Natural History (13.8 billion years BC – 3.3 million BC)

[wjfox]

General news, articles and discussions regarding the Big Bang, early Universe, the first stars and galaxies, the young Earth, and the emergence of life, the evolution of dinosaurs, and the rise of mammals.

[weatheriscool]

Earth's oldest minerals date onset of plate tectonics to 3.6 billion years ago

by Smithsonian

Zircons studied by the research team, photographed using cathodoluminescence, a technique that allowed the team to visualize the interiors of the crystals using a specialized scanning electron microscope. Dark circles on the zircons are the cavities left by the laser that was used to analyze the age and chemistry of the zircons.Scientists led by Michael Ackerson, a research geologist at the Smithsonian's National Museum of Natural History, provide new evidence that modern plate tectonics, a defining feature of Earth and its unique ability to support life, emerged roughly 3.6 billion years ago. The study, published May 14 in the journal Geochemical Perspective Letters, uses zircons, the oldest minerals ever found on Earth, to peer back into the planet's ancient past.The team tested more than 3,500 zircons, each just a couple of human hairs wide, by blasting them with a laser and then measuring their chemical composition with a mass spectrometer. These tests revealed the age and underlying chemistry of each zircon. Of the thousands tested, about 200 were fit for study due to the ravages of the billions of years these minerals endured since their creation. Credit: Michael Ackerson, Smithsonian.

Scientists led by Michael Ackerson, a research geologist at the Smithsonian's National Museum of Natural History, provide new evidence that modern plate tectonics, a defining feature of Earth and its unique ability to support life, emerged roughly 3.6 billion years ago.

Earth is the only planet known to host complex life and that ability is partly predicated on another feature that makes the planet unique: plate tectonics. No other planetary bodies known to science have Earth's dynamic crust, which is split into continental plates that move, fracture and collide with each other over eons. Plate tectonics afford a connection between the chemical reactor of Earth's interior and its surface that has engineered the habitable planet people enjoy today, from the oxygen in the atmosphere to the concentrations of climate-regulating carbon dioxide. But when and how plate tectonics got started has remained mysterious, buried beneath billions of years of geologic time.

https://phys.org/news/2021-05-earth-old ... onset.html

[joe00uk]

Australia crocodile: Skull identified as part of new extinct species

An eight-million-year-old crocodile skull discovered in central Australia is now believed to be part of an extinct species new to scientists.
The skull had been found about 200km (125 miles) from Alice Springs, in the Northern Territory (NT), in 2009.
It was thought to belong to a known reptile of the Baru genus but that has now been updated with new study.
The species is expected to be named in 2022, and there is a Baru exhibition in the NT.
Dr Adam Yates, senior curator of Earth Sciences at the Museum and Art Gallery of the Northern Territory, said the skull was found at the Alcoota fossil site in central Australia.
Dr Yates told the BBC the skull was by far the best specimen of a Baru crocodile yet found.

[weatheriscool]

Microscopic fossils record ancient climate conditions
https://phys.org/news/2021-05-microscop ... tions.html
by Paul Gabrielsen, University of Utah

Transmission electron microscope images of magnetofossils with examples of cuboctahedra (top center, rounded) and elongated prisms (bottom center, square). Credit: Courtney Wagner

Fifty-six million years ago, as the Earth's climate warmed by five to eight degrees C, new land mammals evolved, tropical forests expanded, giant insects and reptiles appeared and the chemistry of the ocean changed. Through it all, bacteria in the ocean in what is now New Jersey kept a record of the changes in their environment through forming tiny magnetic particles. Now, those particles and their record are all that's left of these microorganisms. Thanks to new research tools, that record is finally being read.

In research published in the journal Paleoceanography and Paleoclimatology, researchers including University of Utah doctoral student Courtney Wagner and associate professor Peter Lippert report the climate clues that can be found by analyzing the magnetic fossil particles, or magnetofossils.

[weatheriscool]

An almost complete extinct dwarf emu egg found on King Island
https://phys.org/news/2021-05-extinct-d ... -king.html

A pair of researchers, one with the UK's Natural History Museum, the other a King Island historian, has found an almost complete extinct dwarf emu egg on King Island. In their paper published in the journal Biology Letters, Julian Hume and Christian Robertson describe the egg and compare it to other dwarf emu eggs and also with the eggs from the mainland emu.

The emu is a flightless bird found only in Australia and its nearby islands. It is the second largest bird after the ostrich. Prior research has shown that in addition to the mainland emu, there were several types of dwarf emus living on at least three islands off the southern coast of Australia—all of which went extinct shortly after the arrival of European settlers.

[wjfox]

[wjfox]

How rafts helped primates rule the world

11 May 2021

Millions of years ago, the oceans presented a formidable barrier to the spread of primates – but were ultimately no match. Did rafts of vegetation help them conquer the globe?

Humans evolved in Africa, along with chimpanzees, gorillas and monkeys. But primates themselves appear to have evolved elsewhere – likely in Asia – before colonising Africa. At the time, around 50 million years ago, Africa was an island isolated from the rest of the world by ocean – so how did primates get there?

A land bridge is the obvious explanation, but the geological evidence currently argues against it. Instead, we're left with a far more unlikely scenario: early primates may have rafted to Africa, floating hundreds of miles across oceans on vegetation and debris.

Such oceanic dispersal was once seen as far-fetched and wildly speculative by many scientists. Some still support the land bridge theory, either disputing the geological evidence, or arguing that primate ancestors crossed into Africa long before the current fossil record suggests, before the continents broke up.

But there's an emerging consensus that oceanic dispersal is far more common than once supposed. Plants, insects, reptiles, rodents and primates have all been found to colonise island continents in this way – including a remarkable Atlantic crossing that took monkeys from Africa to South America 35 million years ago. These events are incredibly rare but, given huge spans of time, such freak events inevitably influence evolution – including our own origins.

https://www.bbc.com/future/article/2021 ... -the-world

[wjfox]

[weatheriscool]

Ancient tsunami could have wiped out Scottish cities today, study finds

Research maps the extent of the catastrophic Storegga tsunami 8,200 years ago for the first time

Libby Brooks Scotland correspondent
Fri 4 Jun 2021 01.00 EDT

Towns and cities across Scotland would be devastated if the country’s coastline was hit by a tsunami of the kind that happened 8,200 years ago, according to an academics’ study.

While about 370 miles of Scotland’s northern and eastern coastline were affected when the Storegga tsunami struck, the study suggests a modern-day disaster of the same magnitude would have worse consequences.

The researchers at the universities of Sheffield, St Andrews and York attributed this to denser human populations and higher sea levels that could potentially destroy seafront and port areas of Arbroath, Stonehaven, Aberdeen, Inverness and Wick, all of which have significant built-up areas less than 10 metres above sea level and directly face the sea.

The study which maps the impact of the ancient tsunami for the first time, used modelling to estimate how far the wave would have travelled inland. The estimates suggest the water could have encroached up to 18 miles inland. That distance today would probably leave a town such as Montrose, which overlooks a tidal lagoon and has a population of 12,000, completely devastated.

More:
https://www.theguardian.com/world/2021/ ... tudy-finds

[weatheriscool]

School lesson gone wrong leads to new, bigger megalodon size estimate
https://phys.org/news/2021-06-school-le ... lodon.html
by Natalie Van Hoose and Jerald B. Pinson, Florida Museum of Natural History

A more reliable way of estimating the size of megalodon shows the extinct shark may have been bigger than previously thought, measuring up to 65 feet, nearly the length of two school buses. Earlier studies had ball-parked the massive predator at about 50 to 60 feet long.

The revised estimate is the result of new equations based on the width of megalodon's teeth—and began with a high school lesson that went awry.

Victor Perez, then a doctoral student at the Florida Museum of Natural History, was guiding students through a math exercise that used 3D-printed replicas of fossil teeth from a real megalodon and a set of commonly used equations based on tooth height to estimate the shark's size. But something was off: Students' calculations ranged from about 40 to 148 feet for the same shark. Perez snapped into trouble-shooting mode.

[weatheriscool]

Discovery of the oldest plant fossils on the African continent
https://phys.org/news/2021-06-discovery ... inent.html
by Cyril Prestianni, University de Liege

The analysis of very old plant fossils discovered in South Africa and dating from the Lower Devonian period documents the transition from barren continents to the green planet we know today. Cyrille Prestianni, a palaeobotanist at the EDDy Lab at the University of Liège (Belgium), participated in this study, the results of which have just been published in the journal Scientific Reports.

The greening of continents—or terrestrialisation—is undoubtedly one of the most important processes that our planet has undergone. For most of the Earth's history, the continents were devoid of macroscopic life, but from the Ordovician period (480 million years ago) green algae gradually adapted to life outside the aquatic environment. The conquest of land by plants was a very long process during which plants gradually acquired the ability to stand upright, breathe in the air or disperse their spores. Plant fossils that document these key transitions are very rare. In 2015, during the expansion of the Mpofu Dam (South Africa), researchers discovered numerous plant fossils in geological strata dated to the Lower Devonian (420—410 million years ago), making this a truly exceptional discovery.

[caltrek]

A volcanic eruption 39 million years ago buried a forest in Peru – now the petrified trees are revealing South America’s primeval history

https://theconversation.com/a-volcanic- ... 160160/url

Introduction:

In the hills outside the small village of Sexi, Peru, a fossil forest holds secrets about South America’s past millions of years ago.

When we first visited these petrified trees more than 20 years ago, not much was known about their age or how they came to be preserved. We started by dating the rocks and studying the volcanic processes that preserved the fossils. From there, we began to piece together the story of the forest, starting from the day 39 million years ago when a volcano erupted in northern Peru.

Ash rained down on the forest that day, stripping leaves from the trees. Then flows of ashy material moved through, breaking off the trees and carrying them like logs in a river to the area where they were buried and preserved. Millions of years later, after the modern-day Andes rose and carried the fossils with them, the rocks were exposed to the forces of erosion, and the fossil woods and leaves again saw the light of day.

This petrified forest, El Bosque Perificado Piedra Chamana, is the first fossil forest from the South American tropics to be studied in detail. It is helping paleontologists like us to understand the history of the megadiverse forests of the New World tropics and the past climates and environments of South America.

[Time_Traveller]

Giant rhino that once roamed China may be ‘largest land mammal’ that ever lived

Friday 18 Jun 2021



A giant rhino dug up in China could be ‘the largest land mammal’ that ever lived, say scientists.

The colossal creature was more than 26 feet long, over 16 foot tall and weighed 24 tonnes.

It was four times the size of an African elephant – the biggest animal that walks the Earth today.

The hornless herbivore roamed Asia 26.5 million years ago – browsing the forests for leaves, soft plants and shrubs.

It resembled an overgrown tapir – and has been named Paraceratherium linxiaense. The bizarre animal had a slender skull, short trunk and an unusually long and muscular neck.

https://metro.co.uk/2021/06/18/giant-rh ... -14792600/

[weatheriscool]

The 27.5-million-year cycle of geological activity
https://phys.org/news/2021-06-million-y ... gical.html
by New York University

Geologic activity on Earth appears to follow a 27.5-million-year cycle, giving the planet a 'pulse,' according to a new study published in the journal Geoscience Frontiers.

"Many geologists believe that geological events are random over time. But our study provides statistical evidence for a common cycle, suggesting that these geologic events are correlated and not random," said Michael Rampino, a geologist and professor in New York University's Department of Biology, as well as the study's lead author.

Over the past five decades, researchers have proposed cycles of major geological events—including volcanic activity and mass extinctions on land and sea—ranging from roughly 26 to 36 million years. But early work on these correlations in the geological record was hampered by limitations in the age-dating of geologic events, which prevented scientists from conducting quantitative investigations.

[weatheriscool]

Geochemical study confirms cause of end-Permian mass extinction event

by Heather Tate, Northern Arizona University
https://phys.org/news/2021-06-geochemic ... event.html

The most severe mass extinction event in the past 540 million years eliminated more than 90 percent of Earth's marine species and 75 percent of terrestrial species. Although scientists had previously hypothesized that the end-Permian mass extinction, which took place 251 million years ago, was triggered by voluminous volcanic eruptions in a region of what is now Siberia, they were not able to explain the mechanism by which the eruptions resulted in the extinction of so many different species, both in the oceans and on land.

Associate professor Laura Wasylenki of Northern Arizona University's School of Earth and Sustainability and Department of Chemistry and Biochemistry is co-author on a new paper in Nature Communications entitled, "Nickel isotopes link Siberian Traps aerosol particles to the end-Permian mass extinction," in collaboration with Chinese, Canadian and Swiss scientists. The paper presents the results of nickel isotope analyses performed in Wasylenki's lab on Late Permian sedimentary rocks collected in Arctic Canada. The samples have the lightest nickel isotope ratios ever measured in sedimentary rocks, and the only plausible explanation is that the nickel was sourced from the volcanic terrain, very likely carried by aerosol particles and deposited in the ocean, where it dramatically changed the chemistry of seawater and severely disrupted the marine ecosystem.

[Time_Traveller]

Earth has a ‘pulse’ every 27.5 million years that brings eruptions and mass extinctions

Mon, 21 June 2021

Disastrous events including volcanic eruptions and mass extinctions seem to occur regularly – dictated by a “pulse” that beats every 27.5 million years, a new study found.

Researchers used improved radio-isotope dating technology to precisely pinpoint disasters including sea level rises and volcanic outbursts.

They found that such events are “not random” and appear to be linked to a recurring cycle of major geological events.

The last cycle was 7 million years ago, meaning it should be another 20 million years until another round of such events.

Michael Rampino, a geologist and professor in New York University's Department of Biology, said, "Many geologists believe that geological events are random over time. But our study provides statistical evidence for a common cycle, suggesting that these geologic events are correlated and not random.”

https://uk.news.yahoo.com/pulse-extinct ... 48847.html

[weatheriscool]

Tiny ancient bird from China shares skull features with Tyrannosaurus rex
https://phys.org/news/2021-06-tiny-anci ... skull.html
by Chinese Academy of Sciences

Researchers from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences have discovered a 120-million-year-old partial fossil skeleton of a tiny extinct bird that fits in the palm of the hand and preserves a unique skull with a mix of dinosaurian and bird features.

The two-centimeter-long (0.75 inch) skull of the fossil shares many structural and functional features with the gigantic Tyrannosaurus rex, indicating that early birds kept many features of their dinosaurian ancestors and their skulls functioned much like those of dinosaurs rather than living birds.

Their findings were published in Nature Communications on June 23.

The bird was deposited 120 million years ago in a shallow lake in what is today Liaoning Province in northeastern China.

[wjfox]

[weatheriscool]

Dinosaurs were in decline before the end, according to new study

https://phys.org/news/2021-06-dinosaurs-decline.html

by University of Bristol

The death of the dinosaurs 66 million years ago was caused by the impact of a huge asteroid on the Earth. However, palaeontologists have continued to debate whether they were already in decline or not before the impact.

In a new study, published today in the journal Nature Communications, an international team of scientists, which includes the University of Bristol, show that they were already in decline for as much as ten million years before the final death blow.

Lead author, Fabien Condamine, a CNRS researcher from the Institut des Sciences de l'Evolution de Montpellier (France), said: "We looked at the six most abundant dinosaur families through the whole of the Cretaceous, spanning from 150 to 66 million years ago, and found that they were all evolving and expanding and clearly being successful.

"Then, 76 million years ago, they show a sudden downturn. Their rates of extinction rose and in some cases the rate of origin of new species dropped off."

[Time_Traveller]

'Icelandia': Is Iceland the tip of a vast, sunken continent?

June 30, 2021

Academics believe they have identified a remarkable geological secret: A sunken continent hidden under Iceland and the surrounding ocean,which they have dubbed "Icelandia."

An international team of geologists, led by Gillian Foulger, Emeritus Professor of Geophysics in the Department of Earth Sciences at Durham University (UK), believe the sunken continent could stretch from Greenland all the way to Europe.

It is believed to cover an area of ~600,000 km2 but when adjoining areas west of Britain are included in a "Greater Icelandia," the entire area could be ~1,000,000 km2 in size.

If proven, it means that the giant supercontinent of Pangaea, which is thought to have broken up over 50 million years ago, has in fact not fully broken up.

This new theory challenges long-held scientific ideas around the extent of oceanic and continental crust in the North Atlantic region, and how volcanic islands, like Iceland, formed.

https://phys.org/news/2021-06-icelandia ... inent.html