Abstract

In the poorly studied southeastern part of the Chetlas uplift, ring structures typical for magmatic pipe-type bodies (diatremes) have been established. The main part of the ring structures is located in the areas of the distribution of the Upper Devonian sediments. This fact indicates the lower age threshold of the formation of the objects forming them as Late Devonian, i.e., similar to the age of kimberlites of the Arkhangelsk diamond-bearing province. To assess the prospects of one of the most numerous groups of the ring structures, heavy-mineral concentrate sampling of the modern stream sediments was conducted. While studying the heavy-mineral concentrates, chromium-bearing pyrope—a kimberlite indicator mineral—was revealed, and the first diamond grain was found. About 20% of pyropes are characterized by a high preservation of relict endogenous surfaces. The diamond has the appearance of a flattened aggregate with the distinct octahedron faces modified by surfaces of joint growth with other mineral grains. Findings of diamonds and signs of the formation of the diamond indicator minerals in the stream sediments of the studied area make it possible to detect their nearby original sources.

中文翻译：

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蒂曼中部钻石和钻石指示矿物的新发现及其寻找原始资源的前景

摘要

在切特拉斯隆起的东南部研究较少的地区，已经建立了岩浆管型物体（直径）典型的环形结构。环状结构的主要部分位于上泥盆纪沉积物的分布区域。这一事实表明，形成晚泥盆世的物体形成的年龄阈值较低，即与阿尔汉格尔斯克钻石产区的金伯利岩时代相似。为了评估环形结构中最众多的组之一的前景，对现代河流沉积物进行了重矿物精矿采样。在研究重矿物精矿时，发现了含铬的吡啶氧化物（一种金伯利岩指示矿物），并发现了第一个金刚石晶粒。约20％的焦果的特征是高度保留了lic的内源性表面。钻石具有扁平的聚集体外观，具有明显的八面体面，该八面体面通过与其他矿物晶粒共同生长的表面而改性。在研究区域的河流沉积物中发现钻石并指示钻石指示剂矿物的形成迹象，使其有可能发现其附近的原始来源。