Microdiamonds in Alkalic Dolerites from the North China Craton  

作　　者：Yitao Cai Fei Liu Kan Li Long Li Jingsui Yang 蔡逸涛

机构地区：[1]College of Material Engineering,Jinling Institute of Technology,Nanjing 211169,China [2]Institute of Geology,China Academy of Geological Sciences,Beijing 100037,China [3]Department of Earth and Atmospheric Sciences,University of Alberta,Edmonton T6H 2E3,Canada [4]School of Earth Sciences and Engineering,Nanjing University,Nanjing 210093,China

出　　处：《宝石和宝石学杂志（中英文）》2024年第S01期40-42,共3页Journal of Gems & Gemmology

基　　金：江苏省自然科学基金项目(编号BK20191132);国家自然科学基金青年基金项目(编号41402075);国家留学基金委(编号201908575036)联合资助。

摘　　要：Diamonds on the Earth mainly occur in volcanic rocks such as kimberlites and lamproites^([1-8]),but can also be found in ultrahigh-pressure metamorphic rocks^([9-10]),meteorites^([11])and alluvial deposits^([12]).In recent years,diamonds have been recovered from ophiolites^([13-16])and alkalic dolerites^([17-18]).The discovery of ophiolitic diamonds and alkalic dolerites diamonds has drawn significant research interests to explore the origin of this new class of diamond source and to infer the evolution of their hosting rocks[^(19-21)].This new type of diamond had been initially considered as a result of contamination.However,more and more evidences either directly or indirectly demonstrate that these diamonds are of natural origin^([16,18,19,22-24]).During a geological survey from 2012 to 2015,the geologists from Nanjing Centre of China Geological Survey discovered a large number of yellow microdiamonds in the Langan area in northern Anhui Province^([18,25-29]).The diamond-bearing rocks of these microdiamonds mainly include dolerite and olivine basalt.From 2016 to 2018,four microdiamonds in basic rocks were recovered again in the prospecting work for primary diamond deposits in the Tashan and Zhangji areas in Xuzhou,which is geographically close to Langan[30].All these microdiamonds are similar in colour and shape to ophiolite type diamonds^([31]),and show different characteristics of kimberlite and lamproite type diamonds.Cai,et al.(2019)reported the petrological characteristics of the diamondiferous rocks^([17,21,30]).In this paper,the morphology,infrared spectrum,and carbon isotope compositions of microdiamonds were analysed and discussed by Fourier infrared spectroscopy and carbon isotope test.The types of microdiamonds found in the North China Craton,the age of mantle occurrence,and the source of carbon isotopes were revealed.In the past,many deposits of macro-diamonds,mostly of TypeⅠa orⅡa,were found in the North China Craton,and they have been extensively studied.Microdiamonds recovered from the alkal

关 键 词：microdiamond FTIR carbon isotopic alkalic dolerite North China Craton 

分 类 号：P619.241[天文地球—矿床学]