摘要
黔北北部道真铝土矿床是黔-渝铝土矿富集区重要组成部分,铝土矿产于下伏石炭系上统黄龙组或志留系中下统韩家店组侵蚀面之上的中二叠统梁山组中,矿石中含有大量的碎屑锆石,应用LA-ICP-MS U-Pb定年方法,在道真新民、桃园、三江、三清庙等矿床的典型剖面取样,对梁山组铝土矿（岩）、黄龙组、韩家店组中的碎屑锆石进行了系统的U-Pb年代学研究,结果显示锆石U-Pb年龄变化范围较大（413~2896 Ma）,但绝大部分测点位于锆石U-Pb年龄演化线上,多数年龄分布于400~700 Ma、700~1300 Ma、1700~1900 Ma和2400~2600Ma年龄段,铝土矿、韩家店组、黄龙组的锆石U-Pb年龄分布特征基本一致,主要集中于700~1300 Ma年龄段中,指示铝土矿物源复杂,韩家店组和黄龙组为铝土矿提供过物源,但最终物源应主要来源于杨子地块西缘和华夏陆块南部新元古-中元古岩浆岩,反映了铝土矿成矿物质经历过不止一个侵蚀沉积旋回的分异富集过程。
Bauxite deposits in Daozhen area, Northern Guizhou Province, China, are important parts of Guizhou-Chongqing bauxite belt. The bauxite deposits are belonging to the Lower Permian Liangshan Formation shale, which is overlaid by Upper Carboniferous limestone and Lower-Middle Silurian mud-shale. The bauxites contain large amounts of zircons. Based on LA-ICP-MS U-Pb dating and typical profile samples from Xinmin, Sanjiang, Sanqingmiao deposits, the research shows that the detrital zircons from bauxite ores have a wide range（413―2896 Ma）. The detrital zircon populations of samples studied show four primary age peaks： 400 to 700 Ma, 700 to 1300 Ma, 1700 to 1900 Ma and 2400 to 2600 Ma. The zircon ages obtained are similar with the samples from bauxite, and Hanjiadian Formation and Huanglong Formation sedimentary rocks, concentrated on 700 to 1300 Ma. It is suggested that the source of bauxite deposits are complex, including Hanjiadian and Huanglong Formations, but the final provenances of the bauxites are the Western Yangtze Block and Neoproterozoic-Mesoproterozoic magmatic rocks in the Southern Cathaysia Block. So we include that the bauxites formed not in one stage, but in a process mixed with erosion, deposition and recycle.
出处
《矿物学报》
CAS
CSCD
北大核心
2015年第4期463-472,共10页
Acta Mineralogica Sinica
基金
科技部科技支撑项目(2011BAB04B04)
关键词
铝土矿
U-PB年代学
碎屑锆石
成矿物源
黔北地区
bauxite deposit
U-Pb dating
detrital zircon
ore-forming material
Guizhou Province
