The Ob River , also Obi, is a major river in western Siberia, Russia and is the world’s fifth longest river. It is the westernmost of the three great Siberian rivers that flow into the Arctic Ocean (the other two being the Yenisei River and the Lena River). The Gulf of Ob is the world’s longest estuary.
The Ob is known to the Khanty people as the As, Yag, Kolta and Yema; to the Nenets people as the Kolta or Kuay; and to the Siberian Tatars as the Umar or Omass. Possibly from Proto-Indo-Iranian *ap- ‘river, water’ (compare Tajik ob, ‘water’).
Geography
Map of the Ob River watershed
The Ob forms 16 miles (26 km) southwest of Biysk in Altai Krai at the confluence of the Biya and Katun rivers. Both these streams have their origin in the Altay Mountains, the Biya issuing from Lake Teletskoye, the Katun, 700 kilometres (430 mi) long, bursting out of a glacier on Mount Byelukha.
The river splits into more than one arm, especially after joining the large Irtysh tributary at about 69° E. (Originating in China, the Irtysh is actually longer than the Ob from source to the point of their confluence.) From the source of the Irtysh to the mouth of the Ob, the river flow is the longest in Russia at 5,410 kilometres (3,360 mi). Other noteworthy tributaries are: from the east, the Tom, Chulym, Ket, Tym and Vakh rivers; and, from the west and south, the Vasyugan, Irtysh (with the Ishim and Tobol rivers), and Sosva rivers.
The Ob zigzags west and north until it reaches 55° N, where it curves round to the northwest, and again north, wheeling finally eastwards into the Gulf of Ob, a 600-mile (970 km)-long bay of the Kara Sea, separating the Yamal Peninsula from the Gydan Peninsula.
The combined Ob-Irtysh system, the third-longest river system of Asia (after China’s Yangtze and Yellow rivers), is 5,410 kilometres (3,360 mi) long, and the area of its basin 2,990,000 square kilometres (1,150,000 sq mi). The river basin of the Ob consists mostly of steppe, taiga, swamps, tundra, and semi-desert topography. The floodplains of the Ob are characterized by many tributaries and lakes. The Ob is ice-bound at southern Barnaul from early in November to near the end of April, and at northern Salekhard, 100 miles (160 km) above its mouth, from the end of October to the beginning of June. The Ob River crosses several climatic zones. The upper Ob valley, in the south, grows grapes, melons and watermelons, whereas the lower reaches of the Ob are Arctic tundra. The most comfortable climate for the rest on the Ob – are Biysk, Barnaul, and Novosibirsk.
Note : The above story is based on materials provided by Wikipedia
Chemical Formula: Na2Be2Si6O15 · H2O Locality: Island of Aro, Langesundfiord, Norway. Name Origin: From the Greek epi, “near” and didymos, “twin”, for its dimorphous relationship with eudidymite
Blame the grasses (Image: Per Moller/Johanna Anjar)
IT WAS the superfoods wot dunnit. Woolly mammoths may have starved to death when changes in the climate deprived them of their best food: flowering herbs.
Perhaps unexpectedly given their size and the chilly climates they lived in, woolly mammoths are thought to have survived on a diet of steppe grasses. But that’s not the whole story. A study of frozen stomach contents and frozen DNA found in the dirt across the Arctic suggests that the ice-age megafauna primarily ate a richer class of plants called forbs.
At first glance the difference seems negligible. Forbs are flowering herbs, and modern examples include clover. But whereas grasses are tough to digest and relatively low in nutrients, forbs are high in protein.
By painstakingly looking at the plant DNA found in permafrost samples dug out of 200 locations across the Arctic, Eske Willerslev at the University of Copenhagen in Denmark and his colleagues were able to paint a picture of the landscape between 50,000 years ago and today. They found that at first, the far north was covered in a rich diversity of forbs. What’s more, the gut contents of some of the big animals that lived in the region, like mammoths and woolly rhinoceroses, showed that these nutritious wild flowers were an important part of their diet (Nature, DOI: 10.1038/nature12921).
“This is technically a great achievement,” says Adrian Lister of the Natural History Museum in London.
But the forbs didn’t last. “Around 20,000 years ago, at the height of the ice age, the environment became very, very cold and dry, and we see a major drop-off in the diversity of forbs,” says Willerslev. “They still dominate the ecosystem, but their diversity declines.”
The real killer came at the end of the ice age 12,000 years ago. Grasses and shrubs began to take the place of the forbs – a change in the landscape that coincided with the decline of the iconic ice-age megafauna. As forbs are stimulated by being trampled underfoot, the decline in forbs from 20,000 years ago probably brought about a feedback cycle in which having fewer animals caused plant diversity to fall, further reducing food supplies and animal populations.
“Our study really changes the general concept that before the last warming period you had a massive grass steppe that was fundamental to sustaining a huge diversity of mammals,” says Willerslev. “In fact it was a diverse steppe of forbs and these were probably crucial.”
The theory may also explain why reindeer were the only big ice-age animalsMovie Camera to survive. Today, reindeer munch on grasses and sedges in summer, and eke a living out of low-energy lichen in the winter. The forbs’ decline would have passed them by.
Note : The above story is based on materials provided by Catherine Brahic to newscientist
Mineral mining is on hold (Image: Nautilus Minerals)
Deep-sea mining is floundering. The leading company in the race to mine the ocean floor has fallen out with its host government, while other projects have been delayed until the environmental effects are better understood.
In 2011, Papua New Guinea gave Canadian firm Nautilus Minerals a licence to mine a field of hydrothermal vents in its waters, called Solwara 1, provided the country could buy a 30 per cent stake. The vents contain high-grade metal ores, including copper that is far more concentrated than most land-based deposits.
Scientists say the vents need more study first. “We don’t know enough about the ecology, the ecosystems and the resilience of these systems,” says Joanna Parr of CSIRO in Sydney, Australia.
Now Nautilus claims Papua New Guinea hasn’t paid up, so it is ending the agreement and suing for damages.
Race to the bottom
Nautilus was racing to be the first in the world to mine the sea floor. Now UK Seabed Resources, a subsidiary of Lockheed Martin, could take the lead. It has a licence to explore an area of the Pacific sea floor in international waters for minerals.But it has a lot of work to do to catch up with Nautilus. “There is no proposed mining operation similar to that proposed for Solwara at such an advanced stage,” says Parr.
Meanwhile some governments are delaying deep-sea mining for ecological reasons, says Parr, with moratoria off the coasts of Australia and Namibia.
“Governments are realising this isn’t just a flash in the pan,” she says. “It’s something that is building towards an industry.”
Note : The above story is based on materials provided by Michael Slezak to newscientist
Eosphorite on Rose Quartz with Zanazziite Taquaral, Minas Gerais, Brazil Small Cabinet, 5.9 x 4.7 x 3.3 cm “Courtesy of Rob Lavinsky, The Arkenstone, www.iRocks.com”
Chemical Formula: (Mn,Fe)Al(PO4)(OH)2 · H2O Locality: Branchville, Fairfield County, Connecticut, USA. Name Origin: Named from the Greek for “dawn-bearing,” in allusion to the pink color.Eosphorite is a pink manganese hydrous phosphate mineral with chemical formula: (Mn,Fe)Al(PO4)(OH)2 · H2O.
Eosphorite crystallizes in the monoclinic crystal system. It forms slender prismatic crystals which often form radiating or spherical clusters. The crystals often show pseudo–orthorhombic forms due to twinning.
Eosphorite forms a series with childrenite, the iron rich member, with divalent iron replacing most of the manganese in the crystal lattice. The two endmembers are isostructural but differ in their properties, such as crystal habit, coloration, and optical properties.
It was first described in 1878 for an occurrence in the Branchville Mica Mine in Branchville, Fairfield County, Connecticut, USA. Its name is derived from the Greek έωσφορος for “dawn-bearing,” because of its pink color. It occurs worldwide typically as a secondary mineral in phosphate rich granitic pegmatites in association with rhodochrosite, lithiophilite, triphylite, triploidite, dickinsonite, albite, cookeite, apatite, beryllonite, hydroxyl-herderite, and tourmaline. An attractive combination of eosphorite and rose quartz occurs at Taquaral, Minas Gerais, Brazil.
The Ordovician /ɔrdəˈvɪʃən/ is a geologic period and system, the second of six of the Paleozoic Era, and covers the time between 485.4 ± 1.9 to 443.4 ± 1.5 million years ago (ICS, 2004). It follows the Cambrian Period and is followed by the Silurian Period. The Ordovician, named after the Celtic tribe of the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same rock beds in northern Wales into the Cambrian and Silurian periods respectively.
Lapworth, recognizing that the fossil fauna in the disputed strata were different from those of either the Cambrian or the Silurian periods, realized that they should be placed in a period of their own. While recognition of the distinct Ordovician Period was slow in the United Kingdom, other areas of the world accepted it quickly. It received international sanction in 1960, when it was adopted as an official period of the Paleozoic Era by the International Geological Congress.Life continued to flourish during the Ordovician as it did in the Cambrian, although the end of the period was marked by a significant mass extinction. Invertebrates, namely mollusks and arthropods, dominated the oceans. Fish, the world’s first true vertebrates, continued to evolve, and those with jaws may have first appeared late in the period. Life had yet to diversify on land.
Ordovician-Silurian extinction event- occurred at the end of the period approximately 443 million years ago. 60% of marine genera went extinct. The cause of the extinction was predicted to be a gamma-ray burst.
Cambrian-Ordovician extinction event- occurred at the start of the period 485 million years ago.
Dating
The Ordovician Period started at a major extinction event called the Cambrian–Ordovician extinction events about 485.4 ± 1.9 Mya (million years ago), and lasted for about 44.6 million years. It ended with the Ordovician–Silurian extinction event, about 443.4 ± 1.5 Mya (ICS, 2004) that wiped out 60% of marine genera.
The dates given are recent radiometric dates and vary slightly from those used in other sources. This second period of the Paleozoic era created abundant fossils and in some regions, major petroleum and gas reservoirs.
The boundary chosen for the beginning both of the Ordovician Period and the Tremadocian stage is highly useful. Since it correlates well with the occurrence of widespread graptolite, conodont, and trilobite species, the base of the Tremadocian allows scientists not only to relate these species to each other, but to species that occur with them in other areas as well. This makes it easier to place many more species in time relative to the beginning of the Ordovician Period.
Subdivisions
A number of regional terms have been used to refer to subdivisions of the Ordovician Period. In 2008, the ICS erected a formal international system of subdivisions, illustrated to the right.
The Ordovician Period in Britain was traditionally broken into Early (Tremadocian and Arenig), Middle (Llanvirn [subdivided into Abereiddian and Llandeilian] and Llandeilo) and Late (Caradoc and Ashgill) epochs. The corresponding rocks of the Ordovician System are referred to as coming from the Lower, Middle, or Upper part of the column. The faunal stages (subdivisions of epochs) from youngest to oldest are:
Late Ordovician
Hirnantian/Gamach (Ashgill)
Rawtheyan/Richmond (Ashgill)
Cautleyan/Richmond (Ashgill)
Pusgillian/Maysville/Richmond (Ashgill)
Middle Ordovician
Trenton (Caradoc)
Onnian/Maysville/Eden (Caradoc)
Actonian/Eden (Caradoc)
Marshbrookian/Sherman (Caradoc)
Longvillian/Sherman (Caradoc)
Soudleyan/Kirkfield (Caradoc)
Harnagian/Rockland (Caradoc)
Costonian/Black River (Caradoc)
Chazy (Llandeilo)
Llandeilo (Llandeilo)
Whiterock (Llanvirn)
Llanvirn (Llanvirn)
Early Ordovician
Cassinian (Arenig)
Arenig/Jefferson/Castleman (Arenig)
Tremadoc/Deming/Gaconadian (Tremadoc)
British stages
The Tremadoc corresponds to the (modern) Tremadocian. The Floian corresponds to the lower Arenig; the Arenig continues until the early Darriwilian, subsuming the Dapingian. The Llanvirn occupies the rest of the Darriwilian, and terminates with it at the base of the Late Ordovician. The Sandbian represents the first half of the Caradoc; the Caradoc ends in the mid-Katian, and the Ashgill represents the last half of the Katian, plus the Hirnantian.
Paleogeography
Sea levels were high during the Ordovician; in fact during the Tremadocian, marine transgressions worldwide were the greatest for which evidence is preserved in the rocks.
During the Ordovician, the southern continents were collected into a single continent called Gondwana. Gondwana started the period in equatorial latitudes and, as the period progressed, drifted toward the South Pole. Early in the Ordovician, the continents Laurentia (present-day North America), Siberia, and Baltica (present-day northern Europe) were still independent continents (since the break-up of the supercontinent Pannotia earlier), but Baltica began to move towards Laurentia later in the period, causing the Iapetus Ocean to shrink between them. The small continent Avalonia separated from Gondwana and began to head north towards Baltica and Laurentia. The Rheic Ocean between Gondwana and Avalonia was formed as a result.
A major mountain-building episode was the Taconic orogeny that was well under way in Cambrian times. In the beginning of the Late Ordovician, from 460 to 450 Ma, volcanoes along the margin of the Iapetus Ocean spewed massive amounts of carbon dioxide into the atmosphere, turning the planet into a hothouse. These volcanic island arcs eventually collided with proto North America to form the Appalachian mountains. By the end of the Late Ordovician these volcanic emissions had stopped. Gondwana had by that time neared or approached the pole and was largely glaciated.
Ordovician meteor event
The Ordovician meteor event is a proposed shower of meteors that occurred during the Middle Ordovician period, roughly 470 million years ago. It is not associated with any major extinction event.
Geochemistry
The Ordovician was a time of calcite sea geochemistry in which low-magnesium calcite was the primary inorganic marine precipitate of calcium carbonate. Carbonate hardgrounds were thus very common, along with calcitic ooids, calcitic cements, and invertebrate faunas with dominantly calcitic skeletons.
Unlike Cambrian times, when calcite production was dominated by microbial and non-biological processes, animals (and macroalgae) became a dominant source of calcareous material in Ordovician deposits.
Climate and sea level
The Ordovician saw the highest sea levels of the Paleozoic, and the low relief of the continents led to many shelf deposits being formed under hundreds of metres of water. Sea level rose more or less continuously throughout the Early Ordovician, levelling off somewhat during the middle of the period. Locally, some regressions occurred, but sea level rise continued in the beginning of the Late Ordovician. A change was soon on the cards, however, and sea levels fell steadily in accord with the cooling temperatures for the ~30 million years leading up to the Hirnantian glaciation. Within this icy stage, sea level seems to have risen and dropped somewhat, but despite much study the details remain unresolved.
At the beginning of the period, around 485.4 ± 1.9 million years ago, the climate was very hot due to high levels of CO2, which gave a strong greenhouse effect. The marine waters are assumed to have been around 45°C (113°F), which restricted the diversification of complex multi-cellular organisms. But over time, the climate became cooler, and around 460 million years ago, the ocean temperatures became comparable to those of present day equatorial waters.
As with North America and Europe, Gondwana was largely covered with shallow seas during the Ordovician. Shallow clear waters over continental shelves encouraged the growth of organisms that deposit calcium carbonates in their shells and hard parts. The Panthalassic Ocean covered much of the northern hemisphere, and other minor oceans included Proto-Tethys, Paleo-Tethys, Khanty Ocean, which was closed off by the Late Ordovician, Iapetus Ocean, and the new Rheic Ocean.
As the Ordovician progressed, we see evidence of glaciers on the land we now know as Africa and South America. At the time these land masses were sitting at the South Pole, and covered by ice caps.
Life
For most of the Late Ordovician, life continued to flourish, but at and near the end of the period there were mass-extinction events that seriously affected planktonic forms like conodonts, graptolites, and some groups of trilobites (Agnostida and Ptychopariida, which completely died out, and the Asaphida, which were much reduced). Brachiopods, bryozoans and echinoderms were also heavily affected, and the endocerid cephalopods died out completely, except for possible rare Silurian forms. The Ordovician–Silurian Extinction Events may have been caused by an ice age that occurred at the end of the Ordovician period as the end of the Late Ordovician was one of the coldest times in the last 600 million years of earth history.
On the whole, the fauna that emerged in the Ordovician set the template for the remainder of the Palaeozoic. The fauna was dominated by tiered communities of suspension feeders, mainly with short food chains; this said, the ecological system reached a new grade of complexity far beyond that of the Cambrian fauna, which has persisted until the present day.
Though less famous than the Cambrian explosion, the Ordovician featured an adaptive radiation, the Ordovician radiation, that was no less remarkable; marine faunal genera increased fourfold, resulting in 12% of all known Phanerozoic marine fauna. Another change in the fauna was the strong increase in filter feeding organisms. The trilobite, inarticulate brachiopod, archaeocyathid, and eocrinoid faunas of the Cambrian were succeeded by those that dominated the rest of the Paleozoic, such as articulate brachiopods, cephalopods, and crinoids. Articulate brachiopods, in particular, largely replaced trilobites in shelf communities. Their success epitomizes the greatly increased diversity of carbonate shell-secreting organisms in the Ordovician compared to the Cambrian.
In North America and Europe, the Ordovician was a time of shallow continental seas rich in life. Trilobites and brachiopods in particular were rich and diverse. Although solitary corals date back to at least the Cambrian, reef-forming corals appeared in the early Ordovician, corresponding to an increase in the stability of carbonate and thus a new abundance of calcifying animals.
Molluscs, which appeared during the Cambrian or even the Ediacaran, became common and varied, especially bivalves, gastropods, and nautiloid cephalopods.
Now-extinct marine animals called graptolites thrived in the oceans. Some new cystoids and crinoids appeared.
It was long thought that the first true vertebrates (fish — Ostracoderms) appeared in the Ordovician, but recent discoveries in China reveal that they probably originated in the Early Cambrian. The very first gnathostome (jawed fish) appeared in the Late Ordovician epoch.
During the Middle Ordovician there was a large increase in the intensity and diversity of bioeroding organisms. This is known as the Ordovician Bioerosion Revolution. It is marked by a sudden abundance of hard substrate trace fossils such as Trypanites, Palaeosabella and Petroxestes.
Fossiliferous limestone slab from the Liberty Formation (Upper Ordovician) of Caesar Creek State Park near Waynesville, Ohio. Specimen found by College of Wooster student Willy Nelson.
In the Early Ordovician, trilobites were joined by many new types of organisms, including tabulate corals, strophomenid, rhynchonellid, and many new orthid brachiopods, bryozoans, planktonic graptolites and conodonts, and many types of molluscs and echinoderms, including the ophiuroids (“brittle stars”) and the first sea stars. Nevertheless the trilobites remained abundant, with all the Late Cambrian orders continuing, and being joined by the new group Phacopida. The first evidence of land plants also appeared; see Evolutionary history of life.
In the Middle Ordovician, the trilobite-dominated Early Ordovician communities were replaced by generally more mixed ecosystems, in which brachiopods, bryozoans, molluscs, cornulitids, tentaculitids and echinoderms all flourished, tabulate corals diversified and the first rugose corals appeared; trilobites were no longer predominant. The planktonic graptolites remained diverse, with the Diplograptina making their appearance. Bioerosion became an important process, particularly in the thick calcitic skeletons of corals, bryozoans and brachiopods, and on the extensive carbonate hardgrounds that appear in abundance at this time. One of the earliest known armoured agnathan (“ostracoderm”) vertebrate, Arandaspis, dates from the Middle Ordovician.
Trilobites in the Ordovician were very different from their predecessors in the Cambrian. Many trilobites developed bizarre spines and nodules to defend against predators such as primitive sharks and nautiloids while other trilobites such as Aeglina prisca evolved to become swimming forms. Some trilobites even developed shovel-like snouts for ploughing through muddy sea bottoms. Another unusual clade of trilobites known as the trinucleids developed a broad pitted margin around their head shields. Some trilobites such as Asaphus kowalewski evolved long eyestalks to assist in detecting predators whereas other trilobite eyes in contrast disappeared completely.
Flora
Green algae were common in the Late Cambrian (perhaps earlier) and in the Ordovician. Terrestrial plants probably evolved from green algae, first appearing as tiny non-vascular forms resembling liverworts. Fossil spores from land plants have been identified in uppermost Ordovician sediments. The green algae were similar to today’s sea moss.Colonization of land would have been limited to shorelines
Among the first land fungi may have been arbuscular mycorrhiza fungi (Glomerales), playing a crucial role in facilitating the colonization of land by plants through mycorrhizal symbiosis, which makes mineral nutrients available to plant cells; such fossilized fungal hyphae and spores from the Ordovician of Wisconsin have been found with an age of about 460 million years ago, a time when the land flora most likely only consisted of plants similar to non-vascular bryophytes.
End of the period
The Ordovician came to a close in a series of extinction events that, taken together, comprise the second largest of the five major extinction events in Earth’s history in terms of percentage of genera that went extinct. The only larger one was the Permian-Triassic extinction event.
The extinctions occurred approximately 447–444 million years ago and mark the boundary between the Ordovician and the following Silurian Period. At that time all complex multicellular organisms lived in the sea, and about 49% of genera of fauna disappeared forever; brachiopods and bryozoans were greatly reduced, along with many trilobite, conodont and graptolite families.
The most commonly accepted theory is that these events were triggered by the onset of most cold conditions in the late Katian, followed by an ice age, in the Hirnantian faunal stage, that ended the long, stable greenhouse conditions typical of the Ordovician.
The ice age was possibly not long-lasting, study of oxygen isotopes in fossil brachiopods showing that its duration could have been only 0.5 to 1.5 million years. Other researchers (Page et al.) estimate more temperate conditions did not return until the late Silurian.
The late Ordovician glaciation event was preceded by a fall in atmospheric carbon dioxide (from 7000 ppm to 4400 ppm), which selectively affected the shallow seas where most organisms lived. As the southern supercontinent Gondwana drifted over the South Pole, ice caps formed on it, which have been detected in Upper Ordovician rock strata of North Africa and then-adjacent northeastern South America, which were south-polar locations at the time.
Glaciation locks up water from the world-ocean, and the interglacials free it, causing sea levels repeatedly to drop and rise; the vast shallow intra-continental Ordovician seas withdrew, which eliminated many ecological niches, then returned carrying diminished founder populations lacking many whole families of organisms, then withdrew again with the next pulse of glaciation, eliminating biological diversity at each change.Species limited to a single epicontinental sea on a given landmass were severely affected. Tropical lifeforms were hit particularly hard in the first wave of extinction, while cool-water species were hit worst in the second pulse.
Surviving species were those that coped with the changed conditions and filled the ecological niches left by the extinctions.
At the end of the second event, melting glaciers caused the sea level to rise and stabilise once more. The rebound of life’s diversity with the permanent re-flooding of continental shelves at the onset of the Silurian saw increased biodiversity within the surviving Orders.
Melott et al. (2004) suggested a ten-second gamma ray burst could have destroyed the ozone layer and exposed terrestrial and marine surface-dwelling life to deadly radiation and initiated global cooling.
Note : The above story is based on materials provided by Wikipedia
Map of the Yellow River, whose watershed covers most of northern China and drains to the Bohai Sea
The Yellow River or Huang He is the second-longest river in Asia, following the Yangtze River, and the sixth-longest in the world at the estimated length of 5,464 km (3,395 mi). Originating in the Bayan Har Mountains in Qinghai province of western China, it flows through nine provinces, and it empties into the Bohai Sea near the city of Dongying in Shandong province. The Yellow River basin has an east–west extent of about 1,900 kilometers (1,180 mi) and a north–south extent of about 1,100 km (680 mi). Its total basin area is about 742,443 square kilometers (286,659 sq mi).
The Yellow River is called “the cradle of Chinese civilization”, because its basin was the birthplace of ancient Chinese civilization, and it was the most prosperous region in early Chinese history. However, frequent devastating floods and course changes produced by the continual elevation of the river bed, sometimes above the level of its surrounding farm fields, has also earned it the unenviable names China’s Sorrow and Scourge of the Sons of Han.
Early Chinese literature including the Yu Gong or Tribute of Yu dating to the Warring States period (475 – 221 BC) refers to the Yellow River as simply 河 (Old Chinese: *C.gˤaj), a character that has come to mean “river” in modern usage. The first appearance of the name 黃河 (Old Chinese: *N-kʷˤaŋ C.gˤaj; Middle Chinese: Hwang Ha) is in the Book of Han written during the Western Han dynasty (206 BC – AD 9). The adjective “yellow” describes the perennial color of the muddy water in the lower course of the river, which arises from soil (loess) being carried downstream.
One of its older Mongolian names was the “Black River”, because the river runs clear before it enters the Loess Plateau, but the current name of the river among Inner Mongolians is Ȟatan Gol (Хатан гол, “Queen River”). In Mongolia itself, it is simply called the Šar Mörön (Шар мөрөн, “Yellow River”).
In Qinghai, the river’s Tibetan name is “River of the Peacock” (Tibetan: རྨ་ཆུ།, Ma Chu; Chinese: s 玛曲, t 瑪曲, p Mǎ Qū).
The name Hwang Ho in English is the Postal Map romanization of the river’s Mandarin name.
Geography
According to the China Exploration and Research Society, the source of the Yellow River is at 34° 29′ 31.1″ N, 96° 20′ 24.6″ E in the Bayan Har Mountains near the eastern edge of the Yushu Tibetan Autonomous Prefecture. The source tributuaries drain into Gyaring Lake and Ngoring Lake on the western edge of Golog Prefecture high in the Bayan Har Mountains of Qinghai. In the Zoige Basin along the boundary with Gansu, the Yellow River loops northwest and then northeast before turning south, creating the “Ordos Loop”, and then flows generally eastward across the North China Plain to the Gulf of Bohai, draining a basin of 752,443 square kilometers (290,520 sq mi) which nourishes 140 million people with drinking water and irrigation.
The Yellow River passes through seven present-day provinces and two autonomous regions, namely (from west to east) Qinghai, Gansu, Ningxia, Inner Mongolia, Shaanxi, Shanxi, Henan, and Shandong. Major cities along the present course of the Yellow River include (from west to east) Lanzhou, Yinchuan, Wuhai, Baotou, Luoyang, Zhengzhou, Kaifeng, and Jinan. The current mouth of the Yellow River is located at Kenli County, Shandong.
The river is commonly divided into three stages. These are roughly the northeast of the Tibetan Plateau, the Ordos Loop and the North China Plain. However, different scholars have different opinions on how the three stages are divided.[citation needed] This article adopts the division used by the Yellow River Conservancy Commission.
Note : The above story is based on materials provided by Wikipedia
A hypothetical model of the circum-Atlantic region at present-day, if Africa had split into two parts along the West African Rift system. Here, the north-west part of present day Africa would have moved with the South American continent, forming a “Saharan Atlantic ocean”. Credit: Sascha Brune/Christian Heine
Break-up of the supercontinent Gondwana about 130 Million years ago could have lead to a completely different shape of the African and South American continent with an ocean south of today’s Sahara desert, as geoscientists from the University of Sydney and the GFZ German Research Centre for Geosciences have shown through the use of sophisticated plate tectonic and three-dimensional numerical modelling.
The study highlights the importance of rift orientation relative to extension direction as key factor deciding whether an ocean basin opens or an aborted rift basin forms in the continental interior.
For hundreds of millions of years, the southern continents of South America, Africa, Antarctica, Australia, and India were united in the supercontinent Gondwana. While the causes for Gondwana’s fragmentation are still debated, it is clear that the supercontinent first split along along the East African coast in a western and eastern part before separation of South America from Africa took place. Today’s continental margins along the South Atlantic ocean and the subsurface graben structure of the West African Rift system in the African continent, extending from Nigeria northwards to Libya, provide key insights on the processes that shaped present-day Africa and South America.
Christian Heine (University of Sydney) and Sascha Brune (GFZ) investigated why the South Atlantic part of this giant rift system evolved into an ocean basin, whereas its northern part along the West African Rift became stuck.
“Extension along the so-called South Atlantic and West African rift systems was about to split the African-South American part of Gondwana North-South into nearly equal halves, generating a South Atlantic and a Saharan Atlantic Ocean,” geoscientist Sascha Brune explains. “In a dramatic plate tectonic twist, however, a competing rift along the present-day Equatorial Atlantic margins, won over the West African rift, causing it to become extinct, avoiding the break-up of the African continent and the formation of a Saharan Atlantic ocean.”
The complex numerical models provide a strikingly simple explanation: the larger the angle between rift trend and extensional direction, the more force is required to maintain a rift system. The West African rift featured a nearly orthogonal orientation with respect to westward extension which required distinctly more force than its ultimately successful Equatorial Atlantic opponent.
Note : The above story is based on materials provided by Helmholtz Centre Potsdam – GFZ German Research Centre for Geosciences.
Chemical Formula: MgSiO3 Locality: Common worldwide. Name Origin: From the Greek enstates – “opponent.”
Enstatite is the magnesium endmember of the pyroxene silicate mineral series enstatite (MgSiO3) – ferrosilite (FeSiO3). The magnesium rich members of the solid solution series are common rock-forming minerals found in igneous and metamorphic rocks. The intermediate composition, (Mg,Fe)SiO3, has historically been known as hypersthene, although this name has been formally abandoned and replaced by orthopyroxene. When determined petrographically or chemically the composition is given as relative proportions of enstatite (En) and ferrosilite (Fs) (e.g., En80Fs20).
Cleavage: {110} Distinct, {010} Distinct Color: White, Yellowish green, Brown, Greenish white, Gray. Density: 3.1 – 3.3, Average = 3.2 Diaphaneity: Translucent to opaque Fracture: Brittle – Generally displayed by glasses and most non-metallic minerals. Hardness: 5.5 – Knife Blade Luminescence: Non-fluorescent. Luster: Vitreous – Pearly Streak: gray
Photos :
Enstatite Kilosa District, Morogoro Region, Tanzania Thumbnail, 2.8 x 1.5 x 1.2 cm “Courtesy of Rob Lavinsky, The Arkenstone, www.iRocks.com”Enstatite Thumbnail, 8.40 x 5.11 mm ; 1.13 carats “Courtesy of Rob Lavinsky, The Arkenstone, www.iRocks.com”
This scanning electron microscope image of a polished thin section of a meteorite from Mars shows tunnels and curved microtunnels. Credit: NASA
A team of scientists at NASA’s Johnson Space Center in Houston and the Jet Propulsion Laboratory in Pasadena, Calif., has found evidence of past water movement throughout a Martian meteorite, reviving debate in the scientific community over life on Mars.
In 1996, a group of scientists at Johnson led by David McKay, Everett Gibson and Kathie Thomas-Keprta published an article in Science announcing the discovery of biogenic evidence in the Allan Hills 84001(ALH84001) meteorite. In this new study, Gibson and his colleagues focused on structures deep within a 30-pound (13.7-kilogram) Martian meteorite known as Yamato 000593 (Y000593). The team reports that newly discovered different structures and compositional features within the larger Yamato meteorite suggest biological processes might have been at work on Mars hundreds of millions of years ago.
The team’s findings have been published in the February issue of the journal Astrobiology. The lead author, Lauren White, is based at the Jet Propulsion Laboratory. Co-authors are Gibson, Thomas-Keprta, Simon Clemett and McKay, all based at Johnson. McKay, who led the team that studied the ALH84001 meteorite, died a year ago.
“While robotic missions to Mars continue to shed light on the planet’s history, the only samples from Mars available for study on Earth are Martian meteorites,” said White. “On Earth, we can utilize multiple analytical techniques to take a more in-depth look into meteorites and shed light on the history of Mars. These samples offer clues to the past habitability of this planet. As more Martian meteorites are discovered, continued research focusing on these samples collectively will offer deeper insight into attributes which are indigenous to ancient Mars. Furthermore, as these meteorite studies are compared to present day robotic observations on Mars, the mysteries of the planet’s seemingly wetter past will be revealed.”
Analyses found that the rock was formed about 1.3 billion years ago from a lava flow on Mars. Around 12 million years ago, an impact occurred on Mars which ejected the meteorite from the surface of Mars. The meteorite traveled through space until it fell in Antarctica about 50,000 years ago.
The rock was found on the Yamato Glacier in Antarctica by the Japanese Antarctic Research Expedition in 2000. The meteorite was classified as a nakhlite, a subgroup of Martian meteorites. Martian meteoritic material is distinguished from other meteorites and materials from Earth and the moon by the composition of the oxygen atoms within the silicate minerals and trapped Martian atmospheric gases.
The team found two distinctive sets of features associated with Martian-derived clay. They found tunnel and micro-tunnel structures that thread their way throughout Yamato 000593. The observed micro-tunnels display curved, undulating shapes consistent with bio-alteration textures observed in terrestrial basaltic glasses, previously reported by researchers who study interactions of bacteria with basaltic materials on Earth.
The second set of features consists of nanometer- to-micrometer-sized spherules that are sandwiched between layers within the rock and are distinct from carbonate and the underlying silicate layer. Similar spherical features have been previously seen in the Martian meteorite Nakhla that fell in 1911 in Egypt. Composition measurements of the Y000593 spherules show that they are significantly enriched in carbon compared to the nearby surrounding iddingsite layers.
A striking observation is that these two sets of features in Y000593, recovered from Antarctica after about 50,000 years residence time, are similar to features found in Nakhla, an observed fall collected shortly after landing.
The authors note that they cannot exclude the possibility that the carbon-rich regions in both sets of features may be the product of abiotic mechanisms: however, textural and compositional similarities to features in terrestrial samples, which have been interpreted as biogenic, imply the intriguing possibility that the Martian features were formed by biotic activity.
“The unique features displayed within the Martian meteorite Yamato 000593 are evidence of aqueous alterations as seen in the clay minerals and the presence of carbonaceous matter associated with the clay phases which show that Mars has been a very active body in its past,” said Gibson. “The planet is revealing the presence of an active water reservoir that may also have a significant carbon component.
“The nature and distribution of Martian carbon is one of the major goals of the Mars Exploration Program. Since we have found indigenous carbon in several Mars meteorites, we cannot overstate the importance of having Martian samples available to study in earth-based laboratories. Furthermore, the small sizes of the carbonaceous features within the Yamato 000593 meteorite present major challenges to any analyses attempted by remote techniques on Mars,” Gibson added.
“This is no smoking gun,” said JPL’s White. “We can never eliminate the possibility of contamination in any meteorite. But these features are nonetheless interesting and show that further studies of these meteorites should continue.”
Note : The above story is based on materials provided by NASA/Jet Propulsion Laboratory
Chemical Formula: Cu3AsS4 Locality: Butte, Montana, USA. Name Origin: From the Greek enarges – “obvious.”
Enargite is a copper arsenic sulfosalt mineral with formula: Cu3AsS4. It takes its name from the Greek word enarge, “distinct.” Enargite is a steel gray, blackish gray, to violet black mineral with metallic luster. It forms slender orthorhombic prisms as well as massive aggregates. It has a hardness of 3 and a specific gravity of 4.45.
A plankton bloom in the Capricorn Channel off the Queensland coast of Australia – Trichodesmium a photosynthetic cyanobacteria and nitrogen fixer. Credit: Astronaut photograph ISS005-E-21572 taken December 3, 2002, provided by NASA’s Earth Sciences and Image Analysis
University of Bristol researchers study genomic data of cyanobacteria to shed new light on how complex life evolved on Earth
Plankton in the Earth’s oceans received a huge boost when microorganisms capable of creating soluble nitrogen ‘fertilizer’ directly from the atmosphere diversified and spread throughout the open ocean. This event occurred at around 800 million years ago and it changed forever how carbon was cycled in the ocean.
It has long been believed that the appearance of complex multicellular life towards the end of the Precambrian (the geologic interval lasting up until 541 million years ago) was facilitated by an increase in oxygen, as revealed in the geological record. However, it has remained a mystery as to why oxygen increased at this particular time and what its relationship was to ‘Snowball Earth’ – the most extreme climatic changes the Earth has ever experienced – which were also taking place around then.
This new study shows that it could in fact be what was happening to nitrogen at this time that helps solve the mystery.
The researchers, led by Dr Patricia Sanchez-Baracaldo of the University of Bristol, used genomic data to reconstruct the relationships between those cyanobacteria whose photosynthesis in the open ocean provided oxygen in quantities sufficient to be fundamental in the development of complex life on Earth.
Some of these cyanobacteria were also able to transform atmospheric nitrogen into bioavailable nitrogen in sufficient quantities to contribute to the marine nitrogen cycle, delivering ‘nitrogen fertiliser’ to the ecosystem. Using molecular techniques, the team were able to date when these species first appeared in the geological record to around 800 million years ago.
Dr Sanchez-Baracaldo, a Royal Society Dorothy Hodgkin Research Fellow in Bristol’s Schools of Biological and Geographical Sciences said: “We have known that oxygenic photosynthesis – the process by which microbes fix carbon dioxide into carbohydrates, splitting water and releasing oxygen as a by-product – first evolved in freshwater habitats more than 2.3 billion years ago. But it wasn’t until around 800 million years ago that these oxygenating cyanobacteria were able to colonise the vast oceans (two thirds of our planet) and be fertilised by enough bioavailable nitrogen to then produce oxygen – and carbohydrate food – at levels high enough to facilitate the next ‘great leap forward’ towards complex life.
“Our study suggests that it may have been the fixing of this nitrogen ‘fertiliser’ in the oceans at this time that played a pivotal role in this key moment in the evolution of life on Earth.”
Co-author, Professor Andy Ridgwell said: “The timing of the spread in nitrogen fixers in the open ocean occurs just prior to global glaciations and the appearance of animals. Although further work is required, these evolutionary changes may well have been related to, and perhaps provided a trigger for, the occurrence of extreme glaciation around this time as carbon was now being buried in the sediments on a much larger scale.”
Dr Sanchez-Baracaldo added: “It’s very exciting to have been able to use state of the art genetic techniques to help solve an age-old mystery concerning one of the most important and pivotal moments in the evolution of life on Earth. In recent years, genomic data has been helping re-tell the story of the origins of life with increasing clarity and accuracy. It is a privilege to be contributing to our understanding of how microorganisms have contributed to make our planet habitable.”
Note : The above story is based on materials provided by University of Bristol.
Cleavage: {001} Perfect Color: Gray, Grayish yellow, Silver white, Tin white. Density: 6.3 – 6.5, Average = 6.4 Diaphaneity: Opaque Fracture: Brittle – Generally displayed by glasses and most non-metallic minerals. Hardness: 2 – Gypsum Luminescence: Non-fluorescent. Luster: Metallic Magnetism: Nonmagnetic Streak: black
Photo :
EMPLECTITE Tannenbaum-Stollen, Antonsthal, Breitenbrunn, Erzgebirge, Saxony, Germany, Europe Size: 5.4 x 3.6 x 2.5 cm (Small Cabinet) Owner: Crystal Classics
The Furongian is the fourth and final series of the Cambrian. It lasted from ~497 to 485.4 ± 1.9 million years ago. It succeeds the still unnamed 3rd series of the Cambrian and precedes the Lower Ordovician Tremadocian stage. It is subdivided into three stages: the Paibian, Jiangshanian and the unnamed 10th stage of the Cambrian.
The Furongian was also known as the “Series 4” of the Cambrian and replaced the older term “Upper Cambrian” and equivalent to the local term “Hunanian”. The name “Furongian” was ratified by the International Commission on Stratigraphy in 2003. Furong (芙蓉) means “lotus” in Chinese and refers to Hunan which is known as the “lotus state”.
Definition
The lower boundary is defined in the same way as the GSSP of the Paibian stage. Both begin with the first appearance of the trilobite Glyptagnostus reticulatus around ~497 million years ago. The upper boundary is the lower boundary and GSSP of the Tremadocian stage which is the first appearance of the conodont Iapetognathus fluctivagus around 485.4 ± 1.9 million years ago
Subdivisions
The following table shows the subdivisions of the Furongian series/epoch:
The base of two of three stages of the Furongian are defined as the first appearance of a trilobite. The base of the Paibian is the first appearance of Glyptagnostus reticulatus and the base of the Jiangshanian is the first appearance of Agnostotes orientalis. The still unnamed Cambrian Stage 10 might be defined as the first appearance of Lotagnostus americanus or the conodont Eoconodontus notchpeakensis.
The Furongian can be divided into a number of trilobite zones:
Series
Stage
Trilobite zone
Trilobite GSSP
Furongian
Stage 10
Saukia zone (upper part), Eurekia apopsis zone, Tangshanaspis Zone, Parakoldinioidiazone, Symphysurina zone
Lotagnostus americanus (undecided)
Jiangshanian
Ellipsocephaloides zone, Saukia zone (lower part)
Agnostotes orientalis
Paibian
? (?)
Glyptagnostus reticulatus
Cedaria
Note : The above story is based on materials provided by Wikipedia
Cambrian Series 3 is the still unnamed 3rd Series of the Cambrian. It lasted from about ~509 to ~497 million years ago and is divided into 3 stages: the unnamed Stage 5, the Drumian, and the Guzhangian. Cambrian Series 3 is preceded by also unnamed Cambrian Series 2 and succeeded by the Furongian series.
The International Commission on Stratigraphy still has to decide on the official name of the 2nd series of the Cambrian. The new name will also replace the older term “Middle Cambrian”.
Definition
The lower boundary of Series 3 has the same definition as Cambrian Stage 5. This boundary has not been formally defined yet by the ICS but a number of proposals for fossils and type sections have been made. The most promising fossil markers are the respective first appearances of either trilobite species Ovatoryctocara granulata or Oryctocephalus indicus.[3] Either species should have an age close to ~509. The Series 3-Furongian boundary has the same definition as the Paibian stage. It is defined as the first appearance of Glyptagnostus reticulatus around ~497 million years ago.
Subdivision
Cambrian Series 3 is subdivided into the following stages:
Cambrian Series 2 is the unnamed 2nd series of the Cambrian. It lies above the Terreneuvian series and below the Cambrian Series 3. Series 2 has not been formally defined by the International Commission on Stratigraphy, lacking a precise lower and upper boundary and subdivision into stages. The proposed lower boundary is the first appearance of trilobites which is estimated to be around ~521 million years ago. The upper boundary is proposed as the first appearance of either the trilobite species Oryctocephalus indicus or Ovatoryctocara granulata, currently estimated to be around ~509 million years ago.
The International Commission on Stratigraphy has not named the 2nd stage of the Cambrian yet. The new name will replace the older terms “Lower Cambrian” and “Early Cambrian”. The nomenclature used in Sibera uses the term “Yakutian” for this series.
Subdivisions
The 2nd series is currently subdivided by the ICS into two stages: Cambrian Stage 3 and Cambrian Stage 4. Both of these stages also lack formal definition. The Siberian nomenclature distinguishes three stages (lowest first): Atdabanian, Botomian and Toyonian. In general most subdivisions of this series rely on biostratigraphy of trilobite zones.
Biostratigraphy
The 2nd series of the Cambrian marks the appearance of trilobites. Correlating this event on different continents has proven difficult and resolving this is essential for the definition of the lower boundary of this series. Currently the oldest trilobite known is Lemdadella which marks the beginning of the Fallotaspis zone.
Note : The above story is based on materials provided by Wikipedia
The skeletons are remarkably complete, having being subjected to very little scavenging at death
It is one of the most astonishing fossil discoveries of recent years – a graveyard of whales found beside the Pan-American Highway in Chile.
And now scientists think they can explain how so many of the animals came to be preserved in one location more than five million years ago.
It was the result of not one but four separate mass strandings, they report in a Royal Society journal.
The evidence strongly suggests the whales all ingested toxic algae.
The dead and dying mammals were then washed into an estuary and on to flat sands where they became buried over time.
The scientists brought in a number of digital techniques to record the discoveries
It was well known that this area in Chile’s Atacama Desert preserved whale fossils.
Their bones could be seen sticking out of rock faces, and the spot acquired the name Cerro Ballena (“whale hill”) as a result.
But it was only when a cutting was made to widen the Pan-American Highway that US and Chilean researchers got an opportunity to fully study the fossil beds.
They were given just two weeks to complete their field work before the heavy plant returned to complete construction of the new road.
The team set about recording as much detail as possible, including making 3D digital models of the skeletal remains in situ and then removing bones for further study in the lab.
Identified in the beds were over 40 individual rorquals – the type of large cetacean that includes the modern blue, fin and minke whales.
Among them were other important marine predators and grazers.
“We found extinct creatures such as walrus whales – dolphins that evolved a walrus-like face. And then there were these bizarre aquatic sloths,” recalls Nicholas Pyenson, a palaeontologist at the Smithsonian’s National Museum of Natural History.
“To me, it’s amazing that in 240m of road-cut, we managed to sample all the superstars of the fossil marine-mammal world in South America in the Late Miocene. Just an incredibly dense accumulation of species,” he told BBC News.
The team immediately noticed that the skeletons were nearly all complete, and that their death poses had clear commonalities. Many had come to rest facing in the same direction and upside down, for example.
This all pointed to the creatures succumbing to the same, sudden catastrophe; only, the different fossils levels indicated it was not one event but four separate episodes spread over a period of several thousand years.
The best explanation is that these animals were all poisoned by the toxins that can be generated in some algal blooms.
Such blooms are one of the prevalent causes for repeated mass strandings seen in today’s marine animals.
The Smithsonian has produced tools to allow the public to tour and investigate Cerro Ballena
If large quantities of contaminated prey are consumed, or the algae are simply inhaled – death can be rapid.
“All the creatures we found – whether whales, seals or billfishes – fed high up in marine food webs and that would have made them very susceptible to harmful algal blooms,” said Dr Pyenson.
The researchers believe the then configuration of the coastline at Cerro Ballena in the late Miocene Epoch worked to funnel carcases into a restricted area where they were lifted on to sand flats just above high tide, perhaps by storm waves.
This would have put the bodies beyond marine scavengers. And, being a desert region, there would have been very few land creatures about to steal bones either.
A lot of the fossils at Cerro Ballena are perfect but for a few nicks inflicted by foraging crabs.
The researchers are not in a position to say for sure that harmful algal blooms were responsible for the mass strandings. There were no distinct algal cell fragments in the sediments; such a presence could have amounted to a “smoking gun”. What the team did find, however, were multiple grains encrusted in iron oxides that could hint at past algal activity.
Hundreds of fossils await unearthing and description at Cerro Ballena
“There are tiny spheres about 20 microns across – that’s exactly the right size to be dinoflagellate cysts,” said Dr Pyenson.
“They’re found in algal-like mats all around the site. We can’t say whether those were the killer algae, but they do not falsify the argument for harmful algal blooms being the cause in the way that the sedimentology falsifies tsunami being a potential cause.”
Cerro Ballena is now regarded as one of the densest fossil sites in the world – certainly for whales and other extinct marine mammals. The scientists calculate there could be hundreds of specimens in the area still waiting to be unearthed and investigated.
The University of Chile in Santiago is currently working to establish a research station to carry this into effect.
To coincide with the publication of a scholarly paper in Proceedings B of the Royal Society, the Smithsonian has put much of its digital data, including 3D scans and maps, online at cerroballena.si.edu.
Note : The above story is based on materials provided by Jonathan Amos Science correspondent, BBC News
LLNL scientist Benjamin Santer and his climbing group ascend Mt. St. Helens via the “Dogshead Route” in April 1980, about a month before its major eruption. The group was the last to reach the summit of Mt. St. Helens before its major eruption that May. New research by Santer and his colleagues shows that volcanic eruptions contribute to a recent warming “hiatus.” Credit: Image courtesy of DOE/Lawrence Livermore National Laboratory
Volcanic eruptions in the early part of the 21st century have cooled the planet, according to a study led by Lawrence Livermore National Laboratory. This cooling partly offset the warming produced by greenhouse gases.
Despite continuing increases in atmospheric levels of greenhouse gases, and in the total heat content of the ocean, global-mean temperatures at the surface of the planet and in the troposphere (the lowest portion of Earth’s atmosphere) have shown relatively little warming since 1998. This so-called ‘slow-down’ or ‘hiatus’ has received considerable scientific, political and popular attention. The volcanic contribution to the ‘slow-down’ is the subject of a new paper appearing in the Feb. 23 edition of the journal Nature Geoscience.
Volcanic eruptions inject sulfur dioxide gas into the atmosphere. If the eruptions are large enough to add sulfur dioxide to the stratosphere (the atmospheric layer above the troposphere), the gas forms tiny droplets of sulfuric acid, also known as “volcanic aerosols.” These droplets reflect some portion of the incoming sunlight back into space, cooling Earth’s surface and the lower atmosphere.
“In the last decade, the amount of volcanic aerosol in the stratosphere has increased, so more sunlight is being reflected back into space,” said Lawrence Livermore climate scientist Benjamin Santer, who serves as lead author of the study. “This has created a natural cooling of the planet and has partly offset the increase in surface and atmospheric temperatures due to human influence.”
From 2000-2012, emissions of greenhouse gases into the atmosphere have increased — as they have done since the Industrial Revolution. This human-induced change typically causes the troposphere to warm and the stratosphere to cool. In contrast, large volcanic eruptions cool the troposphere and warm the stratosphere. The researchers report that early 21st century volcanic eruptions have contributed to this recent “warming hiatus,” and that most climate models have not accurately accounted for this effect.
“The recent slow-down in observed surface and tropospheric warming is a fascinating detective story,” Santer said. “There is not a single culprit, as some scientists have claimed. Multiple factors are implicated. One is the temporary cooling effect of internal climate noise. Other factors are the external cooling influences of 21st century volcanic activity, an unusually low and long minimum in the last solar cycle, and an uptick in Chinese emissions of sulfur dioxide.
“The real scientific challenge is to obtain hard quantitative estimates of the contributions of each of these factors to the slow-down.”
The researchers performed two different statistical tests to determine whether recent volcanic eruptions have cooling effects that can be distinguished from the intrinsic variability of the climate. The team found evidence for significant correlations between volcanic aerosol observations and satellite-based estimates of lower tropospheric temperatures as well as the sunlight reflected back to space by the aerosol particles.
“This is the most comprehensive observational evaluation of the role of volcanic activity on climate in the early part of the 21st century,” said co-author Susan Solomon, the Ellen Swallow Richards professor of atmospheric chemistry and climate science at MIT. “We assess the contributions of volcanoes on temperatures in the troposphere — the lowest layer of the atmosphere — and find they’ve certainly played some role in keeping Earth cooler.”
The research is funded by the Department of Energy’s Office of Biological and Environmental Science in the Office of Science. The research involved a large, interdisciplinary team of researchers with expertise in climate modeling, satellite data, stratospheric dynamics and volcanic effects on climate, model evaluation and computer science.
Note : The above story is based on materials provided by DOE/Lawrence Livermore National Laboratory.
Jean-Bernard Caron extracting fossils from the shale. Credit: Gabriela Mangano
Yoho National Park’s 505-million-year-old Burgess Shale — home to some of the planet’s earliest animals, including a very primitive human relative — is one of the world’s most important fossil sites. Now, more than a century after its discovery, a compelling sequel has been unearthed: 42 kilometres away in Kootenay National Park, a new Burgess Shale fossil bed has been located that appears to equal the importance of the original discovery, and may one day even surpass it.
A paper published today in the scientific journal Nature Communications describes Kootenay National Park’s new ‘Marble Canyon’ fossil beds for the first time. The authors suggest that the area and its extraordinary fossils will greatly further our understanding of the sudden explosion of animal life during the Cambrian Period.
The find was made in the summer of 2012 by a team from the Royal Ontario Museum (ROM, Jean-Bernard Caron), Pomona College (Robert Gaines), the University of Toronto (Jean-Bernard Caron, Cédric Aria), the University of Saskatchewan (Gabriela Mángano) and Uppsala University (Michael Streng).
“This new discovery is an epic sequel to a research story that began at the turn of the previous century. There is no doubt in my mind that this new material will significantly increase our understanding of early animal evolution,” said Dr. Jean-Bernard Caron, Curator of Invertebrate Paleontology at the ROM, Associate Professor at the University of Toronto and the study’s lead author. “The rate at which we are finding animals — many of which are new — is astonishing, and there is a high possibility that we’ll eventually find more species here than at the original Yoho National Park site, and potentially more than from anywhere else in the world.”
In a short 15-day field season, the researchers collected thousands of specimens representing more than 50 species, several of which were new to science. Incredibly, many of the species previously known from Yoho are better preserved in Kootenay, retaining very fine, never-before-seen anatomical details that are important for understanding the shape of the animal ‘family tree.’
The new site parallels Yoho in its spectacular richness of arthropods, a group that today represents more than 80% of all living animals, including insects, spiders and lobsters.
Another curious similarity between Marble Canyon and the original discovery is that both sites would still be buried today if not for the dedicated exploratory work of scientists.
In 1909, world-renowned paleontologist Charles Walcott spent a summer exploring Yoho National Park’s mountainous topography in search of hidden treasures, only to stumble upon what he would later name the Burgess Shale on the final day of his field season on August 29. Similarly, in 2012, a ROM field expedition led by Caron spent part of their summer in search of the next big paleontological discovery.
“We were already aware of the presence of some Burgess Shale fossils in Kootenay National Park,” said Dr. Robert Gaines, a geologist from Pomona College, who along with Caron and colleagues had spent August 2008 at a much smaller fossil deposit in the park located near Stanley Glacier. “We had a hunch that if we followed the formation along the mountain topography into new areas with the right rock types, maybe, just maybe, we would get lucky — though we never in our wildest dreams thought we’d track down a motherload like this.”
Just like Walcott a century before, a hunch led Caron and his team to a talus slope high in the Canadian Rockies. Along this rocky slope they found a startling variety of fossils that immediately caught their attention. The researchers then pinpointed the source of the fossils to higher up on the slopes and began to excavate the fossils layer-by-layer.
“It didn’t take us very long at all to realize that we had dug up something special,” added Gaines. “To me, the Burgess Shale is a grand tale in every way imaginable, and we are incredibly proud to be part of this new chapter and to keep the story alive and thriving in everyone’s imagination.”
“We are very excited to go back to the field this summer,” said Caron. “One of our main goals is to discover more new species.”
The new fossil site is protected by Parks Canada, with the exact location remaining confidential to protect its integrity. Future visitor opportunities have not been ruled out.
Burgess Shale facts:
• This new finding is the latest in a recent string of Burgess Shale discoveries, including confirmation that Pikaia, found only in Yoho National Park, is the most primitive known vertebrate and therefore the ancestor of all descendant vertebrates, including humans.
• In over 100 years of research, approximately 200 animal species have been identified at the original Burgess Shale discovery in Yoho National Park in over 600 field days. In just 15 days of field collecting, 50 animal species have already been unearthed at the new Kootenay National Park site.
• Some species found at the new Kootenay site are also found in China’s famous Chengjiang fossil beds, which are 10 million years older. This contributes to the pool of evidence suggesting that the local and worldwide distribution of Cambrian animals, as well as their longevity, might have been underestimated.
• The original Burgess Shale site in Yoho National Park was recognized in 1980 as one of Canada’s first UNESCO World Heritage Sites. Now protected under the larger Rocky Mountain Parks UNESCO World Heritage Site, the Burgess Shale attracts thousands of visitors to Yoho National Park each year for guided hikes to the restricted fossil beds from July to September. Both Parks Canada and the Burgess Shale Geoscience Foundation lead hikes to the fossils.
• All the Burgess Shale fossil specimens in the Marble Canyon area of were collected under a Parks Canada Research and Collection permit and are held in trust for Parks Canada at the Royal Ontario Museum in Toronto.
Note : The above story is based on materials provided by Uppsala Universitet. The original article was written by Linda Koffmar.
The fossil remains of the Spinosaurid sauropod (carnivorous dinosaur). Credit: Image courtesy of ResearchSEA
A team of palaeontology researchers from the Department of Geology, Faculty of Science, University of Malaya and Japanese universities (Waseda University and Kumamoto University) has found dinosaur fossil teeth in the rural interiors of Pahang — the first known discovery of dinosaur remains in Malaysia.
“We have started our collaboration and carried out field expeditions to search for potential dinosaur deposits in Malaysia since Sep. 2012. Recently, we have successfully confirmed the presence of dinosaur remains (fossilised teeth) in Pahang,” said lead researcher, Dr. Masatoshi Sone.
“Acting as a team leader, and one of the collaborators, Professor Ren Hirayama from Waseda University (Tokyo), a specialist in reptile palaeontology, identified that one of the teeth, Sample UM10575, belongs to a spinosaurid dinosaur (known as a carnivorous “fish-eating” dinosaur),” he added.
UM10575 is about 23mm long and 10mm wide. It develops fairly distinct carinae (front and rear edges) with serrations, typical to a tooth of a theropod (carnivorous dinosaur). Well-marked coarse ridges are developed on the surface of the tooth, and the surface bears micro-ornament (very fine sculptures); these characterise a spinosaurid tooth.
The new fossils were found from sedimentary rock strata of late Mesozoic age, most likely Cretaceous (ca. 145-75 million years ago). In the interior of Peninsular Malaysia, Jurassic¬-Cretaceous sediments are known to be widely distributed, so that the team researchers have targeted a potential dinosaur deposit there since.
It is expected that large deposits of dinosaur fossils still remain in Malaysia. We currently continue further research and hope to conduct more extensive field investigations that may disclose more significant finds.
Alongside making the public announcement of this discovery, it is urgent to take measures for the protection and conservation of the present fossil site (and to make it accessible only to the qualified researchers). Since the site is in the open area, it is concerned that, once the public is aware, some destruction due to lawless excavations by private fossil collectors and/or robbers may happen, as has happened, for example, in Thailand, Laos, and Mongolia.
It is also hoped that the current discovery can lead to development of palaeontology study in the country and to eventually establish a Malaysian dinosaur museum in a near future.
Note :The above story is based on materials provided by ResearchSEA.
