川西北地区上三叠统卡尼阶古喀斯特的发现及研究意义

发布时间：2018-03-06 10:21

本文选题：喀斯特　切入点：卡尼期湿润气候事件　出处：《沉积学报》2017年03期 　论文类型：期刊论文

【摘要】：在川西北地区绵竹汉旺、安县雎水剖面上三叠统卡尼阶海绵礁(丘)灰岩顶部发现古喀斯特;野外露头可见明显的花斑状构造以及蜂窝状溶孔,显微镜下可见泥晶化颗粒,喀斯特角砾以及喀斯特溶孔充填物,其中包括泥—亮晶方解石,生物碎屑以及陆源石英颗粒;根据露头岩性和显微薄片特征判断其属于早成岩期喀斯特;喀斯特成单层发育,之上覆盖化石丰富的黄色或黑色页岩,其中的菊石化石鉴定表明其为上卡尼阶底部沉积。该喀斯特是重要的等时界面,且可作为该地区上下卡尼阶的界线。喀斯特之上的岩性在汉旺和雎水有差异:在绵竹汉旺青岩沟剖面,喀斯特灰岩之上覆盖有黑色粉砂质页岩与生屑灰岩(如层状海绵灰岩、海百合灰岩),在汉旺观音崖剖面,喀斯特面之上发育海绵丘灰岩及页岩,在安县雎水剖面,古喀斯特发育在滚落的海绵巨砾之上。综合研究表明,喀斯特的形成与早期龙门山的隆升以及卡尼期湿润气候事件在发生时间上非常相近,推测其成因与龙门山的隆升以及卡尼期湿润气候事件有关。
[Abstract]:Paleo karst was found on the top of the cavernous reef (mound) of Triassic in Hanwang Mianzhu, Anxianjushi section in northwestern Sichuan, and obvious blotchy structure and honeycomb dissolution pore were found in outcrop in the field, and mud-crystallized particles could be seen under microscope. Karst boulders and karst dissolved pore fillers, including mud-bright calcite, bioclastic and terrestrial quartz particles, which belong to the early diagenetic karst stage according to the characteristics of outcrop lithology and microslice, and karst monolayer development, It is covered with fossil rich yellow or black shale, in which the identification of permethrin fossils indicates that it is deposited at the bottom of the upper Carney stage. The karst is an important isochronous interface. The lithology over karst is different between Hanwang and Ju: in the Hanzhu Hanwang blue gully section, karst limestone is covered with black silty shale and bioclastic limestone (such as layered sponge limestone). The lily limestone developed on the Hanwang Guanyin Cliff section, the karst surface developed sponge mound limestone and shale, and the ancient karst developed on the rolling spongy boulder in Anxian Ju Shui section. The formation of karst is closely related to the uplift of the early Longmen Mountains and the humid climatic events of the Carney period, which is related to the uplift of the Longmen Mountains and the humid climate events of the Karni period.
【作者单位】：成都理工大学沉积地质研究院;
【基金】：国家自然科学基金项目(41572085,41272131)~~
【分类号】：P534.51

【相似文献】