The internal mineral separates and whole - rock sm - nd isochron age for gabbro dikes from the dangqiong ophiolite is 373 ? 8ma , inferring a magmatic activity during late devonian , which end ( t ) = + 3 . 3 suggests that its tectonic setting was probably oceanic island 其nd ( t ) = + 3 . 3 ，认为其时形成环境为洋岛，可能代表了新特提斯蛇绿岩形成时所携带的古老洋壳。
3.
Undertaking isotopic geochronological study on ar - ar , adopted the fast - neutron activation dating technique to test 40ar - 39ar age of quartz from au - bering quartz veinlet ore in the deposit , and well - defined plateau age of 210 . 59 ma ? . 92 ma , the lowest apparent age of 208 . 07 ma ? . 22 ma , and isochron age of 207 . 14 ma ? 1 . 92 ma 通过流体包裹体显微测温学研究，表明金矿床的均一温度成矿早阶段为270 320 ，成矿主阶段为170 250 ，成矿晚阶段为110 250 ，呈逐渐降低的趋势，低温成矿作用明显。
4.
The results of combined internal mineral separates and whole - rock sm - nd isochron age for gabbro dikes from : luobusha , angren and xiubugabu in yarlung zangpo ophilite zone are 177ma , 166ma and 173ma respectively . the 4lar - 39ar step heating spectra of rikangba ophiolite suggest that its formation age is also isoma . it indicates that there was a stronger regionally inagmatism during middle - early jurassic , and the time of i75ma was the main period of the magmatic event of yarlung zangpo ophilite 对邬郁盆地嘎扎村组火山岩剖面的年代学研究表明，该区后碰撞期火山岩的~ ( 40 ) ar - ~ ( 39 ) ar年龄为12 ? 14ma ，侵入其中的花岗岩脉的~ ( 40 ) ar - ~ ( 39 ) ar年龄为10 . 84ma ，与冈底斯西段前人研究资料对比，认为冈底斯带后碰撞火山岩时代有自西向东逐渐年轻的趋势。
