EARTHSC 1108 Lecture Notes - Lecture 2: Types Of Volcanic Eruptions, Premier Mine, De Beers
5 Apr 2016
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Document Summary
Color: colorless, all other colors are called fancies. Diamonds atoms are made in 3d network, where graphite are linked in sheets. Form deep within the earth in the mantle (80-200 km) Form under high t and p conditions (temp 900-1300 c & pressure 45-60 kilobars) Carried to surface by kimberlite pipes, kimberlite volcanic rocks. Most diamonds are older than 990 million years old, many are 3. 2 billion years old. Mining of the pipe from above ground and along tunnels (mine shafts) Deepest man-made mining hole 525 m deep 1. 25 km diameter. Ancient times: all diamonds came from alluvial gravels (placer) in india (eroded from kimberlite pipes) 1700"s: diamonds discovered in alluvial gravels of brazil. 1800"s diamonds discovered in alluvial gravels of south africa. Late 1800"s: diamonds discovered in place in kimberlite pipes near kimberly, south. Later: kimberlite and gravel deposits were found in areas of south africa and other. The premier mine has produced the largest diamonds in the world.
