摘要
郯庐断裂带肥东段出露的桃源韧性剪切带内发育有长英质超糜棱岩、长英质伟晶岩脉体等。这两种构造岩与剪切带呈现不同的穿切关系，分别代表着剪切活动不同时期的产物，它们可以为郯庐断裂带的剪切年限提供重要的年代学制约。本次研究从长英质超糜棱岩的U—Pb锆石测年得出了133．3±4．1Ma的变质锆石年龄。结合笔者先前得出的伟晶岩脉129±3．3Ma年龄判断，郯庐断裂带在133Ma左右有一次剪切活动，该次剪切活动在129Ma左右仍有着较弱的持续，指示肥东地区在137～126Ma的时间段内，有一次挤压活动叠加。此外，长英质超糜棱岩样品中捕获的1．9Ga和2．4Ga的锆石，很可能来自华南板块基底。
Felsic mylonite and pegmatite veins generally growed in Feidong Taoyuan ductile shear zone in Tan-Lu fault zone. They show different relationships with the ductile shear zone, and represent products of different periods of the ductile shearing, so they can help in the shearing timing analysis. Through zircon U-Pb dating, we got metamorphic age 133.3±4.1 Ma from the ultra-mylonite sample. Combined with the pegmatite vein age 129 ± 3.3 Ma the writer got before, we hold that during 137-126 Ma, the Tan-Lu fault zone once sheared, and it still last when the pegmatite vein formed. This is a breakthrough for Tan-Lu fault zone. Besides, we got 1.9 Ga and 2.4 Ga basement ages from the felsic uhra-mylonite sample, which may possiblely be complementary to the Paleoproterozoic age of the South China base plate.
出处
《地质科学》
CAS
CSCD
北大核心
2015年第3期800-809,共10页
Chinese Journal of Geology(Scientia Geologica Sinica)
基金
国家自然科学基金项目（编号：41272222,41072161）、高等学校博士学科点专项科研基金项目和中国地质调查局科研项目（编号：1212011121114）资助.
