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Boriana Kalderon-Asael conducts field work at a Middle-Upper Ordovician outcrop near Reedsville, Penn. Credit: Ashleigh Hood

Earth’s climate life story, 3 billion years in the making

Geology Page - July 24, 2021

The Alum Shale, here an example of a coastal deposit, consists of quartz and potassium Feldspar clasts as well as conspicuous Pyrite crystals (here: white) embedded in a clayey matrix. Scanning electron micrograph (scale: lower image edge length corresponds to approx. 40 μm). Credit: Schulz, GFZ

A rock with many perspectives

The early Earth was hotter than it is today and this affected the strength of the crust and mantle.

The Earth has a pulse — a 27.5-million-year cycle of geological activity, researchers say

An artistic representation of the potentially habitable planet Kepler 422-b (left), compared with Earth (right). Credit: Ph03nix1986 / Wikimedia Commons

Earth-like biospheres on other planets may be rare

Zircons studied by the research team, photographed using cathodoluminescence, a technique that allowed the team to visualize the interiors of the crystals using a specialized scanning electron microscope. Dark circles on the zircons are the cavities left by the laser that was used to analyze the age and chemistry of the zircons.Scientists led by Michael Ackerson, a research geologist at the Smithsonian's National Museum of Natural History, provide new evidence that modern plate tectonics, a defining feature of Earth and its unique ability to support life, emerged roughly 3.6 billion years ago. The study, published May 14 in the journal Geochemical Perspective Letters, uses zircons, the oldest minerals ever found on Earth, to peer back into the planet's ancient past.The team tested more than 3,500 zircons, each just a couple of human hairs wide, by blasting them with a laser and then measuring their chemical composition with a mass spectrometer. These tests revealed the age and underlying chemistry of each zircon. Of the thousands tested, about 200 were fit for study due to the ravages of the billions of years these minerals endured since their creation. Credit: Michael Ackerson, Smithsonian.

Earth’s oldest minerals date onset of plate tectonics to 3.6 billion years ago

Basalt, the most-common rock on Earth’s surface, encases green crystals--a geologic "nesting doll" phenomenon called a xenolith. Basalts such as this one derive from a section of the mantle that has been depleted in incompatible trace elements, which is usually attributed to continental crust formation. In their work, Tucker and his collaborators propose another mechanism that would impart this signature. Credit: Carnegie Institution for Science

Probing the origin of the mantle’s chemically distinct ‘scars’

Geology Page - September 1, 2020

Earth

The age of Earth’s inner core revised

Geology Page - August 26, 2020

$-A grain-size comparator chart (to scale). The chart shows the different size fractions from silt (63 µm) through to large cobbles (128256 mm). Such charts are useful for field comparisons.$

Grain Size : What is Grain Size? How is Grain Size...

Geology Page - August 21, 2020

Ol Doinyo Lengai volcano in Tanzania, a source of carbonate-rich magma.

Geologists publish new findings on carbonate melts in Earth’s mantle

Geology Page - August 6, 2020

Workers excavating Hall’s Cave in Central Texas. Image Courtesy of Michael Waters

Cooling of Earth caused by eruptions, not meteors

Geology Page - August 6, 2020

Map of the Earth showing the present-day deviation from expected magnetic field direction. The star is Saint Helena

South Atlantic anomalies existed 8 – 11 million years ago

Geology Page - July 24, 2020

Earth

Study could rewrite Earth’s history

Geology Page - July 16, 2020

Earth magnetic field. Credit: Carnegie Institution for Science

How does Earth sustain its magnetic field?

Geology Page - July 11, 2020

Earth’s geomagnetic field

Earth’s magnetic field can change 10 times faster than previously thought

Geology Page - July 11, 2020

The composition of fossilised zooplankton shells has enabled the reconstruction of past pH and CO2. Credit: University of Southampton

By 2025, carbon dioxide levels in Earth’s atmosphere will be higher...

Geology Page - July 11, 2020

A new study shows that giant ore deposits are tightly distributed above where rigid rocks that comprise the nuclei of ancient continents begin to thin, far below the surface (white areas). Redder areas indicate the thinnest rocks beyond the boundary; bluer ones, the thickest. Circles, triangles and squares show known large sediment-hosted deposits of different metals. (Adapted from Hoggard et al., Nature Geoscience, 2020)

Geologists identify deep-earth structures that may signal hidden metal lodes

Geology Page - July 3, 2020

Our planet has a layered structure of silicate mantle and metallic core. The liquid outer core is located 2900 km below the surface where the pressure and temperature are extremely high, >136 gigapascal (1.36 million atmospheres) and >4000 C. The sound speed and density profiles of the deep-interior of our planet is given by seismological observations.

Precise measurement of liquid iron density under extreme conditions

Geology Page - July 3, 2020

Earth

Uncovering the two ‘faces’ of the Earth

Geology Page - July 3, 2020

Scientists examined hundreds of samples taken along the global ridges that contain recycled ancient oceanic crust in variable amounts. "Depleted" segments of the ridge received lower than "normal" amounts of recycled crust, while "enriched" segments contain a larger proportion of recycled crust.

Geochemists solve mystery of Earth’s vanishing crust

Geology Page - June 27, 2020

Mud Volcanoes

The geological record of mud deposits

Geology Page - June 27, 2020

A lump of coal weathering out from Siberian flood basalts in a quarry near the town of Ust Ilimsk Credit: Scott Simper

Coal-burning in Siberia led to climate change 250 million years ago

Geology Page - June 17, 2020

$Earthquakes send sound waves through the Earth. Seismograms record the echoes as those waves travel along the core-mantle boundary, diffracting and bending around dense rock structures. New research from University of Maryland provides the first broad view of these structures, revealing them to be much more widespread than previously known. Credit: Doyeon Kim/University of Maryland$

Scientists detect unexpected widespread structures near Earth’s core

Geology Page - June 17, 2020

New Curtin University research on the remixing of Earth's stratified deep interior suggests that global plate tectonic processes, which played a pivotal role in the existence of life on Earth, started to operate at least 3.2 billion years ago. Credit: Professor Zheng-Xiang Li

Remixed mantle suggests early start of plate tectonics

Geology Page - June 17, 2020

The Brooks Range stretches across northern Alaska. Boreal forests in North America are among the largest areas experiencing a relatively low human impact. (Jason Riggio/UC Davis)

Half the earth relatively intact from global human influence

Geology Page - June 17, 2020

If ice once covered the entire planet, how did the transition take place and what does it say about Earth's climate? Credit: NASA Goddard photo

Researchers unlock clues to a dramatic chapter of Earth’s geological history

Geology Page - June 17, 2020

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Parts of the Earth’s original crust remain in place today

March 19, 2017

A diagrammatic representation of the Earth in the Archaean showing subducted ocean floor carrying its chemical signature into the deep mantle. The signature which includes water and chlorine is preserved in melt inclusions contained within olivine and carried back up to surface within komatiite lava flows.

Ancient drop of water rewrites Earth’s history

August 8, 2019

Earth’s hot past: Prologue to future climate?

September 15, 2011

This figure illustrates how inorganic carbon cycles through the mantle more quickly than organic carbon, which contains very little of the isotope carbon-13. Both inorganic and organic carbon are drawn into Earth's mantle at subduction zones (top left).

Study points to one cause for several mysteries linked to breathable...

December 2, 2019

MORE ARTICLES

New Evidence for Warm-Blooded Dinosaurs

3-D printing of rocks and fossils

Rapid formation of bubbles in magma may trigger sudden volcanic eruptions

Diamonds in Earth’s oldest zircons are nothing but laboratory contamination