Obsidian scalpel surgery
In these shelters archaeologists have found some of the highest altitude, most accurately dated Pleistocene settlement sites on Earth.
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High in the Andes Mountains, at the astonishingly remote elevations of around 14,500 feet (4,420 meters) above sea level (equivalent to the height of Mount Whitney, the tallest mountain in the United States outside of Alaska), cliffs of volcanic andesite contain alcoves that form ancient rock shelters. More than 12,000 years ago the ancient Andeans were transporting and trading obsidian over long distances. The material also must be of a relatively young age, as the glass becomes unstable over time and its favorable fracturing properties are lost. Superior glass that is free of gas bubbles or small crystals is needed for tools. The conditions that create high-quality obsidian for tools are rare. High-quality obsidian was a valuable trade item, and obsidian artifacts have been found many hundreds of miles from their original source. From spear points and arrows to scrapers, mirrors, beads, and a variety of decorative objects, obsidian was an important natural resource for ancient people. Obsidian artifacts made by Homo sapiens date back to more than 300,000 years ago, and for hundreds of thousands of years before then our ancestors also shaped this volcanic rock. The value of obsidian for making sharp tools – not to mention the allure of the shiny surfaces – was recognized by humans far back in time. Obsidian diffusion in the Mediterranean region circa 9,000 to 3,000 years before present Giacimento/Deposit Industria/Industry site (Wikipedia) This is an extremely valuable tool for archaeologists, as studies of obsidian artifacts can provide information on ancient migration patterns and long-distance exchanges, and can detect differential access to raw material sources that may indicate political boundaries.Īncient people used only four sources of obsidian in the Mediterranean, so they distributed this material widely. Analysis of the trace elements in the obsidian allows researchers to determine the volcanic source of the glass. This form of obsidian is especially common in the Western US in Arizona and Nevada.Įvery volcanic eruption has a distinct chemical signature, based on the unique chemistry of the magma and the path it takes while ascending and erupting. Differences in the cooling history and water content of lava control the formation of Apache tears. They originate as cores of fresh obsidian that are surrounded by a matrix of light-colored, hydrated rhyolitic material known as perlite. The pebbles can be up to about 2 inches (5 cm) in diameter. dime for scale (Wikipedia)Īpache tears are rounded dark pebbles of obsidian, usually of a rhyolite (high silica) composition.
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Assorted shapes of Pele’s tears collected a few kilometers downwind from Mauna Ulu Kilauea Volcano, Hawai`i.