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CIPW NORMS CALCULATIONS The CIPW norm is named after the four petrologists, Cross, Iddings, Pirsson and Washington, who devised it in 1931. What is a Norm and why it is needed? A norm is a means of converting the chemical composition of an igneous rock to an ideal mineral composition. It often reveals similarities in rocks that have quite different modes, or observed mineral assemblages. Some of the factors that can cause such variations are: • Disequilibrium (for example, zoned minerals or reaction rims isolating the interiors of grains) • Temperature • Pressure • Alteration • Water content (otherwise identical rocks might contain biotite, amphibole, or pyroxene, depending on water content) • Other minor constituents. For example, excess sulfur or chlorine might cause scapolite to form instead of feldspar. Boron typically causes tourmaline to form. The CIPW norm calculates mineral composition as if the magma were anhydrous (water is simply treated as a separate phase) and at low press

Fossil evidence indicates a 300,000-year Decline in biodiversity leading up to the Devonian-Carboniferous mass extinction, suggesting the possibility of multiple catastrophes, maybe even multiple supernova explosions. A supernova, on the other hand, delivers a one-two punch, the researchers said. The explosion immediately bathes Earth with damaging UV, X-rays and gamma rays. (Representational Image) (Unsplash) Killer cosmic rays from nearby supernovae could be the culprit behind at least one mass extinction event, researchers said, and finding certain radioactive isotopes in Earth’s rock record could confirm this scenario. A new study led by the University of Illinois, Urbana-Champaign astronomy and physics professor Brian Fields explores the possibility of astronomical events being responsible for an extinction event that occurred 359 million years ago, at the boundary between the Devonian and Carboniferous periods. The paper has been published in the Proceedings of the Na

The latest eruption spewed 5000- metre high column of ash And smoke into the air, with ash covering three districts and darkening the sky. Indonesia’s Mount Sinabung volcano erupted on August 10, 2020; sending a column of ash and smoke more than 16,000 feet into the air. The volcano became active in 2010, erupting after nearly 400 years of inactivity. According to the National Museum of Natural History (NMNH), USA, generally, there are about 20 volcanoes actively erupting every day. As per the weekly volcanic activity report prepared by The Smithsonian and US Geological Survey’s (USGS) Volcano Hazards program, for the week ending August 4, 2020, there were 17 volcanoes across the world with continuing eruptions. As per USGS, there are about 1,500 potentially active volcanoes worldwide. Indonesia is home to many active volcanoes, due to its position on the “Ring of Fire”, or the Circum-Pacific Belt, which is an area along the Pacific Ocean characterised by active volcanoes and frequent