Topic: Geology

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๐Ÿ”— Timeline of the far future

๐Ÿ”— Physics ๐Ÿ”— Lists ๐Ÿ”— Statistics ๐Ÿ”— Astronomy ๐Ÿ”— Time ๐Ÿ”— Futures studies ๐Ÿ”— Geology ๐Ÿ”— Extinction ๐Ÿ”— Solar System ๐Ÿ”— Astronomy/Solar System

While the future can never be predicted with absolute certainty, present understanding in various scientific fields allows for the prediction of some far-future events, if only in the broadest outline. These fields include astrophysics, which has revealed how planets and stars form, interact, and die; particle physics, which has revealed how matter behaves at the smallest scales; evolutionary biology, which predicts how life will evolve over time; and plate tectonics, which shows how continents shift over millennia.

All projections of the future of Earth, the Solar System, and the universe must account for the second law of thermodynamics, which states that entropy, or a loss of the energy available to do work, must rise over time. Stars will eventually exhaust their supply of hydrogen fuel and burn out. Close encounters between astronomical objects gravitationally fling planets from their star systems, and star systems from galaxies.

Physicists expect that matter itself will eventually come under the influence of radioactive decay, as even the most stable materials break apart into subatomic particles. Current data suggest that the universe has a flat geometry (or very close to flat), and thus will not collapse in on itself after a finite time, and the infinite future allows for the occurrence of a number of massively improbable events, such as the formation of Boltzmann brains.

The timelines displayed here cover events from the beginning of the 11th millennium to the furthest reaches of future time. A number of alternative future events are listed to account for questions still unresolved, such as whether humans will become extinct, whether protons decay, and whether the Earth survives when the Sun expands to become a red giant.

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๐Ÿ”— Dallol

๐Ÿ”— Volcanoes ๐Ÿ”— Biology ๐Ÿ”— Africa ๐Ÿ”— Geology ๐Ÿ”— Ethiopia

Dallol is a unique, terrestrial hydrothermal system around a cinder cone volcano in the Danakil Depression, northeast of the Erta Ale Range in Ethiopia. It is known for its unearthly colors and mineral patterns, and the very acidic fluids that discharge from its hydrothermal springs.

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๐Ÿ”— Naturally-Occurring Nuclear Reactors

๐Ÿ”— Physics ๐Ÿ”— Geology

A fossil natural nuclear fission reactor is a uranium deposit where self-sustaining nuclear chain reactions have occurred. This can be examined by analysis of isotope ratios. The conditions under which a natural nuclear reactor could exist had been predicted in 1956 by Paul Kazuo Kuroda. The phenomenon was discovered in 1972 in Oklo, Gabon by French physicist Francis Perrin under conditions very similar to what was predicted.

Oklo is the only known location for this in the world and consists of 16 sites at which self-sustaining nuclear fission reactions are thought to have taken place approximately 1.7 billion years ago, and ran for a few hundred thousand years, averaging probably less than 100 kW of thermal power during that time.

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๐Ÿ”— Wanggongchang Explosion

๐Ÿ”— Military history ๐Ÿ”— Disaster management ๐Ÿ”— Death ๐Ÿ”— China/Chinese history ๐Ÿ”— China ๐Ÿ”— Astronomy ๐Ÿ”— Geology ๐Ÿ”— Military history/Asian military history ๐Ÿ”— Geology/Meteorites ๐Ÿ”— Military history/Chinese military history ๐Ÿ”— Explosives ๐Ÿ”— Astronomy/Solar System

The Wanggongchang Explosion (Chinese: ็Ž‹ๆญๅป ๅคง็ˆ†็‚ธ), also known as the Great Tianqi Explosion (ๅคฉๅ•Ÿๅคง็ˆ†็‚ธ), Wanggongchang Calamity (็Ž‹ๆญๅป ไน‹่ฎŠ) or Beijing Explosive Incident in Late Ming (ๆ™šๆ˜ŽๅŒ—ไบฌ็ˆ†็‚ธไบ‹ไปถ), was an unexplained catastrophic explosion that occurred on May 30 of the Chinese calendar in 1626 AD during the late reign of Tianqi Emperor, at the heavily populated Ming China capital Beijing, and had reportedly killed around 20,000 people. The nature of the explosion is still unclear to this day, as it is estimated to have released energy equivalent to about 10-20 kiloton of TNT, similar to that of the Hiroshima bombing.

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๐Ÿ”— Holocene Extinction

๐Ÿ”— Environment ๐Ÿ”— Geology ๐Ÿ”— Extinction

The Holocene extinction, otherwise referred to as the sixth mass extinction or Anthropocene extinction, is an ongoing extinction event of species during the present Holocene epoch (with the more recent time sometimes called Anthropocene) as a result of human activity. The included extinctions span numerous families of plants and animals, including mammals, birds, amphibians, reptiles and arthropods. With widespread degradation of highly biodiverse habitats such as coral reefs and rainforests, as well as other areas, the vast majority of these extinctions are thought to be undocumented, as the species are undiscovered at the time of their extinction, or no one has yet discovered their extinction. The current rate of extinction of species is estimated at 100 to 1,000 times higher than natural background rates.

The Holocene extinction includes the disappearance of large land animals known as megafauna, starting at the end of the last glacial period. Megafauna outside of the African mainland (thus excluding Madagascar), which did not evolve alongside humans, proved highly sensitive to the introduction of new predation, and many died out shortly after early humans began spreading and hunting across the Earth (many African species have also gone extinct in the Holocene, but โ€“ with few exceptions โ€“ megafauna of the mainland was largely unaffected until a few hundred years ago). These extinctions, occurring near the Pleistoceneโ€“Holocene boundary, are sometimes referred to as the Quaternary extinction event.

The most popular theory is that human overhunting of species added to existing stress conditions as the extinction coincides with human emergence. Although there is debate regarding how much human predation affected their decline, certain population declines have been directly correlated with human activity, such as the extinction events of New Zealand and Hawaii. Aside from humans, climate change may have been a driving factor in the megafaunal extinctions, especially at the end of the Pleistocene.

Ecologically, humanity has been noted as an unprecedented "global superpredator" that consistently preys on the adults of other apex predators, and has worldwide effects on food webs. There have been extinctions of species on every land mass and in every ocean: there are many famous examples within Africa, Asia, Europe, Australia, North and South America, and on smaller islands. Overall, the Holocene extinction can be linked to the human impact on the environment. The Holocene extinction continues into the 21st century, with meat consumption, overfishing, and ocean acidification and the decline in amphibian populations being a few broader examples of a cosmopolitan decline in biodiversity. Human population growth and increasing per capita consumption are considered to be the primary drivers of this decline.

The 2019 Global Assessment Report on Biodiversity and Ecosystem Services, published by the United Nations' Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services, posits that roughly one million species of plants and animals face extinction within decades as the result of human actions.

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๐Ÿ”— Silurian hypothesis

๐Ÿ”— History ๐Ÿ”— Philosophy ๐Ÿ”— Palaeontology ๐Ÿ”— Geology ๐Ÿ”— Archaeology

The Silurian hypothesis is a thought experiment which assesses modern science's ability to detect evidence of a prior advanced civilization, perhaps several million years ago. In a 2018 paper, Adam Frank, an astrophysicist at the University of Rochester, and Gavin Schmidt, director of the NASA Goddard Institute, imagined an advanced civilization before humans and pondered whether it would "be possible to detect an industrial civilization in the geological record". They wrote, "While we strongly doubt that any previous industrial civilization existed before our own, asking the question in a formal way that articulates explicitly what evidence for such a civilization might look like raises its own useful questions related both to astrobiology and to Anthropocene studies." The term "silurian hypothesis" was inspired by a 1970s Dr Who serial Doctor Who and the Silurians which featured a species called the Silurians.

According to Frank and Schmidt, since fossilization is relatively rare and little of Earth's exposed surface is from before the quaternary time period, the chances of finding direct evidence of such a civilization, such as technological artifacts, is small. After a great time span, the researchers concluded, we would be more likely to find indirect evidence such as anomalies in the chemical composition or isotope ratios of sediments. Objects that could indicate possible evidence of past civilizations include plastics and nuclear wastes residues buried deep underground or on the ocean floor.

Prior civilizations could have gone to space and left artifacts on other celestial bodies, such as the Moon and Mars. Evidence for artifacts on these two worlds would be easier to find than on Earth, where erosion and tectonic activity would erase much of it.

Frank first approached Schmidt to discuss how to detect alien civilizations via their potential impact upon climate through the study of ice cores and tree rings. They both realized that the hypothesis could be expanded and applied to Earth and humanity due to the fact that humans have been in their current form for the past 300,000 years and have had sophisticated technology for only the last few centuries.

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๐Ÿ”— Toba catastrophe theory

๐Ÿ”— Volcanoes ๐Ÿ”— Disaster management ๐Ÿ”— Geology ๐Ÿ”— Indonesia

The Toba supereruption was a supervolcanic eruption that occurred about 75,000 years ago at the site of present-day Lake Toba in Sumatra, Indonesia. It is one of the Earth's largest known eruptions. The Toba catastrophe theory holds that this event caused a global volcanic winter of six to ten years and possibly a 1,000-year-long cooling episode.

In 1993, science journalist Ann Gibbons posited that a population bottleneck occurred in human evolution about 70,000 years ago, and she suggested that this was caused by the eruption. Geologist Michael R. Rampino of New York University and volcanologist Stephen Self of the University of Hawaii at Manoa support her suggestion. In 1998, the bottleneck theory was further developed by anthropologist Stanley H. Ambrose of the University of Illinois at Urbanaโ€“Champaign. Both the link and global winter theories are controversial. The Toba event is the most closely studied supereruption.

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๐Ÿ”— Azolla Event

๐Ÿ”— Climate change ๐Ÿ”— Environment ๐Ÿ”— Plants ๐Ÿ”— Arctic ๐Ÿ”— Palaeontology ๐Ÿ”— Geology

The Azolla event is a scenario hypothesized to have occurred in the middle Eocene epoch, around 49ย million years ago, when blooms of the freshwater fern Azolla are thought to have happened in the Arctic Ocean. As they sank to the stagnant sea floor, they were incorporated into the sediment; the resulting draw-down of carbon dioxide has been speculated to have helped transform the planet from a "greenhouse Earth" state, hot enough for turtles and palm trees to prosper at the poles, to the current icehouse Earth known as the Late Cenozoic Ice Age.

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๐Ÿ”— Petoskey stone

๐Ÿ”— Geology ๐Ÿ”— Michigan ๐Ÿ”— Gemology and Jewelry/Gemstones subpage ๐Ÿ”— Gemology and Jewelry

A Petoskey stone is a rock and a fossil, often pebble-shaped, that is composed of a fossilized rugose coral, Hexagonaria percarinata. Such stones were formed as a result of glaciation, in which sheets of ice plucked stones from the bedrock, grinding off their rough edges and depositing them in the northwestern (and some in the northeastern) portion of Michigan's lower peninsula. In those same areas of Michigan, complete fossilized coral colony heads can be found in the source rocks for the Petoskey stones.

Petoskey stones are found in the Gravel Point Formation of the Traverse Group. They are fragments of a coral reef that was originally deposited during the Devonian period. When dry, the stone resembles ordinary limestone but when wet or polished using lapidary techniques, the distinctive mottled pattern of the six-sided coral fossils emerges. It is sometimes made into decorative objects. Other forms of fossilized coral are also found in the same location.

In 1965, it was named the state stone of Michigan.

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๐Ÿ”— Chesapeake Bay Impact Crater

๐Ÿ”— Geology

The Chesapeake Bay impact crater was formed by a bolide that impacted the eastern shore of North America about 35.5 ยฑ 0.3 million years ago, in the late Eocene epoch. It is one of the best-preserved "wet-target" impact craters in the world.

Continued slumping of sediments over the rubble of the crater has helped shape the Chesapeake Bay.

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