开心岭二叠纪地层中铁矿化沉积凝灰岩的发现及找矿意义

开心岭地区位于青藏高原腹地北羌塘构造区,在该地区二叠纪地层中新发现含砾晶屑岩屑铁矿化沉积凝灰岩,对该地层完整采样,并对采集的样品进行专门的实验测试分析。样品显微镜薄片鉴定,具玄武质岩屑,凝灰质岩屑,晶屑主要为石英和长石;化学分析结果TFe为13.80%;X射线衍射分析结果,赤铁矿6%,针铁矿17%,石英16%,斜长石47%,伊利石3%,方解石6%,闪石2%,绿泥石2%。光谱半定量检测分析结果,Ti为0.7%;电子探针检测分析结果,赤铁矿:形态为完整或不完整的几何体和沿其它矿物边部成封闭与局部的丝带,钛铁矿为相对规则的棒状,磷灰石为规则的六边形和已经磨圆的半圆形。激光拉曼光谱分析结果,针铁矿,含磁铁矿。对上述分析结果研究认为,二叠纪开心岭地区可能存在重要的岩浆喷发作用,原始岩浆含铁较高,这可能是该地区金属矿床的物质来源,下一步宜加强该地区的找矿工作。

Discovery of Sedimentary Tuff with Iron Mineralization in the Permian strata of the Kaixinling Area and Its Exploration Significance

Abstract: The Kaixinling area is located in the north Qiangtang tectonic area of the Tibetan Plateau. In the Permian strata of this area, we newly found gravel-containing sedimentary tuff with iron mineralization and conglomerate with crystallinoclatic and debris, and conducted lab tests on the samples collected from the strata. Observations under microscopes suggest that, the samples contains basaltic and tuff debris, and the crystal fragments are mainly quartz and feldspar. The TFe content is 13.80% by chemical analysis; hematite 6% , goethite 17%, quartz 16%, plagioclase 47%, illite 3%, calcite 6%, amphibole 2%, chlorite 2% by X ray diffraction analysis. The Ti content is 0.7% by half-quantitative spectral analysis. Electron probe backscattering analysis results show that, the hematite crystalloid exhibits completed or uncompleted geometry shapes, and the close or unclose fabric belt along the brim of other mineral crystalloid. Ilmenite displays full stick shape. Apatite has hexagon or semicircular appearance. Laser-Raman spectrum analysis results show that, the samples contain goethite and magnetite. It is suggested that maybe there was an important magmatic eruption in the Kaixinling area in the Permian period, and the primitive magma was high in element Fe being the critical source of the metal ore deposits, and the next exploration work should be strengthened.