天然金刚石形成机制新探

An Approach to Genetic Mechanism for Natural Diamond

通过对金刚石有关的单质碳形成途径及其理化性质、金刚石单矿物的杂质成分及其流体包裹体的挥发成分和矿物成分、金刚石的主要共生伴生矿物、人工合成金刚石的方法、碳源、条件的研讨,结合超高压的地质背景,提出形成天然金刚石的新机制为:在地球深部高温高压强还原环境,碳氢化合物在自然单质或金矿物催化下,热裂解围原子碳,生成金刚石晶核并长大,此后它随较快运移的岩浆到达地球浅部,在高压下迅速降温赋存于母岩中,避免和减少了金刚石的溶蚀、氧化和石墨化。

This paper makes an approach to genetic mechanism for natural diamond based on formation and property of simple substance carbon, impurity composition and fluid inclusion composition in natural diamond, associated mineral composition of natural diamond and methodology and conditions of artificial diamond in combination with ultra high-pressure geological condition. The genetic mechanism for natural diamond may be summed up in 3 stages. Atom C was formed from hydrocarbon by thermal decomposition with catalysis of natural simple substance or gold minerals in the first stage. Skeletal crystal of diamond was formed in the second stage. In the third stage, the skeletal crystal ascended from the depth to shallow which resulted in formation of diamond in the parent rock avoiding dissolution, oxidation and graphitization due to the sudden dropping in the temperature.