摘要
文章分析了西藏拉萨达孜侏罗统叶巴组火山角砾凝灰岩的地质背景、波痕及寄主地层特征。结果显示,西藏拉萨达孜叶巴组为一套中酸性火山岩及火山碎屑岩为主的岩石组合,其地球化学特征证实为岛弧环境,其中段火山角砾凝灰岩中发现波痕,波长介于165-235cm,波高约20-30cm,为具宽阔的不对称浪成波痕,其古流向为SSE,形成于滨岸地带。
In the present paper,the geographical background of ripple mark and Early Jurassic Yeba Formation in Dazi,Lhasa.The result showed that the Yeba Formation is composed of intermediate-acid volcanic rock and volcanic breccias and it formed in island arc settings.The ripple marks was discovered in volcanic breccias of Yeba Formation with wavelength between 160 and 235 cm and about 20-30 cm of height,and is a broad asymmetric ripples,it＇s ancient flow direction was SSE and Formed at a transgresive sedimentary area.
基金
2012年度西藏自治区大学生创新性实验训练计划项目"西藏拉萨市夺底沟-哲蚌寺一带壶穴成因探讨"阶段性成果
项目号:2011CX041
关键词
叶巴组
波痕
火山角砾凝灰岩
滨岸沉积
Yeba formation
Ripple marks
Volcanic breccias
Transgresive deposition
