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. ![]() Assorted shapes of Pele’s tears collected a few kilometers downwind from Mauna Ulu Kilauea Volcano, Hawai`i.
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