摘要
藏北改则-色哇缝合带的蛇绿岩,与特罗多斯、岛湾的蛇绿岩剖面对比,区别是厚度小和缺乏席状岩墙。该区的变质超镁铁岩属阿尔卑斯橄榄岩-蛇纹岩组合,其化学成分与玄武岩互补,说明玄武岩浆系地幔岩分熔的产物。
The complete sections of the ophiolitic suite aren't found yet in Gerze-Sewa Suture Zone,North Xizang, because the ophiolitic siute is dismembered by the structural dismemberment. However,all rock types have been found here, so the complete section of the ophiolitic suite may be set up. It canbe compared with the classical ocean curst ophiolite section at Troodos, Cyprus, Bay of Island, New-foundl and. But it is only less in thickness and lacks sheeted dike complex. The geological characteristics show that the metamorphic ultramafic rocks belong to alpine peri-dotite-serpentinite. The relation between the chemical composition of the ultramafic rocks and that ofthe basalts is mutually supplementary, so that the basaltic melt was derived from a partial melting prod-uct of the mantle rock.
关键词
西藏
缝合带
蛇绿岩
侏罗纪
suture zone, ophiolitic suite
peridotite-serpentinite complex
Jurassic
small oceanic basin
