Showing posts with label Heilongjiang Province. Show all posts
Showing posts with label Heilongjiang Province. Show all posts

Friday, 19 January 2024

Neolithic tools from the Late Glacial of the lower Amur River Basin.

The onset of the Neolithic is generally assumed to coincide with the appearance of pottery in northeastern Asia, with some of the earliest pottery appearing in the Amur, or Heilongjiang, River Basin. Two distinct ceramic-producing cultures appeared in the lower Amur River Basin during the Late Glacial, the Osipovka and the Gromatukha, both of which are thought to have emerged as nomadic bands of hunter gatherers began to settle down in the region. The southernmost site associated with the Osipovka Culture is at Xiaonanshan Hill on the west bank of the Ussuri River, a large tributary of the lower Amur.

In a paper published in the journal Antiquity on 13 December 2023, Jian-Ping Yue of the School of History at Anhui University, and the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, You-Qian Li of the Heilongjiang Provincial Institute of Cultural Relics and Archaeology, Xia-Jun Yan of the Shaanxi Archaeological Museum, Xue-Ya Du, also of the School of History at Anhui University, and Shi-Xia Yang, also of the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, and of the Australian Research Centre for Human Evolution at Griffith University, describe a new site on the northern slope of the Xiaonanshan Hill, and report on the lithic tools and dating evidence uncovered there.

Xiaonanshan Hill is located on the west bank of the Ussuri River in Raohe County, Heilongjiang Province, which is the most northeasterly province of China. The first archaeological remains were found on the hill in 1958, with sporadic excavations being caried out in the 1970s, 80s, and 90s. Since 2015 the site has been subjected to more systematic archaeological exploration, with five distinct phases of occupation identidified, ranging from about 16 000 years ago to about 2000 years ago. 

The Redianchang area on the northern flank of Xiaonanshan Hill was explored in 2021, with eight squares, covering a total area of 130 m². Four distinct stratigraphic units were identified, labelled 1-4, with Layer 1 being the uppermost and Layer 4 the lowest. The site was excavated in 50 mm increments, with the location of lithic artefacts larger than 10 mm being recorded. A total of 16 484 such lithic artefacts were recovered, more than 77% of them from Layer 3. This layer also yielded a piece of charcoal, from which a radiocarbon date of 16 785–16 390 years before the present was obtained.

The landscape of Xiaonanshan showing dates of excavations (a) & (b); and excavation squares and stratigraphy of the Redianchang locality in 2021 (c) & (d). Yue et al. (2023).

The majority of the stone tools from Redianchang are made from volcanic tuff, a type of rock readily available in nearby riverbeds, with small amounts of basalt, agate and obsidian also used. Tools were made by microblade, blade and core-flake debitage (flaking) with microblade debitage being the most common type. These had been shaped using the 'Yubetsu technique', which has been recorded at End Pleistocene sites across northeast Asia from Mongolia to Kamchatka, as well as in Japan (where it was first identified). In this technique pebbles or other pieces of rocks were shaped bifacially by the removal of longitudinal spalls to create a platform. Other microblades were made by successive transverse removals to form a platform. Both techniques involved the use of pressure knapping. Simple core-flake and blade reduction are also present.

Microblade cores from Xiaonanshan: (a) & (c)–(f ) microblade cores prepared with the Yubetsu method; (b) & (g) microblade cores with platform formed by successive transverse removals. Yue et al. (2023).

Two hundred formal tools were identified; scrapers, endscrapers, points, borers, notches and denticulates together made up 58% of this material. Most of these were made using flakes as blanks for the creation of the new tools, but there was little morphological standardisation. Bifacial points make up 15% of the total, these showing a high degree of symmetry achieved through careful shaping. Microblades, made by shaping the end to form a fine tip, make up 18.5% of the total, and adzes another 8%, some of which had been shaped by grinding. A single stone sinker (stone with a carved groove, believed to have been used as a fishing weight) was identified.

Crests (a) & (b), microblades (c)–(e) and retouched microblades (f)–(h) from Xiaonanshan. Yue et al. (2023).

The Redianchang assemblage is dominated by microblade debitage tools, made using the Yubetsu techniques, as well as scrapers, bifacial points, retouched microblades and chipped/polished adzes. Similar assemblages were found at other locations on Xiaonanshan during excavations in 2019 and 2020, along with early ceramics, hearths and dwellings. The ceramics comprised low-temperature pottery sherds, often with grass imprints on both sides. Two semi-subterranean dwellings were found, one of which had a central hearth. Radiocarbon dates from these sites yielded dates of between 16 500 and 13 500 years before present, consistent with Xiaonanshan Phase 1. Artefacts show similarities to material from the middle and lower Amur River Basin, including the Gromatukha site, which gives its name to the Gromatukha Culture, and the Gasya, Khummi and Goncharka-1 sites, all of which are associated with the Osipovka Culture.

Bifacial points from Xiaonanshan. Yue et al. (2023).

The combination of technologies seen at Xiaonanshan, including stone-grinding, early pottery, and semi-subterranean dwellings, are consistent with a Late Glacial hunter gatherer population that was starting to settle into a less nomadic lifestyle, and developing new technologies which made better use of locally available resources. This suite of technologies mark the beginning of the Neolithic in the Amur Basin of northeast Asia.

Stone adzes (a) & (b) and sinker (c) from Xiaonanshan. Yue et al. (2023).

See also...




Wednesday, 1 April 2020

Failure of mine tailings dam contaminates Yijimi River in Heilongjiang Province, China.

Emergency water supplies have had to be arranged for about 200 000 people whose water usually derives from the Yijimi River in Heilongjiang Province, China, following a leak from a tailings dam on Saturday 28 March 2020. The leak occurred at a Molybdenum mine operated by Yichun Luming Mining, and is thought to have released about 2.53 million cubic metres (1 530 million litres) of contaminated water into the river, with raised Molybdenum levels being detected 110 kilometres down stream to date, although local authorities are more concerned about the toxic effects of the oil added to the water as a flotation agent (to help separate the metal from the ground ore), which is potentially toxic to both wildlife and humans.

Water contaminated with tailings from a Molybdenum mine flows into the Yijimi River in Heilongjiang Province, China, on Saturday 28 March 2020. Xinhua.

Tailings ponds are used to store sediment-laden waters from mines; such waters typically contain a high proportion of fine silt and clay particles, which take time to settle out of the water. The resulting water may be fairly clean, or may contain other pollutants (typically acids, either generated by the local geology or used in the mining process), and need further treatment. In some instances acid is added to such pools in order to dissolve the product, which is then released from the resultant chemical slurry by further treatment.

The practice is currently widespread in China, however, the Chinese Ministry of Emergency Management has announced plans to introduce strict new controls on such dams, with future dams having to adhere to much tighter safety regulations, and to close older dams which cannot comply with these. The Yichun mine tailings dam had already been flagged as problematic, with the operating company fined for safety breaches associated with the dam twice in 2018.

See also...

https://sciencythoughts.blogspot.com/2019/08/pensioner-killed-by-bear-in-russian-far.htmlhttps://sciencythoughts.blogspot.com/2018/07/palynological-differentation-of-shahezi.html
https://sciencythoughts.blogspot.com/2017/10/magnitide-47-earthquake-in-amur-oblast.htmlhttps://sciencythoughts.blogspot.com/2016/12/explosion-kills-33-at-inner-mongolia.html
https://sciencythoughts.blogspot.com/2016/12/heilongjiang-mine-explosion-kills.htmlhttps://sciencythoughts.blogspot.com/2014/07/around-20-000-evacuated-from-homes.html
Follow Sciency Thoughts on Facebook.

Saturday, 16 November 2019

Lithic technologies at the onset of the Neolithic in the Lesser Khingan Mountains of Northeast China.

The long-term and historically contingent transition from Palaeolithic to Neolithic lifestyles, or Neolithisation, has long been a key issue in archaeological studies, and remains the subject of ongoing debate. The emergence of pottery is often used to define the beginning of the Neolithic period, especially in Russia and Japan. In China, the pre-Holocene material culture associated with early pottery is often attributed to the Palaeolithic-to-Neolithic transition period although it is also sometimes described as late Upper Palaeolithic. In recent decades, studies of the Neolithisation process in China, Russia and Japan have begun to give greater attention to the importance of establishing more secure chronologies and to the climatic and environmental context of these changes. 

In a paper published in the journal Antiquity on 15 July 2019, Jian-Ping Yue of the Key Laboratory of Vertebrate Evolution and Human Origins at the  Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, the Center for Excellence in Life and Paleoenvironment, and the University of the Chinese Academy of Sciences, You-Qian Li of the Heilongjiang Provincial Institute of Cultural Relics and Archaeology, and Shi-Xia Yang, also of the Key Laboratory of Vertebrate Evolution and Human Origins at the  Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, the Center for Excellence in Life and Paleoenvironment, and of the Department of Archaeology at the Max Planck Institute for the Science of Human History, describe the results of excavations at two sites in the Lesser Khingan Mountains of Northeastern China, and the implications of these findings for our understanding of Neolithisation in East Asia.

Northeast China sits between the Korean Peninsula, the Russian Far East, north China and Hokkaido Island. Covering several geological areas, including the Khingan Mountains, Changbaishan Mountains, the Song-Nen Plain, the Sanjiang Plain and the Liaohe Plain, north-east China is separated from north China by the Great Wall. Previous research on this region and its abundant palaeoenvironmental evidence has revealed climatic and environmental changes in the terminal Late Pleistocene. Thus, the region offers an ideal context in which to study the adaptive behaviours of hunter-gatherers and the Neolithisation process. The Palaeolithic-to-Neolithic transition period industries of north-east China, however, are relatively poorly understood, due to a lack of intensive archaeological survey and excavation in the region. In recent years, this picture has gradually improved as archaeological materials have been identified in stratified, datable contexts, such as at the sites of Houtaomuga and Taoshan.

Over the last decade in the southern Lesser Khingan Mountains of north-east China, archaeologists from the Heilongjiang Provincial Institute of Cultural Relics and Archaeology have conducted a series of archaeological surveys in advance of local highway reconstruction projects. This work identified several archaeological sites with associated Palaeolithic-to-Neolithic transition period  assemblages, leading to formal excavations at Huayang and Taoshan. Yue et al. present reports on these two sites, with a particular focus on the lithic assemblages that extend across the Palaeolithic-to-Neolithic transition period boundary. Both sites are stratified and securely dated, and contain cultural remains dating from roughly 18 000 to 5000 years ago (16 000 to 3000 BC). Together, the sites offer a comprehensive view of the Palaeolithic-to-Neolithic transition period lithic industry, allowing an assessment of long-term human behaviour in this region. Yue et al. present these results in relation to the regional archaeological evidence and the context of pre-Holocene climatic and environmental changes in Northeastern Asia.

Topographic map of north-east China showing the excavation areas of the Huayang and Taoshan sites. Yue et al. (2019).

The Huayang site is situated in at approximately 180 m above sealevel and 20m above the local river, on the second terrace of the Tangwanghe River. Discovered in 2011, the site was excavated the following year as a salvage archaeology project under the direction of You-Qian Li. Three excavation areas and many test pits were opened, covering almost 1000 m² of the site, which itself is estimated to cover more than 70 000 m². The main excavation area covers around 560 m², divided into 24 squares labelled from A–V. In addition, another square (MK) was opened as an extension of square M, in response to the discovery of a high-density distribution of lithic artefacts.

Photograph showing the excavation area of the Huayang site. Yue et al. (2019).

In addition to the modern plough soil, three prehistoric cultural layers were identified, labelled CL1, CL2 and CL3. Accelerator mass spectrometry radiocarbon measurements date CL1 to 5992–5916 before the present, CL2 to 14 355–14 025 before the present and CL3 to 18 614–17 885 before the present. The Palaeolithic-to-Neolithic transition period cultural layer (CL2) yielded a few pottery sherds and a significant number of lithic artefacts (25 090), the latter forming the principal lithic assemblage of the site.

The Taoshan site is also located in  on the southern slope of the Taoshan Mountains, approximately 500m from the Hulan River. The site is 241 m above sealevel and approximately 21 m above the local river. Taoshan was discovered in 2011 and excavated in 2013–2014. A total of 36 m² was uncovered, yielding 2908 stone artefacts, 71 pottery shards and five bead fragments made from amazonite. Three prehistoric layers were identified and accelerator mass spectrometry radiocarbon dated. From top to bottom, layer 2 dates to 5588–5051 before the present, layer 3 dates to 15 172–14 044 before the present and layer 4 dates to 19 156–16 557 before the present. Layer 3 corresponds with the Palaeolithic-to-Neolithic transition period and yielded 2281 lithic artefacts and 12 pottery shards.

Photograph showing the excavation area of the Taoshan site. Yue et al. (2019).

Analysis of the lithic assemblage from Huayang includes tools, blades, microblades and related fragments of all sizes. Due to the large quantity of debitage, lithics smaller than 10 mm (of which there were 6613) were excluded from the analysis. The material examined therefore comprises 18 477 artefacts larger than 10 mm from CL2. A techno-typological approach was used to develop an understanding of lithic raw material procurement and exploitation, blank manufacture and tool production at the site.

Rhyolites, comprising predominantly banded rhyolite and felsite, serve as the primary raw material at Huayang, accounting for 90.25 per cent of the lithic assemblage. Shale, dacite and tuff were also procured in relatively large quantities. Other raw materials, such as agate, chert, sandstone and andalusite-hornfels, are present in small amounts. A geological survey of the site and surroundings and a follow-up petrological study were undertaken to document procurement sources. The results suggest that all the lithic raw materials at Huayang were available in close proximity (within 5 km) of the site.

Several methods of debitage production were found at the Huayang site. These can be classified largely into debitage from core-flake, bladelet and microblade production. The presence of predetermined products, such as blades and microblades, informs of the processes that produced the debitage. Although bipolar reduction was occasionally applied for agate and crystal exploitation at the site, it is relatively scarce.

Core-flake reduction is particularly prominent at Huayang and is represented by cores, core fragments, flakes and flake fragments. Rhyolite, chert, dacite and a few other materials were procured. Pebbles, cobbles and blocks were preferentially selected for blanks, as well as some thick flakes. Most of the cores exhibit a simple debitage process, with one or two platforms present. Only two truncated-facetted pieces have been identified; these are flakes that exhibit a truncation face, which serves as a platform for the removal of one or more small flakes.

Cores from the Huayang site. Yue et al. (2019).

Bladelet production is well represented at the site. The bladelet cores can be divided into two main types: prismatic and narrow-faced. These cores appear to have been made exclusively on felsite blocks, and most exhibit a partially retained natural surface. The debitage indicates that full advantage was taken of blank morphology. The debitage surface was usually not elaborately prepared, and the initial blade extraction followed the natural convexities of the core. Preparation of the platform prior to blade removal was common. Indirect percussion was used for bladelet removal.

Microblade debitage is present, although the number of microblades is small. The microblade cores, represented by two pieces, are bifacially shaped, exhibiting a wedge-like morphology. Microblades were detached from the elaborately prepared platform along one end of the core.

Bladelet and microblade cores from the Huayang site: (a)–(e) bladelet core; (f)–(g) microblade core. Yue et al. (2019).

The toolkit at Huayang includes a great diversity of tool types and technical features. The most frequently represented tools are bifacial points, with 138 complete and broken pieces identified. Approximately 91.3% of the bifacial points are broken and some can be conjoined. Banded rhyolite is the most frequently used raw material (94.93%). Themorphology of the points shows a high degree of standardisation, characterised by a pointed or elliptical base, and a V-shaped point with straight or slightly curved sides. Initially, the blanks were made by hard-hammer percussion, and subsequently retouched using a soft hammer.

Stone tools from the Huayang site: (a)–(b) arrowhead; (c) point on bladelet; (d) borer; (e)–(f) convex scraper; (g) bifacial point; (h) backed scraper. Dark red scale bars are 10mm. Yue et al. (2019).

Scrapers are represented by 44 pieces, most of which have one cutting edge, with some showing continuous and elaborate retouch. Arrowheads (5) are small with an average maximum length of 25.57 mm. These pieces are partially bifacially retouched by softhammer percussion and pressure flaking. A small quantity of additional implements, such as notches, points, denticulates, choppers and awls, were also retrieved. Overall, most of the aforementioned formal tools selected flakes as blanks; only three pieces were manufactured on bladelets. Rhyolite dominates the assemblage, along with some chert, dacite and tuff.

Some Palaeolithic-to-Neolithic transition period tools, including axes, adzes and chisels, have also been identified at Huayang. These pieces are made on tuffaceous sandstone, quartzite and diorite, reflecting different raw material preferences and exploitation strategies. Some pieces, particularly the stone chisels, also show evidence of grinding, which is further attested by the presence of two grinding stones. Tabular cobbles in sandstone and quartzite sandstone were selected as grinding stones and show clear traces of ground-stone tool production.

Grinding stones (a)–(b) and ground-stone chisels (c)–(d) from the Huayang site. Yue et al. (2019).

The Taoshan lithic assemblage is dominated by crystal tuff, with lesser amounts of rhyolite and andalusite-hornfels. Other raw material types (e.g. chert, quartz sandstone and agate) are present in smaller quantities. Field survey and statistical analysis of the presence of cortex indicate that almost all the raw materials were taken from the local riverbed.

Flakes and flake fragments constitute the dominant artefact type at Taoshan, while cores of flake debitage are represented by only two pieces, showing a simple debitage method without preparation. Yue et al. therefore suggest that most of the flakes result from the shaping out of microcores—the primary activity at the site.

Lithic artefacts from the Taoshan site: (a)–(b) flake core; (c)–(f) microblade core; g) broken bifacial point; (h) adze; (i) axe. Yue et al. (2019).

Microblade debitage is well represented by six wedge-shaped microblade cores and a series of characteristic debitage products. The blanks are on cobbles or flakes and were shaped using bifacial percussion. The platform was formed with successive transverse preparation and subsequent removal of longitudinal spalls. Microblades were detached by pressure flaking, following the removal of the crested blade, the first bladelet that displays negatives of the bifacial shaping of the core.

Although the Taoshan assemblage contains a relatively small quantity of formal tools, various types have been identified and demonstrate similarities with those of Huayang. Along with some retouched pieces, such as scrapers, denticulates, end-scrapers and notches, relatively large-sized domestic tools, including adzes and axes, have been identified. These pieces were made on cobbles in tuff and andalusite-hornfels, and achieved morphological standardisation through progressive shaping, although they show no evidence of grinding. A single broken bifacial point was also recovered from Taoshan.

The sites of Huayang and Taoshan are located in the southern Lesser Khingan Mountains, approximately 100 km from each other, and are almost contemporaneous, with assemblages exhibiting clear technological similarities. In terms of raw material procurement, igneous rocks were preferentially selected, followed by shale, chert, agate and andalusite-hornfels. All raw materials were obtained from local primary or secondary sources and show clear procurement management strategies. Banded rhyolite, for example, was primarily procured for bifacial point production, while felsite was mainly used for bladelets at Huayang. Several reduction sequences were used at both sites. Flake debitage demonstrates a predominantly simple reduction method, with little evidence for elaborate core preparation. Microblade debitage is characteristic of the bifacial shaping-out of wedge-shaped microblade cores. The toolkits of these two sites are also similar in the types of tool represented and in the evidence for the addition of new forms, including adzes, axes and chisels. There is also a notable presence of early pottery at both sites.

Nonetheless, there are some distinctions in blank debitage and tool production between the two sites. Bladelets and bifacial points, for example, constitute significant components of the Huayang Palaeolithic-to-Neolithic transition period assemblage, while at Taoshan the lithic industry is characterised by microblade technology, with no evidence of bladelets and only a single bifacial point. What, then, might explain the differences between the two assemblages? At other contemporaneous sites in north-east China, blade and microblade items serve as common features of the regional Late Pleistocene lithic industries. Yue et al. note that at the Huayang site, cores and tools of different raw material types, selected for their particular knapping qualities, are found in distinct parts of the excavation area. Felsite, for example, which was used predominantly for bladelet and core-flake production, is concentrated in the southern area, while banded rhyolite, which was used mainly for bifacial point production, concentrates in the western part. Regardless of the small excavation area at Taoshan, it is reasonable to deduce that an uneven spatial distribution of lithic artefacts could explain the lack of blade and bifacial points found at the site. In sum, the lithic assemblages of Huayang and Taoshan site can be clustered into the same techno-complex, which collectively represent the Palaeolithic-to-Neolithic transition period lithic industries in the southern Lesser Khingan Mountains.

The Palaeolithic-to-Neolithic transition period lithic evidence from Huayang and Taoshan demonstrates important technological innovations and developments of the earlier lithic industry, especially the production of adzes, axes and chisels and the initial application of grinding techniques. On the basis of a systematic analysis of the lithic raw materials of Taoshan it has been suggested that a decrease in population mobility was concurrent with greater exploitation of more local raw materials.

In addition to changes in tool types and mobility patterns, a transformation in subsistence strategies is also evidenced by the presence of early pottery in the Palaeolithic-to-Neolithic transition period cultural layers at Huayang and Taoshan. Sherds of sand-tempered vessels fired at low temperatures were recovered from both sites. The development of ceramic containers is suggested to have provided prehistoric hunter-gatherers with new strategies for storing, processing and consuming foodstuffs. Isotopic analysis of charred residues on the early pottery sherds (dated to 13 000 to 11 000 before the present) from the Houtaomuga site on the Song-Nen Plain of north-east China suggests that freshwater fish may have been a major component of the local diet.

Similar changes in technology and subsistence have also been identified in adjacent regions of North-eastern Asia, particularly the Russian Far East and Hokkaido. Early pottery has been widely reported in the Russian Far East, particularly from the Oshipovka Culture layers along the lower Amur River, at such sites as Gasya, Khummi, Goncharka 1, Novotroitskoe 10 and Oshinovaya-rechika 16. Together, these sites suggest a use-life ranging from 14 000 to 12 000 before the present. The earliest pottery on Hokkaido is reported from the Taisho 3 site, is associated with projectile points, burins and axes, and dates from 15 030 to 13 570 years ago. New technological innovations, including stemmed points and axes, also developed contemporaneously in both Hokkaido and the Russian Far East, and are accompanied by the miniaturisation of microblades and a higher frequency in burin (stone tools with chisel points) maintenance. Although local lithic raw materials replaced non-local materials, tool type and inter-site assemblage variability increased.

A combined focus on climatic conditions and cultural developments highlights the important role of environmental changes in the course of the Neolithisation of this region. North-eastern Asia is located on the northern boundary of the modern Asian monsoonal systemand is highly sensitive to rapid changes in climate. A series of high-resolution palaeoclimatic records clearly characterise the vegetation history and climatic variability during the terminal Late Pleistocene, which includes prominent climatic phases, such as the Last Glacial Maximum, the Bølling-Allerød warm phase and the Younger Dryas cold event. Pollen analysis of samples from Taoshan also reveals substantial change in vegetation from a steppe environment, during the layer 4 period (Last Glacial Maximum), to dense forest in layer 3. This change is attributed to increasing precipitation and rising temperature concurrent with the start of the Bølling-Allerød warm phase.

During the Late Glacial phase (15 000 to 11 700 years before present), climatic and environmental conditions changed significantly, which led to an improvement in landscape productivity and a noticeable alteration in plant and animal resources. The population density seems to have increased, as attested by the higher number of archaeological sites and larger amounts of intrasite material remains in the area. Thus, the imbalance between population and available resources could have accelerated over time. All of these factors probably contributed directly to the Neolithisation process, as they enabled local populations to develop new, innovative subsistence strategies and behaviours. During this period, the mobility of prehistoric populations tended to decrease while exploitation of locally available resources, not only faunal and floral resources but also lithic raw materials, intensified. Several technologies indicative of resource intensification (e.g. pottery, axes and adzes) appeared in North-eastern Asia, signalling the beginning of a new period: the Neolithic.

Here, we have focused on the Palaeolithic-to-Neolithic transition period lithic assemblages from the Huayang and Taoshan sites in the southern Lesser Khingan Mountains of northeast China. Analysis of the assemblages in combination with contemporaneous material from adjacent regions, particularly the Russian Far East and Hokkaido Island, demonstrates both a uniformity of the trajectory of the Neolithisation process in North-eastern Asia and a close connection with environmental shifts during the Late Glacial phase. These analyses enrich our understanding of the nature, course and geographic extent of Neolithisation in both north-east China and Northeastern Asia more widely, and facilitate comparative study with neighbouring regions, such as north China, where the Neolithisation process followed a different trajectory.

See also...

https://sciencythoughts.blogspot.com/2019/11/investigating-origins-of-sedentism-and.htmlhttps://sciencythoughts.blogspot.com/2018/09/intentionally-fragmented-stone-blades.html
https://sciencythoughts.blogspot.com/2018/09/stone-tools-from-high-altitude-site-in.htmlhttps://sciencythoughts.blogspot.com/2017/12/using-molecular-genomics-to-understand.html
https://sciencythoughts.blogspot.com/2017/11/reassessing-aitape-skull_22.htmlhttps://sciencythoughts.blogspot.com/2016/08/bubble-like-caves-in-laoshan-granite-of.html
Follow Sciency Thoughts on Facebook.

Monday, 14 October 2019

Bright fireball meteor over northeast China.

Witnesses across northeastern China have reported witnessing a fireball meteor slightly after 0.15 am Beijing Time  on Friday 11 October 2019 (slightly after 4.15 pm on Thursday 10 October GMT). The majority of sightings came from the city of Songyuan in Jilin Province, but with many sightings elsewhere in Jilin and Heilongjiang provinces. A fireball is defined as a meteor (shooting star) brighter than the planet Venus. These are typically caused by pieces of rock burning up in the atmosphere, but can be the result of man-made space-junk burning up on re-entry. 

Dashboard camera image of a fireball over northeastern China on 11 October 2019, seen from Jilin Province. CCTV.

Objects of this size probably enter the Earth's atmosphere several times a year, though unless they do so over populated areas they are unlikely to be noticed. They are officially described as fireballs if they produce a light brighter than the planet Venus. The brightness of a meteor is caused by friction with the Earth's atmosphere, which is typically far greater than that caused by simple falling, due to the initial trajectory of the object. Such objects typically eventually explode in an airburst called by the friction, causing them to vanish as an luminous object. However this is not the end of the story as such explosions result in the production of a number of smaller objects, which fall to the ground under the influence of gravity (which does not cause the luminescence associated with friction-induced heating).
 
These 'dark objects' do not continue along the path of the original bolide, but neither do they fall directly to the ground, but rather follow a course determined by the atmospheric currents (winds) through which the objects pass. Scientists are able to calculate potential trajectories for hypothetical dark objects derived from meteors using data from weather monitoring services.
 
See also...
 
https://sciencythoughts.blogspot.com/2019/10/the-delta-aurigid-meteors.htmlhttps://sciencythoughts.blogspot.com/2019/10/the-southern-taurid-meteor-shower.html
https://sciencythoughts.blogspot.com/2019/10/costa-rican-mud-meterorite-acquired-by.htmlhttps://sciencythoughts.blogspot.com/2019/10/the-draconid-meteor-shower.html
https://sciencythoughts.blogspot.com/2019/09/fireball-meteor-over-east-anglia.html#https://sciencythoughts.blogspot.com/2019/09/fireball-meteor-over-northern-germany.html
Follow Sciency Thoughts on Facebook.

Sunday, 4 December 2016

Heilongjiang mine explosion kills twenty one miners.

Twenty one miners have been confirmed dead following an explosion at a coal mine in the city of Qitaihi in Heilonghiang Province, China on Tuesday 29 November 2016. The incident happened at about 9.00 pm local time, and trapped a further 32 workers bellow ground, one of whom was still trapped on Saturday 3 December. Details of the incident have yet to be released, but photographs of the scene show extensive damage to surface facilities at the mine, implying the explosion was large and close to the surface, and four members of the mine's management team have been arrested, suggesting that local authorities believe there were serious breaches of health and safety regulations at the mine.

Rescue workers at the Qitaihi coal mine in Heilongjiang following the 29 November explosion. Reuters.

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.

Visible damage to surface works at the Qitaihi coal mine in Heilongjiang following the 29 November explosion. Wang Song/Xinhua.

Coal is also comprised more or less of pure carbon, and therefore reacts freely with oxygen (particularly when in dust form), to create carbon dioxide and (more-deadly) carbon dioxide, while at the same time depleting the supply of oxygen. This means that subterranean coal mines need good ventilation systems, and that fatalities can occur if these break down.

See also...

http://sciencythoughts.blogspot.co.uk/2015/04/seven-confirmed-deaths-following-mine.htmlhttp://sciencythoughts.blogspot.co.uk/2016/10/fifteen-confirmed-deaths-following.html

http://sciencythoughts.blogspot.co.uk/2014/07/seventeen-miners-missing-after-gas.htmlhttp://sciencythoughts.blogspot.co.uk/2014/06/twenty-two-dead-in-gas-incident-at.html
http://sciencythoughts.blogspot.co.uk/2014/04/miners-trapped-by-flooding-in-yunnan.htmlhttp://sciencythoughts.blogspot.co.uk/2013/12/six-killed-by-explosion-at-coal-mine-in.html
Follow Sciency Thoughts on Facebook.