Continents rose above sea level around 3 billion years ago
A new study estimates that the first large continents rose above sea level around 3 billion years ago, much earlier than previously thought. More interestingly, it appears that the continental landmass that rose up first from the ocean is what is now India.
The team studied ancient continental fragments (called cratons) in India, Australia and South Africa and found that this pivotal moment in the history of life on Earth — that is the emergence of continents — occurred much earlier than the 2.5 billion years estimated by previous research.
The team said the Singhbhum craton — an ancient piece of continental crust that makes up the eastern parts of India — contains several formations of ancient sandstone, which were formed from sand deposited in beaches, estuaries and rivers. They were then buried and compressed into rock.
The team estimated the age of these deposits by studying microscopic grains of a mineral called zircon preserved within these sandstones.
The zircon grains reveal that the Singhbhum sandstones were deposited around 3 billion years ago, making them some of the oldest beach deposits in the world. This also suggests a continental landmass had emerged in what is now India by at least 3 billion years ago. Read more here
New insights from the Martian surface
An international team of space researchers has analysed data from the Mars InSight lander that was received during the Perseverance rover’s descent earlier this year to learn more about the density of the Martian surface.
While landing on Mars, the rover had dropped heavy blocks on the surface of the red planet.
Scientists usually learn more about the makeup of other planets’ surface by studying seismic activity generated by events like an asteroid impact. But gathering seismic data from other planets is difficult, as such events occur at random.
Instead, the team decided to use the opportunity of the rover’s descent. The rover dropped two tungsten blocks — each weighing approximately 77.5 kg to the surface below. Using the InSight probe, which has been on Mars since 2018, the team was able to better study the impact.
The team found no evidence of the blocks crashing to the surface, which suggested that the surface was of such density that seismic ways created by the impact were muted.
The researchers estimate that less than three per cent of the energy from the blocks hitting the surface made its way into the material below.
A better understanding of such impacts could prove useful for engineers attempting to build structures on Mars for later human habitation. Read more here
Global temperature changes over last 24,000 years mapped
The magnitude and rate of global warming over the last 150 years surpass the magnitude and rate of changes over the last 24,000 years, according to scientists who reconstructed the Earth’s climate since the last ice age.
The research shows how far out of bounds human activity has pushed the climate system. It also confirms that the main drivers of climate change since the last ice age are rising greenhouse gas concentrations and the retreat of the ice sheets. It suggests a general warming trend over the last 10,000 years, settling decades-long debate about whether this period trended warmer or cooler in the paleoclimatology community.
The team created maps of global temperature changes for every 200-year interval going back 24,000 years.
Using these maps, anyone can explore how temperatures have changed across Earth.
To create the maps, researchers looked at the chemical signatures of marine sediments to get information about past temperatures. Because temperature changes over time can affect the chemistry of a long-dead animal’s shell, paleoclimatologists can use those measurements to estimate temperature in an area.
They combined this with computer-simulated climate models to provide temperature information based on scientists’ best understanding of the physics of the climate system. Read more here
Two-legged herbivore dinosaur species discovered in Greenland
Researchers have discovered a species of two-legged dinosaur that lived about 214 million years ago in what is now Greenland.
The long-necked herbivore was a predecessor of the sauropods, the largest land animals ever to live on this planet.
Researchers from Portugal, Denmark and Germany named the dinosaur Issi saaneq — which means cold bone in Greenland’s Inuit language.
Two well-preserved skulls of dinosaur were first unearthed in 1994 during an excavation in East Greenland by paleontologists from Harvard University. The two skulls of the new species come from a juvenile and an almost adult individual.
The team performed a micro-CT scan of the bones, which enabled them to create digital 3D models of the internal structures and the bones still covered by sediment.
The new findings are the first evidence of a distinct Greenlandic dinosaur species, which not only adds to the diverse range of dinosaurs from the Late Triassic (235-201 million years ago) but also allows us to better understand the evolutionary pathways and timeline of the iconic group of sauropods that inhabited the Earth for nearly 150 million years. More on it here
Vegan, biodegradable glitter made from fruits, vegetables
Researchers from the University of Cambridge have found a way to make sustainable, non-toxic, vegan, and biodegradable glitter from plants, fruits and vegetables that’s just as sparkly as the original version.
Any parent who has worked with their child on craft projects knows how hard it is to get rid of glitter. But beyond being hard to wash off, glitter particles are also made of toxic and unsustainable materials — which make them a plastic pollution menace.
But researchers have now made glitter from cellulose — a material found in cell walls of plants. They created nanocrystals out cellulose in a way that they can bend light to create vivid colors.
The physics behind this is the same as what produces some of the brightest colors in nature — such as those of butterfly wings and peacock feathers — and results in hues that do not fade, even after a century.
The team says that their materials could be used to replace the plastic glitter particles and tiny mineral effect pigments which are widely used in cosmetics.
The films of cellulose nanocrystals prepared by the team can be made at a large scale using processes like those used to make paper from wood pulp. Read more here