摘要
本文根据火成岩(SiO_2>52wt%)中钛铁氧化物化学成分的研究,运用桐庐、七宝山,庐枞、宁芜四个火山岩盆地的部分样品资料,解释了钛铁矿中的 MnO 含量、MnO(Mt)-Mn(Il)图解和共存的钛铁氧化物中 T-fO_2图解,并讨论了这些图解在区分火山岩与次火山岩方面的应用效果。
According to the study on chemical composition of Fe-Ti oxides in igneous rocks(SiO_2> 52 wt%)and by using the part data of igneous rocks in four volcanic basins including Tonglu in Zhejiang Province,Qibaoshan in Shandong Province,Lujiang-Zhongyang in Anhui Province and Nanjing-Wuhu in Jiangsu and Anhui Provinces,the applied affects of the MnO content in ilmenite,diagram of MnO(Mt)-MnO(Ⅱ)and diagram of temperature-oxygen fugacity to distin- guish the volcanic rocks from subvolcanic rocks have been explained by the paper. Based on the large amounts of published data,a obvious distinguish feature has been fou- nd on the igneous rock with more than 52 per cent SiO_2.The MnO content of ilmenite in vo- lcanic and subvolcanic rocks has a classific line on 2(wt)per cent,i.e.ilmenite in volcanic rock mostly contains less than 2 per cent MnO. In the procedure of magma crystallization,owing to the conditions and chemical and phy- sical conditions,the content of MnO in magnetite and ilmenite varies regularly which appears to be two areas on MnO(Mt)-MnO(Ⅱ)diagram. In the procedure of upward intrusion of magma,because of the variation of distence of magma from ground surface and physical and chemical conditions,the temperature and oxygen fugacity can exist in and be reflected by the associated Ti-Fe oxides,i.e.temperature,oxygen fugacity of volcanic rock is higher than that of subvolcanic rock.
出处
《江苏地质》
1990年第4期3-8,共6页
Jiangsu Geology
