摘要
广西德保二叠系合山组的含煤地层中,发现了罕见的白色纤维状二八-三八面体含镁铝的绿泥石——须藤石。电镜下为薄的板条状。结构式:K_(0.01)(Li_(0.02) Mg_(1.73)—Al_(3.13)Fe_(0.02))_(4.90)(Si_(3.10) Al_(0.90))4 O_(10)(OH)_8。单斜晶系,Ⅱ_b多型,修正后的晶胞参数:α=0.5226±0.0002nm,b=0.9061±0.0003nm,c=1.4285±0.0005nm,β=97°11′±2′,V=0.671±0.0004nm^3。实测d_((001))=1.417±0.001nm,d_((060))=0.15098±0.00009nm。底面反射以I_((003))为最强。提供了该矿物的热谱及红外光谱,并研究了它的加热相变。须藤石的围岩为碳质的绢母云钠母云累托石粘土岩。须藤石的纤维集合体呈脉状,多分布在平行岩层间和层内裂隙中,或围绕在黄铁矿的周围。其成因为热液充填和交代。
Sudoite, a very rare fibrous di-trioctahedral Al-Mg chlorite, has been found recently in coal-series strata of the Heshan Group of the Upper Permian (P_2h) in Debao County, Guangxi, China. It is a white, fibrous mineral, general occurring as long and thin bars when observed under SEM. Its optical properties have been determined as follows: α′=1.572 and γ′=1.569; mostly parallel extinction; (+)elongation; (-)2ν<10°. Electron probe analysis gave a structural formula of K_(0.01) (Li_(0.02) Mg_(1.73) Al_(3.13) Fe_(0.02))_(4.90) (Si_(3.10) Al_(0.09))_4 O_(10) (OH)_8, indicating that the total number of its octahedral cations, mainly Al and secondly Mg, is slightly less than 5. XRD data on the sudoite indicate that d(001)=14.17+0.01(?) and d(060)=1.5098+0.0009(?), with the 003 reflection being the strongest, but with the 001 being the strongest after heating at 500℃ for two hours. The corrected cell parameters are: α=5.226±0.002, b=9.061±0.003, c=14.285±0.005(?); β=97°11′±2′; V=671±0.4(?)~3; monocline system. The DTA and IR obsorption spectral data of sudoite are also presented.Closely associated with sudoite is a small amount of paragonite. The country rock of sudoite is a black carbonaceous claystone. It is concluded that sudoite was formed by alteration and hydrothermal filling (hydrothermal solutions) during swelling-up of this area after diagenesis.
出处
《矿物学报》
CAS
CSCD
北大核心
1992年第3期206-213,T001,共9页
Acta Mineralogica Sinica
