东天山博格达地层小区托斯巴斯陶组地质时代讨论  

Redefinition of Tuosibastao Formation in Bogda Minor Strata Area in Eastern Tianshan

作　　者：初建朋[1,2] 李勇[1] 郭俊峰[1] 张永明[2] 

机构地区：[1]长安大学地球科学与资源学院,陕西西安710054 [2]山东理工大学资源与环境工程学院,山东淄博255049

出　　处：《新疆地质》2016年第1期7-11,共5页Xinjiang Geology

基　　金：国家自然科学基金(41472015);教育部博士点基金(20100205110003)联合资助

摘　　要：1∶25万三道岭幅区调项目在东天山博格达地层小区托斯巴斯陶组一段采集到大量腕足化石,其中包含不少晚石炭世常见分子,但该组以往被认为是早石炭世地层。通过对腕足化石的鉴定和区域对比发现:一段下部层位发现了Gigantoproductus、Megachonetes和Syringothyris等早石炭世常见分子,可与北疆地层区阿恰勒河组和美路卡河组等早石炭世晚期地层进行对比;一段上部层位发现了Brachythyria、Cancrinella、Ella和Wellerella等晚石炭世地层常见分子,及晚石炭世特征分子Choristites和北疆地层区晚石炭世早期的地方特色分子Paramuirwoodia。研究认为一段上部发现的腕足化石具北疆地层区Choristites-Paramuirwoodia腕足化石组合带的特征,可与晚石炭世早期地层石钱滩组和祁家沟组等进行广泛的对比。托斯巴斯陶组腕足化石组合具早石炭世晚期—晚石炭世早期时代特征,说明该组上部层位已出现晚石炭世地层。Gical age of Tuosibastao Formation in bogda minor strata area in Eastern Tianshan has been questioned. At current, Most researchers supported the geological age of Tuosibastao Formation is the early carboniferous. Recently, the project of 1：250000 regional geological survey in Sandaoling sheet collected a wealth of fossils in the strata of Tuosibastao Formation, especially the discovery of brachiopod fossils provided new evidences for strata division and correlation. The research found those brachiopod fossils of the lower strata, such as Gigantoproductus,Megachonetes,Syringothyris and Striatifera, may been found in the Aqialehe Formation and Meilukahe Formation, the geological age of the lower strata is the late early carboniferous; The higher strata found some elements of late carboniferous, such as Choristites,Brachythyria,Brachythyrina,Chaoiella,Ella,Isogramma,Martinia,Paramuirwoodia,Stenoscisma and Wellerella. The further analysis showed those brachiopod fossils can be grouped into Choristites- Paramuirwoodia fossil assemblage zones in North Xinjiang region, though the early carboniferous elements is advantageous in number, some late carboniferous elements, especially the Choristites which is the characteristic element of late carboniferous strata and the Paramuirwoodia which is the characteristic element of early late carboniferous strata in North Xinjiang region have widespread. Those new fossil evidences can confirmed the geological age of Tuosibastao Formation is late early carboniferous to early late carboniferous. The research can also reveal that its overlying formation Tuckerbasitao Formation and Qijiaojing Formation is late carboniferous too.

关 键 词：岩石地层厘定 东天山 博格达 托斯巴斯陶组 腕足 

分 类 号：P534.45[天文地球—古生物学与地层学]