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川西冕宁-德昌REE成矿带是中国最重要的REE成矿带之一,包括牦牛坪超大型REE矿床、大陆槽大型REE矿床、木落寨中型REE矿床和里庄小型REE矿床以及一系列矿点和矿化点。REE成矿作用与碳酸岩-碱性杂岩体有关,受印度-亚洲大陆碰撞带的一系列新生代走滑断裂系统控制,岩体主要侵位于元古代结晶基底岩石和古生代—中生代沉积盖层中。40Ar/39Ar快中子活化分析表明,大陆槽白云母、里庄黑云母和木落寨金云母的40Ar/39Ar坪年龄分别为13·2Ma、30·6Ma和35·5Ma,结合前人成岩成矿年龄资料,牦牛坪矿床岩浆-热液活动时限约12Ma,大陆槽矿床约5Ma,而里庄矿床则为2Ma,热液活动持续时间与矿床的REE储量存在正相关关系。研究发现,冕宁-德昌REE矿带从北到南,成岩成矿年龄逐渐变新,时间跨度长达27Ma;碳酸岩-正长岩岩浆初始活动时间与雅砻江左旋走滑断裂开始活动时间相一致,成岩成矿年龄的系统变化,有可能是由于雅砻江左旋走滑断裂右侧板片在相对固定的幔源岩浆“热点”上从南至北滑移造成的(相对于左侧板片)。
The Mianning-Dechang REE metallogenic belt in western Sichuan is one of the most important REE metallogenic belts in China, including the Maoniuping super-large REE deposit, the Continental Groove large REE deposit, the Muluozhai medium-sized REE deposit and the Lizhuang small-scale REE deposit, Ore point and mineralization point. REE mineralization is related to carbonatite-alkaline complex and controlled by a series of Cenozoic strike-slip faults in the collision zone of India-Asia continent. The major intrusions of REE are in Proterozoic crystalline basement rocks and Paleozoic-Mesozoic sedimentary cover . The 40Ar / 39Ar fast neutron activation analysis shows that the 40Ar / 39Ar ages of the continental trough muscovite, the Lizhuang biotite and the Muluzhai phlogopite are 13.2Ma, 30.6Ma and 35.5Ma, respectively. Combined with the previous diagenetic mineralization According to the age data, the magmatic-hydrothermal activity time of the Maoniuping deposit is about 12Ma, that of the continental slot deposit is about 5Ma, and that of the Lizhuang deposit is 2Ma. The duration of the hydrothermal activity is positively correlated with the REE reserves of the deposit. The study shows that the age of Mianning-Techang REE ore belt changes from north to south, and the diagenetic and mineralization ages change to a new 27Ma. The initial activity time of carbonate-syenite magmatic and the Yalongjiang left-lateral strike-slip fault begin to move Time, the systematic changes of diagenetic metallogenic age may be due to the slippage of the right plate of the left-lateral strike-slip fault of the Yalong River from south to north on the relatively fixed mantle source “magma” (relative On the left plate).