of Mull and Lismore.

The approximate location of the 26 December 2017 Isle of Mull Earthquake. Google Maps.

Earthquakes become more common as you travel north and west in Great Britain, with the west coast of Scotland being the most quake-prone part of the island and the northwest of Wales being more prone  to quakes than the rest of Wales or most of England.

The precise cause of Earthquakes in the UK can be hard to determine; the country is not close to any obvious single cause of such activity such as a plate margin, but is subject to tectonic pressures from several different sources, with most quakes probably being the result of the interplay between these forces.

Britain is being pushed to the east by the expansion of the Atlantic Ocean and to the north by the impact of Africa into Europe from the south. It is also affected by lesser areas of tectonic spreading beneath the North Sea, Rhine Valley and Bay of Biscay. Finally the country is subject to glacial rebound; until about 10 000 years ago much of the north of the country was covered by a thick layer of glacial ice (this is believed to have been thickest on the west coast of Scotland), pushing the rocks of the British lithosphere down into the underlying mantle. This ice is now gone, and the rocks are springing (slowly) back into their original position, causing the occasional Earthquake in the process. 

 (Top) Simplified diagram showing principle of glacial rebound. Wikipedia. (Bottom) Map showing the rate of glacial rebound in various parts of the UK. Note that some parts of England and Wales show negative values, these areas are being pushed down slightly by uplift in Scotland, as the entire landmass is quite rigid and acts a bit like a see-saw. Climate North East.

  

Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. If you felt this quake, or were in the area but did not (which is also useful information) then you can report it to the British Geological Survey here.

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Dolichothele mottai & Dolichothele camargorum: Two new species of Tarantula from Brazil and Bolivia.

Tarantulas, Theraphosidae, are large and usually hairy Mygalomorph Spiders, the group that also includes Trapdoor and Baboon Spiders, and which is noted for features such as non-oposable fangs and only having two pairs of book-lungs. Most Tarantula species are found in the Americas, and while members of this group are found on every continent, most Old World species referred to as 'Tarantulas' are in fact large members of other groups, usually other Mygalomorphs or Wolf Spiders. Tarantulas seldom bite defensively, instead defending themselves with a dense covering of irritating 'urticating hairs' on their abdomens, which can be loosed by brushing with the hind legs and wafted at potential predators, causing irritation to the eyes and nose.

In a paper published in the journal ZooKeys on 21 December 2017, Irene Soliz Revollo of the Instituto de Biociências at the Universidade Estadual Paulista Júlio de Mesquita Filho, and the Laboratório de Ecologia e Evolução at the Instituto Butantan, Pedro Ismael da Silva Júnior of the Laboratório Especial de Toxinologia Aplicada, also at the Instituto Butantan, and Rogério Bertani, again of the Laboratório de Ecologia e Evolução at the Instituto Butantan, describe two new species of Tarantula from Brazil, both of which are placed in the ground-dwelling genus Dolichothele.

The first new species described is named Dolichothele mottai, in honour of the arachnologist Paulo Cesar Motta, for his work on the Mygalomorph Spiders of the Brazilian Cerrado. The species is described from two specimens, a female with a body length of 9.4 cm and a male with a body length of 8.1 cm. Both sexes are covered in iridescent red hairs. The species was found in Cerrado (savanna) environments in the Distrito Federal and state of Goiás, where they build silk tunnels under rocks and logs, males were seen roaming in search of mates in September to November.

Dolichothele mottai, male specimen. Paulo Cesar Motta in  Seliz Revollo et al. (2017).

The second new species is named Dolichothele camargorum, in honour of Erney Plessmann de Camargo and Luis Marcelo Aranha Camargo, for their work on medical and biological research in the state of Rondônia, Brazil. The species is described from two specimens, a male with a body length of 5.6 cm and a female with a body length of 10.9 cm, both are black and brown with brown hairs. The species was found in Cerrado fragments in Rondônia State in Brazil and the department of La Paz in Bolivia.

Dolichothele camargorum, female specimen. Rogério Bertani in Seliz Revollo et al. (2017).

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Asteroid 2017 YO3 passes the Earth.

Asteroid 2017 YO3 passed by the Earth at a distance of about 799 300 km (2.08 times the average distance between the Earth and the Moon, or 0.53% of the distance between the Earth and the Sun), at about 2.35 pm GMT on Wednesday 20 December 2017. There was no danger of the asteroid hitting us, though were it to do so it would not have presented a significant threat. 2017 YO3 has an estimated equivalent diameter of 4-14 m (i.e. it is estimated that a spherical object with the same volume would be 4-14 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 43 and 27 km above the ground, with only fragmentary material reaching the Earth's surface.

The calculated orbit of 2017 YO3. Minor Planet Center.

2017 YO3 was discovered on 12 December 2017 (eight days before its closest approach to the Earth) by the University of Arizona's Mt. Lemmon Survey at the Steward Observatory on Mount Lemmon in the Catalina Mountains north of Tucson. The designation 2017 YO3 implies that the asteroid was the 89th object (object O3) discovered in the first half of December 2017 (period 2017 Y). 

2017 TO3 has a 240 day orbital period, with an elliptical orbit tilted at an angle of 8.73° to the plain of the Solar System which takes in to 0.49 AU from the Sun (49% of the distance at which the Earth orbits the Sun; slightly outside the orbit of the planet Mercury) and out to 1.02 AU (2% further away from the Sun than the Earth). This means that close encounters between the asteroid and Earth are fairly common, with the last thought to have happened in April 2016 and the next predicted in January 2020. Although it does cross the Earth's orbit and is briefly further from the Sun on each cycle, 2008 TC4 spends most of its time closer to the Sun than we are, and is therefore classified as an Aten Group Asteroid.

2017 YO3 also has frequent close encounters with the planets Mercury, which it is thought to have last passed in September 2013, and is next predicted to pass in January 2032, and Venus, which it last came close to in December 2013 and is next predicted to pass in May 2024. Asteroids which make close passes to multiple planets are considered to be in unstable orbits, and are often eventually knocked out of these orbits by these encounters, either being knocked onto a new, more stable orbit, dropped into the Sun, knocked out of the Solar System or occasionally colliding with a planet.

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Pipeline explosion halts flow of oil from the Es Sider Oilfield, Libya.

The flow of oil from the Es Sider Oil Field to the Mediterranean port of Hariga was halted by an explosion on the pipeline that connects the two on Tuesday 26 December 2017. The explosion occurred about 30 km to the north of the Marada Oasis in Al Wahat District, and has been claimed as an act of deliberate sabotage by the Benghazi Defense Brigades, a group, which in theory supports the current Government of National Accord in Libya, having previously fought against both the Libyan National Army and ISIS militants, but which has been accused of carrying out terrorist attacks by coalition partners. Authorities in Libya have yet to determine the actual cause of the explosion, noting that pipeline operators Waha Oil had a team carrying out maintenance in the area who have not yet been contacted, and that the explosion could have been an industrial accident.

Colomn of smoke over the scene of a pipeline explosion in Libya in Al Wahat District, Libya. The Libya Times.

Fighting between militia groups has occurred sporadically since the overthrow of former leader Muammar Gaddafi, as the various groups that took part in the regime change had little in common and since then have been engaged in an uneasy truce with intervals of open conflict.

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Collapse at coal mine kills five in Afghanistan.

Five miners have died and another one is missing following a collapse at a coal mine at Dahan-e-Tor, in the Dara-e-Soof District of Samagan Province, Afghanistan, on Tuesday 26 December 2017. Several other miners were injured in the event, which was reportedly caused by a methane explosion, which caused a section of tunnel to collapse. The mine is reported to have been an illegal (unlicensed) mine, one of many such mines operated local artisanal miners in the impoverished region.

The approximate location of the Dahan-e-Tor mine. Google Maps.

Coal is formed when buried organic material, principally wood, in heated and pressurised, forcing off hydrogen and oxygen (i.e. water) and leaving more-or-less pure carbon. Methane is formed by the decay of organic material within the coal. There is typically little pore-space within coal, but the methane can be trapped in a liquid form under pressure. Some countries have started to extract this gas as a fuel in its own right. When this pressure is released suddenly, as by mining activity, then the methane turns back to a gas, expanding rapidly causing, an explosion. This is a bit like the pressure being released on a carbonated drink; the term 'explosion' does not necessarily imply fire in this context, although as methane is flammable this is quite likely.

Afghanistan has considerable reserves of coal, iron ore, copper and other minerals, which it has hoped to use to attract foreign investment. However frequent attacks on mining projects by militant groups opposed to foreign involvement in the country has kept investors away, with China pulling out of a US$3 billion copper mining project in Logar Province in the east of the country in 2012. As a result safety standards at Afghan mines tend to be virtually non-existent, with the nation lacking the money to invest in projects that it runs, and many smaller artisanal mines being totally unregulated, and often employing child labour. 

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