摘要
浙江江山下寒武统荷塘组上段产三叶虫化石3属6种:Hunanocephalus sp.,Hunanocephalus ovalis,Hunanocephalus(Duodingia)constricatus,Sinolenus sp.,Shabaella jiangshanensis,Shabaella convexa。Hunanocephalus为早寒武世筇竹寺期Hunanocephalus-Husuaspis带的典型分子,可以与同期湖南下寒武统清虚洞组的Hunanocephalus带、四川秀山水井沱组的Sichuanolenus带进行对比。Sinolenus和Shabealla两属则见于湖南龙山沙坝的水井沱组和石牌组,荷塘组和该两组的所属时代相当,属筇竹寺晚期至沧浪铺早期。荷塘组结合岩性可分为上下两段:下段由石煤层和磷块岩组成,含小壳化石和藻类化石,结合岩性特征指示沉积环境为静水滞留海盆地;上段为粉砂岩、泥质粉砂岩、硅质页岩,三叶虫化石主要产于粉砂岩与硅质页岩中。粉砂岩以及页岩主要呈灰色、灰白色或者灰绿色,发育微细水平层理,有连续的韵律层出现,三叶虫化石未见明显的弯折或破碎,结合岩性特征指示沉积环境水体较深呈弱还原性,反映出早寒武世荷塘组上段为陆棚斜坡相台地环境。
Three genera and six species of trilobites are found in the upper part of Lower Cambrian Hetang Formation in Jiangshan,Zhejiang Province.They are Hunanocephalus sp.,Hunanocephalus ovalis,Hunanocephalus(Duodingia)constricatus,Sinolenus sp.,Shabaella jiangshanensis,Shabaella convex.Hunanocephalus is a typical genus of the Hunanocephalus-Husuaspis belt in the Early Cambrian Qiongzhusi Period,which can be compared with the Hunanocephalus belt of the Lower Cambrian Qingxudong Formation in Hunan Province and the Sichuanolenuus belt of the Shuijingtuo Formation in Xiushan,Sichuan Province.Sinolenus and Shabealla were found in the Shuijingtuo Formation and the Shipai Formation of the Longshanshaba in Hunan.The ages of the two formations were similar to those of the Hetang Formation,which belonged to the late Qiongzhusi Period to the early Canglangpu Period.The Hetang Formation can be divided into upper and lower parts:The lower part consists of stone-coal and phosphorite,containing small shell and algal fossils,with lithological characteristics indicating that the sedimentary environment was a stagnant sea basin;the upper part is siltstone,argillaceous siltstone and siliceous shale.Siltstone and shale are mainly gray,off-white,or gray-green,with fine horizontal bedding and continuous rhythmic layers.Trilobite fossils do not show obvious bending or fragmentation.Combining with lithological characteristics,the sedimentary environment is deeper It is weakly reducing,reflecting that the upper part of the Early Cambrian Hetang Formation is a platform environment with a continental shelf slope.
作者
任玥
时国
乔丹
陶菁
REN Yue;SHI Guo;QIAO Dan;TAO Jing(School of Earth Sciences,East China University of Technology,Nanchang 330013,China)
出处
《地质调查与研究》
2019年第4期282-289,314,共9页
Geological Survey and Research
基金
江西省高等学校省级教改课题“基于OBE理念的资源勘查工程专业实践教学体系改革研究(JXJG-17-6-19)”
东华理工大学校级教改课题“‘古生物学’课程内容建设与教学方法改革”.
关键词
三叶虫
寒武系
浙江江山
荷塘组
沉积环境
trilobites
Cambrian
Zhejiang Jiangshan
Hetang Formation
sedimentary environment
作者简介
任玥(1996-),女,硕士研究生,东华理工大学地球科学学院地质学专业,E-mail:ry6105260720@163.com;通讯作者:时国(1978-),男,副教授,从事沉积学以及古生物地层学研究工作,E-mail:gshi@ecit.edu.cn。
