摘要
对松辽地块南部上古生界哲斯组的碎屑锆石应用LA--ICP--MS U--Pb测试的结果显示了4个主要的年龄段:263～378 Ma(峰值年龄274 Ma);405～547 Ma(峰值515 Ma);660～974 Ma(峰值为923 Ma);其余均为中元古代年龄1 165 Ma、1 369 Ma、1 476 Ma、1 517 Ma。其中最年轻一组锆石年龄263±2 Ma代表了哲斯组主体沉积的下限年龄;～274 Ma的峰期年龄与附近地区的大石寨组火山岩和岛弧岩浆岩的年龄一致;～515 Ma的峰期年龄与东北地区泛非期基底变质杂岩的年龄一致;其余的古老年龄均反映了松辽地块基底的信息。结合松辽地块的北部上古生界土门岭组、西部本巴图组和东缘黑龙宫组的碎屑锆石年龄,显示松辽地块应存在太古代和元古代的变质基底,为古生界地层提供了丰富的物源。松辽地块应为一个稳定的微地块,而不是长期活动的造山带。
The authors studied the detrital zircon aging from the Upper Paleozoic Zhesi Formation in southern Songliao block.The U——Pb dating of detrital zircon from the Zhesi Formation by LA——ICP MS technique showed 4 major age groups： 263~378 Ma（peak age as 274 Ma）;405~547 Ma（peak age 515 Ma）;660~974 Ma（peak age 923 Ma）;and the fourth group including 1 165 Ma,1 369 Ma,1 476 Ma and 1 517 Ma.The youngest zircon age of 263±2 Ma represents the lower limit of the deposition age of the Zhesi Formation,in which the peak age 274 Ma is consistented with the ages of the surrounding volcanic rocks and island arc magmatic rocks in Dashizhai Formation.The peak age 515 Ma showed the age of the Pan-African metamorphic complex in NE China.The rest old ages reflect the information of basement in Songliao block.Considered the ages of the detrital zircon aging of the Upper Paleozoic strata such as the Tumenling Formation in northern Songliao block,Benbatu Formation in western Songliao block and Heilongong Formation in eastern Songliao block,it is suggested that the Songliao block had Archean and Proterozoic metamorphic basement,providing rich source of material for the Paleozoic sediments.The fact indicats that the Songliao block was more likely a stable micro continental block rather than long-term activities of orogenic belt.
出处
《世界地质》
CAS
CSCD
2012年第3期522-535,共14页
World Geology
基金
国家自然科学基金项目(40872121)
国家发改委油气专项(14B09XQ1021)联合资助
