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The Earth Sciences Portal

Earth seen from Moon

Earth science or geoscience includes all fields of natural science related to the planet Earth. This is a branch of science dealing with the physical, chemical, and biological complex constitutions and synergistic linkages of Earth's four spheres: the biosphere, hydrosphere/cryosphere, atmosphere, and geosphere (or lithosphere). Earth science can be considered to be a branch of planetary science but with a much older history. (Full article...)

Selected articles

Image 1

Bryce Canyon National Park (/braɪs/) is a national park of the United States located in southwestern Utah. The major feature of the park is Bryce Canyon, which despite its name, is not a canyon, but a collection of giant natural amphitheaters along the eastern side of the Paunsaugunt Plateau. Bryce is distinctive due to geological structures called hoodoos, formed by frost weathering and stream erosion of the river and lake bed sedimentary rock. The red, orange, and white colors of the rocks provide spectacular views for park visitors. Bryce Canyon National Park is much smaller and sits at a much higher elevation than nearby Zion National Park. The rim at Bryce varies from 8,000 to 9,000 feet (2,400 to 2,700 m).

The area is in portions of Garfield County and Kane County. (Full article...)
Image 2

Lili near peak intensity in the Gulf of Mexico on October 2

Hurricane Lili was the second costliest, deadliest, and strongest hurricane of the 2002 Atlantic hurricane season, only surpassed by Hurricane Isidore, which affected the same areas around a week before Lili. Lili was the twelfth named storm, fourth hurricane, and second major hurricane of the 2002 Atlantic hurricane season. The storm developed from a tropical disturbance in the open Atlantic on September 21. It continued westward, affecting the Lesser Antilles as a tropical storm, then entered the Caribbean. As it moved west, the storm dissipated while being affected by wind shear south of Cuba, and regenerated when the vertical wind shear weakened. It turned to the northwest and strengthened up to category 2 strength on October 1. Lili made two landfalls in western Cuba later that day, and then entered the Gulf of Mexico. The hurricane rapidly strengthened on October 2, reaching Category 4 strength that afternoon. It weakened rapidly thereafter, and hit Louisiana as a Category 1 hurricane on October 3. It moved inland and dissipated on October 6.

Lili caused extensive damage through the Caribbean, particularly to crops and poorly built homes. Mudslides were common on the more mountainous islands, particularly Haiti and Jamaica. In the United States, the storm cut off the production of oil within the Gulf of Mexico, and caused severe damage in parts of Louisiana. Lili was also responsible for severe damage to the barrier islands and marshes in the southern portion of the state. Total damage amounted to $925 million (2002 USD), and the storm killed 15 people during its existence. (Full article...)
Image 3
The inner planets. From left to right: Mercury, Venus, Earth, Mars and terrestrial dwarf planet, Ceres (sizes to scale)

The geology of solar terrestrial planets mainly deals with the geological aspects of the four terrestrial planets of the Solar System – Mercury, Venus, Earth, and Mars – and one terrestrial dwarf planet: Ceres. Earth is the only terrestrial planet known to have an active hydrosphere.

Terrestrial planets are substantially different from the giant planets, which might not have solid surfaces and are composed mostly of some combination of hydrogen, helium, and water existing in various physical states. Terrestrial planets have a compact, rocky surfaces, and Venus, Earth, and Mars each also has an atmosphere. Their size, radius, and density are all similar. (Full article...)
Image 4

View of Mount Samalas along with Mount Rinjani

In 1257, a catastrophic eruption occurred at Samalas, a volcano on the Indonesian island of Lombok. The event had a probable Volcanic Explosivity Index of 7, making it one of the largest volcanic eruptions during the Holocene epoch. It left behind a large caldera that contains Lake Segara Anak. Later volcanic activity created more volcanic centres in the caldera, including the Barujari cone, which remains active.

The event created eruption columns reaching tens of kilometres into the atmosphere and pyroclastic flows that buried much of Lombok and crossed the sea to reach the neighbouring island of Sumbawa. The flows destroyed human habitations, including the city of Pamatan, which was the capital of a kingdom on Lombok. Ash from the eruption fell as far as 340 kilometres (210 mi) away in Java; the volcano deposited more than 10 cubic kilometres (2.4 cu mi) of rocks and ash. (Full article...)
Image 5

Turquoise is an opaque, blue-to-green mineral that is a hydrous phosphate of copper and aluminium, with the chemical formula Cu Al₆(PO₄)₄(OH)₈·4H₂O. It is rare and valuable in finer grades and has been prized as a gemstone for millennia due to its hue.

Like most other opaque gems, turquoise has been devalued by the introduction of treatments, imitations, and synthetics into the market. The robin egg blue or sky blue color of the Persian turquoise mined near the modern city of Nishapur, Iran, has been used as a guiding reference for evaluating turquoise quality. (Full article...)
$Image 6 The ACFEL ice auger showing an ice core pushed up into the core remover barrel. Ice drilling allows scientists studying glaciers and ice sheets to gain access to what is beneath the ice, to take measurements along the interior of the ice, and to retrieve samples. Instruments can be placed in the drilled holes to record temperature, pressure, speed, direction of movement, and for other scientific research, such as neutrino detection. Many different methods have been used since 1840, when the first scientific ice drilling expedition attempted to drill through the Unteraargletscher in the Alps. Two early methods were percussion, in which the ice is fractured and pulverized, and rotary drilling, a method often used in mineral exploration for rock drilling. In the 1940s, thermal drills began to be used; these drills melt the ice by heating the drill. Drills that use jets of hot water or steam to bore through ice soon followed. A growing interest in ice cores, used for palaeoclimatological research, led to ice coring drills being developed in the 1950s and 1960s, and there are now many different coring drills in use. For obtaining ice cores from deep holes, most investigators use cable-suspended electromechanical drills, which use an armoured cable to carry electrical power to a mechanical drill at the bottom of the borehole. (Full article...)$

Image 6
The ACFEL ice auger showing an ice core pushed up into the core remover barrel.

Ice drilling allows scientists studying glaciers and ice sheets to gain access to what is beneath the ice, to take measurements along the interior of the ice, and to retrieve samples. Instruments can be placed in the drilled holes to record temperature, pressure, speed, direction of movement, and for other scientific research, such as neutrino detection.

Many different methods have been used since 1840, when the first scientific ice drilling expedition attempted to drill through the Unteraargletscher in the Alps. Two early methods were percussion, in which the ice is fractured and pulverized, and rotary drilling, a method often used in mineral exploration for rock drilling. In the 1940s, thermal drills began to be used; these drills melt the ice by heating the drill. Drills that use jets of hot water or steam to bore through ice soon followed. A growing interest in ice cores, used for palaeoclimatological research, led to ice coring drills being developed in the 1950s and 1960s, and there are now many different coring drills in use. For obtaining ice cores from deep holes, most investigators use cable-suspended electromechanical drills, which use an armoured cable to carry electrical power to a mechanical drill at the bottom of the borehole. (Full article...)
Image 7

The 2002 Bou'in-Zahra earthquake (also known as the 2002 Avaj earthquake or the 2002 Changureh earthquake) occurred on 22 June 2002. The epicenter was near the city of Bou'in-Zahra in Qazvin Province, a region of northwestern Iran which is crossed by several major faults that is known for destructive earthquakes. The shock measured 6.5 on the M_wc scale, had a maximum Mercalli intensity of VIII (Severe), and was followed by more than 20 aftershocks. At least 230 people were killed and 1,500 more were injured.

According to the International Institute of Earthquake Engineering and Seismology (IIEES), the earthquake was felt as far away as the capital city of Tehran, approximately 290 kilometres (180 mi) east of the epicenter, although no damage was reported there. Most houses in the region were single-story masonry buildings, and virtually all of these collapsed. The public became angry due to the slow official response to victims who needed supplies. Residents of the town of Avaj resorted to throwing stones at the car of a government minister. (Full article...)
Image 8

The Cretaceous–Paleogene (K–Pg) extinction event, also known as the K–T extinction, was the mass extinction of three-quarters of the plant and animal species on Earth approximately 66 million years ago. The event caused the extinction of all non-avian dinosaurs. Most other tetrapods weighing more than 25 kg (55 lb) also became extinct, with the exception of some ectothermic species such as sea turtles and crocodilians. It marked the end of the Cretaceous period, and with it the Mesozoic era, while heralding the beginning of the current era, the Cenozoic. In the geologic record, the K–Pg event is marked by a thin layer of sediment called the K–Pg boundary, Fatkito boundary or K–T boundary, which can be found throughout the world in marine and terrestrial rocks. The boundary clay shows unusually high levels of the metal iridium, which is more common in asteroids than in the Earth's crust.

As originally proposed in 1980 by a team of scientists led by Luis Alvarez and his son Walter, it is now generally thought that the K–Pg extinction was caused by the impact of a massive asteroid 10 to 15 km (6 to 9 mi) wide, 66 million years ago, which devastated the global environment, mainly through a lingering impact winter which halted photosynthesis in plants and plankton. The impact hypothesis, also known as the Alvarez hypothesis, was bolstered by the discovery of the 180 km (112 mi) Chicxulub crater in the Gulf of Mexico's Yucatán Peninsula in the early 1990s, which provided conclusive evidence that the K–Pg boundary clay represented debris from an asteroid impact. The fact that the extinctions occurred simultaneously provides strong evidence that they were caused by the asteroid. A 2016 drilling project into the Chicxulub peak ring confirmed that the peak ring comprised granite ejected within minutes from deep in the earth, but contained hardly any gypsum, the usual sulfate-containing sea floor rock in the region: the gypsum would have vaporized and dispersed as an aerosol into the atmosphere, causing longer-term effects on the climate and food chain. In October 2019, researchers asserted that the event rapidly acidified the oceans and produced long-lasting effects on the climate, detailing the mechanisms of the mass extinction. (Full article...)
Image 9
A scene in Uttarakhand's Valley of Flowers National Park. In contrast to the rain shadow region of Tirunelveli, the park receives ample orographic precipitation due to its location in a mountainous windward-facing region wedged between the Zanskars and the Greater Himalayas.

The climate of India consists of a wide range of weather conditions across a vast geographic scale and varied topography. Based on the Köppen system, India encompasses a diverse array of climatic subtypes. These range from arid and semi-arid regions in the west to highland, sub-arctic, tundra, and ice cap climates in the northern Himalayan regions, varying with elevation. The northern lowlands experience subtropical conditions, with some areas at higher altitudes, like Srinagar, touching continental climates. In contrast, much of the south and the east exhibit tropical climate conditions, which support lush rainforests in these territories. Many regions have starkly different microclimates, making it one of the most climatically diverse countries in the world. The country's meteorological department follows the international standard of four seasons with some local adjustments: winter (December to February), summer (March to May), monsoon or rainy season (June to September), and a post-monsoon period (October and November).

India's geography and geology are climatically pivotal: the Thar Desert in the northwest and the Himalayas in the north work in tandem to create a culturally and economically important monsoonal regime. As Earth's highest and most massive mountain range, the Himalayas bar the influx of frigid katabatic winds from the icy Tibetan Plateau and northerly Central Asia. Most of North India is thus kept warm or is only mildly chilly or cold during winter; the same thermal dam keeps most regions in India hot in summer. The climate in South India is generally warmer, and more humid due to its coastlines. However some hill stations in South India such as Ooty are well known for their cold climate. (Full article...)
Image 10

White Chuck Glacier in the United States in 1973

The retreat of glaciers since 1850 is a well-documented effect of climate change. The retreat of mountain glaciers provide evidence for the rise in global temperatures since the late 19th century. Examples include mountain glaciers in western North America, Asia, the Alps in central Europe, and tropical and subtropical regions of South America and Africa. Since glacial mass is affected by long-term climatic changes, e.g. precipitation, mean temperature, and cloud cover, glacial mass changes are one of the most sensitive indicators of climate change. The retreat of glaciers is also a major reason for sea level rise. Excluding peripheral glaciers of ice sheets, the total cumulated global glacial losses over the 26 years from 1993 to 2018 were likely 5500 gigatons, or 210 gigatons per year.

On Earth, 99% of glacial ice is contained within vast ice sheets (also known as "continental glaciers") in the polar regions. Glaciers also exist in mountain ranges on every continent other than the Australian mainland, including Oceania's high-latitude oceanic island countries such as New Zealand. Glacial bodies larger than 50,000 km² (19,000 sq mi) are called ice sheets. They are several kilometers deep and obscure the underlying topography. (Full article...)
Image 11
Radiocarbon dating helped verify the authenticity of the Dead Sea scrolls.

Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon.

The method was developed in the late 1940s at the University of Chicago by Willard Libby, based on the constant creation of radiocarbon (¹⁴
C) in the Earth's atmosphere by the interaction of cosmic rays with atmospheric nitrogen. The resulting ¹⁴
C combines with atmospheric oxygen to form radioactive carbon dioxide, which is incorporated into plants by photosynthesis; animals then acquire ¹⁴
C by eating the plants. When the animal or plant dies, it stops exchanging carbon with its environment, and thereafter the amount of ¹⁴
C it contains begins to decrease as the ¹⁴
C undergoes radioactive decay. Measuring the proportion of ¹⁴
C in a sample from a dead plant or animal, such as a piece of wood or a fragment of bone, provides information that can be used to calculate when the animal or plant died. The older a sample is, the less ¹⁴
C there is to be detected, and because the half-life of ¹⁴
C (the period of time after which half of a given sample will have decayed) is about 5,730 years, the oldest dates that can be reliably measured by this process date to approximately 50,000 years ago (in this interval about 99.8% of the ¹⁴
C will have decayed), although special preparation methods occasionally make an accurate analysis of older samples possible. In 1960, Libby received the Nobel Prize in Chemistry for his work. (Full article...)
Image 12
Mahameru (Semeru) above Mount Bromo, East Java.

The geography of Indonesia is dominated by volcanoes that are formed due to subduction zones between the Eurasian plate and the Indo-Australian plate. Some of the volcanoes are notable for their eruptions, for instance, Krakatoa for its global effects in 1883, the Lake Toba Caldera for its supervolcanic eruption estimated to have occurred 74,000 years before present which was responsible for six years of volcanic winter, and Mount Tambora for the most violent eruption in recorded history in 1815. (Full article...)
Image 13

Rain-obscured shot of the F3 tornado in Gallatin, Tennessee that killed seven people.

The tornado outbreak of April 6–8, 2006, was a major tornado outbreak in the central and parts of the southern United States that began on April 6, 2006, in the Great Plains and continued until April 8 in South Carolina, with most of the activity on April 7. The hardest-hit region was Middle Tennessee, where several strong tornadoes devastated entire neighborhoods and left ten people dead. Some of the worst damage took place in Gallatin, Tennessee, and other communities north of Nashville also sustained significant damage.

There were 73 tornadoes confirmed across 13 states, with the bulk of them coming on the afternoon and evening of April 7 across the South, particularly in Tennessee. In total, 10 deaths were reported as a result of the tornadoes, and over $650 million in damage was reported, of which over $630 million was in Middle Tennessee. It was the third major outbreak of 2006, occurring just days after another major outbreak on April 2. It was also considered by some to be the worst disaster event in Middle Tennessee since the 1998 tornado outbreak. (Full article...)
Image 14

Darwin, c. 1854, when he was preparing On the Origin of Species

Charles Robert Darwin (/ˈdɑːrwɪn/ DAR-win; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended from a common ancestor is now generally accepted and considered a fundamental scientific concept. In a joint publication with Alfred Russel Wallace, he introduced his scientific theory that this branching pattern of evolution resulted from a process he called natural selection, in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding. Darwin has been described as one of the most influential figures in human history and was honoured by burial in Westminster Abbey.

Darwin's early interest in nature led him to neglect his medical education at the University of Edinburgh; instead, he helped to investigate marine invertebrates. His studies at the University of Cambridge's Christ's College from 1828 to 1831 encouraged his passion for natural science. However, it was his five-year voyage on HMS Beagle from 1831 to 1836 that truly established Darwin as an eminent geologist. The observations and theories he developed during his voyage supported Charles Lyell's concept of gradual geological change. Publication of his journal of the voyage made Darwin famous as a popular author. (Full article...)
$Image 15 Map of Earth's 16 principal tectonic plates Divergent:   Extension zone Convergent:   Collision zone Transform:   Sinistral transform Plate tectonics (from Latin tectonicus, from Ancient Greek τεκτονικός (tektonikós) 'pertaining to building') is the scientific theory that Earth's lithosphere comprises a number of large tectonic plates, which have been slowly moving since 3–4 billion years ago. The model builds on the concept of continental drift, an idea developed during the first decades of the 20th century. Plate tectonics came to be accepted by geoscientists after seafloor spreading was validated in the mid-to-late 1960s. The processes that result in plates and shape Earth's crust are called tectonics. Tectonic plates also occur in other planets and moons. Earth's lithosphere, the rigid outer shell of the planet including the crust and upper mantle, is fractured into seven or eight major plates (depending on how they are defined) and many minor plates or "platelets". Where the plates meet, their relative motion determines the type of plate boundary (or fault): convergent, divergent, or transform. The relative movement of the plates typically ranges from zero to 10 cm annually. Faults tend to be geologically active, experiencing earthquakes, volcanic activity, mountain-building, and oceanic trench formation. (Full article...)$

Image 15
Map of Earth's 16 principal tectonic plates

Divergent:
  Extension zone
Convergent:
  Collision zone
Transform:
  Sinistral transform

Plate tectonics (from Latin tectonicus, from Ancient Greek τεκτονικός (tektonikós) 'pertaining to building') is the scientific theory that Earth's lithosphere comprises a number of large tectonic plates, which have been slowly moving since 3–4 billion years ago. The model builds on the concept of continental drift, an idea developed during the first decades of the 20th century. Plate tectonics came to be accepted by geoscientists after seafloor spreading was validated in the mid-to-late 1960s. The processes that result in plates and shape Earth's crust are called tectonics.
Tectonic plates also occur in other planets and moons.

Earth's lithosphere, the rigid outer shell of the planet including the crust and upper mantle, is fractured into seven or eight major plates (depending on how they are defined) and many minor plates or "platelets". Where the plates meet, their relative motion determines the type of plate boundary (or fault): convergent, divergent, or transform. The relative movement of the plates typically ranges from zero to 10 cm annually. Faults tend to be geologically active, experiencing earthquakes, volcanic activity, mountain-building, and oceanic trench formation. (Full article...)
Image 16

Isabel at peak intensity, northeast of the Leeward Islands, on September 11

Hurricane Isabel was the strongest Atlantic hurricane since Mitch, and the deadliest, costliest, and most intense hurricane in the 2003 Atlantic hurricane season. Hurricane Isabel was also the strongest hurricane in the open waters of the Atlantic, both by wind speed and central pressure, before being surpassed by hurricanes Irma and Dorian in 2017 and 2019, respectively. The ninth named storm, fifth hurricane, and second major hurricane of the season, Isabel formed near the Cape Verde Islands from a tropical wave on September 6, in the tropical Atlantic Ocean. It moved northwestward, and within an environment of light wind shear and warm waters, it steadily strengthened to reach peak winds of 165 mph (266 km/h) on September 11. After fluctuating in intensity for four days, during which it displayed annular characteristics, Isabel gradually weakened and made landfall on the Outer Banks of North Carolina, with winds of 105 mph (169 km/h) on September 18. Isabel quickly weakened over land and became extratropical over western Pennsylvania on the next day. On September 20, the extratropical remnants of Isabel were absorbed into another system over Eastern Canada.

In North Carolina, the storm surge from Isabel washed out a portion of Hatteras Island to form what was unofficially known as Isabel Inlet. Damage was greatest along the Outer Banks, where thousands of homes were damaged or even destroyed. The worst of the effects of Isabel occurred in Virginia, especially in the Hampton Roads area and along the shores of rivers as far west and north as Richmond and Baltimore. Virginia reported the most deaths and damage from the hurricane. About 64% of the damage and 69% of the deaths occurred in North Carolina and Virginia. Electric service was disrupted in areas of Virginia for several days, some more rural areas were without electricity for weeks, and local flooding caused thousands of dollars in damage. (Full article...)
Image 17
Changes in surface air temperature over the past 50 years. The Arctic has warmed the most, and temperatures on land have generally increased more than sea surface temperatures.

Present-day climate change includes both global warming—the ongoing increase in global average temperature—and its wider effects on Earth's climate. Climate change in a broader sense also includes previous long-term changes to Earth's climate. The current rise in global temperatures is driven by human activities, especially fossil fuel burning since the Industrial Revolution. Fossil fuel use, deforestation, and some agricultural and industrial practices release greenhouse gases. These gases absorb some of the heat that the Earth radiates after it warms from sunlight, warming the lower atmosphere. Carbon dioxide, the primary greenhouse gas driving global warming, has grown by about 50% and is at levels unseen for millions of years.

Climate change has an increasingly large impact on the environment. Deserts are expanding, while heat waves and wildfires are becoming more common. Amplified warming in the Arctic has contributed to thawing permafrost, retreat of glaciers and sea ice decline. Higher temperatures are also causing more intense storms, droughts, and other weather extremes. Rapid environmental change in mountains, coral reefs, and the Arctic is forcing many species to relocate or become extinct. Even if efforts to minimize future warming are successful, some effects will continue for centuries. These include ocean heating, ocean acidification and sea level rise. (Full article...)
Image 18

Gloria near peak intensity north of Hispaniola on September 24

Hurricane Gloria was a powerful hurricane that caused significant damage along the east coast of the United States and in Atlantic Canada during the 1985 Atlantic hurricane season. It was the first significant tropical cyclone to strike the northeastern United States since Hurricane Agnes in 1972 and the first major storm to affect New York City and Long Island directly since Hurricane Donna in 1960. Gloria was a Cape Verde hurricane originating from a tropical wave on September 16 in the eastern Atlantic Ocean. After remaining a weak tropical cyclone for several days, Gloria intensified into a hurricane on September 22 north of the Lesser Antilles. During that time, the storm had moved generally westward, although it turned to the northwest due to a weakening of the ridge. Gloria quickly intensified on September 24, and the next day reached peak winds of 145 mph (233 km/h). The hurricane weakened before striking the Outer Banks of North Carolina on September 27. Later that day, Gloria made two subsequent landfalls on Long Island and across the coastline of western Connecticut, before becoming extratropical on September 28 over New England. The remnants moved through Atlantic Canada and went on to impact Western Europe, eventually dissipating on October 4.

Before Gloria made landfall, the National Hurricane Center issued hurricane warnings at some point for the East Coast of the United States from South Carolina to Maine. Hundreds of thousands of people evacuated, and the hurricane was described as the "storm of the century." In general, Gloria's strongest winds remained east of the center, which largely spared locations from North Carolina to New Jersey, and the passage at low tide reduced storm surge. Hurricane-force winds and gusts affected much of the path, which knocked down trees and power lines. This left over 4 million people without power, causing the worst power outage in Connecticut history related to a natural disaster. Fallen trees caused six of the storm's fourteen deaths. (Full article...)
Image 19

Panoramic winter view of Crater Lake from Rim Village

Crater Lake (Klamath: Giiwas) is a volcanic crater lake in south-central Oregon in the Western United States. It is the main feature of Crater Lake National Park and is famous for its deep blue color and water clarity. The lake partly fills a 2,148-foot-deep (655 m) caldera that was formed around 7,700 (± 150) years ago
by the collapse of the volcano Mount Mazama. No rivers flow into or out of the lake; the evaporation is compensated for by rain and snowfall at a rate such that the total amount of water is replaced every 150 years. With a depth of 1,949 feet (594 m), the lake is the deepest in the United States. In the world, it ranks tenth for maximum depth, as well as third for mean (average) depth.

Crater Lake features two small islands. Wizard Island, located near the western shore of the lake, is a cinder cone about 316 acres (128 hectares) in size. Phantom Ship, a natural rock pillar, is located near the southern shore. (Full article...)
Image 20

Imaging from NASA's Shuttle Radar Topography Mission STS-99 reveals part of the diameter ring of the crater in the form of a shallow circular trough. Numerous cenotes (sinkholes) cluster around the trough marking the inner crater rim.

The Chicxulub crater (IPA: [t͡ʃikʃuˈluɓ] cheek-shoo-LOOB) is an impact crater buried underneath the Yucatán Peninsula in Mexico. Its center is offshore, but the crater is named after the onshore community of Chicxulub Pueblo (not the larger coastal town of Chicxulub Puerto). It was formed slightly over 66 million years ago when an asteroid, about ten kilometers (six miles) in diameter, struck Earth. The crater is estimated to be 200 kilometers (120 miles) in diameter and 1 kilometer (0.62 miles) in depth. It is believed to be the second largest impact structure on Earth, and the only one whose peak ring is intact and directly accessible for scientific research.

The crater was discovered by Antonio Camargo and Glen Penfield, geophysicists who had been looking for petroleum in the Yucatán Peninsula during the late 1970s. Penfield was initially unable to obtain evidence that the geological feature was a crater and gave up his search. Later, through contact with Alan R. Hildebrand in 1990, Penfield obtained samples that suggested it was an impact feature. Evidence for the crater's impact origin includes shocked quartz, a gravity anomaly, and tektites in surrounding areas. (Full article...)
Image 21
Calabozos is a Holocene caldera in central Chile's Maule Region (7th Region). Part of the Chilean Andes' volcanic segment, it is considered a member of the Southern Volcanic Zone (SVZ), one of the three distinct volcanic belts of South America. This most active section of the Andes runs along central Chile's western edge, and includes more than 70 of Chile's stratovolcanoes and volcanic fields. Calabozos lies in an extremely remote area of poorly glaciated mountains.

Calabozos and the majority of the Andean volcanoes formed from the subduction of the oceanic Nazca Plate under the continental South American continental lithosphere. The caldera is in a transitional region between thick and thin lithosphere, and is probably supplied by a pool of andesitic and rhyolitic magma. It sits on a historic bed of volcanic and plutonic sedimentary rock (rock formed within the Earth) that in turn sits on top of a layer of merged sedimentary and metamorphic rock. (Full article...)
Image 22
Geologic time shown in a diagram called a geological clock, showing the relative lengths of the eons of Earth's history and noting major events

The geological history of the Earth follows the major geological events in Earth's past based on the geological time scale, a system of chronological measurement based on the study of the planet's rock layers (stratigraphy). Earth formed about 4.54 billion years ago by accretion from the solar nebula, a disk-shaped mass of dust and gas left over from the formation of the Sun, which also created the rest of the Solar System.

Initially, Earth was molten due to extreme volcanism and frequent collisions with other bodies. Eventually, the outer layer of the planet cooled to form a solid crust when water began accumulating in the atmosphere. The Moon formed soon afterwards, possibly as a result of the impact of a planetoid with the Earth. Outgassing and volcanic activity produced the primordial atmosphere. Condensing water vapor, augmented by ice delivered from asteroids, produced the oceans. However, in 2020, researchers reported that sufficient water to fill the oceans may have always been on the Earth since the beginning of the planet's formation. (Full article...)
Image 23
Life in the Ediacaran Period as imagined by researchers in 1980.

The Ediacaran (/ˌiːdiˈækərən/; formerly Vendian) biota is a taxonomic period classification that consists of all life forms that were present on Earth during the Ediacaran Period (c. 635–538.8 Mya). These were enigmatic tubular and frond-shaped, mostly sessile, organisms. Trace fossils of these organisms have been found worldwide, and represent the earliest known complex multicellular organisms. The term "Ediacara biota" has received criticism from some scientists due to its alleged inconsistency, arbitrary exclusion of certain fossils, and inability to be precisely defined.

The Ediacaran biota may have undergone evolutionary radiation in a proposed event called the Avalon explosion, 575 million years ago. This was after the Earth had thawed from the Cryogenian period's extensive glaciation. This biota largely disappeared with the rapid increase in biodiversity known as the Cambrian explosion. Most of the currently existing body plans of animals first appeared in the fossil record of the Cambrian rather than the Ediacaran. For macroorganisms, the Cambrian biota appears to have almost completely replaced the organisms that dominated the Ediacaran fossil record, although relationships are still a matter of debate. (Full article...)
Image 24

Yosemite Valley from Tunnel View

Yosemite National Park (/joʊˈsɛmɪti/ yoh-SEM-ih-tee) is a national park of the United States in California. It is bordered on the southeast by Sierra National Forest and on the northwest by Stanislaus National Forest. The park is managed by the National Park Service and covers 759,620 acres (1,187 sq mi; 3,074 km²) in four counties – centered in Tuolumne and Mariposa, extending north and east to Mono and south to Madera. Designated a World Heritage Site in 1984, Yosemite is internationally recognized for its granite cliffs, waterfalls, clear streams, groves of giant sequoia, lakes, mountains, meadows, glaciers, and biological diversity. Almost 95 percent of the park is designated wilderness. Yosemite is one of the largest and least fragmented habitat blocks in the Sierra Nevada.

Its geology is characterized by granite and remnants of older rock. About 10 million years ago, the Sierra Nevada was uplifted and tilted to form its unique slopes, which increased the steepness of stream and river beds, forming deep, narrow canyons. About one million years ago glaciers formed at higher elevations. They moved downslope, cutting and sculpting the U-shaped Yosemite Valley. (Full article...)
Image 25

Cannikin warhead being lowered into test shaft

Amchitka (/æmˈtʃɪtkə/; Aleut: Amchixtax̂;^{[page needed]}) is a volcanic, tectonically unstable and uninhabited
island in the Rat Islands group of the Aleutian Islands in southwest Alaska. It is part of the Alaska Maritime National Wildlife Refuge. The island, with a land area of roughly 116 square miles (300 km²), is about 42 miles (68 km) long and 1 to 4 miles (1.6 to 6.4 km) wide. The area has a maritime climate, with many storms, and mostly overcast skies.

Amchitka was populated for more than 2,500 years by the Aleut people, but has had no permanent population since 1832. The island has been part of the United States since the Alaska Purchase of 1867. During World War II, it was used as an airfield by US forces in the Aleutian Islands Campaign. (Full article...)

Did you know (auto-generated)

... that life exists in every part of the biosphere, from the deepest parts of the ocean to altitudes of up to 64 km (40 miles) in the atmosphere?
... that Frederick Murray Trotter had a distinguished career as a field geologist despite losing a part of his skull and an eye to shrapnel during World War I?
... that the geology of the Ellsworth Mountains was explored by geologists using motor toboggans in 1961?
... that English amateur geologist Charlotte Eyton wrote a number of papers and pamphlets on the geology of the Wrekin, a part of Shropshire, between 1862 and 1870?
... that the Apollo 12 Solar Wind Spectrometer detected a gas-ion shockwave produced by the impact of the Apollo 13 S-IVB stage on the lunar surface?
... that the Danish geologist Tove Birkelund received a gold medal for her early work on fossils of Scaphites in Greenland?
... that the Iowa Colored Cowboys played softball for audiences of over a thousand people, in an atmosphere similar to a Harlem Globetrotters show?

More did you know? - show different entries

... that plate reconstructions (example pictured) that use magnetic stripe patterns can only go back to the Jurassic period, as there is no older oceanic crust?
...that during hot greenhouse periods in Earth's history, the tropics appeared to be cooler than they are today?
...that the 2002 Sumatra earthquake is considered to be a foreshock of the 2004 Indian Ocean earthquake?
...that the geology of the Grand Canyon area includes more than 40 identified rock layers?
...that Bristol Diamonds were popular souvenirs for visitors to the spa at Hotwells, Bristol in the eighteenth and nineteenth centuries?
...that hoodoos are tall skinny spires of rock that protrude from the bottom of arid basins and badlands?

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Related portals

Selected images

Image 1Petrified log at Petrified Forest National Park, by Moondigger (from Wikipedia:Featured pictures/Sciences/Geology)
Image 2Pyromorphite, by Iifar (from Wikipedia:Featured pictures/Sciences/Geology)
Image 3Platinum, by Alchemist-hp (from Wikipedia:Featured pictures/Sciences/Geology)
Image 4Volcanic tephra, by Godot13 (from Wikipedia:Featured pictures/Sciences/Geology)
Image 5Incandescent Pahoeoe Fountain at Shield volcano, by J.D. Griggs, USGS (from Wikipedia:Featured pictures/Sciences/Geology)
Image 6Smoky quartz, by JJ Harrison (from Wikipedia:Featured pictures/Sciences/Geology)
Image 7Quartz, by JJ Harrison (from Wikipedia:Featured pictures/Sciences/Geology)
Image 8Mimetite, by Iifar (from Wikipedia:Featured pictures/Sciences/Geology)
Image 9Opal, by JJ Harrison (from Wikipedia:Featured pictures/Sciences/Geology)
Image 10A thunderstorm is a form of severe weather involving lightning and thunder. Thunderstorms have had a lasting and powerful influence on mankind. Romans thought them to be battles waged by Jupiter. Thunderstorms were associated with the Thunderbird, held by Native Americans to be a servant of the Great Spirit. (Credit: John Kerstholt.) (from Portal:Earth sciences/Selected pictures)
Image 11Stellerite, by Iifar (from Wikipedia:Featured pictures/Sciences/Geology)
Image 12Dundasite by JJ Harrison (from Wikipedia:Featured pictures/Sciences/Geology)
Image 13Hurricane Katrina was the third most powerful storm of the 2005 Atlantic hurricane season. It first made landfall as a Category 1 hurricane just north of Miami, Florida on August 25, 2005, then again on August 29 along the Central Gulf Coast near Buras-Triumph, Louisiana as a Category 4 storm. This photograph of the eye of the hurricane was taken from a NOAA Hurricane Hunter aircraft on August 28, 2005. (Credit: NOAA.) (from Portal:Earth sciences/Selected pictures)
Image 14Desert rose, by Didier Descouens (from Wikipedia:Featured pictures/Sciences/Geology)
Image 15Petrified wood, by Daniel Schwen (from Wikipedia:Featured pictures/Sciences/Geology)
Image 16Glacier retreat is a type of glacial motion in which more material ablates from its terminus of the glacier than is replenished by flow into that region. In this region of the Bhutan-Himalaya, glacial lakes have been rapidly forming on the surface of the debris-covered glaciers and researchers have found a strong correlation between increasing temperatures and glacial retreat. (Credit: NASA & USGS.) (from Portal:Earth sciences/Selected pictures)
Image 17Prehnite, by Iifar (from Wikipedia:Featured pictures/Sciences/Geology)
Image 18Mount Hood reflected in Mirror Lake, Oregon. (Credit: Oregon's Mt. Hood Territory.) (from Portal:Earth sciences/Selected pictures)
Image 19The Richat Structure is a depression in the country of Mauritania, almost 50 km (30 mi) across. It was originally thought to be the impact of a meteorite. Now it is thought to be a symmetrical uplift (circular anticline or dome) that has been exposed to erosion. In this false-color photo, bedrock is brown, sand is yellow and white, vegetation is green, and salty sediments are blue. (Credit: Landsat 7.) (from Portal:Earth sciences/Selected pictures)
Image 20Specimen from a palaeontological site of Lebanon at Paleontology in Lebanon, by Mila Zinkova (from Wikipedia:Featured pictures/Sciences/Geology)
Image 21Himalayan salt, by Iifar (from Wikipedia:Featured pictures/Sciences/Geology)
Image 22A 2002 eruption of Mount Etna, a volcano on the Italian island of Sicily, viewed from the International Space Station. (Credit: NASA, with image edits by User:Darkone.) (from Portal:Earth sciences/Selected pictures)
Image 23Baryte, by Iifar (from Wikipedia:Featured pictures/Sciences/Geology)
Image 24Winter is one of the four seasons of temperate zones. Meteorological winter is the season having the shortest days (which vary greatly according to latitude) and the lowest temperatures. (Credit: Richard Fabi.) (from Portal:Earth sciences/Selected pictures)
Image 25Erosion of the bluff in Pacifica, by mbz1 (from Wikipedia:Featured pictures/Sciences/Geology)
Image 26Crystalline dolomite and magnesite, by Didier Descouens (from Wikipedia:Featured pictures/Sciences/Geology)
Image 27Malachite, by JJ Harrison (from Wikipedia:Featured pictures/Sciences/Geology)
Image 28Blairmorite, by Paul Glombick (edited by Bammesk) (from Wikipedia:Featured pictures/Sciences/Geology)
Image 29Satellite image of Cyclone Gafilo, a powerful Category 5 tropical cyclone which struck Madagascar in March 2004, causing devastating damage. This was taken just before landfall, when the system was at its peak intensity about 333 km (207 mi) east of Madagascar, with sustained windspeed of 260 km/h (160 mph). At least 250 people were listed dead, with more missing, and 300,000 people were left homeless due to Gafilo. (Credit: Terra satellite, NASA.) (from Portal:Earth sciences/Selected pictures)
Image 30Sandstone, by Moondigger (from Wikipedia:Featured pictures/Sciences/Geology)
Image 31Pyrite, by JJ Harrison (from Wikipedia:Featured pictures/Sciences/Geology)
Image 32Atacamite, by Iifar (from Wikipedia:Featured pictures/Sciences/Geology)
Image 33Cirrus clouds are composed of ice crystals and shaped like hairlike filaments. They are formed at an altitudes above 5000 metres (16,500 feet). The streaks are made of snowflakes that are falling from the cloud and being caught by the high level winds. The streaks point in the direction of the wind and may appear straight giving the clouds the appearance of a comma (cirrus uncinus), or may by seem tangled, an indication of high level turbulence. (Credit: Piccolo Namek.) (from Portal:Earth sciences/Selected pictures)
Image 34Cinnabar, by JJ Harrison (from Wikipedia:Featured pictures/Sciences/Geology)
Image 35Thin section scan, by Kallerna (from Wikipedia:Featured pictures/Sciences/Geology)
Image 36Atmospheric gases scatter blue wavelengths of visible light more than other wavelengths, giving the Earth’s visible edge a blue halo. At higher and higher altitudes, the atmosphere becomes so thin that it essentially ceases to exist. Gradually, the atmospheric halo fades into the blackness of space. (Credit: NASA's Earth Observatory.) (from Portal:Earth sciences/Selected pictures)
Image 37Vanadinite, by Iifar (from Wikipedia:Featured pictures/Sciences/Geology)
Image 38Weathered rocks at Joshua Tree National Park, by Mila Zinkova (from Wikipedia:Featured pictures/Sciences/Geology)
Image 39An October 2002 eruption of Mount Etna, a volcano on the Italian island of Sicily, as seen from the International Space Station. Etna is the largest of Italy's three active volcanoes and one of the most active in the whole entire world. This eruption, one of Etna's most vigorous in years, was triggered by a series of earthquakes. Ashfall was reported as far away as Libya, 600 km (373 mi) to the south. (Credit: Expedition 5 crew.) (from Portal:Earth sciences/Selected pictures)
Image 40Oceans cover almost three quarters (71%) of the surface of the Earth, and nearly half of the world's marine waters are over 3000 m deep. This global, interconnected body of salt water, called the World Ocean, is divided by the continents and archipelagos into the following five bodies, from the largest to the smallest: the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Southern Ocean, and the Arctic Ocean. Official boundaries are defined by the International Hydrographic Organization. (Credit: Alexandre Van de Sande.) (from Portal:Earth sciences/Selected pictures)
Image 41This map shows the tracks of all tropical cyclones that formed worldwide from 1985 to 2005. The points show the locations of the storms at six-hourly intervals and use the color scheme shown on the right from the Saffir-Simpson Hurricane Scale. (Credit: Nilfanion.) (from Portal:Earth sciences/Selected pictures)
Image 42Azurite, by Iifar (from Wikipedia:Featured pictures/Sciences/Geology)
Image 43Erg Chebbi (Arabic: عرج شبّي) is the sole Saharan erg in Morocco. It is 22 km long (North-South) and 5 km wide. Its dunes reach a maximum height of 150 meters. It is located roughly 40 kilometers south-east of Erfoud. The local center for tourists is the village of Merzouga. (Credit: Rosa Cabecinhas and Alcino Cunha.) (from Portal:Earth sciences/Selected pictures)
Image 44Amethyst, by JJ Harrison (from Wikipedia:Featured pictures/Sciences/Geology)
Image 45Azurite, by JJ Harrison (from Wikipedia:Featured pictures/Sciences/Geology)
Image 46Ant trapped in Baltic amber, by Baltic-amber-beetle (edited by AmericanXplorer13) (from Wikipedia:Featured pictures/Sciences/Geology)
Image 47Diatomaceous earth, by Richard Wheeler (from Wikipedia:Featured pictures/Sciences/Geology)
Image 482004 Indian Ocean Earthquake tsunami at 2004 Indian Ocean earthquake and tsunami, by Vasily V. Titov, NOAA (edited by Veledan) (from Wikipedia:Featured pictures/Sciences/Geology)
Image 49A true-color picture of Ireland, as seen from space, with the Atlantic Ocean to the west and the Irish Sea to the east. (from Portal:Earth sciences/Selected pictures)
Image 50Tsunami in Thailand at 2004 Indian Ocean earthquake and tsunami, by David Rydevik (from Wikipedia:Featured pictures/Sciences/Geology)
Image 51Pressure release of granite in the Enchanted Rock State Natural Area of Texas, United States. The photo shows the geological exfoliation of granite dome rock. (Taken by Wing-Chi Poon on 2nd April 2005.) (from Portal:Earth sciences/Selected pictures)
Image 52Hemimorphite, by Iifar (from Wikipedia:Featured pictures/Sciences/Geology)
Image 53The world's largest compass rose, drawn on the desert floor at Edwards Air Force Base in California, United States. Painted on the playa near Dryden Flight Research Center, it is inclined to magnetic north and is used by pilots for calibrating heading indicators. (Credit: NASA.) (from Portal:Earth sciences/Selected pictures)
Image 54Rhodochrosite, by JJ Harrison (from Wikipedia:Featured pictures/Sciences/Geology)
Image 55Acanthite, by Iifar (from Wikipedia:Featured pictures/Sciences/Geology)
Image 56Gypsum, by JJ Harrison (from Wikipedia:Featured pictures/Sciences/Geology)
Image 57Celestine, by Iifar (from Wikipedia:Featured pictures/Sciences/Geology)
Image 58Cerussite, by Iifar (from Wikipedia:Featured pictures/Sciences/Geology)
Image 59Wulfenite, by Didier Descouens (from Wikipedia:Featured pictures/Sciences/Geology)
Image 60Sarychev Peak at Explosive eruption, by NASA (from Wikipedia:Featured pictures/Sciences/Geology)
Image 61Astronauts aboard the Space Shuttle Discovery recorded this rarely seen phenomenon of the full Moon partially obscured by the atmosphere of Earth. The image was recorded with an electronic still camera at 15:15:15 GMT, Dec. 21, 1999. (Credit: NASA.) (from Portal:Earth sciences/Selected pictures)
Image 62Mount Redoubt eruption, by R. Clucas (USGS) (edited by Janke) (from Wikipedia:Featured pictures/Sciences/Geology)
Image 63Bultfonteinite, by Iifar (from Wikipedia:Featured pictures/Sciences/Geology)
Image 64Cassiterite, by Alchemist-hp (from Wikipedia:Featured pictures/Sciences/Geology)
Image 65Creedite, by JJ Harrison (from Wikipedia:Featured pictures/Sciences/Geology)
Image 66Crocoite, by JJ Harrison (from Wikipedia:Featured pictures/Sciences/Geology)
Image 67Sulfur, by Iifar (from Wikipedia:Featured pictures/Sciences/Geology)
Image 68Concretions, by Mbz1 (from Wikipedia:Featured pictures/Sciences/Geology)
Image 69Aragonite, by JJ Harrison (from Wikipedia:Featured pictures/Sciences/Geology)
Image 70Antarctica, the continent surrounding the Earth's South Pole, is the coldest place on earth and is almost entirely covered by ice. Antarctica was discovered in late January 1820. Too cold and dry to support virtually any vascular plants, Antarctica's flora presently consists of around 250 lichens, 100 mosses, 25-30 liverworts, and around 700 terrestrial and aquatic algal species. (Credit: NASA.) (from Portal:Earth sciences/Selected pictures)
Image 71Mohawkite, by Alchemist-hp (from Wikipedia:Featured pictures/Sciences/Geology)
Image 72Sand particles, by Siim (from Wikipedia:Featured pictures/Sciences/Geology)
Image 73Wulfenite, by Iifar (from Wikipedia:Featured pictures/Sciences/Geology)
Image 74Aegirine, by Iifar (from Wikipedia:Featured pictures/Sciences/Geology)
Image 75Northern shore meadows of Sihlsee, an artificial lake near Einsiedeln in the Canton of Schwyz, Switzerland. (Credit: Markus Bernet.) (from Portal:Earth sciences/Selected pictures)

In the news

5 November 2024 –: Researchers at Kyoto University in Japan launch LignoSat, the world's first wooden satellite constructed without screws or glue, into space. It will orbit Earth for six months. (DW)
19 October 2024 –: Intelsat communications satellite Intelsat 33e breaks up in Earth's orbit, resulting in network disruptions to customers in Europe, Africa and parts of the Asia-Pacific region. The United States Space Force says they are tracking at least "20 associated pieces" of the satellite. (BBC News)

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