Friday, 5 August 2022

The first Neolithic farmers on Luzon Island, the Philippines.

The island of Taiwan, 125 km from the southeast coast of China, is thought to be the first island to the south of China to have been settled by Neolithic farmers, with the Dabenkeng Culture appearing here between 5500 and 5000 years before the present. Taiwan is also thought to have been the origin point of the first Neolithic settlers to arrive in the northern Philippines, more than 4000 years ago. Work on ancient DNA from archaeological sites on Luzon, the Mariana Islands, and the islands of the southwest Pacific has concluded that much of the genetic heritage of the non-Melanesian peoples of the islands of Southeast Asia and the Pacific Islands derives from an ancient migration from China via Taiwan and the Philippines.

All of this makes Luzon Island, the first major landmass likely to have been reached by Neolithic sailors heading south from Taiwan, likely to have been an important staging post in this migration, quite possibly the place in which many important cultural developments occurred. The Austronesian language family, for example, has two major divisions, one including the indigenous Formosan language of Taiwan, the other all the other significant languages of the Malay-Polynesian world, from the Philippines to Madagascar to Rapa Nui (Easter Island). The Proto-Austronesian language from which all these languages are descended is thought to have originated somewhere in the northern Philippines, probably Luzon or the Batanes Islands, or possibly on eastern Taiwan.

Northern Luzon Island is also likely to have been the first place were migrating proto-Malayo-Polynesians would have encountered people different from themselves. This island had long before been settled by the Melanesian Negrito people of the Philippines, who lived as hunter-gatherers on the island prior to the arrival of Neolithic settlers with domestic Dogs and Pigs, and a culture built around Rice-farming, between about 4200 and 4000 years ago. 

The Cagayan Valley on northern Luzon Island is the longest and widest river valley in the Philippines, with a broad alluvial plain extensively settled by Rice farmers. However, the area is still home to populations of Negrito foragers, particularly in the Sierra Madre hills to the east of the river. These people can be shown to be genetically related to the earliest, pre-Neolithic settlers in the region, though many parts of their culture are clearly more recent, including speaking a Malayo-Polynesian language and living only in remote forested areas unsuitable for Rice farming.

During the past two decades the Cagayan Valley has become a centre of great interest to archaeologists, with the uncovering of a series of shell middens which cover much of the history of settlement on the island, including the transition from a strictly foraging culture to one based around farming with foraging occurring as a supplementary activity.

In a paper published in the journal Antiquity on 1 June 2022, Hsiao-chun Hung of the Department of Archaeology and Natural History at the Australian National University, Cheng-hwa Tsang of the Institute of Anthropology at the National Tsing Hua University, Zhenhua Deng of the Center for the Study of Chinese Archaeology and School of Archaeology and Museology at Peking University, Mary Jane Louise Bolunia and Rey Santiago of the Archaeology Division at the National Museum of the Philippines, Mike Carson of the Micronesian Area Research Center at the University of Guam, and Peter Bellwood of the School of Archaeology and Anthropology at the Australian National University, present a time-frame for the settlement of the valley based upon the radiocarbon dating of material from these shell middens, and a revised cultural and historical hypothesis based upon this.

The most westerly Pacific island chain, running from Taiwan southwards through the Philippines, has long been central in debates about the origins and early migrations of Austronesian-speaking peoples from the Asian mainland into the islands of Southeast Asia and Oceania. Hung et al. (2022).

Hung et al. identify three historical phases within the shell middens, which they term Preceramic (i.e. before the advent of ceramics), Neolithic (where ceramics have appeared), and Metal Age (where both ceramics and metal are present). The River Cagayan flows about 446 km from its headwaters in the Caraballo Mountains of central Luzon to the Babuyan Chanel where it enters the sea. The Cagayan coastal alluvial plain first formed about 7000 years ago, when rising post-glacial sealevels turned the area from a remote mountain valley into a coastal riverplain. Because Luzon is an volcanic oceanic island (albeit a rather large one), it has no surrounding continental shelf, instead rising sharply from the deep ocean. At the Last Glacial Maximum (between about 24 000 and 18 000 years ago) the sea level would have been about 120 m lower, with the Cagayan Estuary extending inwards about 100 km. It is quite possible that there are coastal and riverplain settlements lower down in the valley, but these would now be submerged and covered by metres of sediment.

(1) The Cagayan River in the Lal-Lo area; (2) part of the Magapit shell midden; (3) archaeological excavation of square P15 at Nagsabaran; (4) the Nagsabaran site, viewed from a distance. Hsiao-chun Hung in Hung et al. (2022).

The first shell midden in the Cagayan Valley was discovered at Magapit in 1971. Since this time a further 30 such shell middens have been discovered in the area, the densest concentration of shell middens anywhere in Island Southeast Asia, a reflection of the abundant shellfish available in the area in the Middle Holocene.

Most of these sites are located along a 30 km stretch of the valley between the cities of Gattaran and Lal-lo. To the north of Lal-lo the alluvium is to young to contain Neolithic sites. All of the Neolithic shell middens have been located either because they were exposed by the river cutting into them, or because they formed distinct, visible mounds. The middens are made up predominantly of shells of the Kabibe Clam, Batissa childreni, with smaller numbers of other Molluscs present, including the freshwater Snails Thiara rudis, Thiara winteri, Melanoides tuberculata, Melanoides granifera, and Melanoides maculata, the freshwater Clam Corbicula fluminea and the marine Clam Nitidotellina minuta. The largest shell middens are more than 5 m deep, and many overlie layers containing pottery or other Neolithic artifacts.

As well as the shell middens, there are a number of other archaeological sites in the region, particularly in the limestone hills to the east. These include deposits which run from the Preceramic to Metal Age periods, including evidence of interactions between foraging and farming communities. The largest of these sites is at Callao Cave, and includes remains attributed the Hominin Homo luzenonsis, which lived in the area more than 50 000 years ago.

The shell middens contain layers covering time intervals from the Preceramic to the Metal age, although no midden covers the whole of this period. The Gaerlan Midden, on the east side of the river 45 km upstream of its mouth, contains Preceramic and Neolithic layers, the latter containing potsherds, while the Lal-lo, Catugan, Irigayen, and Nagsabaran middens contain Neolithic and Metal Age layers, with the Neolithic layer, including red-slipped and incised pottery, extends downwards beyond the shell middens.

While none of the middens record the full 7000 years of occupation in the valley, some of the other archaeological sites might. For example the Pintú Rockshelter, 250 km to the south of Lal-lo, has a sequence of core-and-flake stone tools which appear to span the whole sequence, with pottery fragments in the middle and upper layers. Tadiocarbon dates obtained from the Pintú Rockshelter give dates from the Preceramic layers, of roughly 4960-3683 years ago, while layers containing 'reddish-orange ware' with stamped circles on the interior of the rims, similar to that found in the Cagayan Valley, appear between 4100 and 2949 years ago.

The oldest, Preceramic, shell midden layers are found at four sites, Ulet, Leodivico Capiña, Miguel Supnet and Gaerlan. These sites would have been close to a broader Cagayan Estuary between 7000 and 4200 (the estuary has moved northwards since this time as more sediment has been washed down the river and deposited). 

The oldest site, at Ulet, has yielded stone flakes but no pottery from a layer dated to between 6745 and 6495 years before the present. The Gaerlan site has a lower layer from which chert and andesite flakes have been recovered, which has been dated to 4295-4090 years before the present, overlain by a younger layer with red-slipped pottery fragments, dated to 4092-3687 years before the present.

The major archaeological sites and landscape changes through time in the lower Cagayan Valley: (1) Ulet; (2) Leodivico Capiña; (3) Callao Cave; (4) Musang Cave; (5) Arku Cave; (6) Miguel Supnet; (7) Gaerlan; (8) Nagsabaran; (9) Irigayen; (10) Magapit; (11) Pamittan; (12) Andarayan. Mike Carson in Hung et al. (2022).

The Leodivico Capiña and Miguel Supnet sites are 1.5 and 3 m deep shell middens on the west bank of the river which have yielded chert flakes and bones attributed to Wild Pigs, Deer, Rats, Birds, Turtles, and Fish, and Plant remains including nuts and tubers, but no evidence for cereals. When first discovered in the 1990s these sites were interpreted as Neolithic, due to the large amounts of pottery found in the topsoil above the middens, but neither has produced any pottery or other material associated with the Philippines Neolithic from the midden layers, and the sites are now considered to be Preceramic. Dates produced from material from the midden layers range from 7074 to 4514 years before the present.

Shell middens dating from over 7000 years ago to about 4500 years ago have been found in Vietnam, Thailand, Peninsula Malaysia, Sumatra, Sulawesi, Mindanao, and southern China. Many of these are associated with the skeletal remains of people thought to be of Melanesian affinities, and some sites in southern China and Vietnam have also included pottery. However, none of the Cagayan Valley sites of this age have produced either pottery or Human remains.

The location of the study area (lower Cagayan Valley, North Luzon), and the locations of representative (pre-farming) shell middens in southern China and Southeast Asia during the Middle Holocene, roughly 7000–4500 years before present. Hung et al. (2022).

The arrival of the Neolithic in the Cagayan Valley can be marked by the appearance of a complete new tool-set including pottery, baked clay spindle whorls, polished stone adzes, bark-cloth beakers, and a range of body ornaments including ear-pendants, bracelets, and beads made from shells, clay, schist, and semi-precious stones, including jade from Fegtian in eastern Taiwan. Stone tools from this period include few chert flakes, with most tools being highly polished.

Nagsabaran Metal Age Indo-Pacific glass beads (1), bronze bell-shaped ornaments (2), iron knife (3) and black pottery (4)–(12); Neolithic red-slipped pottery (13)–(14), clay spindle whorls (15)–(16), clay object (17), flaked chert (18)–(19), polished andesite adze (20), tuffaceous sandstone stepped-adze preform (21), green quartz schist beads (22) and Taiwan nephrite bracelet fragment (23). Scale bars are in centimetres. Hsiao-chun Hung in Hung et al. (2022).

The earliest of these sites can be dated to about 4200-4000 years before the present, with culturally similar sites of the same age also appearing in the Batanes Islands to the north. The Batanes Islands and Luzon are thought to have been settled at roughly the same time by people with a common linguistic and cultural heritage; however the two areas differ in that these were (as far as we can tell) the first people to settle the Batanes Islands, whereas the new arrivals on Luzon were entering a landscape already inhabited by an earlier, and culturally different, population.

The middens at Nagsbaran and Magapit contain layers assigned to the Neolithic contain the bones of Domestic Pigs, which have been dated to between 4448 and 4246 years before the present. These layers also contain remains of Rice, and Job's Tears (Adlay Millet or Chinese Pear Barley). Foxtail Millet is also present at Magapit - but does not appear till the Metal Age. A Rice grain from Magapit produced a radiocarbon date of 3200-3000 years before the present. Possible phytoliths (mineral grains that develop inside the leaves of a Plant) from Bananas were also found at Magapit.

Plant remains from Nagsabaran (a)–(c) and Magapit (d)–(f): (a) & (d) Rice, Oryza sativa, grains; (b) Foxtail Millet, Setaria italica, grain; (c) Job’s Tear, Coix lacryma-jobi, grain; (e) Rice spikelet base; (f) phytolith of cf. Musa sp.; item (b) is Metal Age, while all others are from Neolithic layers. Zenhua Deng in Hung et al. (2022).

Recent studies have uncovered evidence for mixed Rice and Millet agriculture during the Neolithic, from sites on the Pearl River Delta in Guangdong Province, China (dated to 4800-4600 years before the present), and Nanguanglidong in southern Taiwan (dated to more than 4500 years before the present).

The Andarayan site, which is about 80 km to the south of Magapit, has produced Neolithic red-slipped pottery from a layer which has yielded dates of 3935-3378 years before the present (from a Rice inclusion) and 3890-3060 years before the present (from a charcoal fragment). This provides three examples of Neolithic Rice production from separate sites within the Cagayan Valley, despite the alluvial plains being much smaller and less well developed at this time.

The Neolithic pottery fragments recovered from shell middens in the Cagayan Valley can be distinguished by the use of sand as a tempering agent (something added to clay to prevent pottery from cracking as it cools after baking) and the use of a red slip (a slurry added as an outer layer to form a sort of glaze). Similar pottery has been found at the Andarayan site, and at Chaolaiqiao in southeastern Taiwan, at Minanga Sipakko in West Sulawesi, and at Yinian on southeastern Hainan Island, where it has been dated to 3560-3380 years before the present. 

The presence of this distinctive pottery on Hainan is interesting, as Hainan has not previously considered to have been part of the Neolithic Austronesian expansion. The Tsat language spoken on Hainan was brought to the island by a population from northern Cham, in what is now Vietnam, fled to the island in 982 AD, following the fall of their capital to the Vietnamese. The minority Hlai people of the island speak a language called  Kra-Dai, which some linguists have suggested is related to Austronesian languages, and in particular languages from the Malayo-Polynesian branch of Austronesia, which are spoken across Island Southeast Asia. 

About 1% of the red-slipped ware from sites in the Cagayan Valley is also marked with incised and impressed decorations, and stamped geometric shapes. The most common patterns are rows of rounded or pointed impressions, intermixed with round stamps, sometimes within fields outlined with incised lines. These patterns are most common around the rims, shoulders, and feet of the vessels, where they form strait or zigzagged lines, or sometimes other geometric patterns. Some of the impressions contain traces of a white infill.

Examples of this pottery have been found in the shell middens at Gaerlan, Irigayen, Nagsabaran, and Magapit. The precise date at which such pottery appears is impossible to determine, but based upon stratigraphic extrapolation from radiocarbon dated material, Hung et al. place this somewhere between 3700 and 3500 years before the present. 

Pottery with similar patterns, including the presence of white infill material, has been found at the Neolithic sites of Man Bac and Xom Ren in Vietnam, where it has been dated to between 3900 and 3500 years before the present, although this pottery lacks the red slip seen on the pottery from Luzon and elsewhere in Island Southeast Asia. Baked clay earings of similar form have also been found in both Cagayan sites and northern Vietnam, further supporting the idea of contact between these areas in the Neolithic.

Red-slipped pottery (1)–(5), (7)–(9) & (11)–(14) and associated Rice, Oryza sativa, remains (6) & (15) phytoliths, (10) grain, from Chaolaiqiao, Nagsabaran, Yinian and Minanga Sipakko. Incised and impressed red-slipped pottery from Magapit: (16) open-mouthed pot on a pedestal, shown upside-down to reveal the stamped circles and possible fingernail impression decoration; (17) punctate-stamped sherd with lime or white clay infill in decoration; (18) sherd also displaying traces of white infill in incised lozenge motif with punctate infilling and impressed circles. Similarly decorated, red-slipped pottery from Nagsabaran (19)–(20) and Xom Ren (26)–(30) but without red slip. Baked clay earrings from Nagsabaran (21)–(25) and similar from Thach Lac (31)–(34). Hung et al. (2022).

Overlaying the Neolithic layers with red-slipped pottery at many of the Cagayan Valley sites, are later layers with black-slipped pottery. This can be achieved by firing the clay in an oxygen-deprived environment, possibly beneath Rice husks. This pottery is associated with metal objects, including iron blades and bronze ornaments, as well as monochrome glass beads. The origin of these metal objects is uncertain, but the glass beads, and similar glass beads from elsewhere in the Indo-Pacific, are thought to originate from South Asia or Mainland Southeast Asia.

Although the black-slipped and red-slipped potteries are distinct in form, the Magapit and Nagsabaran sites contain transitional layers, with both types of pottery present, suggesting that one did not suddenly displace the other. In addition, studies of DNA obtained from skeletal remains at Nagsabaran show affinities with the modern Ami people of eastern Taiwan, supporting the idea that there was a genetic continuity from the Neolithic into the metal age, despite the cultural change, although no DNA has been recovered from Neolithic skeletons in the area. 

The shell middens of the lower Cagayan Valley provide a unique archaeological resource within the Philippines, giving a more-or-less continuous record from the Preceramic hunter-gatherers of the Middle Holocene (roughly 7000 years ago), through the Neolithic and Metal Age periods into recent times; modern villagers in the area still consume shellfish and contribute to shell middens.

By the advent of the Neolithic, many of these shell middens were already covered large areas and were several metres deep. Similar shell middens are also known from other sites in South China, Vietnam, and Malaysia, but these were largely abandoned during the Neolithic, following the adoption of a Rice-farming lifestyle, whereas those in the Cagayan Valley continued to grow.

The Neolithic inhabitants of Luzon Island are known to have been highly skilled in the production and use of canoes, and to have produced a type of red-slipped pottery also found far from the island; examples have been found on Hainan Island 1000 km to the west, in the Mariana Islands, 2500 km to the east, on Sulawesi 1200 km to the south, and in the Bismark Archipelago, 3500 km to the southeast. This strongly supports the idea that, while Taiwan is still the undisputed ancestral homeland of the Austronesian language family and Malayo-Polynesian peoples, the island of Luzon, and in particular the Cagayan Valley, were very important steps in their early dispersal.

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Tuesday, 2 August 2022

First recording of a Light-mantled Albatross from Asia.

Albatrosses, Diomedeidae, are large-bodied Seabirds with an almost entirely Southern Hemisphere distribution. The Light-mantled Albatross, Phoebetria palpebrata, is generally restricted to Southern Ocean. This species is currently considered Near Threatened under the terms of the International Union for the Conservation of Nature's Red List of Threatened Species, largely due to their being caught as bycatch by longline fisheries. The global population of Light-mantled Albatrosses was last estimated at 21 600 breeding pairs in 1998.

In a paper published in the Journal of Threatened Taxa on 26 July 2022, Hameed Byju of the Centre of Advanced Study in Marine Biology at Annamalai University, and Natarajan Raveendram of the Iragukal Amritha Nature Trust record of a Light-mantled Albatross from Rameswaram Island, off the southeast coast of Tamil Nadu State, India, which is, to the best of their knowledge, the first recording of this Bird from anywhere in Asia.

The Albatross was first spotted on 8 September 2020, in on Anthoniyapuram Beach by local fishermen, who informed the Tamil Nadu Forest Department as the Bird appeared weak and unable to fly. The Albatross was collected and allowed to rest, before flying away. It would not take food.

A Light-mantled Albatross, Phoebetria palpebrata, on Anthoniyapuram Beach on Rameswaram Island, Tamil Nadu, on 8 September 2022. Francis Aravind in Byju & Raveendram (2022).

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Investigations begin after a giant sinkhole opens up near a copper mine in Chile.

Authorities in Chile have opened an investigation after a giant sinkhole opened up close to a copper mine in Copiapó Province, Chile, on Saturday 30 July 2022. Sernageomin, the body responsible for mine safety in Chile, ordered all activities to cease at the mine pending the outcome of the investigation, after it was made aware of the situation at the Alcaparossa Mine on Sunday 31 July. The mine's owners, the Canadian mining giant Lundin Mining, have issued a statement to the effect that no workers have been harmed by the event, but has otherwise declined to comment at this time. The sinkhole is described as being 25 m across, at least 600 m across, and flooded at the bottom.

A giant sinkhole which opened up close to the Alcaparossa Copper Mine near the town of Tierra Amerilla in Copiapó Province, Chile, on Saturday 30 July 2022. Reuters.

Sinkholes are generally caused by water eroding soft limestone or unconsolidated deposits from beneath, causing a hole that works its way upwards and eventually opening spectacularly at the surface. Where there are unconsolidated deposits at the surface they can infill from the sides, apparently swallowing objects at the surface, including people, without trace. 

While the vast majority of sinkholes are natural in origin, the mining industry clearly has the capacity to bring about conditions leading to sinkholes, and sinkholes at mining, or former mining, sites are a problem around the world. The most obvious way in which a mine can cause a sinkhole is by direct undermining; over-enthusiastic removal of material without leaving enough in place to support the overlying rocks will eventually lead to a collapse, and often a sinkhole at the surface. However, sinkholes often occur in places close to mines but where the mine does not pass directly underneath. This is usually as a result of the mine providing a conduit through which water enters susceptible strata, leading to erosion and sinkhole formation away from the mining activity.

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Three-dimensionally preserved Dinosaur remains from a new Jehol Biota outcrop in Inner Mongolia.

The Jehol Biota produces a wide range of exquisitely preserved Early Cretaceous fossils from locations across Liaoning, Inner Mongolia, and Hebei provinces in northeastern China. However, in almost all cases these are two-dimensionally preserved (i.e. flattened), with only a single site, an outcrop of the the Lujiatun Unit of the Yixian Formation in western Liaoning, producing fossils in three dimensions. The fossils from this location are predominantly Dinosaurs, with some Lizards and Mammals, and show signs of representing an area with an area with a different faunal composition and ecology to the rest of the Jehol Biota, as well as having a different taphonomy (mode of preservation).

In a paper published in the journal Acta Palaeontologica Polonica on 20 June 2022, Honggang Zhang of the College of Earth Science and Engineering, and Paleontological Institute at Shandong University of Science & Technology, Dongxiang Yu, also of the College of Earth Science and Engineering at Shandong University of Science & Technology, Yuhui Feng, also of the Paleontological Institute at Shandong University of Science & Technology, Rui Pei of the Key Laboratory of Evolutionary Systematics of Vertebrates at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, and Chang-Fu Zhou, again of the College of Earth Science and Engineering at Shandong University of Science & Technology, describe a second outcrop producing three-dimensionally preserved fossils from the Jehol Biota, this time located in the Ningcheng Basin of Inner Mongolia.

The new outcrop, at a site called Xidayingzi in Ningcheng County, comprises an outcrop of interbedded volcanic and sedimentary rocks about 80 m thick. The volcanic rocks here are predominantly basaltic andesites, rhyolitic breccia lavas and andesitic tuffs, while the sedimentary units are gravel-rich siltstones, sandstones, and conglomerates, all containing volcanically derived material.

Map of the Inner Mongolia, Liaoning and Hebei (A) showing location of the Xidayingzi site and the outcrops of the Lujiatun Unit of the Yixian Formation of the Jehol Biota in Beipiao, western Liaoning Province. Stratigraphic column (B) and corresponding photographic image (C) of the Early Cretaceous Xidayingzi site. Zhang et al. (2022).

Initial investigations at this site uncovered the remains of Dinosaurs from four different groups, plus Lizard and Mammal remains, all preserved in three dimensions and many in a semi-articulated state, although most material is individual bones.

Fossils found in the Xidayingzi site from the Early Cretaceous Ningcheng Basin, Inner Mongolia. (A) Sinovenator-like Troodontid Dinosaur (SDUST-V1062), the left pes is exposed in medial view. (B) Ceratopsian Dinosaur Psittacosaurus sp. (PMOL-AD00163), the maxilary teeth are loosely arranged and exposed in lateral view. (C) Neornithischian Dinosaur Jeholosaurus sp. (SDUST-V1063), the scapulocoracoid, humerus, ulna, and radius in lateral view. (D) Euhelopus-like Sauropod (SDUST-V1064), digital image of the tooth crown in medial view. (E) Indeterminated Lizard (PMOLAR00268), digital image of the fragmentary mandible in lingual view. (F) Symmetrodont-like Mammal (PMOL-AM00036), digital image of the mandible in lingual view. Zhang et al. (2022).

The most notable specimen from the site (SDUST-V1062) is the articulated post-cranial skeleton of a Troodontid Dinosaur, possibly a specimen of Sinovenator; the specimen resembles Sinovenator changii in most regards, but differs in having having a round anterior margin of the preacetabular process of the ilium and a moderately developed ambiens process of the pubis, and may therefore represent a second species in the genus.

Three Sauropod teeth were found at the site, two of them well preserved and similar to those of Euhelopus, a Titanosauriform of similar age to the Jehol Biota, but not previously reported from there.

Eight Neornithischian Dinosaur fossils were found at the site, with four being semi-articulated partial postcranial skeletons. These all resemble  Jeholosaurus shangyuanensis, a small Neornithischian previously only known from the Lujiatun Unit of the Jehol Biota.

Six specimens of Ceratopsian Dinosaurs were found, although these were rather fragmentary in nature. All appear similar to the early-diverging Psittacosaurus, often used as an index fossil for the Lower Cretaceous in East Asia, and common in the Jehol Biota. Curiously, the maxillary teeth of the new specimens appear to be spaced apart rather than being imbricated as in all other known Psittacosaurs, which may again indicate they belong to a new species.

A single fragment of a Lizard mandible (PMOL-AR00268) was found. This has pleurodont, conical, single-cusped, and closely packed teeth, which, are features common in a range of Mesozoic Lizards, and not helpful diagnostically.

Mammals are also represented by a single mandible (PMOL-AM00036), which has one premolar, five molars, and eight empty alveoli; the molars have acutely-triangulated molar cusps, which allows the specimen to be referred to the Symetrodonts, although this is a polyphyletic assemblage of Mammals, made up of members of different groups which converged on a similar morphology, possibly as a response to some Mesozoic ecological condition.

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Monday, 1 August 2022

Magnitude 5.6 Earthquake off the coast of Balochistan Province, Pakistan.

The United States Geological Survey recorded a Magnitude 5.6 Earthquake at a depth of 10.0 km, roughly 14 km off the coast of the city of Pasni in Balochistan Province, Pakistan, slightly after 6.40 pm local time (slightly after 2.40 pm GMT), on Sunday 31 July 2022.There are no reports of any damage or injuries associated with this event, though it was felt locally.

The location of the 31 July 2022 Balochistan Earthquake. USGS.

Pakistan lies on the boundary between the Indian and Eurasian tectonic plates, which runs through northern Afghanistan. The Indian Plate is moving northward relative to the Eurasian Plate, causing folding and uplift along this boundary, which has led to the formation of the Hindu Kush Mountains of Afghanistan, the Himalayas and the other mountain ranges of Central Asia., and which makes the nations in this boundary zone prone to Earthquakes.

Plate boundaries and movements beneath southern Pakistan, Iran and the Arabian Sea. University of Southampton.

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Thirty seven Cholera related deaths in Somalia so far this year.

Between 1 January to 10 July 2022, a cumulative number of 7796 cases of Cholera including 37 associated deaths (a case fatality ratio of 0.5%) have been reported from 25 drought-affected districts, according to a press release issued by the World Health Organization on 20 July 2022. Cholera is endemic in Somalia with recurrent outbreaks reported since 2017. 

The current Cholera outbreak is taking place in the context of other ongoing outbreaks, high rates of malnutrition, and the escalating drought, all of which are exacerbating the fragility of Somalia’s humanitarian situation and have led to large displacement of people, placing additional pressure on an already over-burdened and underperforming healthcare system. Currently, the country has limited capacity to respond to the outbreak, increasing the risk of serious public health impact.

From 1 January to 10 July 2022, according to the Ministry of Health Somalia, a cumulative number of 7796 cases of cholera including 37 associated deaths have been reported from 25 drought-affected districts in Banadir region, South-West State and Hirshabelle State. The districts reporting the highest number of cases include Baidoa (2033), Daynile (1080), Jowhar (825) and Afgoi (681). In addition to being the drought-affected districts, many of these districts also host Internally Displaced Populations in camps resulting from three decades of conflict and the escalating drought situation.

Geographic distribution of Cholera cases in Somalia (%) from 1 January to 10 July 2022. World Health Organization.

Over half of the cases (53.5%) were among children below two years of age, with males and females equally affected. Severe dehydration was reported in 27% of cases.  None of the cases reported having received .Oral Cholera Vaccine  Oral Cholera Vaccine campaigns were carried out in Somalia in 2017, 2018 and 2019.

As of 10 July, a total of 677 stool samples were collected and analysed (by culture) by the National Public Health Laboratory in Mogadishu. Of these, 145 samples (21.4%) tested positive for Vibrio cholerae.

The number of cases reported in the first six months of 2022 has exceeded the number of cases reported in 2021 in the same drought affected districts, when a total of 6205 acute watery diarrhoea/suspected cholera cases including 39 deaths (a case fatality ratio of 0.63%) were reported. In 2021, the outbreak started following flash floods.

Number of suspected Cholera cases in Somalia reported from 1 January 2021 through 10 July 2022. World Health Organization.

Cholera is an acute enteric infection caused by ingesting the Bacterium Vibrio cholerae, a Gram-negative, comma-shaped Gammaproteobacteria, related to other pathogenic Bacteria such as Yersinia pestis (Bubonic Plague), and Esherchia coli (food poisoning), which present in contaminated water or food. It is mainly linked to insufficient access to safe drinking water and inadequate sanitation. It is an extremely virulent disease that can cause severe acute watery diarrhoea resulting in high morbidity and mortality, and can spread rapidly, depending on the frequency of exposure, the exposed population and the setting. Cholera affects both children and adults and can be fatal if untreated.

SEM image of Vibrio cholerae Bacteria. Kim et al. (2000).

The incubation period is between 12 hours and five days after ingestion of contaminated food or water. Most people infected with Vibrio cholerae do not develop any symptoms, although the Bacteria are present in their faeces for 1-10 days after infection and are shed back into the environment, potentially infecting other people. Among people who develop symptoms, the majority have mild or moderate symptoms, while a minority develop acute watery diarrhoea with severe dehydration. Cholera is an easily treatable disease. Most people can be treated successfully through prompt administration of oral rehydration solution.

Cholera can be endemic or epidemic. A Cholera-endemic area is an area where confirmed Cholera cases were detected during the last three years with evidence of local transmission (cases are not imported from elsewhere). A Cholera epidemic can occur in both endemic countries and in non-endemic countries. Uninfected dead bodies have never been reported as the source of epidemics.

The consequences of a humanitarian crisis – such as disruption of water and sanitation systems, or the displacement of populations to inadequate and overcrowded camps – can increase the risk of Cholera transmission, should the bacteria be present or introduced.

A multisectoral approach including a combination of surveillance, improving access to clean water, sanitation, and hygiene promotion, rapid access to treatment, risk communication and community engagement and oral cholera vaccines is essential to control cholera outbreaks and to reduce deaths.

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Fireball meteor over Texas.

The American Meteor Society has received reports of a bright fireball meteor being seen over Texas slightly after 10.25 pm local time on Sunday 24 July 2022 (slightly after 3.25 am on Monday 25 July, GMT). People witnesses observing the event from Texas, Louisiana, and Oklahoma, reporting that it moved roughly southeast to northwest. 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. 

Image of the 24 July 2022 Texas Fireball Meteor captured by a Doorbell Camera in College Station, Texas. American Meteor Society.

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).

Heat map showing areas where sightings of the meteor were reported (warmer colours indicate more sightings), and the apparent path of the object (blue arrow). American Meteor Society. 

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.

Witness reports can help astronomers to understand these events. If you witness a fireball-type meteor over the US you can report it to the American Meteor Society here. 

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