Reference Terms
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Dune
In physical geography, a dune is a hill of sand built by eolian processes. Bare dunes are subject to shifting location and size based on their interaction with the wind. The "valley" or trough between dunes is called a slack. A "dune field" is an area covered by extensive sand dunes. Large dune fields are known as ergs.
Some coastal areas have one or more sets of dunes running parallel to the shoreline directly inland from the beach. In most such cases the dunes are important in protecting the land against potential ravages by storm waves from the sea. Although the most widely distributed dunes are those associated with coastal regions, the largest complexes of dunes are found inland in dry regions and associated with ancient lake or sea beds.
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Earth & Climate News
September 29, 2025
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Sep. 23, 2025 — A long-term study in Colorado reveals that insect populations are plummeting even in remote, undisturbed areas. Over two decades, flying insect abundance dropped by more than 70%, closely linked to rising summer temperatures. The results suggest ...
Sep. 22, 2025 — A team at RMIT University has created a cement-free construction material using only cardboard, soil, and water. Strong enough for low-rise buildings, it reduces emissions, costs, and waste compared to concrete. The lightweight, on-site process ...
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Sep. 21, 2025 — University of Maine researchers developed a new process to make HBL, a key ingredient in many medicines, from renewable glucose instead of petroleum. The approach not only lowers drug production costs but also reduces ...
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Sep. 23, 2025 — South African diamonds have revealed nickel-rich metallic inclusions, offering the first direct evidence of reactions predicted to occur deep in Earth’s mantle. The study shows how oxidized melts ...
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Sep. 19, 2025 — MIT scientists have unraveled the hidden energy balance of earthquakes by recreating them in the lab. Their findings show that while only a sliver of energy goes into the shaking we feel on the ...
Sep. 18, 2025 — America already mines all the critical minerals it needs for energy, defense, and technology, but most are being wasted as mine tailings. Researchers discovered that minerals like cobalt, germanium, ...
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