西藏罗布莎铬铁矿穆斯堡尔谱特征及其地质意义

CHARACTERISTIC MSSBAUER SPECTRA AND THEIR GEOLOGICAL SIGNIFICANCE OF CHROMITE IN LUOBUSHA,TIBET(XIZANG)

讨论了在温度为300 K 条件下西藏罗布莎铬铁矿穆斯堡尔谱的特征。根据谱形将全谱分解成三套双峰,其中第Ⅰ、第Ⅱ套是由四面体中的Fe2+ 产生的,第Ⅲ套是由八面体中Fe3+ 产生的;总结出了中心位移值(δ)与铬铁矿平衡压力以及四级分裂值(QS)、铬铁矿平衡温度之间的关系;探讨了铬铁矿的成因。研究结果表明,铬铁矿穆斯堡尔谱的两个重要参数δ和QS在铬铁矿成矿预测中可以作为矿物学标型特征来推测矿床的成因,参数的质量达到了铬铁矿床成矿预测之要求。

Mssbauer spectra of chromite from Luobusha deposit have been recorded at the temperature of 300 K.Based on the mssbauer patterns,all the spectra are fitted by three boublets:the first two are attributed to the tetrahedral site Fe 2+ ,the third to the octahedral site Fe 3+ .This paper summarizes the relation of the centre shifts with the chromite quilibrium pressure and the guadrupole splittings with the chromite quilibrium temperature,and investigates the genesis of chromite.Results show two chief parameters of mssbauer spectra of chromite.The centre shifts and the guadrupole splittings are inferred as the deposit genesis with the typomorphism characteristics of mineralogy in the minerogenetic prediction of chromite.The qualities of parameter satisfy the demand of minerogenetic prediction of chromite bodies.