Gemological Institute of America, 50 West 47th Street, New York, NY 10036, USA.
Department of Terrestrial Magnetism, Carnegie Institution for Science, 5241 Broad Branch Road NW, Washington, DC 20015, USA.
Science. 2019 Apr 26;364(6438):383-385. doi: 10.1126/science.aaw9548.
Neoproterozoic West African diamonds contain sulfide inclusions with mass-independently fractionated (MIF) sulfur isotopes that trace Archean surficial signatures into the mantle. Two episodes of subduction are recorded in these West African sulfide inclusions: thickening of the continental lithosphere through horizontal processes around 3 billion years ago and reworking and diamond growth around 650 million years ago. We find that the sulfur isotope record in worldwide diamond inclusions is consistent with changes in tectonic processes that formed the continental lithosphere in the Archean. Slave craton diamonds that formed 3.5 billion years ago do not contain any MIF sulfur. Younger diamonds from the Kaapvaal, Zimbabwe, and West African cratons do contain MIF sulfur, which suggests craton construction by advective thickening of mantle lithosphere through conventional subduction-style horizontal tectonics.
新元古代西非钻石中含有硫化物包裹体，其硫同位素具有质量独立分馏（MIF）特征，可将太古宙地表特征追溯到地幔中。这些西非硫化物包裹体记录了两个俯冲事件：大约 30 亿年前通过水平过程加厚大陆岩石圈，以及大约 6.5 亿年前的改造和钻石生长。我们发现，全球钻石包裹体中的硫同位素记录与形成太古宙大陆岩石圈的构造过程变化一致。35 亿年前形成的斯莱夫克拉通钻石不含任何 MIF 硫。来自卡普瓦尔、津巴布韦和西非克拉通的较年轻钻石含有 MIF 硫，这表明克拉通是通过传统俯冲式水平构造使地幔岩石圈的平流增厚而形成的。
