Geology














Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which they change. Geology can also refer generally to the study of the solid features of any celestial body (such as the geology of the Moon or Mars).

Geology gives insight into the history of the Earth by providing the primary evidence for plate tectonics, the evolutionary history of life, and past climates. In modern times, geology is commercially important for mineral and hydrocarbon exploration/exploitation as well as for evaluating water resources. It is publicly important for the prediction and understanding of natural hazards, the remediation of environmental problems, and for providing insights into past climate change. Geology also plays a role in geotechnical engineering and is a major academic discipline.

Astrogeology refers to the application of geologic principles to other bodies of the solar system. However, specialised terms such as selenology (studies of the Moon), areology (of Mars), etc., are also in use.

The word "geology" was first used by Jean-Andre Deluc in the year 1778 and introduced as a fixed term by Horace-Benedict de Saussure in the year 1779. An older meaning of the word was first used by Richard de Bury. He used it to distinguish between earthly and theological jurisprudence.




Timeline

The geologic time scale encompasses the history of the Earth. It is bracketed at the old end by the dates of the earliest solar system material at 4.567 Ga, (gigaannum: billion years ago) and the age of the Earth at 4.54 Ga at the beginning of the informally recognized Hadean eon. At the young end of the scale, it is bracketed by the present day in the Holocene epoch.

The following four timelines show the geologic time scale. The first shows the entire time from the formation of the Earth to the present, but this compresses the most recent eon. Therefore the second scale shows the most recent eon with an expanded scale. The second scale compresses the most recent era, so the most recent era is expanded in the third scale. Since the Quaternary is a very short period with short epochs, it is further expanded in the fourth scale. The second, third, and fourth timelines are therefore each subsections of their preceding timeline as indicated by asterisks. The Holocene (the latest epoch) is too small to be shown clearly on the third timeline on the right, another reason for expanding the fourth scale. The Pleistocene (P) epoch. Q stands for the Quaternary period.




History

In China, the polymath Shen Kua (1031 - 1095) formulated a hypothesis for the process of land formation: based on his observation of fossil shells in a geological stratum in a mountain hundreds of miles from the ocean, he inferred that the land was formed by erosion of the mountains and by deposition of silt.

The work Peri lithon (On Stones) by Theophrastus (372 - 287 BC), a student of Aristotle, remained authoritative for millennia. Its interpretation of fossils was not overturned until after the Scientific Revolution. It was translated into Latin and the other languages of Europe such as French.

Georg Agricola (1494-1555)), a physician, wrote the first systematic treatise about mining and smelting works, De re metallica libri XII, with an appendix Buch von den Lebewesen unter Tage (Book of the Creatures Beneath the Earth). He covered subjects like wind energy, hydrodynamic power, melting cookers, transport of ores, extraction of soda, sulfur and alum, and administrative issues. The book was published in 1556.

Nicolaus Steno (1638-1686) is credited with the law of superposition, the principle of original horizontality, and the principle of lateral continuity: three defining principles of stratigraphy.

By the 1700s Jean-Etienne Guettard and Nicolas Desmarest hiked central France and recorded their observations on geological maps; Guettard recorded the first observation of the volcanic origins of this part of France.

William Smith (1769-1839) drew some of the first geological maps and began the process of ordering rock strata (layers) by examining the fossils contained in them.

James Hutton is often viewed as the first modern geologist. In 1785 he presented a paper entitled Theory of the Earth to the Royal Society of Edinburgh. In his paper, he explained his theory that the Earth must be much older than had previously been supposed in order to allow enough time for mountains to be eroded and for sediment to form new rocks at the bottom of the sea, which in turn were raised up to become dry land. Hutton published a two-volume version of his ideas in 1795.

Followers of Hutton were known as Plutonists because they believed that some rocks were formed by vulcanism which is the deposition of lava from volcanoes, as opposed to the Neptunists, who believed that all rocks had settled out of a large ocean whose level gradually dropped over time.

In 1811 Georges Cuvier and Alexandre Brongniart published their explanation of the antiquity of the Earth, inspired by Cuvier's discovery of fossil elephant bones in Paris. To prove this, they formulated the principle of stratigraphic succession of the layers of the earth. They were independently anticipated by William Smith's stratigraphic studies on England and Scotland.

Sir Charles Lyell first published his famous book, Principles of Geology, in 1830 and continued to publish new revisions until he died in 1875. He successfully promoted the doctrine of uniformitarianism. This theory states that slow geological processes have occurred throughout the Earth's history and are still occurring today. In contrast, catastrophism is the theory that Earth's features formed in single, catastrophic events and remained unchanged thereafter. Though Hutton believed in uniformitarianism, the idea was not widely accepted at the time.

By 1827 Charles Lyell's Principles of Geology reiterated Hutton's uniformitarianism, which influenced the thought of Charles Darwin.

19th Century geology revolved around the question of the Earth's exact age. Estimates varied from a few 100,000 to billions of years. The most significant advance in 20th century geology has been the development of the theory of plate tectonics in the 1960s. Plate tectonic theory arose out of two separate geological observations: seafloor spreading and continental drift. The theory revolutionized the Earth sciences.

The theory of continental drift was proposed by Alfred Wegener in 1912 and by Arthur Holmes, but wasn't broadly accepted until the 1960s when the theory of plate tectonics was developed.

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Vredefort Crater in South Africa

The largest verified impact crater on Earth





Hoodoo Sky Bryce Canyon
NASA -July 3, 2008



Hoodoos Bryce Canyon

Hoodoos are tall thin spires of rock that protrude from the bottom of arid basins and badlands. They are composed of soft sedimentary rock and are topped by a piece of harder, less easily-eroded stone that protects the column from the elements. They are mainly located in the desert in dry, hot areas. In common usage, the difference between hoodoos and pinnacles or spires is that hoodoos have a variable thickness often described as having a "totem pole-shaped body." A spire, on the other hand, has a smoother profile or uniform thickness that tapers from the ground upward. (Geology purists do note that only a tall formation should be called a hoodoo; any other shape is called a 'hoodoo rock'.) Hoodoos are most commonly found in the High Plateaus region of the Colorado Plateau and in the Badlands regions of the Northern Great Plains (both in North America). While hoodoos are scattered throughout these areas, nowhere in the world are they as abundant as in the northern section of Bryce Canyon National Park. WED Enterprises (now Walt Disney Imagineering) notably based the design of the Disneyland version of the popular Big Thunder Mountain Railroad around a series of hoodoos, although these were constructed out of steel and concrete.

Hoodoos range in size from that of an average human to heights exceeding a 10-story building. Formed in sedimentary rock, hoodoo shapes are affected by the erosional patterns of alternating hard and softer rock layers. Minerals deposited within different rock types cause hoodoos to have different colors throughout their height. Good examples of hoodoos are found at Bryce Canyon National Park, located in the U.S. state of Utah.




Geology In the News ...





Scientists uncover insights into the formation of Earth's oldest continental crust   Science Daily - September 19, 2016

Addressing fundamental unknowns about the earliest history of Earth's crust, scientists have precisely dated the world's oldest rock unit at 4.02 billion years old. The findings suggest that early Earth was largely covered with an oceanic crust-like surface. It gives us important information about how the early continents formed. While it is well known that the oldest rocks formed prior to 4 billion years ago, the unique twist on the rock is the presence of well-preserved grains of the mineral zircon, leaving no doubt about the date it formed.




Wavy Greenland rock features 'are oldest fossils'   BBC - August 31, 2016
Some of the world's earliest life forms may have been captured in squiggles found in ancient rocks from Greenland. The rocks were part of the seafloor 3.7 billion years ago, and the wavy lines, just a few centimetres across, would be remnants of primordial microbial colonies called stromatolites. The evidence is presented in the academic journal Nature. If confirmed, the colonies would predate the previously oldest known fossils by over 200 million years. To put that in context, traveling back a similar time from today would be to leap into the world of the first dinosaurs. But all claims of extremely early life are hotly contested, and this find is as well. The find was made in a desolate expanse of uplands that butt up against the Greenland ice cap, called the Isua Supercrustal Belt. The host rocks were exposed only recently after permanent snow cover melted. The region is famous in geoscience because it is the oldest surviving piece of the Earth's surface.




Scientists find 3.7 billion-year-old fossil, oldest yet   PhysOrg - August 31, 2016
Scientists have found what they think is the oldest fossil on Earth, a remnant of life from 3.7 billion years ago when Earth's skies were orange and its oceans green. In a newly melted part of Greenland, Australian scientists found the leftover structure from a community of microbes that lived on an ancient seafloor.




Geologists search for Anthropocene 'golden spike'   BBC - August 30, 2016

The notion that we have entered a new geological age is real and should be formally recognized, according to an international report. The verdict comes from a panel set up to judge the merits of adding an Anthropocene ("Age of Humans") time segment to the history of the Earth. The group delivered its preliminary evidence and recommendations. It now needs to identify a suitable marker in the environment that epitomizes the start of the new phase. The hunt is now on for a "golden spike", as it is known - the marker that scientists can point to years hence - perhaps millions of years hence - and say, "There! That's the start of the Anthropocene Epoch."

Earth entered new Anthropocene epoch in 1950, scientists say   Telegraph - August 29, 2016
The rapid industrialization of the last century has caused the Earth to enter its first new geological epoch in more than 11,500 years, scientists believe.




Cataclysm at Meteor Crater: Crystal sheds light on Earth, moon, Mars   PhysOrg - July 27, 2016
In molten sandstone extracted by prospectors a century ago, an international team of scientists has discovered microscopic crystals telling of unimaginable pressures and temperatures when a 50-meter asteroid (traveling 12 kilometers per second) formed Meteor Crater in northern Arizona some 49,000 years ago. The crystals, called zircons, have endured temperatures of 2,000 degrees Celsius or more, hot enough to melt any rock on Earth. In our planet's crust, such temperatures occur only briefly inside impact zones.




Massive 'Lava Lamp' Blobs Deep Inside Earth Have Scientists Puzzled   Live Science - July 5, 2016

Two continent-size blobs of hot - and possibly molten - rock can be found deep underground, about halfway to the center of the Earth, according to a new study. These curious structures - each of which is so large that it would be 100 times taller than Mount Everest - could be made up of materials that may shed light on how the Earth formed, the researchers said. One of the blobs is located beneath the Pacific Ocean, and the other can be found beneath the Atlantic. These underground structures start where the Earth's mantle meets the core, but they send "plumes" up through the rock like a Lava Lamp, the researchers said. Scientists now think these masses differ from the surrounding rock in more than just temperature. They're also "compositionally distinct," meaning they could contain materials not typically found in the rest of the Earth's mantle. Yet even some of the most basic information about the blobs is still a mystery.




Continents Rose Above Oceans 3 Billion Years Ago   Live Science - June 27, 2015
The continents may have first risen high above the oceans of the world about 3 billion years ago, researchers say. That's about a billion years earlier than geoscientists had suspected for the emergence of a good chunk of the continents. Earth is the only known planet whose surface is divided into continents and oceans. Currently, the continents rise an average of about 2.5 miles (4 kilometers) above the seafloor. The continents are composed of a thick, buoyant crust that's about 21 miles (35 km) deep, on average, whereas the comparatively thin, dense crust of the ocean floor is only an average of about 4 miles (7 km) thick. Because the continents are so thick and buoyant, they are less likely to get dragged downward. That's why so many ancient continental rocks have survived in the Earth's crust. Still, much about the earliest days of continents, and when and how they formed, remains hotly contested.




'Crazy Craters' Found in Swiss Lake   Live Science - May 20, 2015
Four giant craters were found by accident in the muddy floor of one of Switzerland's largest lakes, a new study reports. Researchers surveying Lake Neuchatel for evidence of past earthquakes spotted the craters near the lake's northwestern shore near the Jura Mountains. The biggest crater is 525 feet (160 meters) wide and almost 100 feet (30 m) deep. The pits are among the largest and deepest pockmarks ever found in Earth's lakes, the researchers said. The giant craters are similar in size to seafloor pockmarks created by methane-gas explosions. However, the researchers think that erupting groundwater excavated these "crazy craters."




Earth's surprise inside: Geologists unlock mysteries of the planet's inner core   Science Daily - February 10, 2015

Seismic waves are helping scientists to plumb the world's deepest mystery: the planet's inner core. Thanks to a novel application of earthquake-reading technology, researchers have found that the Earth's inner core has an inner core of its own, which has surprising properties that could reveal information about our planet.




Heart of Earth's inner core revealed   BBC - February 10, 2015

Scientists say they have gained new insight into what lies at the very centre of the Earth. Research from China and the US suggests that the innermost core of our planet has another, distinct region at its center. Scientists use echoes generated by earthquakes to study the core, by analyzing how they change as they travel through the different layers of our planet.




Ancient Earth Had Weird Chemistry: Vanilla Rocks, Lemon-Juice Soil   Live Science - February 3, 2015

During the worst mass extinction in Earth's history, acid rain may have at times made the ground as acidic as lemon juice, new research shows. The mass extinction at the end of the Permian period, about 250 million years ago, was the most extreme die-off in Earth's history. The catastrophe killed as much as 95 percent of ocean species. The highly level of acidity in the soil at the time of the extinction was revealed in the new study when researchers looked at levels of a compound called vanillin in rocks that date to that time. The chemical is the main ingredient in natural vanilla extract and is also produced when wood decomposes. Normally, bacteria in the soil convert vanillin into vanillic acid, but acidic conditions hinder this process.




Breakup of ancient supercontinent Pangea hints at future fate of Atlantic Ocean   PhysOrg - December 1, 2014

Breakup of ancient supercontinent Pangea hints at future fate of Atlantic Ocean ... Pangea, the supercontinent that contained most of the Earth's landmass until about 180 million years ago, endured an apocalyptic undoing during the Jurassic period, when the Atlantic Ocean opened up. This is well understood. But what is less clear is how Pangea came into being in the first place.




Rare Mineral Discovered in Ancient Meteorite Impact Crater   Live Science - November 3, 2014
A rare mineral known from just three massive meteorite impacts has now turned up in a Wisconsin crater. Researchers discovered the mineral, called reidite, at the Rock Elm impact structure in western Wisconsin. Reidite is a dense form of zircon, one of the hardiest minerals on Earth. This is the oldest reidite ever found,, said Aaron Cavosie, a geochemist at the University of Puerto Rico in Mayaguez. The Rock Elm meteorite crater is 450 million to 470 million years old, he said.




Four-billion-year-old rocks yield clues about Earth's earliest crust   Science Daily - May 30, 2014

It looks like just another rock, but what researchers are examining is a four-billion-year-old chunk of an ancient protocontinent that holds clues about how Earth's first continents formed. Continents today form when one tectonic plate shifts beneath another into Earth's mantle and cause magma to rise to the surface, a process called subduction. It's unclear whether plate tectonics existed 2.5 billion to four billion years ago or if another process was at play.




Mineral hints at bright blue rocks deep in the Earth   BBC - March 12, 2014

Minerals preserved in diamond have revealed hints of the bright blue rocks that exist deep within the Earth.They also provide the first direct evidence that there may be as much water trapped in those rocks as there is in all the oceans. The diamond, from central-west Brazil, contains minerals that formed as deep as 600km down and that have significant amounts of water trapped within them.




Rare Diamond Reveals Earth's Interior is All Wet   Live Science - March 12, 2014
A battered diamond that survived a trip from "hell" confirms a long-held theory: Earth's mantle holds an ocean's worth of water. "It's actually the confirmation that there is a very, very large amount of water that's trapped in a really distinct layer in the deep Earth," said Graham Pearson, lead study author and a geochemist at the University of Alberta in Canada. The worthless-looking diamond encloses a tiny piece of an olivine mineral called ringwoodite, and it's the first time the mineral has been found on Earth's surface in anything other than meteorites or laboratories. Ringwoodite only forms under extreme pressure, such as the crushing load about 320 miles (515 kilometers) deep in the mantle.




Fragments of ancient continent buried under Indian Ocean   BBC - February 25, 2013

Fragments of an ancient continent are buried beneath the floor of the Indian Ocean, a study suggests. Researchers have found evidence for a landmass that would have existed between 2,000 and 85 million years ago. The strip of land, which scientists have called Mauritia, eventually fragmented and vanished beneath the waves as the modern world started to take shape. Until about 750 million years ago, the Earth's landmass was gathered into a vast single continent called Rodinia. And although they are now separated by thousands of kilometres of ocean, India was once located next to Madagascar. Now researchers believe they have found evidence of a sliver of continent - known as a microcontinent - that was once tucked between the two.




Ancient 'Micro-Continent' Found Under Indian Ocean   Live Science - February 25, 2013
The remains of a micro-continent scientist call Mauritia might be preserved under huge amounts of ancient lava beneath the Indian Ocean, a new analysis of island sands in the area suggests. These findings hint that such micro-continents may have occurred more frequently than previously thought. Researchers analyzed sands from the isle of Mauritius in the western Indian Ocean. Mauritius is part of a volcanic chain that, strangely, exists far from the edges of its tectonic plate. In contrast, most volcanoes are found at the borders of the tectonic plates that make up the surface of the Earth.




Hawaiian Island is Dissolving From Within December 28, 2012 - Various links and a blog from Ellie




UNL discovery has implications for finding life on Earth, Mars   PhysOrg - August 16, 2012
Moqui marbles, unusual balls of rock that can be found rolling around the southwestern U.S. sandstone regions, were formed roughly 2 million years ago with the help of microorganisms. This discovery by a University of Nebraska-Lincoln research team has implications for finding life on Mars and for better understanding Earth's past.




'Meteor Crater' in Arizona helps unlock planetary history   MSNBC - December 8, 2011
The Barringer meteorite crater - known popularly as "Meteor Crater" - near Winslow, Ariz., was formed some 50,000 years ago in the flat-lying sedimentary rocks of the Southern Colorado Plateau in Arizona. Now, scientists are using the crater to study mysteries near and far. This out-of-the-blue geological feature is considered a prime example of a young, well-preserved and well-documented simple impact crater.




  Undersea mountains march into the abyss   BBC - December 6, 2011

Startling new images from the depths of the Pacific Ocean reveal one of Earth's most violent processes: the destruction of massive underwater mountains. The pictures were created by sonar in waters up to 6km (4mi) deep. They expose how tectonic action is dragging giant volcanoes into a chasm in the seabed. The volcanoes are strung across several thousand kilometres of ocean floor and are moving westward on the Pacific tectonic plate at up to 6cm per year. The extraordinary scene was captured along the Tonga Trench during a research expedition last summer.




Lost landscape discovered off Scottish coast   BBC - July 14, 2011
Geologists have discovered a vast new landscape that rose above the north Atlantic waves 56 million years ago. It was caused by a sudden up-welling from the Earth's mantle and may explain rapid climate change that took place at about that time.




Ancient rock under Haiti came from 1,000+ miles away, 1 billion years older than previously thought   PhysOrg - July 12, 2011
Earthquakes and volcanoes are known for their ability to transform Earth's surface, but new research in the Caribbean has found they can also move ancient Earth rock foundations more than 1,000 miles.




Geologist's discoveries resolve debate about oxygen in Earth's mantle   PhysOrg - December 15, 2010
Analysis of erupted rock from Agrigan volcano in the western Pacific near Guam found it to be highly oxidized as a result of its exposure to oxygen when it formed in the Earth's mantle. When, over millions of years, seafloor rocks are transported back into the Earth's mantle at subduction zones – sites on the seafloor where tectonic plates have collided, forcing one plate beneath the other – they deliver more oxygen into the mantle.




Scottish rocks record ancient oxygen clues   BBC - November 11, 2010
Oxygen levels on Earth reached a critical threshold to enable the evolution of complex life much earlier than thought, say scientists. The evidence is found in 1.2-billion-year-old rocks from Scotland. These rocks retain signatures of bacterial activity known to occur when there is copious atmospheric oxygen. The microbes' behavior is seen 400 million years further back in time than any previous discovery.




Infant, Magma-Ball Earth Glimpsed Via Newfound Rocks   National Geographic - August 12, 2010

Canada's Baffin Island, home to perhaps the world's oldest rocks




Arctic rocks may contain oldest remnants of Earth   BBC - August 11, 2010

Scientists have found Arctic rocks that may preserve the earliest remnants of Earth. Over billions of years, much of the material that made up the early Earth was modified by processes such as melting and mixing. But the Arctic rocks seem to contain chemical signatures that date from just after the Earth's violent origin.




Canyon Carved in Just Three Days in Texas Flood: Insight Into Ancient Flood Events on Earth and Mars   Science Daily - June 21, 2010

In the summer of 2002, a week of heavy rains in Central Texas caused Canyon Lake -- the reservoir of the Canyon Dam -- to flood over its spillway and down the Guadalupe River Valley in a planned diversion to save the dam from catastrophic failure. The flood excavated a 2.2-kilometer-long, 7-meter-deep canyon in the bedrock. According to a new analysis, that canyon formed in just three days.




Earth's Gooey Insides Ooze Faster Than Thought   Live Science - May 20, 2010
The scorching, molten rock inside the Earth - known as the Earth's mantle - oozes around faster than expected in certain spots, a new study suggests.The Earth's surface is made of rocky plates floating on the mantle, which is solid but can flow under the enormous pressure and temperature of the deep Earth. At plate boundaries, the plates may rub alongside each other or one may dive under the other and sink into the mantle, creating what is called a subduction zone. As the plate sinks, it drags the mantle material along with it, said Magali Billen, associate professor of geology at the University of California, Davis. Geologists previously thought that the mantle and a sinking plate moved at the same rate. But a new model used by Billen and her colleagues shows that this isn't the case.




Earth's mantle flows fast   PhysOrg - May 20, 2010
The Earth's mantle flows far more rapidly around a sinking tectonic plate than previously thought, according to new computer modeling by UC Davis geologists. The findings could change the way that we think about plate tectonics and the amount of energy available for earthquakes.




Silver tells a volatile story of Earth's origin: Water was present during its birth   PhysOrg - May 13, 2010
iny variations in the isotopic composition of silver in meteorites and Earth rocks are helping scientists put together a timetable of how our planet was assembled beginning 4.568 billion years ago. The new study, published in the journal Science, indicates that water and other key volatiles may have been present in at least some of Earth's original building blocks, rather than acquired later from comets, as some scientists have suggested.




Quantum mechanics reveals new details of deep earth   PhysOrg - May 11, 2010
Scientists have used quantum mechanics to reveal that the most common mineral on Earth is relatively uncommon deep within the planet. Using several of the largest supercomputers in the nation, a team of physicists led by Ohio State University has been able to simulate the behavior of silica in a high-temperature, high-pressure form that is particularly difficult to study firsthand in the lab.




The age of Aquarius? Nope, it's the Anthropocene epoch   PhysOrg - April 15, 2010

The geologic time scale might be amended in the future to include a new period called the "Anthropocene epoch" that is marked by stunning population growth and unprecedented changes in human activity. In just two centuries, humans have wrought such vast and unprecedented changes to our world that we actually might be ushering in a new geological time period that could alter the planet for millions of years, according to a group of prominent scientists that includes a Nobel Laureate. They say the dawning of this new epoch could lead to the sixth largest mass extinction in the Earth's history.




Geologist discovers pattern in Earth's long-term climate record   PhysOrg - April 6, 2010
In an analysis of the past 1.2 million years, UC Santa Barbara geologist Lorraine Lisiecki discovered a pattern that connects the regular changes of the Earth's orbital cycle to changes in the Earth's climate. She concludes that the pattern of climate change over the past million years likely involves complicated interactions between different parts of the climate system, as well as three different orbital systems. The first two orbital systems are the orbit's eccentricity, and tilt. The third is "precession," or a change in the orientation of the rotation axis.




Study reveals ancient rocks linked to old Earth's crust   PhysOrg - February 24, 2010
A new geological study which took place in the Pilbara region of Western Australia brings us one step closer to understanding more precisely the timing of when the primordial earth crust was formed and its composition. The findings provide further evidence that the crust on Earth started to form between 4.3 and 4.5 billion years ago. This crust may represent a part of the early “skin” covering what is widely considered to have been a magma-ocean early Earth. The preservation of geochemical relics of this ancient period of Earth history may help unravel part of the early history of our planet.




Britain cut off from Europe by 'super-river' as little as 30,000 years ago   Telegraph.co.uk - November 30, 2009
Researchers have found sediment on the ocean floor off France which originated in the north of the channel which must have been transported by the river originally fed by the Thames and the Rhine. The samples, taken from the Atlantic sea bed, have provided scientists with the final piece in a geological jigsaw, enabling them to reconstruct the story of the Fleuve Manche (Channel River) – a giant waterway that flowed through the area now occupied by the English Channel. Earlier studies have already suggested that the river existed during a sequence of ice ages that began 450,000 years ago. It formed when a huge glacial lake in the North Sea overflowed, causing a prehistoric mega-flood, which sent water surging into the basin between Britain and France and gouging through the hills of chalky rock connecting them.




A glimpse at the Earth's crust deep below the Atlantic   PhysOrg - November 12, 2009
Long-term variations in volcanism help explain the birth, evolution and death of striking geological features called oceanic core complexes on the ocean floor.




Central Africa's Tropical Congo Basin Was Arid, Treeless In Late Jurassic   Science Daily - November 11, 2009

The lush, tropical Congo Basin was much different 150 million to 200 million years ago when dinosaurs roamed Gondwana, the single continent formed by Africa and South America. Geochemical analysis of rare ancient soils from Central Africa suggests the land was arid, with a small amount of seasonal rainfall, and few bushes or trees. There's very little data for the paleoclimate of the Late Jurassic, but it's important because climate determines plant communities.




Giant Crack in Africa Will Create a New Ocean   Live Science - November 3, 2009

A 35-mile rift in the desert of Ethiopia will likely become a new ocean eventually, researchers now confirm. The crack, 20 feet wide in spots, opened in 2005 and some geologists believed then that it would spawn a new ocean. But that view was controversial, and the rift had not been well studied. A new study involving an international team of scientists and reported in the journal Geophysical Research Letters finds the processes creating the rift are nearly identical to what goes on at the bottom of oceans, further indication a sea is in the region's future.




African Desert Rift Confirmed As New Ocean In The Making   Science Daily - November 3, 2009

In 2005, a gigantic, 35-mile-long rift broke open the desert ground in Ethiopia. At the time, some geologists believed the rift was the beginning of a new ocean as two parts of the African continent pulled apart, but the claim was controversial. Now, scientists from several countries have confirmed that the volcanic processes at work beneath the Ethiopian rift are nearly identical to those at the bottom of the world's oceans.




Deep-sea Rocks Point To Early Oxygen On Earth   Science Daily - March 26, 2009

Red jasper cored from layers 3.46 billion years old suggests that not only did the oceans contain abundant oxygen then, but that the atmosphere was as oxygen rich as it is today, according to geologists. Red jasper cored from layers 3.46 billion years old suggests that not only did the oceans contain abundant oxygen then, but that the atmosphere was as oxygen rich as it is today, according to geologists.




21st Century Detective Work Reveals How Ancient Rock Got Off To A Hot Start Science Daily - October 28, 2008

A new technique using X-rays has enabled scientists to play "detective" and solve the debate about the origins of a three billion-year-old rock fragment. Dr Berry believes this technique can now be used to explain Earth's internal processes such as the rate at which its interior has been cooling, how the forces affecting the Earth's crust have changed over time, and the distribution of radioactive elements which internally heat the planet. He believes this information could then be used to build new detailed models to explain the evolution of the planet. He concludes: "It is amazing that we can look at a fragment of magma only a fraction of a millimetre in size and use it to determine the temperature of rocks tens of kilometres below the surface billions of years ago. How's that for a piece of detective work?"




Quebec: Oldest Rocks on Earth Found Live Science - September 25, 2008

Scientists have found the oldest known rocks on Earth. They are 4.28 billion years old, making them 250 million years more ancient than any previously discovered rocks. Earth formed about 4.6 billion years ago from a disk of gas and dust circling the sun. Remnants of crust from Earth's infancy are hard to come by because most of that material has been recycled into Earth's interior several times by the plate tectonics that continue to shape our planet's surface. In 2001, geologists found an expanse of bedrock, known as the Nuvvuagittuq greenstone belt, exposed on the eastern shore of Hudson Bay in northern Quebec.




Diamonds hint at 'earliest life' on Earth BBC - July 2, 2008

Tiny slivers of diamond forged on an infant Earth may contain the earliest traces of life, a study has shown. Analysis of the crystals showed they contain a form of carbon often associated with plants and bacteria. The rare gems were found inside zircon crystals, formed a few hundred million years after the Earth came into being. Writing in the journal Nature, the researchers caution that their results are not definitive proof of early life but do "not exclude" the possibility.




Researchers confirm discovery of Earth's inner, innermost core Science Daily - March 11, 2008

Geologists have confirmed the discovery of Earth's inner, innermost core, and have created a three-dimensional model that describes the seismic anisotropy and texturing of iron crystals within the inner core. Although the anisotropy of the inner core was proposed 20 years ago, "this is the first time we have been able to piece everything together to create a three-dimensional view," Song said. "This view should help us better understand the character, mineral properties and evolution of Earth's inner core."




Ancient oil points to 'cradle of life' BBC - August 4, 2000

Australian scientists have discovered the world's oldest oil in rocks that date back 3.2 billion years. The find suggests that oil-forming micro-organisms were widespread very early in the Earth's history. The researchers say that oil-forming bacteria may have been among the earliest inhabitants of our planet and that the sulphur-springs that formed the rocks studied by the researchers may have been the "cradle of life on Earth". The scientists are now looking for molecular fossils that might be present in the oil.




Mysterious Tremors' Strength Ebbs With Tides National Geographic - November 22, 2007

The intensities of strange, long-lasting tremors in North America's Pacific Northwest ramp up and quiet down with the rise and fall of the ocean's tides, according to a new study. These so-called nonvolcanic tremors are very faint seismic signals that were not discovered until 2002. Their exact cause remains a mystery.




Undersea slide set off giant flow BBC - November 22, 2007

An enormous underwater landslide 60,000 years ago produced the longest flow of sand and mud yet found on Earth. The landslide off the coast of north-west Africa dumped 225 billion metric tons of sediment into the ocean in a matter of hours or days. The flow traveled 1,500km (932 miles) - the distance from London to Rome - before depositing its sediment.




How The Discovery Of Geologic Time Changed Our View Of The World Science Daily - September 18, 2007
In 1911 the discovery that the world was billions of years old changed our view of the world forever. Imagine trying to understand history without any dates. You know, for example, that the First World War came before the Second World War, but how long before? Was it tens, hundreds or even thousands of years before? Before radiometric dating there was no way of knowing.




Without Hot Rock, Much Of North America Would Be Underwater Science Daily - June 26, 2007

A news study shows that various regions of North America are kept afloat by heat within Earth's rocky crust, and describes how much of the continent would sink beneath sea level if not for heat that makes rock buoyant. Of coastal cities, New York City would sit 1,427 feet under the Atlantic, Boston would be 1,823 feet deep, Miami would reside 2,410 feet undersea and Los Angeles would rest 3,756 feet beneath the Pacific.




Thick Layer of Magma Found Under American Southwest Live Science - June 23, 2007

Scientists have spotted a thick layer of melted rock beneath the Earth's crust that could be part of a fluid band of hot magma circling the globe. The magma ring has until now remained a theory.




Thick Layer of Magma Found Under American Southwest Live Science - June 23, 2007
Scientists have spotted a thick layer of melted rock beneath the Earth's crust that could be part of a fluid band of hot magma circling the globe. The magma ring has until now remained a theory.




Oldest Known Ocean Crust Found on Greenland National Geographic - March 26, 2007

Scientists have discovered a 3.8-billion-year-old rock formation in Greenland that they say is the earliest example of oceanic crust ever to be discovered.




Sea floor records ancient Earth BBC - March 26, 2007

A sliver of four-billion-year-old sea floor has offered a glimpse into the inner workings of an adolescent Earth. The baked and twisted rocks, now part of Greenland, show the earliest evidence of plate tectonics, colossal movements of the planet's outer shell. Until now, researchers were unable to say when the process, which explains how oceans and continents form, began. Plate tectonics is a geological theory used to explain the observed large-scale motions of the Earth's surface.




Ancient Rocks Show How Young Earth Avoided Becoming Giant Snowball Science Daily - February 6, 2007

A rock from a banded iron formation in northern Quebec, Canada. The bands vary in thickness from approximately 10 microns (less than the width of a human hair), to 10 meters (30 feet). This sample is measures a few inches across. At 3.75 billion years of age, it is one of the oldest rocks on Earth. "These rocks, with meteorites, are the only time travel machines into the early history of our planet," said University of Chicago geoscientist Nicolas Dauphas.




Weird Australia Rocks Are Earliest Signs of Life, Study Says National Geographic - June 8, 2006

Weird cone- and egg-carton-shaped formations in Western Australia are almost certainly among the earliest evidence of life on Earth, according to a new study. The 3.43-billion-year-old Strelley Pool Chert formations, called stromatolites, are sediment structures, not fossilized life forms. But their unusual features have inspired scientists to debate their origin.




Ancient rocks 'built by microbes' BBC - June 7, 2006
Odd-shaped rocks in the Pilbara region of Western Australia offer compelling evidence they were built by microbes 3.43 billion years ago, scientists say. The structures, known as stromatolites, could only have taken the forms they have if bacteria had been present, a Sydney-led team tells Nature journal. The rocks' origin is disputed, with some claiming purely chemical processes could have made them.




Redefining the geological time scale Science Daily - November 2004

A team led by Jacques Laskar from the Institut de Mecanique Celeste et de Calcul des Ephemerides (IMCCE) and the Paris Observatory has released new computational results for the long-term evolution of the orbital and rotational motion of the Earth. Thanks to new astronomical computations, the new Geological Time Scale has been much improved for the Neogene period (the past 23 Myr) so that it is now dated with an accuracy of about 40 000 years. The next step to improve the Geological Time Scale is to provide an astronomical calibration of the Paleogene period that covers the past 23-65.5 Myr. This will require both an extension of collections of geological data and a greater refinement of the computational modeling of the Earth's past orbit.




Geological time gets a new period BBC - May 2004

Geologists have added a new period to their official calendar of Earth's history - the first in 120 years. The Ediacaran Period covers some 50 million years of ancient time on our planet from 600 million years ago to about 542 million years ago.




Quakes reveal 'core within a core' October 2002 - BBC

Scientists probing the secrets of the Earth's inner core say there is evidence of another, smaller, core hidden within it. If they are correct, it could reveal more about how the Earth itself formed. The inner core was first discovered in the 1930s, and scientists have been looking ever since for ways to measure it. It is solid, about 2,440 km across, and composed mainly of iron and nickel. A new way of measuring the composition of the core was found when the shock-waves from earthquakes on one side of the world were measured by sensors on the opposite surface.




Earth's early battering revealed July 2002 - BBC

The first convincing evidence that the Earth was bombarded by a devastating and prolonged storm of meteoroids and asteroids four billion years ago has been found in the Earth's oldest rocks. The British and Australian researchers say there is no other conceivable explanation for new-found traces of an isotope, or form, of tungsten in 3.7-billion-year-old rocks from Greenland and Canada. The finding had been expected as several lines of evidence from Moon rocks and ancient craters on the Moon indicate the satellite was subjected to a so-called late heavy bombardment. Because the Earth is a larger target with a stronger pull of gravity, it was supposed that our planet must have been subjected to the same storm, too.




Ancient rock points to life's origin BBC - July 2002

The continents were moving across the face of the Earth much sooner than had been thought, according to new evidence from China. The new data come from a huge chunk of the rock that lay beneath the sea floor 2.5 billion years ago. Tim Kusky, of St Louis University, US, says it is the first large intact piece of oceanic mantle ever found from our planet's earliest period, the Archean. Located not far from the Great Wall of China, the ancient mantle rocks are preserved in a highly faulted belt 100 kilometres (62 miles) long.




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