中国地质调查2016，Vol.3Issue(6)：37-48,12.
藏北阿里地区改则县雀康一带纳丁措组火山岩锆石U－Pb年龄和地球化学特征
Nadingco Formation volcano rocks zircon U-Pb age and geochemical characteristics in Gêrzê county area of northern Tibet area
摘要
Abstract
Volcanic rocks of the Nadingco Formation is mainly distributed in the north of the Bangong lake-Nu-jiang suture zone.It is belong to the volcano rock formation of the Qiangtang-Sanjiang composite plate Duoma stratigraphic division Quegang district formation,and represents the volcanic activity of the south of Qiangtang area in Paleogene.Its main rock type is latite-trachyte.There are 3 dating samples which show the ages of (35 .99 ± 0.29)Ma、(37.2 ±0.65)Ma and (35.23 ±0.37)Ma.The geochemistry samples exhibit w(SiO2)=58.7%-65.51% which is high,A/NFC =0.046 -1 .029 which is low,w(MgO)=1 .1 0% -2.95% which is high,∑REE=243.38 ×1 0 -6 -31 3.48 ×1 0 -6,and δEu=0.77-0.91 .It indicates that the basalt is slightly enriched in light rare earth elements(LREE)and without remarkable Eu depletion.Large ion affinity rock elements such as Rb and Th are high content.High field-strength elements such as Hf and heavy rare earth elements (HREE ) are low content.Most samples shows that Ti,Ta and Nb are low content.w(La)/w(Sm)shows stable content.w (Sm)/w(Yb)=4.3 -6.7,which is low.According to the features of rock geochemistry,the primitive magma originates from the special crust mantle transitional zone,which is based on the thickened continental crust of the Qinghai Tibet Plateau.Its forming is the initial intraplate continental extensional rift environment near the orogenic belt.关键词
藏北阿里/古近纪/纳丁措组火山岩/锆石U-Pb年龄/地球化学特征Key words
Northern Tibet Ali/Paleogene/Nadingco Fromation volcanic rocks/zircon U-Pb dating/geochem-istry分类
天文与地球科学引用本文复制引用
褚慧力..藏北阿里地区改则县雀康一带纳丁措组火山岩锆石U－Pb年龄和地球化学特征[J].中国地质调查,2016,3(6):37-48,12.基金项目
中国地质调查局“西藏改则县1∶5万六幅区域地质矿产调查（编号1212011221080）”项目资助。 （）
