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欧龙布鲁克地块全吉群下部的下部砂砾岩段(Pt3qna)样品与石英砂岩段(Pt3qnb)样品在主量元素、微量元素等方面存在明显差异。石英砂岩段(Pt3qnb)样品除Si O2、V、Zr、Hf含量高于砂砾岩段(Pt3qna)样品外,其余元素明显低于砂砾岩段(Pt3qna)样品。该套碎屑岩沉积于南倾的被动大陆边缘盆地,碎屑物质均来自于中元古界达肯大阪群。鱼卡-沙柳河裂陷槽裂陷的不同阶段以及古气候环境的差异是造成欧龙布鲁克地块全吉群砂砾岩岩石学类型、地球化学特征巨大差异的直接原因。新元古代早期,鱼卡-沙柳河构造带形成裂谷,随后裂陷槽逐渐扩张,研究区构造活动逐渐趋于稳定,自下而上,全吉群陆源碎屑岩成分成熟度及结构成熟均明显增高。化学蚀变指数(CIA)的大幅度变化表明研究区受新元古代早期低纬度冰川事件的影响,下部砂砾岩段(Pt3qna)极低的CIA值是“雪球地球”在研究区的表现;石英砂岩段(Pt3qnb)极高的CIA值所反映的湿热古气候环境则是研究区该时期处于低纬度的正常表现。
The samples of the lower glutenite section (Pt3qna) and the quartz sandstone section (Pt3qnb) of the lower part of the Quanji Group in the Oolongbrook Block have significant differences in the major and trace elements. The samples of quartz sandstone (Pt3qnb) samples were significantly lower than those of samples of glutenite (Pt3qna), except Si O2, V, Zr and Hf. The set of clastic rocks deposited in the passive south margin of the continental margin basin, debris from the Proterozoic Dhaka Osaka group. The different stages of the fissure of the fish-shaliu rift trough and the difference in paleoclimate environment are the direct causes of the great difference in the petrological types and geochemical characteristics of the glutenite of the Quanjiqun in the Oulongbuluke block. Early Neoproterozoic, the Yuka-Shalihe tectonic belt formed a rift, and then the rift trough gradually expanded. The tectonic activity in the study area gradually stabilized. From the bottom up, the maturity and structure of the terrigenous clastic rocks in the whole Jiqun Significantly increased. The significant change of chemical alteration index (CIA) indicates that the study area was affected by the early Neoproterozoic low-latitude glacier event. The very low CIA value of the lower glutenite segment (Pt3qna) is “Snowball Earth” in the study area The paleo-climatic environment reflected by the extremely high CIA value of quartz sandstone (Pt3qnb) is the normal performance of the study area at low latitudes during this period.