Tuesday 31 July 2018

Volcanic Activity on Asamayama, Japan.

The Japan Meteorological Agency reported volcanic activity on Asamayama, a volcanic complex in central Honshū this month, for the first time since December 2017, with several white plumes observed over the volcano between 16 and 23 July 2018. The volcano has not undergone a major eruption since February 2009, when it produced an ash column 2 km high, through rocks as far as 1 km and caused ash falls as far away as Tokyo. Due to the remote location of Asamayama, even major eruptions seldom cause fatalities, but the volcano is still considered to be dangerous, due to a major eruptive episode in 1783, which covered fields across Honshū with ash, triggering a famine which killed over 20 000 people.

The approximate location of the Asamayama volcano. Google Maps.

Japan has a complex tectonic situation, with parts of the country on four different tectonic plates. Kyūshū Island lies at the northeast end of the Ryukyu Island Arc, which sits on top of the boundary between the Eurasian and Philippine Plates. The Philippine Plate is being subducted beneath the Eurasian Plate, in the Ryukyo Trench, to the Southeast of the Islands. As it is drawn into the interior of the Earth, the tectonic plate is partially melted by the heat of the Earth's interior, and liquid magma rises up through the overlying Eurasian Plate to form the volcanoes of the Ryukyu Islands and Kyūshū.

The movement of the Pacific and Philippine Plates beneath eastern Honshu. Laurent Jolivet/Institut des Sciences de la Terre d'Orléans/Sciences de la Terre et de l'Environnement.

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Lingwulong shenqi: A new species of Diplodocoid Sauropod Dinosaur from the Middle Jurassic of the Ningxia Hui Autonomous Region of northwest China.

Sauropod dinosaurs were massive, long-necked, long-tailed creatures that have long been regarded as the largest land animals ever to have lived. They reached their most diverse in the Late Jurassic, when the break-up of the supercontinent of Pangea facilitated the splitting of the group into several regional subgroups, each of which underwent an evolutionary radiation in their local environment.

In a paper published in the journal Nature Communications on 24 July 2018, Xing Xu of the Institute of Vertebrate Paleontology & Paleoanthropology of the Chinese Academy of Sciences, Paul Upchurch of the Department of Earth Sciences at University College London, Philip Mannion of the Department of Earth Science and Engineering at Imperial College London, Paul Barrett of the Department of Earth Sciences at the Natural History Museum, Omar Regalado-Fernandez, also of the Department of Earth Sciences at University College London, Jinyou Mo of the Natural History Museum of Guangxi, Jinfu Ma of the Lingwu National Geopark Administration, and Hongan Liu of the Lingwu Historic Relic Administration, describe a new species of Diplodocoid Sauropod Dinosaur from the Middle Jurassic of the Ningxia Hui Autonomous Region of northwest China.

The new species is named Lingwulong shenqi, where 'Lingwulong' means 'Drangon of Lingwu', in reference to the Lingwu National Geopark, where the specimen from which it is described was found, and 'shenqi' means 'amazing'. Lingwulong shenqi is described from a partial skull and partial skeleton from the Middle Jurassic Yanan Formation; these were recovered from the same location, and probably come from the same individual, though this cannot be stated with absolute confidence. A number of other partial skeletons from the same location also thought to belong to the same species. 

Skeletal reconstruction and exemplar skeletal remains of Lingwulong shenqi. Silhouette showing preserved elements (a); middle cervical vertebra in left lateral (b) and anterior (c) views; anterior dorsal vertebra in left lateral (d) and anterior (e) views; posterior dorsal vertebra in lateral view (f); sacrum and ilium in left lateral view (g); anterior caudal vertebra in left lateral (h) and anterior (i) views; right scapulocoracoid in lateral view (j); right humerus in anterior view (k); left pubis in lateral view (l); right ischium in lateral (m) views; right femur in posterior view (n); and right tibia in lateral view (o). Abbreviations: ap, ambiens process; ar, acromial ridge; ip, iliac peduncle; naf, notch anterior to glenoid; np, neural spine; podl, postzygodiapophyseal lamina; ppr, prezygapophyseal process ridge; prp, prezygapophysis; pvf, posteroventral fossa; slf, shallow lateral fossa; spol, spinopostzygapophyseal lamina; sprl, spinoprezygapophyseal lamina; wls, wing-like structure. Scale bars are100 cm for (a) and 5 cm for (b)–(o). Xu et al. (2018).

Lingwulong shenqi has a number of features which lead Xu et al. to conclude that it should unequivocally be placed within the Diplodocoidea, a group previously thought to have been excluded from East Asia by the break-up of Pangea. The presence of a Diplodocoid  in this area implies that (1) either the supercontinent did not break up as soon as is currently thought, a timeline based upon numerous lines of evidence and considered to be highly robust, or that Diplodocoids, and by extension Neosuaropods (the group that includes Diplodocoids and Titanosaurs) first appeared at least 15 million years earlier than previously supposed.

Paleogeographic maps showing the formation and disappearance of an epicontinental seaway between Europe and Central Asia during the Middle Jurassic through Early Cretaceous. (a) Middle Jurassic, 170 million years ago; (b) Late Jurassic, 160 million years ago; (c) Early Cretaceous, 138 million years ago. Green indicates land, light blue shallow sea, and deep blue ocean. Abbreviations: R, Russian Platform Sea; T, Turgai Sea. Xu et al. (2018).

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Apis dalica: A new species of Honey Bee from the Middle Miocene of Yunnan Province, China.

Honey Bees. Apis spp., are highly social Bees extensively domesticated by Humans for their Honey and Wax, which also makes them the most extensively studied Bee group. They have a fossil record dating back to the Oligocene, and like other social Bees, their fossils are much more abundant than those of solitary Bees, probably due to their higher population levels. Honey Bees today are native to Eurasia and Africa, however almost all known fossil Honey Bees are known from Europe, with Asian specimens being much more rare.

In a paper published in the journal ZooKeys on 19 July 2018, Michael Engel of the Division of Entomology at the Natural History Museum of the University of Kansas, the Department of Ecology & Evolutionary Biology, also at the University of Kansas, and the Division of Invertebrate Zoology at the American Museum of Natural History, Bo Wang of the State Key Laboratory of Palaeobiology and Stratigraphy at the Nanjing Institute of Geology and Palaeontology, and the Key Laboratory of Zoological Systematics and Evolution of the Institute of Zoology of the Chinese Academy of Sciences, Abdulaziz Alqarni of the Department of Plant Protection at King Saud University, Lin-Bo Jia of the Key Laboratory for Plant Diversity and Biogeography of East Asia at the Kunming Institute of Botany, Tao Su of the Key Laboratory of Tropical Forest Ecology at the Xishuangbanna Tropical Botanical Garden, Zhe-kun Zhou, also of the Key Laboratory for Plant Diversity and Biogeography of East Asia at the Kunming Institute of Botany, and the Key Laboratory of Tropical Forest Ecology at the Xishuangbanna Tropical Botanical Garden, and Torsten Wappler of the Natural History Department at the Hessisches Landesmuseum Darmstadt, describe a new species of Honey Bee from the Huazhige Formation of the northwestern Maguan Basin in Maguan County of Yunnan Province, China.

The Huazhige Formation is a finely laminated grey and yellow siltstone and mudstone deposit laid down in a lake bed between 16.5 and 15.2 million years ago (i.e. during the Middle Miocene). This formation has produced numerous fossil Insects, Fish, Birds and Plants, which are interpreted as having come from a subtropical evergreen forest with a warm and wet environment.

The new Bee species is named Apis dalica, in reference to the Medieval Dali Kingdom, which occupied roughly the same territory as Yunnan Province between 937 and 1253 (when it was invaded by a Mongol army under Kublai Khan). The species is described from a single Worker Bee preserved with its underside showing, this is 17.06 mm in length, and charcoal black in colour. Little detail of the head, body and legs are preserved, but the wings are clearly visible, allowing comparison to other Bees, fossil and extant. This is the first fossil Honey Bee from South China.

Worker of Apis dalica, from Maguan County, southeastern Yunnan Province, China. (4) Entire specimen as preserved. (5) Reconstruction of wing venation; forewing above, hind wing below. (6) Detail of foreleg. (7) Detail of apical sterna. Abbreviations: ppl, propleuron; mcx mesocoxa; tr, trochanter; fm, femur; tb, tibia. Engel et al. (2018).

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Magnitude 1.7 Earthquake on the Isle of Islay, Scotland.

The British Geological Survey recorded a Magnitude 1.7 Earthquake at a depth of about 4 km on the Isle of Islay in the Inner Hebrides Islands,slightly before 4.10 am British Summertime (slightly before 3.10 am GMT) on Sunday 29 July 2018. This was not a major event, and presented no threat to human life or property, but may have been felt on the island.
The approximate location of the 29 July 2018 Isle of Islay 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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Monday 30 July 2018

Palynological differentation of the Shahezi Formation of Liaoning Province, China.

Pollen is extremely useful to archaeologists and palaeontologists. It is resilient both and distinctive, and plants produce it in large amounts, and scatter it freely in the environment. Scientists who study pollen, called palynologists, are able to use pollen to date ancient sediments and to reconstruct the vegetation, and therefore climate, of ancient sites. 

The Shahezi Formation is a coal-bearing Cretaceous sedimentary sequence from the Songliao Basin of northeast China. It comprises two components, a lower member composed of tuff and tuffaceous mudstone, and an upper member composed of mudstone, siltstone, conglomerate and coal, and is considired important for both its (economically useful) coal, and its potential insights into the evolution of the Songliao Basin, and geological events related to the carbon cycle and greenhouse climate change during the Early Cretaceous. However, It is is difficult to differentiate the Shahezi Formation from other coal-bearing strata in the region, such as the Jehol Biota-producing Yingcheng Formation, on lithology alone, which hampers the study of this formation, and therefore limits its usefulness.

In a paper published in the journal Acta Geological Sinica on 27 February 2018, Wang Chenglong and Zhang Meisheng of the College of Earth Sciences at Jilin University, Liu Xuesong, also of the College of Earth Sciences, and of the Museum of Geology at Jilin University, and Sun Kai of the Exploration and Development Research Institute of Jilin Oilfield Company, present the results of a palynological study of the Shahezi Formation, which appears to be able to differentiate it from other coal-bearing formations in the region.

Wang et al. collected six samples for analysis from the Shahezi Coal Mine in Changtu County, the type locality for the Shahezi Formation, five of which were found to contain palynological fossils, once treated with hydrochloric and hydrofluoric acid to remove carbonates and silicates, respectively.

The samples were found to contain between 71.43% and 84.48% Gymnosperm pollen, dominated by Perinopollenites, (13.39%−18.97%), Taxodiaceaepollenites (7.14%−10.17%), and Abietineaepollenites (6.78% −12.07% ), and between 15.52% and 28.57% Pteridophyte spores, dominated by Granulatisporites (1.72% −6.25% ), Polypodiaceaesporites (1.72%−5.36%), and Cyathidites (1.69% −5.17% ). 

 Typical palynological fossils from the Shahezi Formation in the Shahezi Coal Mine. (1), Cyathidites; (2), Baculatisporites; (3), Cicatricosisporites; (4), Granulatisporites; (5), Polypodiaceaesporites; (6), Schizosporis; (7), Inaperturopllenites; (8), Pinuspollenites; (9), Concentrisporites; (10), Taxodiaceaepollenites; (11), Abietineaepollenites; (12), Cycadopites; (13), Perinopollenites; (14), Paleoconiferus. Wang et al. (2018).

The samples did not contain any Angiosperm pollen, which is found in the Yingcheng Formation, nor warm-climate adapted Fern spores such as Ruffordia and Coniopteris, which dominate the Yingcheng Formation, allowing differentiation of the two formations.

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Sunday 29 July 2018

Landslide kills eight in Nan Province, Thailand.

Eight people have been confirmed dead following a landslide in Nan Province in northern Thailand. The event happened at about 6.10 am local time on Saturday 28 July 2018, when a 200 m wide section of the hillslope above the village of Baan Huay Khab collapsed, destroying most of the community's houses, following heavy rains in the region associated with the Southwest Monsoon. 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. The number of fatalities was initially feared to be much higher, but all local residents have now been accounted for,

The aftermath of a landslide that destroyed the village of Baan Huay Khab on 28 July 2018. Thai Residents.

Monsoons are tropical sea breezes triggered by heating of the land during the warmer part of the year (summer). Both the land and sea are warmed by the Sun, but the land has a lower ability to absorb heat, radiating it back so that the air above landmasses becomes significantly warmer than that over the sea, causing the air above the land to rise and drawing in water from over the sea; since this has also been warmed it carries a high evaporated water content, and brings with it heavy rainfall. In the tropical dry season the situation is reversed, as the air over the land cools more rapidly with the seasons, leading to warmer air over the sea, and thus breezes moving from the shore to the sea (where air is rising more rapidly) and a drying of the climate.

 Diagrammatic representation of wind and rainfall patterns in a tropical monsoon climate. Geosciences/University of Arizona.

Much of Southeast Asia has two distinct Monsoon Seasons, with a Northeast Monsoon driven by winds from  the South China Sea that lasts from November to February and a Southwest Monsoon driven by winds from the southern Indian Ocean from March to October. Such a double Monsoon Season is common close to the equator, where the Sun is highest overhead around the equinoxes and lowest on the horizons around the solstices, making the solstices the coolest part of the year and the equinoxes the hottest. However northern Thailand is largely protected from the Northeast Monsoon by the mountains separating the country from Myanmar.
 The winds that drive the Northeast and Southwest Monsoons in Southeast Asia. Mynewshub.
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