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An 8-mile-long "canvas" filled with ice age drawings of mastodons, giant sloths and other extinct beasts has been discovered in the Amazon rainforest. The gorgeous art, drawn with ochre — a red pigment frequently used as paint in the ancient world — spans nearly 8 miles (13 kilometers) of rock on the hills above three rock shelters in the Colombian Amazon, a new study finds. "These really are incredible images, produced by the earliest people to live in western Amazonia," study co-researcher Mark Robinson, an archaeologist at the University of Exeter, who analyzed the rock art alongside Colombian scientists, said...

Findings also suggest exoplanets lying within habitable zones may be susceptible to ice ages. ============================================================================= At least twice in Earth’s history, nearly the entire planet was encased in a sheet of snow and ice. These dramatic “Snowball Earth” events occurred in quick succession, somewhere around 700 million years ago, and evidence suggests that the consecutive global ice ages set the stage for the subsequent explosion of complex, multicellular life on Earth. Scientists have considered multiple scenarios for what may have tipped the planet into each ice age. While no single driving process has been identified, it’s assumed that whatever triggered...

During the past 2.6 million years, Earth’s climate has alternated between warm periods known as interglacials, when conditions were similar to those of today, and cold glacials, when ice sheets spread across North America and northern Europe. Before about 1 million years ago, the warm periods recurred every 40,000 years, but after that, the return period lengthened to an average of about 100,000 years. It has often been suggested that a decline in the atmospheric concentration of carbon dioxide was responsible for this fundamental change. Writing in Nature, Yan et al.1 report the first direct measurements of atmospheric CO2 concentrations...

There are two reasons, according to Jim Adovasio, we don’t think of baskets or textiles when we think of the Stone Age. One is that stones and bones, being far more durable, are far more common at archeological sites than artifacts made of fiber... And yet it has been around a long time, as four small pieces of clay described by Adovasio this past year make clear. Found at a site called Pavlov in the Czech Republic, they are 27,000 years old--and impressed with patterns that could only have been created by woven fibers. These artifacts push back the date...

A bird that had previously gone extinct came back to life thanks to a rare evolutionary process known as "iterative evolution." The white-throated rail bird can presently be found on the island of Aldabra. Early fossils of the bird suggest it lived there thousands of years ago and died out because it could not fly to higher ground when rising sea levels threatened its safety. But thanks to "iterative evolution," which evolves similar body parts due to genetics from a similar ancestor, the bird came back from the dead. **SNIP** In order to make the determination that the extinct bird...

For several million years, the Earth cycled through ice ages at a regular pace, but then, 1.25 million to 700,000 years ago, something changed: ice ages went from lasting 40,000 years to 100,000. … By looking at the microscopic shells of microorganisms called foraminifera, Adam Hasenfratz of the Geological Institute in Zürich, Switzerland, and colleagues, find evidence of a reduction in deep water circulation, causing less carbon dioxide to be released into the air. Oceanic changes in the Antarctic Zone could have ensured “that glacial conditions persisted despite orbital changes to the contrary”, the study says. The new research, presented...

https://www.youtube.com/watch?v=L_861us8D9M

Following the discovery of the 19.2-mile wide Hiawatha impact crater beneath the northwest margin of the Greenland Ice Sheet, Dr. Joe MacGregor of NASA’s Goddard Space Flight Center and colleagues explored satellite and aerogeophysical data in search of additional such craters and found a possible second impact crater that is 22.7 miles wide and 114 miles southeast of the Hiawatha crater. The discovery is described in a paper in the journal Geophysical Research Letters. ..." Following the finding of that first crater, Dr. MacGregor and co-authors checked topographic maps of the rock beneath Greenland’s ice for signs of other craters....

The Bering land bridge was exposed at various times over an almost three million year period, when wide scale glaciation lowered sea levels by as much as 150 metres. The land bridge was part of "Beringia," which refers to the stretch of land between present day Siberia and Yukon Territory. It's been home to woolly mammoths, steppe bison and humans. Jeff Bond, a geologist with Yukon Geological Survey in Whitehorse, has produced a map showing what Beringia looked like 18,000 years ago. At that time, much of the earth was glaciated, but Beringia remained predominantly ice-free due to its arid...

The Grand Canyon is a gigantic geological library, with rocky layers that tell much of the story of Earth’s history. Curiously though, a sizeable layer representing anywhere from 250 million years to 1.2 billion years is missing. Known as the Great Unconformity, this massive temporal gap can be found not just in this famous crevasse, but in places all over the world. In one layer, you have the Cambrian period, which started roughly 540 million years ago and left behind sedimentary rocks packed with the fossils of complex, multicellular life. Directly below, you have fossil-free crystalline basement rock, which formed...

Like any spinning object, Earth is subject to centrifugal force, which tugs on the planet's fluid interior. At the equator, where this force is strongest, Earth is more than 26 miles larger in diameter than at the poles. Gordon said true polar wander may occur when dense, highly viscous bumps of mantle build up at latitudes away from the equator. If the mantle anomalies are massive enough, they can unbalance the planet, and the equator will gradually shift to bring the excess mass closer to the equator. The planet still spins once every 24 hours and true polar wander does...

An international team of geoscientists from the United States, Canada and Europe has discovered a large impact crater beneath the Hiawatha Glacier in remote northwest Greenland. A paper on the discovery was published in the journal Science Advances. The Hiawatha impact crater is approximately 19.2 miles (31 km) wide and lies under an ice sheet that is 0.6 miles (1 km) thick.The scientists believe this crater was formed by a 0.6-mile wide iron asteroid that slammed into the Earth at the end of the Pleistocene epoch, perhaps as recently as 12,000 years ago. ..." “Researchers were looking at the map...

On a bright July day 2 years ago, Kurt Kjær was in a helicopter flying over northwest Greenland—an expanse of ice, sheer white and sparkling. Soon, his target came into view: Hiawatha Glacier, a slow-moving sheet of ice more than a kilometer thick. It advances on the Arctic Ocean not in a straight wall, but in a conspicuous semicircle, as though spilling out of a basin. Kjær, a geologist at the Natural History Museum of Denmark in Copenhagen, suspected the glacier was hiding an explosive secret. The helicopter landed near the surging river that drains the glacier, sweeping out rocks...

Climatologists find familiar fluctuations in Pacific's past - test. “During past ice ages the tropical Pacific Ocean behaved rather as it does today in an El Niño event, bringing downpours to some places and drought to others.” Thus began a 2002 article Nature magazine (12 Jul 2002) For example, it could explain the low atmospheric levels of greenhouse gases, such as carbon dioxide, methane and nitrous oxide, during the last ice age. It is not clear whether this was a cause or a consequence of the difference in global climate, but such decreases would have lowered global temperatures still further,...

Consider the ancient human fossils from a Moroccan cave called Jebel Irhoud, which were described just last year. These 315,000-year-old bones are the oldest known fossils of Homo sapiens. They not only pushed back the proposed dawn of our species, but they added northwest Africa to the list of possible origin sites. They also had an odd combination of features, combining the flat faces of modern humans with the elongated skulls of ancient species like Homo erectus. From the front, they could have passed for us; from the side, they would have stood out. Fossils from all over Africa have...

Had you searched the sky with a telescope just a few hundred thousand years ago, you would have struggled to find a red planet. Instead, you would have seen a gleaming-white ice ball where Mars should be. A team of astronomers led by Isaac Smith, an astrophysicist at the Southwest Research Institute in Boulder, Colorado, has collected the first concrete evidence that Mars has just exited an extreme ice age, one so intense it would have put Earth's recent frosty foray to shame. Using cameras and a radar-pinging device on board NASA's Mars Reconnaissance Orbiter, Smith's team deduced this history...

Europe went through a major population upheaval about 14,500 years ago, at the end of the last ice age, according to DNA from the bones of hunter-gatherers. Ancient DNA studies published in the last five years have transformed what we know about the early peopling of Europe. The picture they paint is one in which successive waves of immigration wash over the continent, bringing in new people, new genes and new technologies. These studies helped confirm that Europe's early hunter-gatherers - who arrived about 40,000 years ago - were largely replaced by farmers arriving from the Middle East about 8000...

In our planet's early history, 720 to 640 million years ago, thick sheets of ice covered the majority of the surface, as the Earth was locked in a deep freeze. But explosive underwater volcanoes changed the chemistry of the Earth's oceans and were key to breaking the planet from its icy state, according to a new study. Researchers at the University of Southampton believe underwater volcanoes helped to thaw out "Snowball Earth", and even led to runaway chemical chain reactions, which created the conditions for an explosion of life on Earth. While much of the driving forces behind glaciation during...

The team found 14,000-year-old evidence that could lead to a new understanding of culture and the environment at the dawn of human civilization in the region. At that time, this area used to get much more rain and was able to sustain human settlement... Underneath the volcanic basalt on the windswept, arid and rocky plain, within sight of the Syrian border, the bones of a child and adult are slowly coming to the surface after at least 14,000 years entombed in the desert. By analysing bones, seeds and other remains scientists hope to discover that in this area, 14.000 years...

The Maunder Minimum (also known as the prolonged sunspot minimum) is the name used for the period roughly spanning 1645 to 1715 when sunspots became exceedingly rare, as noted by solar observers of the time. Like the Dalton Minimum and Spörer Minimum, the Maunder Minimum coincided with a period of lower-than-average global temperatures. During one 30-year period within the Maunder Minimum, astronomers observed only about 50 sunspots, as opposed to a more typical 40,000-50,000 spots. (Source) Climatologist John Casey, a former space shuttle engineer and NASA consultant, thinks that last year’s winter, described by USA Today as “one of...