黑龙江鹤岗地区侏罗纪含煤地层中似累托石的矿物特征及成因

Mineralogy and origin of the rectorites-like in the Jurassic coal-bearing strata in Hegang District of Heilongjiang Province

运用X射线衍射分析、傅里叶红外光谱分析以及热重-热流分析等手段，对黑龙江鹤岗地区侏罗系上统石头河子组的含煤地层粘土岩夹矸中的似累托石进行了矿物学的研究．结果表明：研究区18＃煤夹矸中含有70％～97％的似累托石，d（001）＝2．659～2．696 nm，其他各基面衍射峰与d（001）基本呈整数倍关系，与累托石不同的是其各基面衍射峰半高宽相差较大，d（060）较累托石宽缓．似累托石与累托石和普通不规则伊蒙间层矿物之间的矿物特征差异表明似累托石并不是累托石而是介于累托石与不规则伊/蒙间层之间的过渡矿物．研究区似累托石的50～200℃低温吸热复谷表明其中的蒙脱石晶层为Ca-蒙脱石，870 cm-1附近的Fe-OH弯曲振动吸收带和474 cm-1附近的Si-O-Fe振动吸收带以及529℃左右脱羟基吸热谷均表明似累托石晶层中的一部分八面体Al和Mg被Fe所替代．研究区似累托石属于成岩作用成因，形成温度在120～140℃．

The mineralogical characteristics of the rectorites -like occurred in coal parting of Shitouhezi Formation of upper Jurassic in Heilongjiang Province,were studied by XRD,IR and TGA-DSC analysis.The results indicated that the rectorites-like proportion in the partings of NO.18 Coal in the research area is ranged from 70%to 97%,and d（001）is between 2.659 nm and 2.696 nm,which is the multiples of other basal diffraction spacings,but the FWHM of all the basal diffraction spacings have large difference and d（060） was much wider, which is different from that of rectorites.The significant mineralogical difference between rectorite -like and rectorite and irregular smectie illite interlayer indicated that the former is the transitional mineral between the two laters.The lower temperature endothermal multi-peak of the rectorites-like between 50℃and 200℃indicated that the rectorite-like layers are rich in Ca.Fe-OH bending vibration absorption band at 870 cm-1 ,Si-O-Fe vibration absorption band at 474 cm-1 and the dehydroxylation endothermal peak of rectorite-like layers at 529 ℃indicated that some octahedral Al and Mg are substituted by Fe.The rectorites-like in research area were resulted from diagenesis,the forming temperature of which was between 120 ℃and 140 ℃.