含沉积物的 As-Sb-Tl-Pb ± Hg ± Au Janjevo 矿点位于 Kizhnica-Hajvalia-Badovc 矿田的南部，位于科索沃的特雷普卡 (Trepča) 矿带 (TMB)。As-Sb-Tl-Pb ± Hg ± Au 矿化由上三叠纪大理岩承载，并以石英辉锑矿脉和与碧玉岩相关的白云石化不规则袋的形式出现。在所研究的矿化中最普遍的主要硫化物是黄铁矿，它是铊的主要载体。广泛的技术被用来表征 Janjevo 的黄铁矿/白铁矿的地球化学和结构演化：偏振反射光显微镜、电子微探针 (EPMA)、激光烧蚀电感耦合等离子体质谱 (LA-ICP-MS)、X-射线粉末衍射 (XRPD)、穆斯堡尔光谱和同位素研究。对 42 个薄的和抛光的切片的研究导致了 4 代黄铁矿/白铁矿的鉴定。与前矿阶段相关的第一代黄铁矿表现为具有不同演化程度的framboidal 黄铁矿(Py1a)，以及重结晶黄铁矿/白铁矿(Py1b)。富金黄铁矿 (Py2) 以细长的纤维聚集体形式出现，并且在遗传学上与辉锑矿脉（Sb 阶段）的形成有关。As-Tl-Sb-Hg 黄铁矿 (Py3) 形成不规则的胶体聚集体，填充缝合线并长满老一代的黄铁矿。最年轻的一代以形成自形晶体的白铁矿 (Py4) 为代表。在所有黄铁矿/白铁矿世代中，Co/Ni 比率 < 1 意味着沉积指纹。另一方面，δ 与前矿阶段相关的第一代黄铁矿表现为具有不同演化程度的framboidal 黄铁矿(Py1a)，以及重结晶黄铁矿/白铁矿(Py1b)。富金黄铁矿 (Py2) 以细长的纤维聚集体形式出现，并且在遗传学上与辉锑矿脉（Sb 阶段）的形成有关。As-Tl-Sb-Hg 黄铁矿 (Py3) 形成不规则的胶体聚集体，填充缝合线并长满老一代的黄铁矿。最年轻的一代以形成自形晶体的白铁矿 (Py4) 为代表。在所有黄铁矿/白铁矿世代中，Co/Ni 比率 < 1 意味着沉积指纹。另一方面，δ 与前矿阶段相关的第一代黄铁矿表现为具有不同演化程度的framboidal 黄铁矿(Py1a)，以及重结晶黄铁矿/白铁矿(Py1b)。富金黄铁矿 (Py2) 以细长的纤维聚集体形式出现，并且在遗传学上与辉锑矿脉（Sb 阶段）的形成有关。As-Tl-Sb-Hg 黄铁矿 (Py3) 形成不规则的胶体聚集体，填充缝合线并长满老一代的黄铁矿。最年轻的一代以形成自形晶体的白铁矿 (Py4) 为代表。在所有黄铁矿/白铁矿世代中，Co/Ni 比率 < 1 意味着沉积指纹。另一方面，δ 富金黄铁矿 (Py2) 以细长的纤维聚集体形式出现，并且在遗传学上与辉锑矿脉（Sb 阶段）的形成有关。As-Tl-Sb-Hg 黄铁矿 (Py3) 形成不规则的胶体聚集体，填充缝合线并长满老一代的黄铁矿。最年轻的一代以形成自形晶体的白铁矿 (Py4) 为代表。在所有黄铁矿/白铁矿世代中，Co/Ni 比率 < 1 意味着沉积指纹。另一方面，δ 富金黄铁矿 (Py2) 以细长的纤维聚集体形式出现，并且在遗传学上与辉锑矿脉（Sb 阶段）的形成有关。As-Tl-Sb-Hg 黄铁矿 (Py3) 形成不规则的胶体聚集体，填充缝合线并长满老一代的黄铁矿。最年轻的一代以形成自形晶体的白铁矿 (Py4) 为代表。在所有黄铁矿/白铁矿世代中，Co/Ni 比率 < 1 意味着沉积指纹。另一方面，δ34 S 同位素研究证实了 As-Tl-Sb-Hg 黄铁矿 (Py3) 以及同生辉锑矿和雄黄的岩浆硫来源。黄铁矿/白铁矿中最重要的微量和微量元素是 As（高达 14.1 %）、Tl（高达 3.94 %）、Sb（高达 3.73 %）和 Hg（高达 0.55 %），它们主要存在于Py3。除了砷、铊、锑和汞外，其他世代的黄铁矿还富含 Ni、Co 和 Cu（framboidal 黄铁矿 Py1）、Au 和 Se（富 Au 黄铁矿 Py2）和 Se（白铁矿 Py4）。Py2 记录的最高金含量高达 6.08 ppm。Py3 地球化学研究证实了 2Fe 2+ ↔ Tl + + Sb 3+的存在黄铁矿中的异价取代。As-Tl-Sb-Hg 黄铁矿 (Py3) 是所研究矿化中主要的铊宿主矿物，Pb-Sb ± Tl ± As 磺酸盐中的铊含量明显较少。此外，Py3 的高砷含量是由于砷以 As 1−和 As 0的形式存在，与无定形富砷纳米粒子有关。报道的 Py3 是胶体富 As-Tl-Sb-Hg 黄铁矿在水热条件下结晶的最佳现象。Janjevo 富含黄铁矿沉积物的 As-Sb-Tl-Pb ± Hg ± Au 矿化与隐蔽斑岩系统的远端表现有关。
"点击查看英文标题和摘要"
Geochemistry and textural evolution of As-Tl-Sb-Hg-rich pyrite from a sediment-hosted As-Sb-Tl-Pb ± Hg ± Au mineralization in Janjevo, Kosovo
The sediment-hosted As-Sb-Tl-Pb ± Hg ± Au Janjevo occurrence is located in the southern part of the Kizhnica-Hajvalia-Badovc ore field, in the Trepça (Trepča) Mineral Belt (TMB) in Kosovo. The As-Sb-Tl-Pb ± Hg ± Au mineralization is hosted by Upper Triassic marbles and occurs in the form of quartz-stibnite veins and dolomitized irregular pockets associated with jasperoid rocks. The main sulfide most widespread in the mineralization studied is pyrite which is the main carrier of thallium. A wide range of techniques was used to characterize the geochemistry and textural evolution of pyrite/marcasite from Janjevo: polarized reflected-light microscopy, electron microprobe (EPMA), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), X-ray powder diffraction (XRPD), Mössbauer spectroscopy, and isotopic studies. The study of 42 thin and polished sections resulted in the identification of 4 generations of pyrite/marcasite. The first generation of pyrite related to the pre-ore stage occurs as framboidal pyrite with different degrees of evolution (Py1a), as well as recrystallized pyrite/marcasite (Py1b). Au-enriched pyrite (Py2) occurs as elongated fibrous aggregates and is genetically associated with the formation of stibnite veins (Sb stage). As-Tl-Sb-Hg pyrite (Py3) forms irregular colloform aggregates which fill the stylolites and also overgrow older generations of pyrite. The youngest generation is represented by marcasite (Py4), which forms euhedral crystals. Co/Ni ratio < 1 in all pyrite/marcasite generations implies a sedimentary fingerprint. On the other hand, δ34S isotopic studies confirm a magmatic sulfur source for As-Tl-Sb-Hg pyrite (Py3), as well as co-occurring stibnite and realgar. The most important minor and trace elements in pyrite/marcasite are As (up to 14.1 %), Tl (up to 3.94 %), Sb (up to 3.73 %), and Hg (up to 0.55 %), which are mainly hosted by Py3. In addition to arsenic, thallium, antimony, and mercury, other generations of pyrite show enrichment in Ni, Co, and Cu (framboidal pyrite Py1), Au, and Se (Au-enriched pyrite Py2), and Se (marcasite Py4). The highest gold content of up to 6.08 ppm was recorded at Py2. Studies on Py3 geochemistry confirm the presence of 2Fe2+ ↔ Tl+ + Sb3+ heterovalent substitution in pyrite. As-Tl-Sb-Hg pyrite (Py3) is the main thallium host mineral in the mineralization studied, with significantly less thallium present in the Pb-Sb ± Tl ± As sulfosalts. In addition, the high arsenic content of Py3 is due to the presence of arsenic in the form of As1− and As0 related to amorphous arsenic-rich nanoparticles. The reported Py3 is the best phenomenon of the crystallization of colloform As-Tl-Sb-Hg-rich pyrite under hydrothermal conditions. Pyrite-rich sediment-hosted As-Sb-Tl-Pb ± Hg ± Au mineralization from Janjevo is associated with the distal manifestation of a concealed porphyry system.
京公网安备 11010802027423号