哈薩克超高壓變質岩之石榴子石內所含微鑽石分布研究

Abstract

地質學家在歐亞大陸與非洲的超高壓變質帶岩層中，發現一些微小的鑽石與柯矽石，他們被包裹在石榴子石、斜輝石、鋯石之中。在哈薩克所發現的微鑽石，超高壓變質礦物群中鑽石的出現，代表這些超高壓變質岩來自至少100公里深的地底，此深度的碳元素以高壓型的鑽石相生成。簡言之，當板塊向下隱沒至上部地函的深度時，岩石發生再結晶作用，形成超高壓變質岩，而石墨與石英分別變成鑽石與柯矽石。爾後，地殼隆起，使超高壓變質岩露出地表。根據前人的研究結果顯示，變質岩微鑽石通常出現在礦物的裂縫中。 本研究以哈薩克斯坦北方科克切塔夫Kumdy-kol湖區的超高壓變質帶地區所取得的四個標本為實驗樣品，實驗的流程為利用光學、掃描式電子顯微鏡（SEM）及拉曼儀光譜儀，鑑定礦物組織及鑽石在礦物中的分布情形，並以能量分散光譜，分析礦物的碳含量。在進行拉曼光譜實驗中，主要探討變質岩中的石榴子石內所含微鑽石的三度空間分布情形，並建立三度空間立體模式，將每一層不同深度的拉曼光譜訊號透過繪圖軟體3D-Max，進行三維空間立體疊圖，以更理想的模式呈現，並探討微鑽石在礦物中的分布。Geologists have discovered tiny inclusions of diamond and coesite in container grains of garnet, clinopyroxene, and zircon from ultrahigh pressure metamorphic rocks within the Eurasia and Africa terrains, Micro-diamonds found in Kazakhstan and UHP groups of minerals appearance. The occurrence of micro-diamonds means that portions of this UHP crystal terrane were exhumed from depths exceeding 100 kilometers, as such depths are necessary for the formation of diamond. In brief, when the slabs subduction to the depth of the upper portion of the mantle and returned to shallow depths after recrystallization, The UHPM terrane formation, then graphite and quartz transform micro-diamonds and coesite in respectively. Thereafter upthrust, UHPM slabs return to the surface; According to the predecessor study, the micro-diamonds usually found in the crack of the mineral. This paper results from UHPM of the Kumdy-kol lake region, the area four samples as the experiment sample with Kokchetav of the North of Kazakhstan, Procedures of the experiment are Optics Microscope, Scanning Electron Microscope (SEM) and Ramon Laser Spectrometer, Identify the mineral petrology and distribution situation in the mineral of diamond, and use Energy Dispersive X-ray Spectrometer to analysis the content of carbon in the mineral. In Raman Spectrum experiment and software 3D-Max, the three-dimensional model distribution analysis and create are important to this thesis, the model provides more ideal chart, in the mineral of micro-diamonds distribution.