DOI: 10.1016/j.earscirev.2019.02.013
论文题名: A new approach to understanding diamond surface features based on a review of experimental and natural diamond studies
作者: Fedortchouk Y.
刊名: Earth Science Reviews
ISSN: 00128252
出版年: 2019
卷: 193 起始页码: 45
结束页码: 65
语种: 英语
中文关键词: Diamond classification
; Diamond morphology
; Kimberlite facies
; Kimberlite fluid
; Mantle metasomatism
; Resorption features
英文关键词: classification
; diamond
; emplacement
; experimental study
; kimberlite
; literature review
; mantle upwelling
; metasomatism
; resorption
; Botswana
; Canada
英文摘要: Diamonds originate deep in the Earth's mantle since billions of years ago. Through their long history diamonds accumulate information about the Earth's evolution, and preserve it owing to their extreme chemical and mechanical stability. The surface of natural diamonds shows a variety of growth and dissolution features, which reflect the diversity of conditions in the mantle and in kimberlite magma, providing an important clue for understanding the deep regions of subcratonic mantle. However, such studies are hampered by an absence of a systematic approach for studying diamond surface features and morphology. This review integrates studies of natural diamonds with the results of diamond dissolution experiments to explore the origin of the most typical resorption features of diamonds and the information they provide. It uses detailed studies of over ~ 3500 diamonds from eight kimberlite bodies in the Northwest Territories in Canada and Orapa kimberlite cluster in Botswana, and the data from diamond dissolution experiments covering a pressure range of between 0.1 MPa – 7.5 GPa, temperature range of between 900 °C – 1750 °C, and over 12 log units of oxygen fugacity values. Examining the effects of these parameters on diamond resorption morphology shows that the shape and size of the etch pits depends on the temperature and H 2 O:CO 2 ratio in the fluid, whereas pressure affects the efficiency of diamond crystal shape transformation from octahedral into rounded resorbed forms. The effect of pressure on the physical properties of the reacting fluid / melt controls the character of diamond etching. A comparison between the experimentally-induced and naturally occurring diamond resorption demonstrates a clear difference between the features developed in kimberlite magma and features inherited from the mantle source. Kimberlite-induced resorption on diamonds shows a strong correlation with the geology and emplacement mode of the hosting kimberlite unit. Low-relief surfaces develop on diamonds from pyroclastic kimberlites in all kimberlite classes, whereas surface features on diamonds from coherent kimberlites differ between kimberlite localities and often show corrosive character. Diamond resorption morphology can offer a robust method to better understand emplacement processes in different kimberlite localities, which are a matter of significant debate. The proposed here classification scheme for diamond resorption features is based on the features observable under a stereomicroscope. It helps differentiating resorption produced in the mantle source from that in the kimberlite magma and assigning diamond resorption to a particular mode of kimberlite emplacement, or a mantle metasomatic event. © 2019 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165799
Appears in Collections: 气候变化与战略
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作者单位: Department of Earth Sciences, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
Recommended Citation:
Fedortchouk Y.. A new approach to understanding diamond surface features based on a review of experimental and natural diamond studies[J]. Earth Science Reviews,2019-01-01,193