Articles tagged with "geology"
1.4 billion-year-old salt crystals reveal Earth’s ancient oxygen spike
Researchers from Rensselaer Polytechnic Institute analyzed 1.4-billion-year-old halite (salt) crystals from ancient subtropical lakes in present-day Ontario, Canada, which trapped microscopic bubbles of air and droplets of brine. These "fluid inclusions" preserved a direct record of Earth's Mesoproterozoic atmosphere, extending the atmospheric record by over a billion years. By developing custom laboratory techniques to correct for chemical interactions between gases and the trapped brine, the team obtained accurate measurements of ancient atmospheric gases, including oxygen and carbon dioxide. Their findings challenge the notion of the Mesoproterozoic era (1.8 to 0.8 billion years ago) as the "Boring Billion" by revealing a transient oxygenation event with oxygen levels at about 3.7% of modern concentrations—potentially sufficient to support complex multicellular life, which appeared much later. Carbon dioxide levels were found to be roughly ten times higher than today, explaining the warm, ice-free climate
materialsgeologyancient-atmospherehalite-crystalsclimate-historyoxygen-levelsMesoproterozoic-eraHelium isotope could help pinpoint location of gold deposits that originate in deep Earth
Scientists have discovered that helium isotope analysis can help pinpoint the location of buried gold deposits originating from deep within the Earth, particularly beneath Scotland and Ireland. By using high-precision mass spectrometric analysis of gases trapped in gold-bearing sulfide minerals from the Caledonian orogenic belt, researchers found that the presence of deep-sourced helium isotopes (3He/4He ratios) indicates that mantle melting plays a crucial role in forming these gold deposits. This finding supports the idea that mantle heat drives the circulation of mineralizing fluids responsible for major gold deposits in the region, including active mines such as Cononish, Curraghinalt, and Cavanacaw. The Caledonian mountain belt, formed 490-390 million years ago through the collision of ancient continental plates, hosts these gold deposits, which are closely linked to mantle melting beneath the colliding crustal plates. The study, published in the journal Geology, suggests that the proportion of mantle-derived helium and the temperature of
materialsmineral-explorationhelium-isotopesgold-depositsgeologymantle-meltingearth-science1,000-ton gold reserve discovered in China's Kunlun mountains: Report
Chinese geologists have reported the discovery of a potentially large gold deposit in the Kunlun Mountains of Xinjiang Uyghur Autonomous Region. This newly identified deposit is described as a belt of scattered gold veins that could yield over 1,000 tons of gold if further exploration confirms its extent and economic viability. However, the discovery remains at an early stage, with estimates still theoretical until extensive drilling can verify the continuity, grade, and depth of the deposit. Only a portion of the gold present is expected to be economically mineable. This find is the third reported 1,000-ton-plus gold deposit in China within the past year, following discoveries in Liaoning and Hunan provinces. The Liaoning deposit, while large, is low-grade and would require moving vast amounts of ore to extract gold, impacting profitability. The Wangu field deposit is geologically promising with some very high-grade samples but is located at great depths, making mining costly. These discoveries come amid China’s intensified geological exploration efforts aimed
materialsmininggold-depositgeologynatural-resourcesmineral-explorationChinaDiamonds reveal first natural evidence of deep mantle metal alloys
Two diamonds from the Voorspoed mine in South Africa have provided the first direct natural evidence of nickel-iron metallic alloys and nickel-rich carbonates existing deep within Earth’s mantle, at depths between 280 and 470 kilometers. Researchers from Hebrew University of Jerusalem analyzed tiny nano- and micro-inclusions trapped inside these diamonds, which act as “time capsules” preserving chemical reactions and mantle conditions that would otherwise be lost. This discovery confirms long-standing geological models predicting the formation of nickel-rich metal alloys at these depths and reveals a rare coexistence of nickel-iron alloy and nickel-rich carbonate minerals, which typically would react and not coexist. The study explains this coexistence through a metasomatic redox-freezing reaction, where an oxidized, carbon-rich melt infiltrates a reduced, metal-bearing mantle rock, producing nickel-rich carbonates and oxidizing the surrounding mantle. This process also supports the theory that natural diamonds can form from reactions between carbonate fluids and reduced metals deep in the mantle, particularly as
materialsearth-sciencegeologydiamond-inclusionsmantle-chemistrynickel-iron-alloysmineralogySouth America find 13 million tons in copper, gold, silver deposits
materialscoppergoldsilverminingresourcesgeologyNASA’s Perseverance Rover Finds Strange Rocks on Mars
MarsNASAPerseverance-Rovergeologyspace-explorationastrobiologyscientific-research